Persistent lactic acidosis in the Mauriac syndrome in type 1 diabetes mellitus

Mauriac syndrome is an uncommon clinical condition arising in the setting of poorly controlled type 1 diabetes mellitus. Clinical features include hepatomegaly and liver abnormalities indistinguishable from nonalcoholic fatty liver disease. Early diagnosis and management are essential, as Mauriac syndrome is reversible.

Effect of a serum lactate monitoring recommendation policy on patients treated with linezolid

Lactic acidosis is one of the most fatal adverse effects of linezolid, an antibiotic used to treat serious infections caused by antibiotic-resistant bacteria. However, the measures to prevent lactic acidosis have not been well established.We performed a retrospective study to analyze the impact of applying a serum lactate monitoring recommendation policy in patients treated with linezolid.Since September 2011, we have recommended inpatient monitoring of serum lactate levels in patients treated with linezolid at our hospital. Patients were divided into two groups according to whether they were seen during the non-recommendation or recommendation periods. The frequency of serum lactate monitoring, linezolid-induced lactatemia, lactic acidosis, critical illness, and death were compared between the two periods.After September 2011, adherence to the recommendation to monitor serum lactate increased from 6.1% to 60.1%. No difference was observed in the incidence of linezolid-induced lactatemia and lactic acidosis between the two periods. However, there was a significant difference in the incidence of linezolid-induced critical illness between the non-recommendation and recommendation periods (3 vs 0 cases, P = .044).In patients treated with linezolid, serum lactate monitoring led to early detection of lactatemia, thus enabling rapid rescue. We recommend regular monitoring of serum lactate in all patients treated with linezolid.

Lactic Acidosis in Diabetic Ketoacidosis: A Marker of Severity or Alternate Substrate for Metabolism

PURPOSE

The lactate level is being increasingly used as a marker of severity of illness and prognosis in multitude of critical conditions. However, its role in diabetic ketoacidosis (DKA) is not well defined.

AIM

To determine the prevalence and clinical importance along with the underlying role of metformin in lactic acidosis (LA) in patients admitted with DKA.

METHODS

A 2-year prospective and observational study involving 62 consenting in hospital DKA patients. Plasma lactate level on arrival, its clinical significance and relationship with morbidity and mortality in patients with DKA was evaluated.

RESULTS

The prevalence of LA (lactate ≥2.5 mmol/l) among the study cohort was found to be 55% with significant LA (≥5 mmol/l) documented in 16%. The median lactate level was 2.55 mmol/l (interquartile range, 1.70-3.20). No significant difference in the severity of LA was seen with metformin use. Lactate correlated positively with initial plasma glucose (IPG) (P = 0.001) and APACHE-II Score (P = 0.002); correlated negatively with systolic blood pressure (P = 0.003), pH (P = 0.002) and severity of DKA (P = 0.001). After controlling for AKI, APACHE II score and blood pressure, lactate continued to correlate positively with IPG (P = 0.002). No mortality or significant morbidity was documented in the entire cohort.

CONCLUSIONS

LA has a significant presence in patients with DKA; however, it is not associated with mortality or significant morbidity. Moreover, there was no significant difference in severity of LA with metformin use. Elevated lactate levels may be an adaptation to provide alternate substrate for metabolism in the presence of hypoinsulinemic state. The study results provide rationale for large well-designed studies evaluating in-depth clinical relationship of lactate in DKA.

Confirmed Hypoglycemia Without Whipple Triad: A Rare Case of Hyper-Warburgism

Spontaneous hypoglycemia in nondiabetic patients poses a diagnostic challenge. Hypoglycemia in malignancy has several etiologies; an extremely rare mechanism is the Warburg effect causing excess lactate production and avid glucose consumption. We describe the clinical course of a 52-year-old man admitted for chest wall mass and severe but asymptomatic hypoglycemia. Laboratory workup was obtained for insulin vs noninsulin-mediated hypoglycemia, and biopsy of the chest wall mass and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) scan were performed. D10 infusion and intravenous/oral steroids started for severe hypoglycemia. Chemotherapy was initiated after biopsy, and blood glucose (BG) and lactate levels followed with clinical response in tumor size and changes in PET/CT. Investigations were significant for venous BG in the 40s (Ademolus Classification of Hypoglycemia grade 2 hypoglycemia), plasma insulin of less than 2 µU/mL (2-20 µU/mL), C-peptide of 0.2 ng/mL (0.8-6.0 ng/mL), insulin-like growth factor 2 (IGF-2) of 113 ng/mL (333-967 ng/mL), serum lactate of 16 mmol/L (0.5-2 mmol/L), and albumin of 2.3 g/dL (3.4-5.4 g/dL). Biopsy showed diffuse large B-cell lymphoma, and PET revealed highly FDG-avid disease in the chest, abdomen, and pelvis, but no FDG uptake was seen in the brain. Hypoglycemia and lactic acidosis improved remarkably after chemotherapy. PET/CT at 4 weeks showed complete metabolic response with reappearance of physiological FDG uptake in the brain. Noninsulin-mediated hypoglycemia was likely due to the combination of profound malnutrition and rapid glucose use by cancer cells. The patient presented with exaggerated Warburg effect (hyper-Warburgism), evident by extreme glucose consumption, severe lactic acidosis, and large tumor burden on PET/CT. Absence of cognitive symptoms was probably due to use of lactate by the brain. Chemotherapy corrected these abnormalities rapidly, and must be instituted in a timely manner.

Lactic acidosis incidence with metformin in patients with type 2 diabetes and chronic kidney disease: A retrospective nested case-control study

Objective

Compare rates of lactic acidosis (LA) among metformin-exposed and unexposed patients with type 2 diabetes mellitus and varying degrees of chronic kidney disease (CKD).

Research Design and Methods

Retrospective, nested case-control study using data from national VA Corporate Data Warehouse. All adult patients with type 2 diabetes and CKD newly dispensed any antihyperglycaemic medication during FY 2003-13 were included. The outcome was LA hospitalization or serum lactate >5 mEq/L. Exposure to metformin was evaluated in the three months prior to event. Estimates were adjusted for 31 covariates, including demographics, comorbidities and medications.

Results

Overall, 320 882 patients were included, contributing a total of 1 331 784 person-years of follow-up. LA occurred in 2 665 patients, generating an overall incidence rate of 2.00 (95% CI 1.93-2.08) per 1000 person-years. Metformin exposure in the prior 3 months was associated with an elevated adjusted hazard of LA (HR 1.97, 95% CI 1.69-2.29). No association was evident in patients with CKD stage 1 or 2 (HR 1.05, 95% CI 0.71-1.57), but associations were present and progressively greater in patients with CKD stage 3a through 5: HR 3.09, 95% CI 2.19-4.35 in CKD 3a, HR 3.34, 95% CI 1.95-5.72 in CKD 3b, HR 7.87, 95% CI 3.51-17.61 in CKD stage 4&5.

Conclusion

Metformin was not associated with an elevated risk of LA in persons with stage 1-2 CKD, but was associated with a progressively higher risk at more advanced stages of CKD.

Two cases of carbonic anhydrase VA deficiency-An ultrarare metabolic decompensation syndrome presenting with hyperammonemia, lactic acidosis, ketonuria, and good clinical outcome

The combination of neonatal hyperammonemia, lactic acidosis, ketonuria, and hypoglycemia is pathognomonic for carbonic anhydrase VA (CA-VA) deficiency. We present two cases of this rare inborn error of metabolism. Both newborns with South Asian ancestry presented with a metabolic decompensation characterized by hyperammonemia, lactic acidosis and ketonuria; one also had hypoglycemia. Standard metabolic investigations (plasma amino acids, acylcarnitine profile, and urine organic acids) were not indicative of a specific organic aciduria or fatty acid oxidation defect but had some overlapping features with a urea cycle disorder (elevated glutamine, orotic acid, and low arginine). Hyperammonemia was treated initially with nitrogen scavenger therapy and carglumic acid. One patient required hemodialysis. Both have had a favorable long-term prognosis after their initial metabolic decompensation. Genetic testing confirmed the diagnosis of carbonic anhydrase VA (CA-VA) deficiency due to biallelic pathogenic variants in CA5A. These cases are in line with 15 cases previously described in the literature, making the phenotypic presentation pathognomonic for this ultrarare (potentially underdiagnosed) inborn error of metabolism with a good prognosis.

Effect of time until sample analysis on lactate in dogs with shock

INTRODUCTION

Lactate concentrations can increase with hypoperfusion in dogs and could be used as a prognostic indicator in sick dogs. In a busy emergency service, sample evaluation could be delayed. However, sample evaluation delays have been shown to cause lactate concentration increases in healthy dogs. In sick dogs, the magnitude of increased lactate is unknown. The goal of this study was to prospectively evaluate the effect of room temperature storage times on lactate measurements in dogs presenting to an emergency service.

METHODS

We evaluated the precision and accuracy of the NOVA Lactate Plus, using standard procedures. To assess the impact of time on lactate concentrations in sick dogs, we prospectively enrolled dogs presenting to an emergency service. Lactate concentrations were measured at six time points using samples stored at room temperature. A Friedman test, followed by a Wilcoxon rank test with a Bonferroni correction was used to evaluate time points.

RESULTS

Forty-five dogs were enrolled in this prospective observational study. The Lactate Plus and table-top analyzer compared favorably, with an R² of .98, and a mean bias of 0.26 in 50 canine samples. Precision was acceptable, with a percent coefficient of variation of 5.39. Statistically significant increases in lactate concentrations were found at all time points over baseline (P = .008).

CONCLUSIONS

In as little as 7.5 minutes, lactate concentrations increased significantly in samples stored at room temperature. Dogs with lower initial lactate concentrations had had higher increases in lactate concentration percentages over 90 minutes.

Lactic Acidosis Interferes With Toxicity of Perifosine to Colorectal Cancer Spheroids: Multimodal Imaging Analysis

Colorectal cancer (CRC) is a disease with constantly increasing incidence and high mortality. The treatment efficacy could be curtailed by drug resistance resulting from poor drug penetration into tumor tissue and the tumor-specific microenvironment, such as hypoxia and acidosis. Furthermore, CRC tumors can be exposed to different pH depending on the position in the intestinal tract. CRC tumors often share upregulation of the Akt signaling pathway. In this study, we investigated the role of external pH in control of cytotoxicity of perifosine, the Akt signaling pathway inhibitor, to CRC cells using 2D and 3D tumor models. In 3D settings, we employed an innovative strategy for simultaneous detection of spatial drug distribution and biological markers of proliferation/apoptosis using a combination of mass spectrometry imaging and immunohistochemistry. In 3D conditions, low and heterogeneous penetration of perifosine into the inner parts of the spheroids was observed. The depth of penetration depended on the treatment duration but not on the external pH. However, pH alteration in the tumor microenvironment affected the distribution of proliferation- and apoptosis-specific markers in the perifosine-treated spheroid. Accurate co-registration of perifosine distribution and biological response in the same spheroid section revealed dynamic changes in apoptotic and proliferative markers occurring not only in the perifosine-exposed cells, but also in the perifosine-free regions. Cytotoxicity of perifosine to both 2D and 3D cultures decreased in an acidic environment below pH 6.7. External pH affects cytotoxicity of the other Akt inhibitor, MK-2206, in a similar way. Our innovative approach for accurate determination of drug efficiency in 3D tumor tissue revealed that cytotoxicity of Akt inhibitors to CRC cells is strongly dependent on pH of the tumor microenvironment. Therefore, the effect of pH should be considered during the design and pre-clinical/clinical testing of the Akt-targeted cancer therapy.

Regional Citrate Anticoagulation Protocol for Patients with Presumed Absent Citrate Metabolism

Background

Regional citrate anticoagulation (RCA) is not recommended in patients with shock or severe liver failure. We designed a protocol with personalized precalculated flow settings for patients with absent citrate metabolism that abrogates risk of citrate toxicity, and maintains neutral continuous KRT (CKRT) circuit calcium mass balance and normal systemic ionized calcium levels.

Methods

A single-center prospective cohort study of patients in five adult intensive care units triaged to the CVVHDF-RCA "Shock" protocol.

Results

Of 31 patients included in the study, 30 (97%) had AKI, 16 (52%) had acute liver failure, and five (16%) had cirrhosis at the start of CKRT. The median lactate was 5 mmol/L (interquartile range [IQR], 3.2-10.7), AST 822 U/L (IQR, 122-2950), ALT 352 U/L (IQR, 41-2238), total bilirubin 2.7 mg/dl (IQR, 1.0-5.1), and INR two (IQR, 1.5-2.6). The median first hemofilter life censored for causes other than clotting exceeded 70 hours. The cumulative incidence of hypernatremia (Na >148 mM), metabolic alkalosis (HCO3- >30 mM), and hypophosphatemia (P<2 mg/dl) were one out of 26 (4%), zero out of 30 (0%), and one out of 30 (3%), respectively, and were not clinically significant. Mild hypocalcemia occurred in the first 4 hours in two out of 31 patients, and corrected by hour 6 with no additional Ca supplementation beyond the per-protocol administered Ca infusion. The maximum systemic total Ca (tCa; mM)/ionized Ca (iCa; mM) ratio never exceeded 2.5.

Conclusions

The Shock protocol can be used without contraindications and is effective in maintaining circuit patency with a high, fixed ACDA infusion rate to blood flow ratio. Keeping single-pass citrate extraction on the dialyzer >0.75 minimizes the risk of citrate toxicity even in patients with absent citrate metabolism. Precalculated, personalized dosing of the initial Ca-infusion rate from a table on the basis of the patient's albumin level and the filter effluent flow rate maintains neutral CKRT circuit calcium mass balance and a normal systemic iCa level.

Effects of Continuous Albuterol Inhalation on Serum Metabolome in Healthy Subjects: More Than Just Lactic Acid

Treatment with β2-agonists may cause elevated lactic acid, the end product of anaerobic metabolism of glucose. It has been proposed that lactic acidosis associated with β2-agonists is caused by changes to direct biochemical impacts on glycolysis, gluconeogenesis, pyruvate metabolism, and free fatty acid production. However, much remains unknown, and there is a paucity of evidence regarding the underlying chemical changes associated with this lactic acidosis. The goal of our study was to investigate the impact of 1 hour of continuous albuterol on the untargeted serum metabolome of healthy subjects. Twenty-four healthy participants received 7.5 mg of continuous albuterol for 1 hour. Baseline, 1-hour, and 2-hour lactic acid levels were drawn. Samples obtained at baseline and 1 hour were sent for untargeted metabolomic profiling. Participants had a baseline lactic acid of 1.45 ± 0.46 mmol/L. On average, lactate levels increased 0.33 ± 0.67 mmol/L after 1 hour (P = .02) and remained elevated at 2 hours (0.32 ± 0.72 mmol/L, P = .02), although there was overlap in lactate levels across times. For metabolomic analysis, fatty acids, organic acids, and sugars were elevated, and amino acids were reduced. Lactic acid and pyruvic acid metabolites, however, did not significantly change (after false discovery rate adjustment). In healthy participants, continuous albuterol alters the serum metabolome, but this change may not be clinically significant. The data support recent hypotheses that β2-receptor activation stimulates lactic acid production, altering aerobic glycolysis, gluconeogenesis, and free fatty acid production.

Linezolid Induced Lactic Acidosis: The Side Effect, Clinician Should Be Aware of

Linezolid is a synthetic antibiotic that functions through the inhibition of bacterial protein synthesis by binding to ribosomal ribonucleic acid (rRNA). Deliverable in both intravenous and oral form, with a low level of resistance amongst Methicillin-resistant Staphylococcus aureus (MRSA) strains, it is recommended for a wide range of gram-positive infections. We present a case of a male patient who underwent endovascular abdominal aortic aneurysm repair complicated by abdominal sepsis due to bowel ischemia; several days after linezolid therapy was initiated, he presented with signs of lactic acidosis. After excluding other sources such as metabolic, hypoxia, or organ damage, the resulting lactic acidosis was determined to be a side effect of linezolid.

The Δ Anion Gap/Δ Bicarbonate Ratio in Early Lactic Acidosis: Time for Another Delta?

Background

The ratio of Δ anion gap and Δ bicarbonate (ΔAG/ΔHCO₃) is used to detect coexisting acid-base disorders in patients with high anion gap metabolic acidosis. Classic teaching holds that, in lactic acidosis, the ΔAG/ΔHCO₃ is 1:1 within the first few hours of onset and subsequently rises to 1.8:1. However, this classic 1:1 stoichiometry in early lactic acidosis was derived primarily from animal models and only limited human data. The objective of this study was to examine the ΔAG/ΔHCO₃ within the first hours of the development of lactic acidosis.

Methods

Data were obtained prospectively from a convenience sample of adult (age >18 years) trauma-designated patients at a single level-1 trauma center. Venous samples, including a chemistry panel and serum lactate, were drawn before initiation of intravenous fluid resuscitation.

Results

A total of 108 patients were included. Of these, 63 patients had normal serum lactate levels (≤2.1 mmol/L) with a mean AG of 7.1 mEq/L, the value used to calculate subsequent ΔAG values. ΔAG/ΔHCO₃ was calculated for 45 patients who had elevated serum lactate levels (>2.1 mmol/L). The mean ΔAG/ΔHCO₃ for all patients with elevated serum lactate levels was 1.86 (SD, 1.40).

Conclusions

The mean ΔAG/ΔHCO₃ was 1.86 within the first hours of the development of lactic acidosis due to hypovolemic shock, confirming a small prior human study. This contradicts the traditional belief that, in lactic acidosis, the ΔAG/ΔHCO₃ is 1:1 within the first several hours. The classic 1:1 stoichiometry was determined on the basis of animal models in which lactic acid is infused into the extracellular space, facilitating extracellular buffering of protons by bicarbonate. In contrast, our results demonstrate a higher initial ΔAG/ΔHCO₃ ratio in early endogenous lactic acidosis in humans. Our analysis indicates this is likely due to unmeasured anions contributing to an elevation in AG.

A MELAS Patient Developing Fatal Acute Renal Failure with Lactic Acidosis and Rhabdomyolysis

We herein present a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), who developed serious acute renal failure with lactic acidosis, followed by rhabdomyolysis. Despite receiving intensive care, he suffered multiple cardiopulmonary arrests and died 10 days after presentation due to a sudden deterioration of his symptoms. Renal pathology revealed diffuse tubular necrosis with interstitial edema and tubular dilatation on light microscopy, and a severe degeneration of intracellular organelles on electron microscopy. These pathological findings could have resulted from multiple cardiopulmonary arrests; however, we must be aware of the extremely rare but sudden occurrence of these fatal conditions in MELAS patients.

Utility of specific amino acid ratios in screening for pyruvate dehydrogenase complex deficiencies and other mitochondrial disorders associated with congenital lactic acidosis and newborn screening prospects

Pyruvate dehydrogenase complex deficiencies (PDCDs) and other mitochondrial disorders (MtDs) can (a) result in congenital lactic acidosis with elevations of blood alanine (Ala) and proline (Pro), (b) lead to decreased ATP production, and (c) result in high morbidity and mortality. With ~140,000 live births annually in Ohio and ~1 in 9,000 overall prevalence of MtDs, we estimate 2 to 3 newborns will have PDCD and 13 to 14 others likely will have another MtD annually. We compared the sensitivities of plasma amino acids (AA) Alanine (Ala), Alanine:Leucine (Ala:Leu), Alanine:Lysine and the combination of Ala:Leu and Proline:Leucine (Pro:Leu), in subjects with known primary-specific PDCD due to PDHA1 and PDHB mutations vs controls. Furthermore, in collaboration with the Ohio newborn screening (NBS) laboratory, we determined Ala and Pro concentrations in dried blood spot (DBS) specimens using existing NBS analytic approaches and evaluated Ala:Leu and Pro:Leu ratios from DBS specimens of 123,414 Ohio newborns in a 12-month period. We used the combined Ala:Leu ≥4.0 and Pro:Leu ≥3.0 ratio criterion from both DBS and plasma specimens as a screening tool in our retrospective review of newborn data. The screening tool applied on DBS and/or plasma (or serum) AA specimens successfully identified three unrelated females with novel de novo PDHA1 mutations, one male with a novel de novo X-linked HSD17B10 mutation, and a female with VARS2 mutations. This work lays the first step for piloting an NBS protocol in Ohio for identifying newborns at high risk for primary-specific PDCD and other MtDs who might benefit from neonatal diagnosis and early institution of known therapy and/or potential novel therapies for such disorders.

Mortality and renal prognosis in isolated metformin-associated lactic acidosis treated with continuous renal replacement therapy and citrate-calcium-anticoagulation

INTRODUCTION

Use of metformin increases plasma lactate concentration and may lead to metformin-associated lactic acidosis (MALA). Previous studies have suggested severe MALA to have a mortality of 17%-21%, but have included patients with other coincident conditions such as sepsis. The treatment of choice is continuous renal replacement therapy (CRRT), which has been performed using heparin analogues or no anticoagulation in former studies.

MATERIALS AND METHODS

Patients admitted to the Intensive Care Unit of Turku University Hospital Finland with lactic acidosis without any other recognizable etiology than concomitant metformin treatment who required CRRT between years 2010 and 2019 were included. CRRT was performed using regional citrate-calcium-anticoagulation. Data extracted included patient demographics, comorbidities, and clinical parameters at 6-hour intervals about 72 hours from admission. Creatinine and estimated glomerular filtration rate (eGFR) were measured at 1 year after MALA.

RESULTS

A total of 23 patients with isolated MALA were included in the study. Median (IQR) pH was 6.88 (6.81-7.07) and lactate 16.1 (11.9-23.0) mmol/L on admission. Median (IQR) duration of CRRT was 62 (41-70) hours. Seven patients (30%) required mechanical ventilation with a mean duration of 6.0 ± 3.0 days. 90-day mortality was 4.3% and 1-year mortality 13.0%. Creatinine (P = .02) and eGFR (P = .03) remained significantly altered at 1 year of follow-up compared to baseline.

CONCLUSIONS

MALA can be treated effectively and safely with CRRT and citrate-calcium-anticoagulation, usually required for 2-3 days. Mortality of patients with MALA treated with CRRT is low when other conditions inducing lactic acidosis are excluded. MALA episode may be associated with long-lasting kidney injury.

Clinicopathological abnormalities associated with increased animal triage trauma score in cats presenting for vehicular trauma: 75 cases (1998-2009)

OBJECTIVE

To document the clinical and clinicopathological changes in cats presenting with vehicular trauma (VT) and to determine whether the calculated animal trauma triage (ATT) score was associated with any clinicopathological abnormalities.

DESIGN

Retrospective descriptive study conducted between 1998 and 2009.

SETTING

University veterinary teaching hospital.

ANIMALS

Seventy-five client-owned cats that presented for VT to an urban veterinary hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pertinent history, physical examination findings, results of biochemical testing, and outcome were extracted from medical records. ATT score was calculated based on physical examination. Patients were classified as having either a low (<5) ATT (n = 30) or a high (≥5) ATT (n = 45) score. Male cats were overrepresented (60.0%), and a majority of cats had outdoor access (65.3%). Low PCV (P = 0.024), low total plasma protein concentration (P = 0.032), low venous blood pH (P = 0.047), high plasma lactate concentration (P = 0.047), low plasma bicarbonate concentration (P = 0.047), low base excess (P = 0.047), and high plasma glucose concentration (P = 0.047) were associated with higher ATT scores. In addition, low noninvasive blood pressure measurements (P = 0.008) were associated with higher ATT scores.

CONCLUSIONS

There was a significant association between lower PCV, lower total plasma protein concentration, lower venous blood pH, higher plasma lactate concentration, lower plasma bicarbonate concentration, lower base excess, higher whole blood glucose concentration, and lower noninvasive blood pressure and higher ATT scores at presentation in feline patients suffering from VT. Prospective evaluation of these values may prove useful in furthering understanding of the pathophysiology of trauma in cats.

Acute Liver Failure With Severe Lactic Acidosis Secondary to Infiltrative Diffuse Large B-Cell Lymphoma: An Imaging-Negative Presentation

Liver involvement by non-Hodgkin’s lymphoma is common in late stage disease but rarely results in severe hepatic dysfunction. Here, we discuss a case of acute liver failure (ALF) with severe lactic acidosis in a 75-year-old female with diffuse large B-cell lymphoma (DLBCL). The patient was admitted with nausea, fevers, and mild acidosis. Although radiographic imaging did not demonstrate any liver abnormality, the patient soon developed signs of ALF along with severe lactic acidosis. Despite initiation of chemotherapy, the patient deteriorated quickly and was ultimately put on comfort measures. This case highlights an uncommon manifestation of DLBCL and suggests that an accelerated timeline for beginning chemotherapy may be warranted in patients with high clinical suspicion of secondary hepatic lymphoma.

Disturbance of consciousness due to hyperammonemia and lactic acidosis during mFOLFOX6 regimen: Case report

INTRODUCTION

FOLFOX therapy is the main chemotherapy regimen for colorectal cancer. Peripheral neuropathy, hematotoxicity, and digestive symptoms are known to be the most frequent adverse events. Hyperammonemia and lactic acidosis rarely occur simultaneously during treatment with FOLFOX therapy; the number of case reports is limited worldwide. We report a case of disturbance of consciousness, considered to be caused by hyperammonemia and lactic acidosis that occurred during treatment with mFOLFOX6 therapy that was administered as postoperative adjuvant treatment for rectal cancer.

PATIENT CONCERNS

This case was of a 71-year-old man who had been receiving oral treatment for chronic kidney disease and diabetes mellitus. Laparoscopic low anterior resection and artificial anal construction surgery were performed for stage III rectal cancer. As adjuvant postoperative therapy, mFOLFOX6 therapy was started but was followed by a disturbance of consciousness.

DIAGNOSES

Results of the blood tests revealed notable hyperammonemia (ammonia level, 1,163 μg/dl) and lactic acidosis (pH 7.207; lactate, 17.56 mmol/L); however, imaging diagnosis did not reveal intracranial lesions that could cause disturbance of consciousness.

INTERVENTIONS

For hyperammonemia, branched-chain amino acid agents and Ringers solution supplementation were administered. For acidosis, 7% sodium hydrogen carbonate was administered as treatment.

OUTCOMES

The disturbance of consciousness improved within 12 hours of initiating the treatment, and the patient was discharged with no sequelae on 7th day after hospitalization.

CONCLUSION

In patients with chronic kidney disease, FOLFOX regimen may confer risks of hyperammonemia and lactic acidosis.

Linezolid and the risk of lactic acidosis: Data mining and analysis of the FDA Adverse Event Reporting System

WHAT IS KNOWN AND OBJECTIVE

Lactic acidosis (LA) is a rare but potentially lethal side effect of linezolid (LZD). However, limited by the study population, the number of patients with LA is insufficient to summarize all the clinical characteristics and risk factors.

METHODS

We evaluated the association between LZD and LA using the reporting odd ratio (ROR) for mining the adverse event report signals in the FDA Adverse Event Reporting System database from January 2013 to December 2019.

RESULTS AND DISCUSSION

There were 6218 reports of LZD as the primary suspected drug or secondary suspected drug, of which 275 (4.42%) reports were of LA. The ROR of LA with the use of LZD was 39.976 (95% CI 35.365-45.189). In the age composition of patients, elderly individuals (aged ≥60 years) accounted for the higher proportion, 42.54% (n = 117). LA usually occurred two weeks after LZD administration (n = 33). LZD was the unique suspected drug, accounting for 37.45% (n = 103) of all reports of LA. The drug with the most frequent occurrence of combination with LZD was 'meropenem' and 'warfarin'.

WHAT IS NEW AND CONCLUSIONS

The ROR of LA caused by LZD was very high, and the number of reports about LA caused by other antibiotics was significantly different from that of LA caused by LZD. The drug combined with LZD did not seem to affect the occurrence of LA, and the high occurrence of warfarin in the reports deserves the attention of doctors.

Increasing metformin concentrations and its excretion in both rat and porcine ex vivo normothermic kidney perfusion model

INTRODUCTION

Metformin can accumulate and cause lactic acidosis in patients with renal insufficiency. Metformin is known to inhibit mitochondria, while renal secretion of the drug by proximal tubules indirectly requires energy. We investigated whether addition of metformin before or during ex vivo isolated normothermic machine perfusion (NMP) of porcine and rat kidneys affects its elimination.

RESEARCH DESIGN AND METHODS

First, Lewis rats were pretreated with metformin or saline the day before nephrectomy. Subsequently, NMP of the kidney was performed for 90 min. Metformin was added to the perfusion fluid in one of three different concentrations (none, 30 mg/L or 300 mg/L). Second, metformin was added in increasing doses to the perfusion fluid during 4 hours of NMP of porcine kidneys. Metformin concentration was determined in the perfusion fluid and urine by liquid chromatography-tandem mass spectrometry.

RESULTS

Metformin clearance was approximately 4-5 times higher than creatinine clearance in both models, underscoring secretion of the drug. Metformin clearance at the end of NMP in rat kidneys perfused with 30 mg/L was lower than in metformin pretreated rats without the addition of metformin during perfusion (both p≤0.05), but kidneys perfused with 300 mg/L trended toward lower metformin clearance (p=0.06). Creatinine clearance was not different between treatment groups. During NMP of porcine kidneys, metformin clearance peaked at 90 min of NMP (18.2±13.7 mL/min/100 g). Thereafter, metformin clearance declined, while creatinine clearance remained stable. This observation can be explained by saturation of metformin transporters with a Michaelis-Menten constant (95% CI) of 23.0 (10.0 to 52.3) mg/L.

CONCLUSIONS

Metformin was secreted during NMP of both rat and porcine kidneys. Excretion of metformin decreased under increasing concentrations of metformin, which might be explained by saturation of metformin transporters rather than a self-inhibitory effect. It remains unknown whether a self-inhibitory effect contributes to metformin accumulation in humans with longer exposure times.

Effects of carbohydrate quality and amount on plasma lactate: results from the OmniCarb trial

INTRODUCTION

Plasma lactate is a marker of non-oxidative glucose metabolism associated with progression to diabetes. We examined the effect of carbohydrate quality (glycemic index (GI)) and amount (%kcal) on plasma lactate. We hypothesized that low GI (≤45 (g)) versus high (≥65 (G)) and low %kcal from carbohydrate (40% kcal (c)) versus high (58% kcal (C)) each would reduce lactate levels.

RESEARCH DESIGN AND METHODS

We measured lactate in OmniCarb, a randomized, cross-over trial of four diets in overweight/obese adults without diabetes or cardiovascular disease (N=163). The four diets were high carbohydrate+high GI (CG, reference), high carbohydrate+low GI (Cg), low carbohydrate+high GI (cG), and low carbohydrate+low GI (cg). Participants (N=163) consumed each of the four diets over a 5-week period, separated by 2-week washout periods. Plasma lactate levels were measured at baseline, during which the participants consumed their own diets, and after each 5-week period.

RESULTS

Baseline plasma lactate was 1.2 mmol/L. In the setting of high carbohydrate amount, reducing GI lowered plasma lactate non-significantly by 0.08 mmol/L (Cg vs CG: 95% CI -0.16 to 0.00; p=0.06). In the setting of high GI, reducing carbohydrate amount lowered plasma lactate by 0.10 mmol/L (cG vs CG: 95% CI -0.19 to -0.02; p=0.02). The combined effect of reducing GI and carbohydrate proportion in the diet (cg vs CG) was similar (cg vs CG: -0.08; 95% CI -0.16 to 0.00; p=0.04). All four diets reduced plasma lactate compared with baseline.

CONCLUSIONS

Compared with a diet with high GI and high carbohydrate amount, diets with low GI and/or low carbohydrate amount reduced plasma lactate. Whether this change in lactate leads to long-term change in glucose metabolism needs to be examined.

TRIAL REGISTRATION NUMBER

NCT00608049.

A Rare Case of Metformin Intoxication with Mortal Course

Metformin-associated lactic acidosis is a rare side effect in metformin poisoning. There is conflicting data about mortality rates changing from 3% to 83%. We aimed to discuss a case that developed lactic acidosis and acute renal failure progressing to mortality due to metformin intoxication. A 33 year-old female patient was admitted to the emergency department, with nausea and vomiting after taking 30 tablets of 1000 mg metformin. In the 2nd hour of follow-up, patient was observed to develop lactic acidosis which did not recover despite the infusion replacement treatments and hemodialysis. Following the development of respiratory failure, under mechanical ventilation, the patient developed cardiac arrest at the 48th hour of her admission. In metformin intoxications, it should be remembered that acidosis deepens very quickly and can progress with mortality despite optimal supportive therapy. More specific recommendations and further studies are required for the management and treatment of acute metformin-associated lactic acidosis.

The expanding LARS2 phenotypic spectrum: HLASA, Perrault syndrome with leukodystrophy, and mitochondrial myopathy

LARS2 variants are associated with Perrault syndrome, characterized by premature ovarian failure and hearing loss, and with an infantile lethal multisystem disorder: Hydrops, lactic acidosis, sideroblastic anemia (HLASA) in one individual. Recently we reported LARS2 deafness with (ovario) leukodystrophy. Here we describe five patients with a range of phenotypes, in whom we identified biallelic LARS2 variants: three patients with a HLASA-like phenotype, an individual with Perrault syndrome whose affected siblings also had leukodystrophy, and an individual with a reversible mitochondrial myopathy, lactic acidosis, and developmental delay. Three HLASA cases from two unrelated families were identified. All were males with genital anomalies. Two survived multisystem disease in the neonatal period; both have developmental delay and hearing loss. A 55-year old male with deafness has not displayed neurological symptoms while his female siblings with Perrault syndrome developed leukodystrophy and died in their 30s. Analysis of muscle from a child with a reversible myopathy showed reduced LARS2 and mitochondrial complex I levels, and an unusual form of degeneration. Analysis of recombinant LARS2 variant proteins showed they had reduced aminoacylation efficiency, with HLASA-associated variants having the most severe effect. A broad phenotypic spectrum should be considered in association with LARS2 variants.

Lactic Acidosis Secondary to Thiamin Deficiency Following Autologous Stem Cell Transplantation

A 22-month-old female with high-risk neuroblastoma completed 5 cycles of chemotherapy then underwent high-dose chemotherapy with autologous stem cell rescue (ASCR). Parenteral nutrition was administered from day +2 following ASCR, as she was unable to tolerate nasogastric feeds because of grade IV mucositis and vomiting. On day +12, she developed worsening metabolic acidosis with above reportable levels of lactic acid. Given the patient's well clinical appearance and paucity of evidence of end-organ dysfunction on physical examination and on laboratory studies, there was high suspicion that the patient's lactic acidosis did not result from tissue hypoxia and was, in fact, a type B lactic acidosis. Thiamin was empirically administered, with rapid improvement in lactic acidosis. Thiamin deficiency was later confirmed by laboratory studies drawn prior to thiamin administration.