Clinical outcomes following discontinuation of metformin in patients with type 2 diabetes and advanced chronic kidney disease in Hong Kong: a territory-wide, retrospective cohort and target trial emulation study

Background

Current labelling advises discontinuation of metformin when estimated glomerular filtration rate (eGFR) < 30 ml/min/1.73 m2 due to increased risk of lactic acidosis. However, in real-world practice, the risk-benefit ratios remain uncertain. We examined the risk associations of discontinued-metformin use with cardiorenal and clinical outcomes in patients with type 2 diabetes (T2D) and advanced chronic kidney disease.

Methods

In this territory-wide, retrospective cohort and target trial emulation study, we included Chinese patients attending the Hong Kong Hospital Authority (HA) and enrolled in the Risk-Assessment-and-Management-Programme-for-Diabetes-Mellitus (RAMP-DM) from 2002 to 2019. Patients were stratified by discontinuation of metformin within six months after reaching eGFR < 30 ml/min/1.73 m2 from January 1, 2002 to December 31, 2018, and followed up until December 31 2019. We excluded patients who had observational time <6 months from eGFR < 30 ml/min/1.73 m2, and had their eGFR measured during a hospitalisation episode due to acute kidney injury, or missing diagnosis date of diabetes. We compared the risk associations of metformin discontinuation with clinical outcomes. The primary outcomes were major adverse cardiovascular events (MACE), end-stage kidney disease (ESKD), cancer, and all-cause mortality. A Cox-model with time-dependent exposure and covariates was used to estimate the hazard ratio (HR) of outcomes in a propensity-score overlap-weighted cohort. The risk of occurrence of lactic acidosis (serum lactate > 5.0 mmol/L with a concomitant blood pH < 7.35 or ICD-9 codes of 276.2) in discontinued-metformin versus continued-metformin users was assessed in a separate register-based cohort.

Findings

A total of 33,586 metformin users with new-onset eGFR < 30 ml/min/1.73 m2 were included in the study, 7500 (22.3%) of whom discontinued metformin within 6 months whereas 26,086 (77.7%) continued use of metformin. During a median follow-up of 3.8 (IQR: 2.2-6.1) years, 16.4% (5505/33,586), 30.1% (10,113/33,586), and 7.1% (2171/30,682) had incident MACE, ESKD, and cancer respectively, and 44.4% (14,917/33,586) died. Compared to continued-metformin use, discontinuation was associated with higher risk of MACE (weighted and adjusted HR = 1.40, 95% CI: 1.29-1.52), ESKD (HR = 1.52, 1.42-1.62), and death (HR = 1.22, 1.18-1.27). No association was observed for cancer (HR = 0.93, 0.85-1.01). Discontinued-metformin users had higher change in HbA1c change at 6-month of follow-up versus continued-metformin users (weighted mean HbA1c level change: 0.5% [0.4-0.6%] versus 0.2% [0.1-0.2]). In the separate register-based cohort (n = 3235), null association was observed between metformin use and risk of lactic acidosis (weighted HR = 0.94 [0.53-1.64]).

Interpretation

Our results suggest that discontinuation of metformin in patients with T2D and chronic kidney disease may be associated with increased risk of cardiovascular-renal events. Use of metformin below eGFR of 30 ml/min/1.73 m2 may be associated with cardiovascular, renal, and mortality benefits that need to be weighed against the risk of lactic acidosis, but further research is needed to validate these findings.

Funding

CUHK Impact Research Fellowship Scheme.

Association between hypomagnesemia and serum lactate levels in patients with sepsis: a retrospective observational study

BACKGROUND

Sepsis-3 emphasizes the recognition of sepsis-induced cellular metabolic abnormalities, and utilizes serum lactate level as a biomarker of cellular metabolic abnormalities. Magnesium plays an important role as a cofactor in glucose metabolism, although it is not well known that magnesium deficiency causes elevated serum lactate levels. Additionally, it remains unclear how magnesium status affects the role of serum lactate levels as a marker of metabolic abnormalities in sepsis. Thus, this study aimed to investigate the association between serum magnesium and lactate levels in patients with sepsis and explore this relationship from the perspectives of time course and circulatory abnormalities.

METHODS

This retrospective observational study of adult patients with sepsis was performed at the 16-bed intensive care unit of Jichi Medical University Hospital between June 2011 and December 2017. The relationship between serum magnesium and lactate levels for 5 days from intensive care unit admission was investigated along the time course. Multivariate logistic regression analysis was performed to evaluate the association between serum magnesium and lactate levels during intensive care unit admission.

RESULTS

Among 759 patients included, 105 had hypomagnesemia (magnesium level < 1.6 mg/dL), 558 had normal serum magnesium levels (1.6-2.4 mg/dL), and 96 had hypermagnesemia (magnesium level > 2.4 mg/dL) at intensive care unit admission. From intensive care unit admission to day 5, the hypomagnesemia group had higher serum lactate levels and a higher frequency of lactic acidosis than the normal magnesium level and hypermagnesemia groups (70% vs. 51.6% vs. 50%; P < 0.001). Hypomagnesemia at intensive care unit admission was independently associated with lactic acidosis, i.e., lactic acid level > 2 mmol/L (odds ratio, 2.76; 95% confidence interval, 1.60-4.76; P < 0.001).

CONCLUSIONS

Hypomagnesemia was associated with serum lactate levels in the early and post-resuscitation phases of sepsis. Further studies are needed to elucidate whether the magnesium status is associated with sepsis-induced cellular and metabolic abnormalities.

Metabolic effects of SGLT2i and metformin on 3-hydroxybutyric acid and lactate in db/db mice

Combining a Sodium-Glucose-Cotransporter-2-inhibitor (SGLT2i) with metformin is recommended for managing hyperglycemia in patients with type 2 diabetes (T2D) who have cardio-renal complications. Our study aimed to investigate the metabolic effects of SGLT2i and metformin, both individually and synergistically. We treated leptin receptor-deficient (db/db) mice with these drugs for two weeks and conducted metabolite profiling, identifying 861 metabolites across kidney, liver, muscle, fat, and plasma. Using linear regression and mixed-effects models, we identified two SGLT2i-specific metabolites, X-12465 and 3-hydroxybutyric acid (3HBA), a ketone body, across all examined tissues. The levels of 3HBA were significantly higher under SGLT2i monotherapy compared to controls and were attenuated when combined with metformin. We observed similar modulatory effects on metabolites involved in protein catabolism (e.g., branched-chain amino acids) and gluconeogenesis. Moreover, combination therapy significantly raised pipecolate levels, which may enhance mTOR1 activity, while modulating GSK3, a common target of SGLT2i and 3HBA inhibition. The combination therapy also led to significant reductions in body weight and lactate levels, contrasted with monotherapies. Our findings advocate for the combined approach to better manage muscle loss, and the risks of DKA and lactic acidosis, presenting a more effective strategy for T2D treatment.

Metformin-Associated Lactic Acidosis-Is This on Your Radar?

BACKGROUND

Metformin is a biguanide hyperglycemic agent used to manage non-insulin-dependent diabetes mellitus. Adverse reactions include mainly mild gastrointestinal adverse effects, but severe complications, such as metformin-associated lactic acidosis (MALA) can occur. Metformin is excreted renally and, therefore, not recommended in patients with renal impairment. The reported incidence of MALA is 3 cases per 100,000 patient-years.

CASE REPORT

A 79-year-old woman with a complex medical history, including end-stage renal disease on dialysis and type 2 diabetes, presented to the emergency department (ED) for altered mental status. Prior to arrival, she was found to be hypoglycemic. Her laboratory results were significant for creatinine of 6.56 mg/dL and an anion gap of 52 mmol/L. The venous blood gas revealed a venous pH of 6.857 [reference range (7.32-7.43)], pCO2 of 15.9 mm Hg (40.6-60 mm Hg), HCO3 of 2.7 mmol/L (21-30 mmol/L), lactate of 27 mmol/L (0.5-2 mmol/L), and ammonia of 233 µmol/L. The patient was dialyzed emergently in the ED; repeat laboratory test results showed blood urea nitrogen of 10 mg/dL, creatinine of 1.65 mg/dL, carbon dioxide of 26 mmol/L, and anion gap of 13 mmol/L. The repeat ammonia was 16 µmol/L. The patient's metabolic encephalopathy resolved, and she was discharged home on hospital day 3. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: MALA has a high mortality rate (36%). Laboratory markers have not been found to be a reliable predictor of mortality. Sodium bicarbonate is controversial, but a pH < 7.15 indicates consideration of its use. A pH < 7.1 and a lactate level > 20 mmol/L indicate the need for emergent hemodialysis. Prompt recognition and management in the ED with early hemodialysis can result in good patient outcomes, with a return to their baseline function despite severe laboratory findings.

Resolution of insulin resistance, lactic acidosis, and decrease in mechanical support requirements in patients post orthotopic heart transplant with the use of long-acting insulin glargine

OBJECTIVE

This study investigates the efficacy of using a long-acting insulin analog, along with the infusion of regular insulin, in achieving appropriate glycemic control and correcting lactic acidosis in patients post orthotopic heart transplant who demonstrate severe lactic acidosis and insulin resistance.

METHODS

This was a retrospective study of two cohorts (IRB FLA 20-003) of patients post orthotopic heart transplant with severe lactic acidosis and insulin resistance who were admitted to a tertiary intensive care unit and treated with (group 1) or without long-acting insulin analog (group 2) within the first 24 h of admission to the intensive care unit. Insulin resistance is defined as the requirement for intravenous regular insulin infusion of more than 20 units/h without the ability to achieve appropriate serum glucose level (120-180 mg /dL). Severe lactic acidosis is defined as arterial lactic acid of more than 10 mmol/L. The following parameters were investigated: time to correct lactic acidosis, duration of postoperative mechanical ventilation, the need for periprocedural mechanical circulatory support, and 28-day mortality.

RESULTS

The 28-day mortality was zero in both groups. Two patients required periprocedural mechanical support in group one, and ten patients required mechanical support in group two (RR = 0.224, 95%, confidence interval 0.052-0.95, Z = 2.029, p = 0.042). Three patients required tracheostomy in group one, and four patients required tracheostomy in group two (RR 0.84, 95 confidence interval 0.20-3.48, Z = 0.23, P = 0.81). Wilcoxon rank-sum test was used to compare time to correct lactic acidosis, with lactic acid resolution being faster in group one ([Formula: see text]1 = 19.7 h, SD ± 12.6 h [Formula: see text]2 = 29.3 h, SD ± 19.6 h, Z-value - 2.02, p-value 0.043). The duration of mechanical ventilation was less in group one ([Formula: see text]1 = 29 h, SD ± 12.7 h, [Formula: see text]2 = 55.1 h, SD ± 44.5 h, Z-value: - 1.92, p-value 0.05).

CONCLUSION

Administration of low-dose long-acting insulin glargine led to the resolution of the lactic acidosis, insulin resistance, and decreased requirements for pressor and inotropic support, which led to decreased need for mechanical circulatory support.

Impact of postoperative hyperlactatemia in orthotopic heart transplantation

BACKGROUND

Hyperlactatemia (HL) is a common phenomenon after cardiac surgery which is related to tissue hypoperfusion and hypoxia and associated with poor outcomes. It is also often seen in the postoperative period after orthotopic heart transplantation (OHTx), but the association between HL and outcomes after OHTx is not well known. We evaluated the incidence and outcome of HL after OHTx.

METHODS

This was a retrospective study of 209 patients who underwent OHTx between January 2011 and December 2020. Patients were classified into 3 groups according to their peak lactate levels within the first 72 h postoperatively: group 1, normal to mild hyperlactatemia (<5 mmol/L, n = 42); group 2, moderate hyperlactatemia (5-10 mmol/L, n = 110); and group 3, severe hyperlactatemia (>10 mmol/L, n = 57). The primary composite endpoint was all-cause mortality or postoperative initiation of veno-arterial extracorporeal membrane oxygenation (VA ECMO) within 30 days. Secondary endpoints included duration of mechanical ventilation, intensive care unit length of stay, and hospital length of stay.

RESULTS

Patients with higher postoperative peak lactate levels were more commonly transplanted from left ventricular assist device support (33.3 % vs 50.9 % vs 64.9, p < 0.01) and had longer cardiopulmonary bypass time [127 min (109-148) vs 141 min (116-186) vs 153 min (127-182), p = 0.02]. Composite primary endpoint was met in 18 patients (8.6 %) and was significantly more common in patients with higher postoperative peak lactate levels (0.0 % vs 6.4 % vs 19.3 %, p < 0.01).

CONCLUSIONS

Severe hyperlactatemia following orthotopic heart transplant was associated with an increased risk of post-transplant VA ECMO initiation and mortality at 30 days.

The synergism of cytosolic acidosis and reduced NAD+/NADH ratio is responsible for lactic acidosis-induced vascular smooth muscle cell impairment in sepsis

BACKGROUND

During sepsis, serve vascular dysfunctions lead to life-threatening multiple organ failure, due to vascular smooth muscle cells (VSMC) impairments, resulting in vasoplegia, hypotension and hypoperfusion. In addition, septic patients have an altered cell metabolism that leads to lactic acidosis. Septic patients suffering from lactic acidosis have a high risk of mortality. In addition, septic survivors are at risk of secondary vascular disease. The underlying mechanisms of whether and how lactic acidosis leads to the changes in VSMCs is not well understood. The aim of this study was to comprehensively investigate the effect of lactic acidosis on VSMCs and additionally compare the effects with those induced by pure acidosis and sodium lactate.

METHODS

Primary human aortic smooth muscle cells (HAoSMCs) were treated for 48 h with lactic acidosis (LA_pH 6.8), hydrochloric acid (HCl_pH 6.8), sodium lactate (Na+-lactate_pH 7.4) and the respective controls (ctrl._pH 7.4; hyperosmolarity control: mannitol_pH 7.4) and comparatively analyzed for changes in (i) transcriptome, (ii) energy metabolism, and (iii) phenotype.

RESULTS

Both types of acidosis led to comparable and sustained intracellular acidification without affecting cell viability. RNA sequencing and detailed transcriptome analysis revealed more significant changes for lactic acidosis than for hydrochloric acidosis, with lactate being almost ineffective, suggesting qualitative and quantitative synergism of acidosis and lactate. Bioinformatic predictions in energy metabolism and phenotype were confirmed experimentally. Lactic acidosis resulted in strong inhibition of glycolysis, glutaminolysis, and altered mitochondrial respiration which reduced cellular ATP content, likely due to increased TXNIP expression and altered NAD+/NADH ratio. Hydrochloric acidosis induced significantly smaller effects without changing the NAD+/NADH ratio, with the ATP content remaining constant. These metabolic changes led to osteo-/chondrogenic/senescent transdifferentiation of VSMCs, with the effect being more pronounced in lactic acidosis than in pure acidosis.

CONCLUSIONS

Overall, lactic acidosis exerted a much stronger effect on energy metabolism than pure acidosis, whereas lactate had almost no effect, reflecting the qualitative and quantitative synergism of acidosis and lactate. As a consequence, lactic acidosis may lead to acute functional impairments of VSMC, sustained perturbations of the transcriptome and cellular dedifferentiation. Moreover, these effects may contribute to the acute and prolonged vascular pathomechanisms in septic patients.

Severe perioperative lactic acidosis in a pediatric patient with glycogen storage disease type Ia: a case report

BACKGROUND

Glycogen storage disease (GSD) is a group of rare inherited metabolic disorders caused by enzyme deficiencies in glycogen catabolism. GSD type Ia is a congenital deficiency of the enzyme responsible for the final step in glucose production by glycolysis, resulting in impaired carbohydrate metabolism.

CASE PRESENTATION

A 14-year-old boy with GSD type Ia was scheduled for a maxillary cystectomy under general anesthesia. He was taking oral sugars such as uncooked cornstarch regularly to prevent hypoglycemia. Perioperatively, glucose was administered via the peripheral vein for fasting; however, severe lactic acidosis occurred. He also developed hypercapnia because of intraoperative poor ventilation caused by hepatomegaly.

CONCLUSIONS

We experienced a child with GSD type Ia who developed severe lactic acidosis despite continuous glucose infusion. Further studies are required to determine appropriate perioperative management for patients with GSD, including fasting glucose administration.

Reversible acute blindness in suspected metformin-associated lactic acidosis: a case report

BACKGROUND

Metformin is commonly used for the treatment of type 2 diabetes mellitus. Its multiple advantages include low risk of hypoglycemia, weight neutrality, low cost, and cardioprotective and anti-inflammatory effects. Renal insufficiency is one of the contraindications for its use. Inadvertent prescription in patients with renal insufficiency may lead to metformin-associated lactic acidosis, which brings a high risk of mortality. The early recognition and management of metformin-associated lactic acidosis are essential.

CASE REPORT

We present the case of a 58-year-old Hui woman with a history of type 2 diabetes mellitus with nephropathy and heart disease for which she was treated with metformin, insulin, and heart medications. She developed nausea, vomiting, anion gap metabolic acidosis due to hyperlactatemia, and acute kidney injury. She was hospitalized to receive intravenous hydration and correction of metabolic acidosis after she suddenly developed blindness. The diagnostic workup ruled out central causes and her symptoms resolved briefly after continuous venovenous hemodialysis was initiated, confirming the diagnosis of metformin-associated lactic acidosis.

CONCLUSIONS

Metabolic disruption can cause acute blindness. Metabolic acidosis in a patient with a history of metformin intake should suggest the possibility of metformin-associated lactic acidosis, which must be treated immediately, without waiting for the results of other examinations, especially in patients with sudden blindness. Further study of reversible blindness-associated severe metabolic acidosis is needed.

Severe lactic acidosis with euglycemic diabetic ketoacidosis due to metformin overdose

Metformin-associated lactic acidosis is a well-known metformin treatment complication; however, the development of euglycemic diabetic ketoacidosis (euDKA) has rarely been reported. Here we report a case of lactic acidosis and euDKA after metformin overdose. A 57-year-old female patient was transferred to our hospital with severe metabolic acidosis and acute kidney injury. She had type 2 diabetes mellitus and was on oral antidiabetic therapy of vildagliptin metformin hydrochloride daily. On the admission day, she had committed suicide by overdosing 50 tablets of vildagliptin metformin hydrochloride, which was equivalent to 25,000 mg of metformin and 2500 mg of vildagliptin. She had severe lactic acidosis 5 h after overdosing. However, after 34 h of overdosing, serum lactate levels decreased while serum anion gap levels increased. She received single hemodialysis treatment. Serum total ketone bodies, β-hydroxybutyrate acetoacetic acid, and acetone were increased even after hemodialysis treatment. Her blood glucose levels have never exceeded 250 mg/dL since admission. Therefore, we considered that the cause of metabolic acidosis in this patient was not only lactic acidosis but also euDKA. The causes of euDKA in our patient might be hepatic production of ketone bodies due to metformin overdose in addition to type 2 diabetes mellitus, starvation, infection, and stressful physical conditions such as vomiting and diarrhea. We propose that not only lactic acidosis but also ketoacidosis is one of the important pathological conditions in patients with metformin overdose.

Regulating mitochondrial metabolism by targeting pyruvate dehydrogenase with dichloroacetate, a metabolic messenger

Dichloroacetate (DCA) is a naturally occurring xenobiotic that has been used as an investigational drug for over 50 years. Originally found to lower blood glucose levels and alter fat metabolism in diabetic rats, this small molecule was found to serve primarily as a pyruvate dehydrogenase kinase inhibitor. Pyruvate dehydrogenase kinase inhibits pyruvate dehydrogenase complex, the catalyst for oxidative decarboxylation of pyruvate to produce acetyl coenzyme A. Several congenital and acquired disease states share a similar pathobiology with respect to glucose homeostasis under distress that leads to a preferential shift from the more efficient oxidative phosphorylation to glycolysis. By reversing this process, DCA can increase available energy and reduce lactic acidosis. The purpose of this review is to examine the literature surrounding this metabolic messenger as it presents exciting opportunities for future investigation and clinical application in therapy including cancer, metabolic disorders, cerebral ischemia, trauma, and sepsis.

Daily dose of metformin caused acute kidney injury with lactic acidosis: a case report

BACKGROUND

Metformin-induced lactic acidosis with acute kidney injury is rare but well known. Here we report a case of a Japanese patient taking metformin who experienced severe acute renal failure accompanied with significantly elevated metformin plasma concentrations and signs of lactic acidosis.

CASE PRESENTATION

A 60-year-old Japanese man with type II diabetes, who was taking metformin (500 mg three times a day) along with several other medications, visited the emergency department with dizziness, malaise, and oliguria. The initial laboratory test results showed elevated levels of serum creatinine and blood urea nitrogen, although his renal function was normal approximately 2 weeks earlier. His lactate level was raised (4.27 mmol/L), and he was diagnosed with lactic acidosis. Considering the low creatinine clearance and elevated urinary albumin/serum creatinine ratio, urinary N-acetyl-β-D-glucosaminidase level, and β2-microglobulin level, the patient was further diagnosed with AKI (in other words, acute tubular necrosis). A renal biopsy performed on day 3 after admission revealed renal tubular epithelium necrosis, supporting this diagnosis. The patient underwent intermittent hemodialysis until he was discharged on day 13. The metformin concentrations on days 3, 5, and 7 were 8.95, 2.58, and 0.16 μg/mL, respectively, which is significantly higher than the maximal steady-state concentration of metformin at the recommended dosage (approximately 1 μg/mL). The calculated pharmacokinetic parameters of metformin suggested poor renal excretion and a low distribution volume at higher metformin levels. Other possible acute kidney injury-causing factors included dehydration, alcohol consumption, and the use of an angiotensin receptor blocker or SGLT2 inhibitor.

CONCLUSIONS

This is the first reported case of acute kidney injury possibly caused by high levels of metformin with lactic acidosis in a patient treated with the recommended metformin dose. Thus, the development of metformin-induced acute kidney injury should be considered for patients with several acute kidney injury risk factors who are taking metformin.

Calcium-Citrate Anticoagulation during Continuous Renal Replacement Therapy in Patients with Metformin Intoxication: A Case Series, Mathematical Estimation of Citrate Accumulation, and Literature Review

INTRODUCTION

Metformin intoxication causes lactic acidosis by inhibiting Krebs' cycle and oxidative phosphorylation. Continuous renal replacement therapy (CRRT) is recommended for metformin removal in critically ill patients. According to current guidelines, regional citrate anticoagulation (RCA) is the first-line strategy. However, since metformin also inhibits citrate metabolism, a risk of citrate accumulation could be hypothesized. In the present study, we monitored the potential citrate accumulation in metformin-associated lactic acidosis (MALA) patients treated with CRRT and RCA using the physical-chemical approach to acid-base interpretation.

METHODS

We collected a case series of 3 patients with MALA. Patients were treated with continuous venovenous hemofiltration (CVVH), and RCA was performed with diluted citrate solution. Citrate accumulation was monitored through two methods: the ratio between total and ionized plasma calcium concentrations (T/I calcium ratio) above 2.5 and the strong ion gap (SIG) to identify an increased concentration of unmeasured anions. Lastly, a mathematical model was developed to estimate the expected citrate accumulation during CVVH and RCA.

RESULTS

All 3 patients showed a resolution of MALA after the treatment with CVVH. The T/I calcium ratio was consistently below 2.5, and SIG decreased, reaching values lower than 6 mEq/L after 48 h of CVVH treatment. According to the mathematical model, the estimated SIG without citrate metabolism should have been around 21 mEq/L due to citrate accumulation.

CONCLUSIONS

In our clinical management, no signs of citrate accumulation were recorded in MALA patients during treatment with CVVH and RCA. Our data support the safe use of diluted citrate to perform RCA during metformin intoxication.

Two cases of metformin-associated lactic acidosis in post-operative period in emergency department: time to be aware-case reports

Background

Diabetic patients on metformin therapy may be vulnerable to lactic acidosis during acute illness. This is particularly true since the comorbid conditions among patients with diabetes and the frequent use of renin-angiotensin system blockers increase the risk of renal dysfunction.

Case Description

We present two cases of metformin-associated lactic acidosis (MALA) occurred after abdominal surgery. A 74-year-old woman presented to emergency department (ED) for a transient loss of consciousness. She had vomiting, diarrhea, and lack of appetite in the last 3 days and she had had an abdominal adhesiolysis surgery 12 days before. A 78-year-old man, with history of right hemicolectomy performed 15 days before admission to ED. Patient presented with diffuse abdominal pain, diarrhea, nausea, and vomiting). Arterial blood gas analysis showed acidemia (pH 7.031), elevated anion gap (AG), lactate >15.5 mmol/L. Due to the patients' critical condition, vasopressor infusion and fluid resuscitation were started and an urgent continuous veno-venous hemodialysis with citrate and calcium (CVVHD-CiCa) treatment was provided.

Conclusions

A promptly differential diagnosis at ED and early treatment with vital support and CVVHD-CiCa enabled the resolution of MALA, which can often be a fatal complication in diabetic patients taking metformin. Close collaboration with the surgical and endocrinological team would be necessary for the management of the postoperative period planning the reintroduction of metformin in patients undergoing major abdominal surgery, to avoid the possibility of the onset of MALA.

Paraneoplastic syndrome in malignant lymphoma: A case report

Hypercalcaemia associated with malignancy is a complication of advanced tumors. Lactic acidosis is also an extremely rare paraneoplastic syndrome of malignancy, and the presence of both usually indicates an extremely poor prognosis for the tumour. Diffuse large B-cell lymphoma is the most common type of non-Hodgkin's lymphoma and is also a common aggressive lymphoma. It is extremely rare for patients with diffuse large B-cell lymphoma to develop both hypercalcaemia and severe lactic acidosis. In this article, we report a case of CD5 positive diffuse large B-cell lymphoma with hypercalcaemic crisis and persistent lactic acidosis, in which calcium was rapidly reduced to normal after rehydration, diuresis, calcitonin and zoledronate, and continuous renal replacement therapy (CRRT). After correction of acidosis with sodium bicarbonate, diuresis, vitamin B1 and CRRT, the patient's lactate remained at a high level. The aim of this article is to analyse the experience of the combination of hypercalcaemia and intractable lactic acidosis, which should be considered as a serious electrolyte disorder possibly associated with abnormal metabolism of malignant tumors, and to identify and treat the primary lesion as early as possible.

Perioperative considerations of pyruvate dehydrogenase complex deficiency: a case report of two consecutive anesthesia

BACKGROUND

Pyruvate dehydrogenase complex (PDHC) deficiency is a rare mitochondrial disorder caused by a genetic mutation affecting the activity of the PDHC enzyme, which plays a major role in the tricarboxylic cycle. Few cases of surgery or anesthesia have been reported. Moreover, there is no recommended anesthetic method.

CASE

A 24-month-old child with a PDHC deficiency presented to the emergency room with respiratory failure, mental decline, systemic cyanosis, and lactic acidosis. During hospitalization period, the patient presented with pneumothorax, pneumoperitoneum, and multiple air pockets in the heart. Two surgeries were performed under general anesthesia using an inhalational anesthetic agent. The patient was discharged with home ventilation.

CONCLUSIONS

Anesthesiologists should be wary of multiple factors when administering anesthesia to patients with PDHC deficiency, including airway abnormalities, acid-base imbalance, intraoperative fluid management, selection of appropriate anesthetics, and monitoring of lactic acid levels.

Lactic acidosis switches cancer cells from dependence on glycolysis to OXPHOS and renders them highly sensitive to OXPHOS inhibitors

Targeting oxidative phosphorylation (OXPHOS) has emerged as a strategy for cancer treatment. However, most tumor cells exhibit Warburg effect, they primarily rely on glycolysis to generate ATP, and hence they are resistant to OXPHOS inhibitors. Here, we report that lactic acidosis, a ubiquitous factor in the tumor microenvironment, increases the sensitivity of glycolysis-dependent cancer cells to OXPHOS inhibitors by 2-4 orders of magnitude. Lactic acidosis reduces glycolysis by 79-86% and increases OXPHOS by 177-218%, making the latter the main production pathway of ATP. In conclusion, we revealed that lactic acidosis renders cancer cells with typical Warburg effect phenotype highly sensitive to OXPHOS inhibitors, thereby greatly expanding the anti-cancer spectrum of OXPHOS inhibitors. In addition, as lactic acidosis is a ubiquitous factor of TME, it is a potential indicator to predict the efficacy of OXPHOS inhibitors in cancer treatment.

Pulmonary artery catheter usage in diagnosis of Shoshin beriberi presented with unexplained lactic acidosis

Wet beriberi is a rare but fatal disease in modern society. The nonspecific clinical manifestations, including symptoms of heart failure and recalcitrant lactic acidosis, can prevent timely diagnosis. The use of a pulmonary artery catheter can promptly confirm a high cardiac output state and plays a crucial role in rapidly deteriorating cases. Appropriate treatment with intravenous administration of thiamine leads to dramatic recovery within hours. We present two cases of Shoshin beriberi, a fulminant variant of wet beriberi, diagnosed in 2016 and 2022 at our institute. The patients experienced haemodynamic collapse and refractory lactic acidosis, which were successfully diagnosed with the use of a pulmonary artery catheter and reversed by thiamine supplementation. We also reviewed 19 cases of wet beriberi reported between 2010 and 2022.

Raise vigilance against refractory distributive shock due to severe wet beriberi

Differentiating the type and cause of shock is crucial for intensive care. The rapid aggravation of lactic acidosis in patients often indicates a severe impairment of oxygen uptake in tissues. Herein, we presented a rare case of refractory distributive shock with severe wet beriberi. A 40-year-old male was admitted to the emergency department (ED) with recurrent chest tightness and lower extremity edema. The condition of the patient continued to deteriorate after symptomatic treatments. After several turnovers, the medical history of the patient was requested again and finally obtained. Our emergency management team hypothesized that the thiamine-deficient diet caused an aerobic metabolism disorder in the patient. Overall, we aimed to alert clinicians to unusual causes of distributive shock and further discussed the application of thiamine supplementary therapy in critical care.

Shoshin beriberi in a young man with gambling addiction

We report a case of a 24-year-old previously healthy Japanese man who presented to the emergency department due to cardiopulmonary arrest lasting for 4 min. He had complained of chest pain and worsening dyspnea but was well until 3 days before admission. He had no history of alcohol consumption. Marked lactic acidosis, high-output heart failure, and hypotension with widened pulse pressure led to a diagnosis of shoshin beriberi. The patient recovered successfully without any residual symptoms after appropriate thiamine therapy. Because of the complexity of the clinical presentation and the lack of rapid diagnostic tests, thiamine deficiency remains difficult to diagnose. In this patient, we suspected that shoshin beriberi was caused by long-term poor nutritional status secondary to a severe gambling addiction to Japanese pinball games, known as 'pachinko'. Alcoholism, long-term intravenous alimentation, and diuretic use are well-known causes. We should not miss the opportunity for early intervention, even in young non-alcoholic patients such as this case. If left untreated, patients may die from cardiopulmonary collapse within hours of symptom onset. Thiamine should be administered as soon as suspicion for thiamine deficiency arises, such as in conditions of widened pulse pressure in a young patient.

Learning objective

Alcoholism, long-term intravenous alimentation, and diuretic use are well-known causes of thiamine deficiency. However the complexity of the clinical presentation and the lack of rapid diagnostic tests make its diagnosis difficult. Shoshin beriberi is a fulminant form of this disease. We should not miss opportunities for early intervention. Thiamine should be administered as soon as its deficiency is suspected, such as in conditions of widened pulse pressure especially in a young patient.

Renal Complications after Percutaneous Coronary Interventions on Concurrent Metformin Therapy: A Systematic Review with Meta-Analysis

Objective: Metformin, commonly prescribed in diabetic patients, can cause lactic acidosis. Although generally rare, this side effect remains a source of concern in procedures requiring contrast media, due to the risk of contrast-induced nephropathy. Temporarily withdrawing metformin during the peri-procedural period is often practiced, but clinical decisions are difficult in emergency situations, such as acute coronary syndromes. In this systematic review with meta-analysis, we aimed to further investigate the safety of percutaneous coronary interventions in patients on concurrent metformin therapy.Design, Setting and Participants: We analyzed studies in patients undergoing (elective or emergency) percutaneous coronary interventions with or without concurrent metformin administration, reporting on the incidence of metformin-associated lactic acidosis and peri-procedural renal function.Methods: PubMed, ClinicalTrials.gov, Cochrane Library, and Scopus were systematically searched without language restrictions throughout August 2022. Randomized clinical trials and observational studies were assessed with the Revised Cochrane Collaboration Risk of Bias tool and the Newcastle-Ottawa quality scale, respectively. Data synthesis addressed the mean drop in estimated glomerular filtration rate (eGFR) and the incidence of contrast-induced nephropathy, in addition to lactic acidosis.Results: Nine studies were included, totaling 2235 patients (1076 continuing metformin during the peri-procedural period), mostly with eGFR above 30 mL/min/1.73m² No cases of lactic acidosis were reported. The mean post-procedural drop in eGFR was 6.81mL/min/1.73m² (95% confidence interval [CI]: 3.41 to 10.21) in the presence of metformin and 5.34 mL/min/1.73m² (95% CI: 2.98 to 7.70) in its absence. The incidence of contrast-induced nephropathy was not affected by concurrent metformin, as shown by a (between-groups) standardized mean difference of 0.0007 (95% CI: -0.1007 to 0.1022).Conclusion: Concurrent metformin during percutaneous coronary interventions in patients with relatively preserved renal function is safe, without added risk of lactic acidosis or contrast-induced nephropathy. Thus, emergency revascularization in the context of acute coronary syndromes should not be deferred. More data from clinical trials in patients with severe renal disease are needed.

Thyrotoxic periodic paralysis associated with lactic metabolic acidosis: Case report of an African man and review of literature

BACKGROUND

Thyrotoxic periodic paralysis (TPP) is a rare and most often acquired subtype of hypokalemic periodic paralysis. The association of varying degrees of muscle weakness, hyperthyroidism and hypokalemia characterizes it. The treatment requires potassium supplementation, control of hyperthyroidism and prevention measures. It is a frequent disease in Asian men, but much rare in Caucasian or African populations. This is the first report of TPP associated with lactic metabolic acidosis in an African man.

CASE PRESENTATION

A 23 year-old African man, native from Morocco, with recurrent episodes of tetraparesis for eleven months, and abdominal pain, was referred for evaluation. Biochemical investigations showed severe hypokalemia associated with hyperthyroidism and lactic metabolic acidosis. His EKG showed signs of hypokalemia such as sinus tachycardia and U waves. After potassium supplementation, neurological recuperation was quick and complete. Thyroid ultrasound identified a hypoechogenic and hypervascularized goiter, associated with high levels of thyroid antibodies, in favor of Grave's disease. With antithyroid drugs and life-style changes, the patient did not have any other attack.

REVIEW OF LITERATURE

In addition to the case report, this article presents an extended review of literature, from the first large study reporting the diagnosis and incidence of TPP in 1957 to nowadays. Are reported here the latest information concerning epidemiology, clinical manifestations, complementary examinations, management and genetic finding. The lactic acidosis observed initially is exceptional, never described in TPP. TPP is a diagnostic and therapeutic emergency, requiring careful potassium supplementation, in order to avoid the risk of the onset of rebound hyperkalemia, to be maintained until the etiological treatment is effective. Paraclinical assessment with emergency EKG and electromyogram are essential to assess the impact.

DISCUSSION

It is essential in the face of any hypokalaemic periodic paralysis, including in non-Asian subjects, to search hyperthyroidism.

CONCLUSIONS

This report demonstrates the importance of thyroid testing in case of acute muscle weakness, even in non-Asian patients in order to diagnose TPP. This is a rare but possible etiology, to be distinguished from the familial form of hypokalemic periodic paralysis. It also questions on the impact of TPP on energetic metabolism, in particular on lactic metabolism.

Metformin's Role in Hyperlactatemia and Lactic Acidosis in ICU Patients: A Systematic Review

INTRODUCTION

Metformin-treated patients may experience severe hyperlactatemia or lactic acidosis (LA). LA often requires intensive-care-unit (ICU) treatment, and mortality rates are high. Here, we investigate the impact of renal dysfunction and renal replacement therapy (RRT) on the outcomes of critically ill patients with metformin-associated LA (MALA). Furthermore, we assessed associations between mortality and metformin dose, metformin plasma/serum concentrations, lactate level, and arterial pH. Finally, we investigated whether the recommended classification in MALA, metformin-unrelated LA, metformin-induced LA, and LA in metformin therapy appears useful in this regard.

METHODS

We performed a retrospective analysis based on a systematic PubMed search for publications on hyperlactatemia/LA in metformin-treated ICU patients from January 1995 to February 2020. Case-level data including demographics and clinical conditions were extracted, and logistic regression analyses were performed.

RESULTS

A total of 92 ICU patients were reported. Two of these patients had no comorbidities interfering with lactate metabolism. In the overall group, arterial pH, lactate levels, and metformin plasma/serum concentrations were similar in survivors versus non-survivors. Ingested daily metformin doses and plasma/serum creatinine levels were significantly higher in survivors versus non-survivors (p = 0.007 vs. p = 0.024, respectively). Higher plasma/serum creatinine levels, higher lactate levels, and lower arterial pH were all associated with patients receiving RRT (all p < 0.05). Overall mortality was 22% (20 out of 92 patients) and did not differ between the RRT and non-RRT groups.

CONCLUSION

Mortality is high in ICU patients with metformin-associated hyperlactatemia/LA. Unexpectedly, higher ingested metformin dose and plasma/serum creatinine were associated with a better outcome. Survival was similar in patients with or without need for RRT.

Sufentanil: a risk factor for lactic acidosis in patients after heart valve surgery

Backgrounds

Hyperlactatemia is a common metabolic disorder after cardiac surgery with cardiopulmonary bypass. Epinephrine use has been identified as a potential cause of increased lactate levels after cardiac surgery. Stress can lead to an increase in catecholamines, mainly epinephrine, in the body. Exogenous epinephrine causes hyperlactatemia, whereas endogenous epinephrine released by stress may have the same effect. Opioids are the most effective anesthetics to suppress the stress response in the body. The authors sought to provide evidence through a retrospective data analysis that helps investigate the relationship between intraoperative opioid dosage and postoperative lactic acidosis after cardiac surgery.

Methods

The clinical data of 215 patients who underwent valvular heart surgery with cardiopulmonary bypass from July 2016 to July 2019 were analyzed retrospectively. Blood lactate levels were measured at 0.1 h, 2 h, 4 h, and 8 h after surgery. Patients with continuous increases in lactate levels and lactate levels exceeding 5 mmol/L at two or more time points were included in the lactic acidosis group, whereas the other patients were included in the control group. First, univariate correlation analysis was used to identify parameters that were significantly different between the two groups, and then multivariate regression analysis was conducted to elucidate the independent risk factors for lactic acidosis. Fifty-one pairs of patients were screened by propensity score matching analysis (PSM). Then, lactic acid levels at four time points in both groups were analyzed by repeated measures ANOVA.

Results

he EF (heart ejection fraction) (OR = 0.94, P = 0.003), aortic occlusion time (OR = 10.17, P < 0.001) and relative infusion rate (OR = 2.23, P = 0.01) of sufentanil was an independent risk factor for lactic acidosis after valvular heart surgery. The patients were further divided into two groups with the mean sufentanil infusion rate as the reference point. The data were filtered with PSM (Propensity Score Matching). Lactic acid values in both groups peaked at 4 h after surgery and then declined. The rate of lactic acid decline was significantly faster in the group with a higher sufentanil dosage than in the lower group. The difference was statistically significant (P < 0.05). There was also a significant difference in lactic acid levels at the four time points (0.1 h, 2 h, 4 h and 8 h after surgery) in both groups (P < 0.001).

Conclusion

The inadequate intraoperative infusion rate of sufentanil is an independent risk factor for lactic acidosis after heart valve surgery. The possibility of lactic acidosis caused by this factor after cardiac surgery should be considered, which is helpful for postoperative patient management.

Severe hyperlactatemia in unselected surgical patients: retrospective analysis of prognostic outcome factors

Background

Etiology of hyperlactatemia in ICU patients is heterogeneous—septic, cardiogenic or hemorrhagic shock seem to be predominant reasons. Multiple studies show hyperlactatemia as an independent predictor for ICU mortality. Only limited data exists about the etiology of hyperlactatemia and lactate clearance and their influence on mortality. The goal of this single-center retrospective study, was to evaluate the effect of severe hyperlactatemia and reduced lactate clearance rate on the outcome of unselected ICU surgical patients.

Methods

Overall, 239 surgical patients with severe hyperlactatemia (> 10 mmol/L) who were treated in the surgical ICU at the University Medical Center Freiburg between June 2011 and August 2017, were included in this study. The cause of the hyperlactatemia as well as the postoperative course and the patient morbidity and mortality were retrospectively analyzed. Lactate clearance was calculated by comparing lactate level 12 h after first measurement of > 10 mmol/L.

Results

The overall mortality rate in our cohort was 82.4%. Severe hyperlactatemia was associated with death in the ICU (p < 0.001). The main etiologic factor was sepsis (51.9%), followed by mesenteric ischemia (15.1%), hemorrhagic shock (13.8%) and liver failure (9.6%). Higher lactate levels at ICU admission were associated with increased mortality (p < 0.001). Lactate clearance after 12 h was found to predict ICU mortality (ANOVA p < 0.001) with an overall clearance of under 50% within 12 h. The median percentage of clearance was 60.3% within 12 h for the survivor and 29.1% for the non-survivor group (p < 0.001).

Conclusion

Lactate levels appropriately reflect disease severity and are associated with short-term mortality in critically ill patients. The main etiologic factor for surgical patients is sepsis. When elevated lactate levels persist more than 12 h, survival chances are low and the benefit of continued maximum therapy should be evaluated.

Resistant lactic acidemia due to accidental cheese starter culture ingestion: A case report

Lactic acid is the end-product of anaerobic glycolysis. It is generally believed that elevated blood lactate levels are associated with poor patient outcomes. Literature reports that lactic acidosis can be related to supplementary food intake in the pediatric age group however, in adult patients, it is not common to see lactic acidosis due to oral ingestion unless the patient has a history of short bowel syndrome or jejunoileal bypass surgery. With the current case presentation, we report an accidental cheese starter culture intake that resulted in resistant lactic acidosis with no signs of critical illnesses.

Late Onset Subacute Profound Biotinidase Deficiency Caused by a Novel Homozygous Variant c.466-3T>G in the BTD Gene

Biotinidase deficiency (BD) is an autosomal recessive disorder caused by bi-allelic mutation in the BTD gene. Clinical manifestations in BD mainly depends on residual biotinidase enzyme activity, although there are some exceptions. Broadly BD disorders are classified as profound BD and partial BD. Further profound BD can be early onset, late onset, and sometimes may be asymptomatic. Clinically late-onset profound BD can present with spectrum of manifestations ranging from single organ to multiple organ involvement, typically affecting function of brain, eye, ear, and skin. Here, a first-born child to consanguineous parents with late-onset profound BD presenting with hyperventilation secondary to lactic acidosis, hypotonia, evolving spasticity, and abnormal neuroimaging findings caused by novel homozygous variant, c.466-3T>G in the BTD gene is reported.

A patient with severe metformin-associated lactic acidosis complicated by acute coronary syndrome: a case report

Introduction

Metformin-associated lactic acidosis (MALA) is a rare but life-threatening condition. Here, we report the outcome of a patient with MALA complicated by acute coronary syndrome.

Case presentation

A 47-year-old obese woman of Caucasian ethnicity was admitted for syncope and tachypnea with Kussmaul breathing. She had a type-2 diabetes and was on oral antidiabetic therapy. Hemoglobin A1c was 6.6%. On admission, a severe acute kidney injury (serum creatinine: 1251 µmol/L) with hyperkalemia (7.5 mmol/L) and severe lactic acidosis (ph:7.042, bicarbonate: 9.9 mmol/L, partial pressure of carbon dioxide: 21.8 mmHg, lactate: 20.0 mmol/L) was found. Despite bicarbonate therapy, ph further decreased. Within 2.5 h of admission, a temporary hemodialysis catheter was placed, and one session of a high-efficiency hemodialysis was performed. 8 h after admission, a continuous venovenous hemodiafiltration was initiated and maintained for 2 days. The metformin therapy was stopped. Supplemental oxygen, intravenous catecholamines (4 days) and antibiotic therapy (7 days) were applied. During this therapy of lactic acidosis, an acute coronary syndrome evolved by day 2 after admission and resolved by day 5 in hospital. After recovery, the patient was transferred to a general ward on day 7 and left the hospital on day 11. By discharge, both the acute kidney injury and the acute coronary syndrome were reversible.

Conclusion

In the patient with MALA complicated by acute coronary syndrome, the combination of a high-efficiency hemodialysis and, consecutively, continuous venovenous hemodiafiltration led to a favorable outcome.

Severe lactic acidosis and persistent diastolic hypotension following standard dose of intermittent nebulized salbutamol in a child: a case report

Background

Salbutamol is a selective β2-receptor agonist widely used to treat asthma in both emergency and outpatient settings. However, it has been associated with a broad spectrum of side effects. Lactic acidosis and diastolic hypotension are rarely reported together following intermittent salbutamol nebulization in children, even less so at standard therapeutic doses.

Case presentation

We present the case of a 12-year-old Italian boy, 34 kg body weight, who experienced a serious drug reaction during a moderate asthma exacerbation with associated dehydration (blood urea nitrogen/creatinine 0.25), following intermittent inhaled (0.2 mg at 3-hour intervals—overall 1.4 mg in 24 hours before arrival) and nebulized treatment (3.25 mg at 20-minute intervals in 60 minutes, overall 11.25 mg in our emergency department). The patient developed hyperglycemia (peak concentration 222 mg/dL), hypokalemia (lowest concentration 2.6 mEq/L), electrocardiogram alterations (corrected QT interval 467 ms), long-lasting arterial hypotension despite fluid boluses (lowest value 87/33 mmHg), and elevated blood lactate levels (peak concentration 8.1 mmol/L), following the third nebulized dose. Infections, liver dysfunction, and toxicity following other medications were ruled out. The aforementioned alterations improved within 24 hours after discontinuation of salbutamol.

Conclusions

We reinforce the message that even the use of intermittent nebulized salbutamol for acute moderate asthma can lead to severe transient complications in children. Then, healthcare providers should pay attention not only in emergency settings, to achieve prompt recognition and proper management of this adverse reaction. Careful reassessment could prevent similar reactions.

A concealed history behind the disaster: Extremely rare presentations of metformin toxicity in a patient with body dysmorphic disorder

Metformin is a widely used anti-hyperglycemic agent with weight loss effect properties but besides its various utilities, despite being very rare, it has its characteristic toxicity and adverse effects when used in large doses and for the long-term or in patients with renal impairment. We presented here a case of a 36-year-old woman who developed several presentations with diverse features during three years comprising neuropathic symptoms, severe lactic acidosis, three episodes of cardiogenic shock, acute kidney injury, megaloblastic anemia, pancytopenia, and hyponatremia and did not receive a definite diagnosis after each presentation until when she inadvertently disclosed her abuse of extremely unusual doses of metformin during these three years with aim of weight reduction obsessively without knowing that her symptoms could pertain to metformin overdose. She was eventually diagnosed with a body dysmorphic disorder which led to unreasonable abuse of metformin pills that consequently caused its toxicity. Thereafter, with cease of metformin use and psychiatric treatment, her symptoms did not recur and she was doing well after one year of her last admission. Based on the review of the literature, this is the first case of metformin toxicity in a patient with body dysmorphic disorder who was affected with extremely rare features of this intoxication, nevertheless, every manifestation of the patient was discussed exhaustively according to the current and available medical literature.

Intravenous ketogenic diet therapy for neonatal-onset pyruvate dehydrogenase complex deficiency

BACKGROUND

Pyruvate dehydrogenase complex (PDHC) deficiency is an inborn error of metabolism that causes lactic acidosis and neurodevelopmental changes. Five causative genes have been identified: PDHA1, PDHB, DLAT, DLD, and PDHX. Four neurological phenotypes have been reported: neonatal encephalopathy with lactic acidosis, non-progressive infantile encephalopathy, Leigh syndrome, and relapsing ataxia. Of these, neonatal encephalopathy has the worst mortality and morbidity and there is no effective treatment.

SUBJECTS AND METHODS

We studied two girls who were clinically diagnosed with PDHC deficiency as neonates; they were subsequently found to have PDHA1 mutations. The clinical diagnosis was based on white matter loss and a lateral ventricular septum on fetal MRI, spasticity of the lower extremities, and lactic acidosis worsening after birth. Intravenous ketogenic diets were started within 24 h after birth. The ketogenic ratio was increased until the blood lactate level was controlled, while monitoring for side effects.

RESULTS

In both cases, the lactic acidosis improved immediately with no apparent side effects. Both children had better developmental outcomes than previously reported cases; neither exhibited epilepsy.

CONCLUSIONS

Intravenous ketogenic diet therapy is a treatment option for neonatal-onset PDHC deficiency. Further studies are needed to optimize this therapy.

Successful treatment of linezolid-induced severe lactic acidosis with continuous venovenous hemodiafiltration: A case report

Linezolid is an oxazolidinone antibiotic. Linezolid-associated lactic acidosis has been reported in 6.8% of linezolid-treated patients. Lactic acidosis is associated with poor clinical outcomes, with high blood lactate levels resulting in organ dysfunction and mortality. This case report describes the development of lactic acidosis in a 64-year-old Chinese woman who had received 33 days of treatment with antituberculosis drugs and 28 days of treatment with oral linezolid for tuberculous meningitis. Severe lactic acidosis was reversed by withdrawing antituberculosis drugs and using continuous venovenous hemodiafiltration (CVVH). When the patient's condition was stable, she was transferred to the infectious disease department, and antituberculosis drugs, with the exception of linezolid, were reintroduced. This did not result in recurrence of lactic acidosis. The causal relationship between lactic acidosis and linezolid was categorized as 'probable' on the Adverse Drug Reaction Probability Scale. This case demonstrates that CVVH has potential as an alternative to discontinuation of linezolid alone for rapid reversal of linezolid-associated severe lactic acidosis.

Unexplained Metabolic Acidosis: Alcoholic Ketoacidosis or Propylene Glycol Toxicity

INTRODUCTION

Severe metabolic acidosis with elevated anion and osmol gap is suggestive of toxic alcohol ingestion. The absence of detectable methanol or ethylene glycol in the serum could mean that metabolism is complete or that other hypotheses have to be considered. Ingestion of less common alcohol or alcoholic ketoacidosis should be investigated as illustrated by the present observation.

CASE REPORT

A 46-year-old woman was admitted with altered consciousness in the Emergency Department. In the presence of a high anion gap (peak value 39 mEq/L) metabolic acidosis with mildly increased osmol gap (peak value 19 mOsm/kg), there was a high suspicion of toxic alcohol ingestion in an individual with alcohol use disorder (AUD). Serum arterial lactate concentration was particularly high at 27 mmol/L. Urinalysis failed to reveal the presence of ketone bodies or oxalate crystals. The results of the serum determination of ethanol, methanol, ethylene glycol, and isopropanol were obtained within 2 h and were negative. Due to the severity of lactic metabolic acidosis and the persisting suspicion of intoxication by a less common toxic alcohol, antidotal therapy with ethanol was initiated together with hemodialysis. Correction of lactic metabolic acidosis was obtained. Results of urinalysis obtained later revealed the presence not only of propylene glycol and D-lactate but also of significant concentrations of ß-hydroxybutyrate as a marker of alcoholic ketoacidosis.

DISCUSSION

The combination of propylene glycol ingestion and alcoholic ketoacidosis may have contributed to the severity of lactic acidosis.

Refractory vasodilatory shock secondary to metformin overdose supported with VA ECMO

•

Metformin overdose can lead to vasodilatory shock refractory to medical management.

•

Extracorporeal circulatory support with venoarterial ECMO is an effective way to manage profound shock associated with metformin overdose.

•

We report the highest recorded serum metformin level in the literature to date.

Metformin overdose may result in vasodilatory shock, lactic acidosis and death. Hemodialysis is an effective means of extracorporeal elimination, but may be insufficient in the shock setting. We present a case of a 39 yo male who presented with hypotension, coma, hypoglycemia, and lactate of 6.5 mmol/L after ingesting an unknown medication. Metformin overdose was suspected, and he was started on hemodialysis. He developed profound vasoplegia refractory to high doses of norepinephrine, vasopressin, epinephrine and phenylephrine. Venoarterial extracorporeal membrane oxygenation (VA ECMO) was initiated and he had full recovery. Serum analysis with high resolution liquid chromatography mass spectrometry revealed a metformin level of 678 μg/mL and trazodone level of 2.1 μg/mL. This case is one of only a handful of reported cases of metformin overdose requiring ECMO support, and we report the highest serum metformin levels in the literature to date. We recommend early aggressive hemodialysis and vasopressor support in all suspected cases of metformin toxicity as well as VA ECMO if refractory to these therapies.

Objective

We present a case of vasodilatory shock secondary to metformin overdose requiring venoarterial extracorporeal membrane oxygenation (VA ECMO) support. This case is one of only a handful of reported cases of metformin overdose requiring ECMO support, and we report the highest serum metformin levels in the literature to date.

Data sources

University of San Francisco, Fresno.

Study design

Case report.

Data extraction

Clinical records and high resolution liquid chromatography mass spectroscopy analysis.

Data synthesis

None.

Conclusions

Venoarterial ECMO provided an effective means of hemodynamic support for a patient with severe metformin toxicity.

Hypoglycemia with lactic acidosis caused by a new MRPS2 gene mutation in a Chinese girl: a case report

BACKGROUND

Mitochondrial ribosomal protein S2 (MRPS2) gene mutation, which is related to severe hypoglycemia and lactic acidosis, is rarely reported globally.

CASE PRESENTATION

We report a case of a new MRPS2 gene mutation in a Chinese girl who presented with hypoglycemia and lactic acidosis. A homozygous C.412C > G variant that could cause complex oxidative phosphorylation deficiency and had not been reported before was identified. The clinical manifestations included recurrent vomiting, hypoglycemia, lactic acidosis, sensorineural hearing loss, and gall bladder calculi. Hypoglycemia and lactic acidosis improved after the administration of sugary liquid and supportive treatments.

CONCLUSIONS

Recurrent hypoglycemia with lactic acidosis and sensorineural hearing loss should lead to suspicion of mitochondrial defects and the early refinement of genetic tests.

Hyperglycemia and Lactic Acidosis Associated with Linezolid Therapy in an Extremely Premature Infant

The use of linezolid is relatively safe for all age categories, including premature infants. The case of an extremely premature infant with hyperglycemia and lactic acidosis associated with linezolid is reported. A 350-g male infant was born at 24 weeks by cesarean section. His Apgar scores were 1 and 1 at 1 and 5 min, respectively. On the day of life (DOL) 7, linezolid was started at a dose of 10 mg/kg/dose every 8 h for a catheter-related blood stream infection caused by methicillin-resistant coagulase-negative Staphylococci. After linezolid was given, serum lactate and glucose levels increased gradually. After discontinuation of linezolid on DOL 16, hyperglycemia and lactic acidosis improved immediately. In conclusion, a rare case of an extremely premature infant with hyperglycemia and lactic acidosis associated with linezolid was reported. It is crucial to monitor glucose levels along with lactate and pH levels during linezolid therapy.

Mind the B2: Life-Threatening Neonatal Complications of a Strict Vegan Diet during Pregnancy

An increasing number of women of reproductive age follow vegan diets. Because vegan diets are deficient in a number of essential nutrients, guidelines address the necessity of supplementations such as iron, zinc, and vitamin B12. However, the risk of riboflavin (vitamin B2) deficiency is not properly addressed. We report a case of a male neonate with a life-threatening hypoglycaemia and lactic acidosis due to severe riboflavin deficiency. The mother followed a strict vegan diet with intermittent use of supplements (folic acid, vitamin B12, vitamin D, omega 3). This case highlights the importance of adequate counselling of all pregnant women adhering to vegan diets to ensure sufficient intake of essential nutrients and vitamins, including riboflavin.

Lactic acidosis associated with standard dose linezolid in a kidney recipient with impaired renal function

Severe lactic acidosis, a mitochondrial toxicity caused by the recommended standard dosage of linezolid (LZD), may occur in patients with impaired renal function. We describe an adult male who underwent kidney transplantation with stably impaired renal function, severe dyspnea, and abdominal discomfort. He received a standard oral dose of LZD (600 mg twice daily) and azithromycin for three weeks with a reduced immunosuppressant dose due to pulmonary non-tuberculosis mycobacterial infection. He was alert and afebrile, with a blood pressure of 140/60 mmHg. Pertinent laboratory data showed: pH 7.12, PaCO2 13.6 mmHg; HCO3- 4.3 mmol/L and serum lactate 18.4 mmol/L. His trough serum LZD concentration reached toxic levels (21.4 μg/mL). With hemodialysis, his clinical symptoms improved, with a decline in serum LZD (9.8μg/mL) and lactate (3.2 mmol/L). Chronic standard dose LZD in patients with impaired renal function can lead to life-threatening lactic acidosis, especially in coexisting conditions that reduce LZD metabolism.

Metformin-associated lactic acidosis exacerbated by acute kidney injury in an overseas traveler

We report the case of metformin-associated lactic acidosis (MALA) exacerbated by acute kidney injury (AKI) in a 65-year-old Asian American woman who was an overseas traveler. She had vomiting and diarrhea before arriving in Osaka, Japan, from the Philippines. She suffered from worsening respiratory distress, consciousness loss and anuria the day after coming to Japan. When she arrived at our emergency room via ambulance, she appeared to be in a state shock. Arterial blood gas analysis revealed severe lactic acidosis (pH 6.681, PO₂ 302 Torr under O₂ supplementation, PCO₂ 15 Torr, HCO₃⁻1.7 mmol/L, and lactate 17.00 mmol/L). She also had renal failure (BUN 108 mg/dL and serum creatinine 8.68 mg/dL) with hyperkalemia (6.1 mEq/L). We collected medical information from family members, and found her prescription medicines including metformin, diuretics and angiotensin-converting enzyme inhibitor (ACEI). We diagnosed her with MALA due to an unintended overdose of metformin resulting from acute kidney injury that can be induced by ACEI and diuretics in the volume-depleted condition. We immediately started hemodialysis therapy. Although she had a temporary cardiopulmonary arrest at the beginning of the treatment, her physical status was gradually improved and the severe acidemia resolved. On hospital day 4, she had urine and no longer needed hemodialysis therapy. On day 14, she was discharged and returned to the United States without noticeable sequelae. This is a case report of an overseas traveler who was successfully rescued through the collection of accurate medical information and understanding of the pathological condition.

Continuous use of metformin in patients receiving contrast medium: what is the evidence? A systematic review and meta-analysis

OBJECTIVES

Substantial inconsistencies exist in current guidelines regarding recommendations of metformin usage with the administration of a contrast medium. We aimed to perform a meta-analysis to determine whether the risks of contrast-induced acute kidney injury (CI-AKI) and lactic acidosis increase with metformin use in diabetic patients receiving a contrast medium.

METHODS

Studies were retrieved from databases from inception to May 15, 2021. Studies that compared the outcomes of using metformin with not using metformin during contrast medium administration were included. The primary outcomes were incidence of CI-AKI and lactic acidosis. The secondary outcomes were renal function changes from baseline. Data analysis was using risk ratio (RR) for dichotomous outcomes and mean differences (MD) with 95% confidence intervals (CI) for continuous outcomes.

RESULTS

Analyses of two randomized controlled trials and four retrospective cohorts examining a total of 1459 patients revealed no significant differences in the incidence of CI-AKI (RR = 1.08; 95% CI, 0.72 to 1.63) and in changes in renal function measurements (serum creatinine: MD = 0.00 mg/dL, 95% CI, - 0.05 to 0.05; estimated glomerular filtration rate: MD = 0.22, 95% CI, - 2.47 to 2.91) after contrast medium administration between patients using and not using metformin.

CONCLUSIONS

There is no evidence that continuing metformin during contrast medium administration is associated with a higher risk of CI-AKI, lactic acidosis, or renal function deterioration compared to patients who discontinued metformin or who were not metformin users. The limited quality of the included studies may compromise the strength of evidence provided in this meta-analysis.

KEY POINTS

There is no need to discontinue metformin either before or after intravenous contrast medium exposure in patients with eGFR > 30 mL/min/1.73 m². In patients receiving intra-arterial contrast medium with first-pass renal exposure, there is no need to withhold metformin if eGFR is above 60 mL/min/1.73 m². For patients who have an eGFR level between 30 and 60 mL/min/1.73 m² and are receiving intra-arterial contrast medium with first-pass renal exposure, no case of lactic acidosis was observed based on present data, but further evidence is needed to make a strong suggestion regarding its safety.

The phenotypic spectrum of dihydrolipoamide dehydrogenase deficiency in Saudi Arabia

Background

Dihydrolipoamide dehydrogenase deficiency (DLDD) is a rare metabolic disorder inherited in an autosomal recessive manner. This heterogeneous disease has a variable clinical presentation, onset, and biochemical markers.

Materials and methods

We retrospectively reviewed the clinical and molecular diagnosis of eight cases with DLDD from four referral centers in Saudi Arabia.

Results

Remarkably, we found hepatic involvement ranging from acute hepatic failure to chronic hepatitis in five patients. In addition, neurological disorders in the form of seizures, developmental delay, ataxia, hypotonia and psychomotor symptoms were found in five patients, two of them with a combination of hepatic and neurological symptoms. In addition, only one patient had recurrent episodes of hypoglycemia. While most patients had the hepatic form of homozygous variant c.685G > T in the DLD gene, one patient was found to have a novel variant c.623C > T that had neurological and hepatic symptoms.

Conclusions

We describe the largest reported DLDD cohort in the Saudi population. Clinical, biochemical, radiological, and molecular characterization was reviewed and no clear genotype-phenotype correlation was found in this cohort.

Lactic Acidosis as an Unusual Finding in Undifferentiated Carcinoma

Lactic acidosis associated with solid neoplasms is a rare complication; its occurrence is poorly described, and it is associated with a poor prognosis. We present the case of an 84-year-old woman who was admitted to the internal medicine department with a diagnosis of urinary tract infection accompanied by a blood gas analysis showing lactic acidosis. During her admission, an abdominal mass was evidenced and finally diagnosed as undifferentiated carcinoma. We wanted to emphasize the importance of correlating clinical and laboratory data at the time of making a diagnostic approach and also highlight other possible explanations of lactic acidosis that should be considered in addition to hypoperfusion due to sepsis, especially in the elderly who are at increased risk of malignancy.

Propylene glycol toxicity from compulsive corn starch ingestion: A case report and review

INTRODUCTION

Propylene glycol (PG) is usually considered safe, however, toxicity can develop with high doses or when used for prolonged periods of time. PG can be found in some medications as well as some food products. We report a case of likely PG toxicity that occurred after compulsive daily ingestion of large amounts of corn starch.

CASE REPORT

Our patient initially presented to an outside hospital (OSH) via ambulance for altered mental status. Her mental status improved after her blood sugar of 25 was corrected. On admission to OSH Emergency Department her initial vital signs included a heart rate of 115 bpm, blood pressure 113/59 mm/hg, temperature 35.8C. Pertinent labs included: sodium 119 mEq/L, bicarbonate 9 mEq/L, anion gap 29 mEq/L, creatinine 2.5 mg/dL and lactic acid 20 mEq/L. On transfer to our hospital her repeat lactic acid was 20 mEq/L, osmolar gap was 20. Her PG level, which was drawn several hours after her initial presentation, was 11 mg/dL. Our patient noted that she ingested a 16 oz. package of corn starch mixed with baking soda approximately every 2 days. Given the concerns for PG she was underwent intermittent hemodialysis. PG and lactic acid levels improved, however, she ultimately died due to complications from her hospitalization.

DISCUSSION

PG causes toxicity through metabolism to lactic acid. While there are small amounts in food products and medications, under the right circumstances, PG can accumulate and lead to significant toxicity.

Lactic acidosis and hyperlactatemia associated with lamivudine accumulation and sepsis in a kidney transplant recipient-a case report and review of the literature

Background

We report a case of sudden, lethal metabolic acidosis in a 70-year-old man on long-term nucleoside reverse transcriptase inhibitor (NRTI) -based antiretroviral therapy (ART) who had developed atypical necrotizing fasciitis 1 month after kidney transplantation.

Case presentation

The HIV infection of the patient was treated for the last four months with an integrase strand inhibitor (dolutegravir 50 mg/d) plus a NRTI backbone including lamivudine (150 mg/d) and abacavir (600 mg/d). In this renal transplant patient we hypothesize that the co-existence of sepsis, renal failure and an accumulation of lamivudine led to the development of fatal metabolic acidosis and hyperlactatemia. Although lamivudine is only rarely associated with hyperlactatemia, there is evidence that overdose may be a risk factor for developing it. In our patient the lamivudine concentration two days after stopping and during hemodiafiltration was more than 50 times higher than therapeutic target trough concentrations. Likely reasons for this were renal impairment and concurrent treatment with trimethoprim, known to inhibit the renal elimination of lamivudine.

Conclusions

NRTIs could trigger the development of hyperlactatemia in septic patients. The use of NRTI sparing regimens might be considered in the presence of this critical condition.

Acute poisoning with acetamiprid: a case report

BACKGROUND

Acetamiprid is a potent new first-generation neonicotinoid insecticide in agricultural practices. It is well described that it has low toxicity among animals and is lethal if consumed in large amounts. However, toxicity in humans is rarely reported in literature. Here, we describe acetamiprid toxicity complicated with severe lactic acidosis, myocardial ischemia, refractory hypotension, and severe hypokalemia in a middle-aged man who presented with deliberate self-harming with acetamiprid poisoning in Sri Lanka.

CASE PRESENTATION

We describe a case of acute poisoning with an acetamiprid in a middle-aged Sri Lankan Tamil farmer for suicidal purposes following family conflicts with his wife. He presented with severe nausea, vomiting, and altered level of consciousness. He had electrocardiogram changes, hypoxia, and lactic acidosis. With intensive care management including ventilatory support, inotropic therapy along with intraarterial blood pressure monitoring, correction of acidosis, and administration of electrolytes, he made good clinical recovery. He was discharged without any further complications 6 days after ingestion of acetamiprid.

CONCLUSIONS

This case illustrates a rare, acute poisoning with acetamiprid in human, as well as its clinical manifestations and successful management with supportive therapy. This will be helpful for clinicians to identify clinical manifestations and to guide management of acute poisoning with acetamiprid in the future.

A multicenter randomized clinical trial of pharmacological vitamin B1 administration to critically ill patients who develop hypophosphatemia during enteral nutrition (The THIAMINE 4 HYPOPHOSPHATEMIA trial)

BACKGROUND

Hypophosphatemia may be a useful biomarker to identify thiamine deficiency in critically ill enterally-fed patients. The objective was to determine whether intravenous thiamine affects blood lactate, biochemical and clinical outcomes in this group.

METHOD

This randomized clinical trial was conducted across 5 Intensive Care Units. Ninety critically ill adult patients with a serum phosphate ≤0.65 mmol/L within 72 h of commencing enteral nutrition were randomized to intravenous thiamine (200 mg every 12 h for up to 14 doses) or usual care (control). The primary outcome was blood lactate over time and data are median [IQR] unless specified.

RESULTS

Baseline variables were well balanced (thiamine: lactate 1.2 [1.0, 1.6] mmol/L, phosphate 0.56 [0.44, 0.64] mmol/L vs. control: lactate 1.0 [0.8, 1.3], phosphate 0.54 [0.44, 0.61]). Patients randomized to the intervention received a median of 11 [7.5, 13.5] doses for a total of 2200 [1500, 2700] mg of thiamine. Blood lactate over the entire 7 days of treatment was similar between groups (mean difference = -0.1 (95 % CI -0.2 to 0.1) mmol/L; P = 0.55). The percentage change from lactate pre-randomization to T = 24 h was not statistically different (thiamine: -32 (-39, -26) vs. control: -24 (-31, -16) percent, P = 0.09). Clinical outcomes were not statistically different (days of vasopressor administration: thiamine 2 [1, 4] vs. control 2 [0, 5.5] days; P = 0.37, and deaths 9 (21 %) vs. 5 (11 %); P = 0.25).

CONCLUSIONS

In critically ill enterally-fed patients who developed hypophosphatemia, intravenous thiamine did not cause measurable differences in blood lactate or clinical outcomes.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ACTRN12619000121167).

The conundrum of Thiamine Responsive Acute Pulmonary Hypertension (TRAPH) syndrome in the Emergency Department

BACKGROUND

Management of acute pulmonary hypertension in the Emergency Department(ED) can be challenging. The treatment is specialised, requires rapid identification and correction of the precipitating cause; failing which the patient enters a vortex of deterioration. We describe a lesser-known cause for the same, Thiamine responsive acute pulmonary hypertension (TRAPH) syndrome where timely appropriate treatment can result in dramatic improvement.

METHODOLOGY

Medical records with ICD code E51.12 (Wet Beriberi) from Mar 2018 to Mar 2020 were screened. The data regarding presenting symptoms, initial vitals, lab and radiological investigations, and treatment received were retrieved from patient files and the Hospital Informatics System, entered into an MS Excel sheet and compared.

RESULTS

The study includes eight cases, which we believe to be TRAPH syndrome. Majority were young adult males, ethanol users. All patients presented with acute shortness of breath with tachypnea and shock index more than 0.9. Gross right atrioventricular dilatation, tricuspid regurgitation and mild to moderate pulmonary arterial hypertension was identified in echocardiography. The initial blood gas revealed median pH 6.98 (IQR 6.81-7.09), Bicarbonate 3.4 meq/L (IQR 2.5-5) and lactate 172 mg/dL (IQR 132-200) which improved within 12-16 h of admission. Patients received median 400 mg IV Thiamine. The mean duration of ICU stay was 2.5 days and total hospital stay was 7 days.

CONCLUSION

Thiamine Responsive Acute Pulmonary Hypertension (TRAPH) Syndrome is an under-recognised entity which should be included in differentials for acute right ventricular dysfunction in the ED. Early diagnosis and rapid protocolised management of the same can cause quick recovery of patients.

Assessment of safety and tolerability of remogliflozin etabonate (GSK189075) when administered with total daily dose of 2000 mg of metformin

Background

Patients with type 2 diabetes mellitus (T2DM) are characterized by an elevated glycemic index and are at a higher risk for complications such as cardiovascular disease, nephropathy, retinopathy and peripheral neuropathy. Normalization of glycemic index can be achieved by dosing combinations of metformin with other anti-diabetic drugs. The present study (Clintrials number NCT00519480) was conducted to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of remogliflozinetabonate, an SGLT2 inhibitor, withdoses (500 mg and 750 mg BID) greater than the commercial dose (100 mg BID)in combination with metformin with minimum daily dose of 2000 mg given in two divided doses.

Methods

This was a randomized, double-blinded, repeat dose study in 50 subjects with T2DM. The study was conducted in three phases; run-in, randomization, and treatment. All subjects were on a stable metformin dosing regimen. Cohort 1 subjects were randomly allocated to receive either remogliflozin etabonate 500 mg BID or placebo BID (2:1) in addition to metformin. Cohort 2 subjects were administered with either remogliflozin etabonate 750 mg BID or placebo BID (2:1) in addition to metformin for 13 days. All the subjects were assessed for safety (adverse events, lactic acid levels, vital signs, electrocardiogram [ECG]), pharmacokinetic evaluation, and pharmacodynamics (Oral Glucose Tolerance Testing) parameters.

Results

Co-administration of remogliflozin etabonate and metformin was well tolerated in all subjects during the observation period. There were no severe or serious adverse events (SAEs) and no increase in lactic acid concentration was reported during the study. The statistical results showed that concomitant administration of remogliflozin etabonate, either 500 mg or 750 mg BID, with metformin had no effect on the pharmacokinetics of metformin. The accumulation ratios, Day 13 vs. Day 1, for AUC values of remogliflozin etabonate and its metabolites were all very close to 1, indicating no accumulation in plasma concentrations of remogliflozin etabonate and its metabolites. Mean glucose values from baseline and glucose and insulin values following oral glucose tolerance test (OGTT) were decreased in all treatment groups.

Conclusion

Co-administration of doses of remogliflozin etabonate (500 mg BID or 750 mg BID) greater than the commercial dose (100 mg BID) with metformin (2000 mg BID) was shown to be safe and effective during the observation period.

Trial registration

ClinicalTrials.gov, NCT00519480. Registered:22 August 2007.