Diuretics and Disorders of Calcium Homeostasis

Hypocalcemia in the Immediate Postoperative Period Following Metabolic Bariatric Surgery - Hype or Harm?

PURPOSE

Hypocalcemia post-metabolic bariatric surgery (MBS) is a known long-term complication after hypoabsorptive procedures. However, data on immediate postoperative calcium are limited. Our aim was to evaluate the prevalence of hypocalcemia on the 1st postoperative day after MBS and correlate it with potential associated factors.

MATERIALS AND METHODS

We analyzed data from all consecutive index MBS over 1 year. We collected data on demographics and on preoperative and postoperative values of serum calcium (TC), albumin, adjusted calcium (AC-Payne formula), magnesium, phosphorus, preoperative vitamin-D, and postoperative 24-h urine output, intravenous fluids (IVF), bolus intravenous furosemide, and creatine phosphokinase (CPK). Continuous data are expressed as means ± SD (range). Categorical data are presented as frequencies (%). Linear regression was implemented to designate potential correlations.

RESULTS

The cohort included 86 patients (58.1% females). The mean preoperative TC was 9.4mg/dL ± 0.4 (8.5-10.5) and mean postoperative TC 7.8mg/dL ± 0.6 (6.3-9.3, 17.0% decrease). The mean preoperative AC was 10.1mg/dL ± 0.4 (9.2-11.2) and mean postoperative AC 8.5mg/dL ± 0.6 (7.0-10.0, 15.8% decrease). Seventy-three patients (84.8%) had abnormally low TC (< 8.5mg/dL), and 43 (50%) abnormally low AC. There was only weak correlation between postoperative TC and AC with magnesium (r = 0.258), phosphorus (r = 0.269), vitamin-D (-0.163), 24-h urine output (r = -0.168), IVF (r = -0.237), bolus furosemide (r = 0.155), and mean operative time (r = 0.010).

CONCLUSIONS

In our cohort of patients, hypocalcemia was a real problem but we did not find any significant correlation with the examined factors. Further studies are warranted to validate our findings and investigate other potential correlations.

The Prognostic Value of Serum Calcium Levels in Elderly Dilated Cardiomyopathy Patients

Background

It is unclear whether serum calcium on admission is associated with clinical outcomes in dilated cardiomyopathy (DCM). In this study, we conducted a retrospective study spanning a decade to investigate the prognostic value of baseline calcium in elderly patients with DCM.

Methods

A total of 1,089 consecutive elderly patients (age ≥60 years) diagnosed with DCM were retrospectively enrolled from January 2010 to December 2019. Univariate and multivariate analyses were performed to investigate the association of serum calcium with their clinical outcomes.

Results

In this study, the average age of the subjects was 68.36 ± 6.31 years. Receiver operating characteristic (ROC) curve analysis showed that serum calcium level had a great sensitivity and specificity for predicting in-hospital death, with an AUC of 0.732. Kaplan-Meier survival analysis showed that patients with a serum calcium >8.62 mg/dL had a better prognosis than those with a serum calcium ≤8.62 mg/dL (log-rank χ2 40.84, p < 0.001). After adjusting for several common risk factors, a serum calcium ≤8.62 mg/dL was related to a higher risk of long-term mortality (HR: 1.449; 95% CI: 1.115~1.882; p = 0.005).

Conclusions

Serum calcium level could be served as a simple and affordable tool to evaluate patients' prognosis in DCM.

Secondary Osteoporosis

Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ -2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed.

Iatrogenic Toxicities in the Intensive Care Unit

Drug-induced iatrogenic toxicities are common in critically ill patients and have been associated with increased morbidity and mortality. Early recognition and management of iatrogenic toxicities is essential; however, the diagnosis is usually complicated by the underlying critical illness, comorbidities, and administration of multiple medications. This article reviews several types of iatrogenic toxicities associated with medications that are commonly used in critically ill patients. The mechanism of the iatrogenic toxicities, clinical presentation, and diagnosis, as well as management are discussed.

Hypercalcemia induced pancreatitis as a rare presentation of primary hyperparathyroidism

Acute pancreatitis (AP) is an inflammatory process of the pancreas. It is a relatively common cause of acute upper abdominal pain and is potentially associated with high morbidity and mortality. Underlying hypercalcemia as a cause of AP is very rare. We present a case of a hypercalcemia-induced acute pancreatitis with an underlying parathyroid adenoma in an 81-year-old woman with no previous symptoms of hypercalcemia. The parathyroid adenoma was semi-urgently surgically resected with normalization of calcium-levels. This case report summarizes the causes of acute pancreatitis and hypercalcemia and its management.

Low serum calcium is associated with higher long-term mortality in myocardial infarction patients from a population-based registry

Calcium plays an essential role in physiology of the cardiovascular system. Aberrations from normal serum calcium levels are known to be associated with several cardiovascular diseases. Its possible role as a predictor for long-term mortality after acute myocardial infarction (AMI) is still uncertain. In this study, a total of 3732 patients (aged 25–74 years) with incident AMI surviving at least 28 days after AMI was included. The median follow-up time was 6.0 years. Admission total serum calcium levels were divided into quartiles. The Kaplan–Meier-Curve suggested a division of the follow up time in two different time periods. So, Cox regression models were calculated to assess association between admission serum calcium levels and all-cause long-term mortality with two observation periods: 28–2500 days and > 2500 days. The final model was adjusted for various comorbidities, clinical characteristics, in-hospital treatment and medication. The third quartile (normal-high Calcium levels) served as the reference group. The fully adjusted Cox-regression model shows significantly higher mortality risk for low serum calcium (quartile 1) within the timeframe 28–2500 days after the event (OR 1.53 [1.19–1.98]). The other groups did not differ significantly from each other. In the later observation period (from 2500 days until death or censoring) no more significant differences were seen between the four calcium quartiles. In summary, low serum calcium is an independent predictor of adverse outcome in the first 2500 days (about 7 years) after AMI. On later points in time this effect attenuates, so that no more significant differences can be observed.

[Differential diagnosis of normocalcemic hyperparathyroidism and idiopathic hypercalciuria on the example of clinical case]

Idiopathic hypercalciuria is a heterogeneous generalized disorder caused by various defects in calcium transport and increased urinary calcium excretion. The main etiopathogenetic factors are violations of vitamin D metabolism, changes in the sensitivity of calcitriol receptors and violations of the processes of calcium reabsorption in the proximal tubules and in the ascending knee of the Henle loop. This article presents a clinical observation of patient with idiopathic hypercalciuria, initially high levels of parathyroid hormone (PTH) in the absence of hyperparathyroidism. Therapy with thiazide diuretics allowed to achieve normalization of daily urinary calcium excretion and reducing PTH. Despite the low prevalence of idiopathic hypercalciuria, differential diagnosis of this metabolic disorder should be carried out with mandatory consideration of clinical and laboratory data, as well as with diseases that may cause increased PTH production.

Parathyroid hormone independent hypercalcemia in adults

Parathyroid independent hypercalcemia is characterized by suppressed parathyroid hormone (PTH) in the presence of hypercalcemia. Well known causes and mechanisms are redistribution of calcium from the skeleton, by malignant diseases; inadequately increased intestinal calcium uptake mediated by increased vitamin D activity, and reduced renal elimination due to medications. Frequent and infrequent causes are discussed, and more recent mechanistic models presented in this review. Most hypercalcemic conditions are stable and in equilibrium between the different organs, whereas the utmost severe cases are characterized by rapid rising calcium levels and renal failure, resulting in a vicious circle where a disequilibrium state is developed. Management and treatment depends on the underlying condition and severity. The aim of this review is to discuss non-parathyroid hypercalcemic conditions as seen in the modern clinic, with a focus on areas where recent gain of knowledge has been achieved.

Risk of cardiovascular mortality predicted by the serum calcium level and calcification score at the initiation of dialysis

BACKGROUND

The relationship between serum corrected calcium (CCa) level and vessel calcification at dialysis initiation and survival has seldom been evaluated. Therefore, we evaluated the efficacy of CCa levels and the calcification score at the initiation of dialysis for predicting all-cause and cardiovascular (CV) mortality in patients with end-stage renal disease (ESRD).

METHODS

The study group included 407 patients with ESRD, who started hemodialysis between January 2009 and December 2016 at the Red Cross Ishinomaki Hospital. The primary outcomes were the 1- and 3-year all-cause and CV mortality rate, with the association between CCa level and CVD-specific mortality evaluated using the Kaplan-Meier method and Cox proportional hazard regression analysis.

RESULTS

Patients with a high initial CCa level were at higher risk for CVD-related, but not all-cause, mortality than patients with a low initial CCa level [hazard ratio (HR) 2.81; 95% confidence interval 1.05-7.55]. The HR for CVD-related mortality was also higher for patients with an Agatston vessel calcification score > 2000 (HR 13.9; 95% CI 1.63-118.2). Overall, the 3-year CVD-free rate was 88.2% (range 76.4-94.3%). Higher CCa level was associated with a higher Agatston score and cardiac valve calcification.

CONCLUSION

High serum CCa levels and an Agatston score > 2000 are independent risk factors of CVD mortality due to advanced vessel calcification.

The evidence and rationale for the perioperative use of loop diuretics during kidney transplantation: A comprehensive review

PURPOSE

Loop diuretics (LD) attenuate ischemic injury in nephrons. They are thought to decrease delayed graft function (DGF) during kidney transplantation (KT). This review aimed to summarize the current evidence for the perioperative use of LD during KT.

METHODS

We performed an analysis of all articles that were published since the inception of Medline and Embase: 26 studies were selected for inclusion. Scope was LD use during the perioperative phase of KT only.

RESULTS

Six animal studies demonstrated mixed results in terms of renal function and survival. Of the 20 studies performed in humans, 4 were randomized clinical trials. The risk of bias was mostly unclear. Evidence supporting the role of LD to increase diuresis was mixed and to prevent DGF was weak. There was poor evidence to support LD use to improve initial and long-term graft function. No data on patient survival could be found. Overall, there was a lack of any robust clinical evidence for LD use perioperatively during KT.

IMPLICATIONS

There is poor evidence to support the perioperative use of LD during KT. Well-designed trials are needed to further explore their safety and efficacy, and we summarize several rationales. Pragmatic rationales include volume management. There is evidence to suggest that LD have a vasodilatory effect, and decrease edema, congestion and oxygen requirements. Lastly, there are several theoretical rationales to explore LD use during KT, in particular, attenuating ischemia-reperfusion injury and modulating autophagy.

The pathogenesis of diclofenac induced immunoallergic hepatitis in a canine model of liver injury

Hypersensitivity to non-steroidal anti-inflammatory drugs is a common adverse drug reaction and may result in serious inflammatory reactions of the liver. To investigate mechanism of immunoallergic hepatitis beagle dogs were given 1 or 3 mg/kg/day (HD) oral diclofenac for 28 days. HD diclofenac treatment caused liver function test abnormalities, reduced haematocrit and haemoglobin but induced reticulocyte, WBC, platelet, neutrophil and eosinophil counts. Histopathology evidenced hepatic steatosis and glycogen depletion, apoptosis, acute lobular hepatitis, granulomas and mastocytosis. Whole genome scans revealed 663 significantly regulated genes of which 82, 47 and 25 code for stress, immune response and inflammation. Immunopathology confirmed strong induction of IgM, the complement factors C3&B, SAA, SERPING1 and others of the classical and alternate pathway. Alike, marked expression of CD205 and CD74 in Kupffer cells and lymphocytes facilitate antigen presentation and B-cell differentiation. The highly induced HIF1A and KLF6 protein expression in mast cells and macrophages sustain inflammation. Furthermore, immunogenomics discovered 24, 17, 6 and 11 significantly regulated marker genes to hallmark M1/M2 polarized macrophages, lymphocytic and granulocytic infiltrates; note, the latter was confirmed by CAE staining. Other highly regulated genes included alpha-2-macroglobulin, CRP, hepcidin, IL1R1, S100A8 and CCL20. Diclofenac treatment caused unprecedented induction of myeloperoxidase in macrophages and oxidative stress as shown by SOD1/SOD2 immunohistochemistry. Lastly, bioinformatics defined molecular circuits of inflammation and consisted of 161 regulated genes.

Altogether, the mechanism of diclofenac induced liver hypersensitivity reactions involved oxidative stress, macrophage polarization, mastocytosis, complement activation and an erroneous programming of the innate and adaptive immune system.

Risk factors for poor bone health in primary mitochondrial disease

INTRODUCTION

Primary mitochondrial disease is caused by either mitochondrial or nuclear DNA mutations that impact the function of the mitochondrial respiratory chain. Individuals with mitochondrial disorders have comorbid conditions that may increase their risk for poor bone health. The objective of this retrospective electronic medical record (EMR) review was to examine risk factors for poor bone health in children and adults with primary mitochondrial disease.

METHODS

Eighty individuals with confirmed clinical and genetic diagnoses of primary mitochondrial disease at the Children's Hospital of Philadelphia (CHOP) were included in this study. Risk factors and bone health outcomes were collected systematically, including: anthropometrics (low BMI), risk-conferring co-morbidities and medications, vitamin D status, nutrition, immobility, fracture history, and, where available, dual energy x-ray absorptiometry (DXA) bone mineral density (BMD) results.

RESULTS

Of patients 73% (n = 58) had at least one risk factor and 30% (n = 24) had four or more risk factors for poor bone health. The median number of risk factors per participant was 2, with an interquartile interval (IQI 0-4). In the subset of the cohort who were known to have sustained any lifetime fracture (n = 11), a total of 16 fractures were reported, six of which were fragility fractures, indicative of a clinically significant decrease in bone strength.

CONCLUSIONS

The prevalence of risk factors for poor bone health in primary mitochondrial disease is high. As part of supportive care, practitioners should address modifiable risk factors to optimize bone health, and have a low threshold to evaluate clinical symptoms that could suggest occult fragility fracture.

[Diagnostic approach and management of hypercalcaemia in dogs exemplary of primary hyperparathyroidism]

Hypercalcaemia can be caused by many different diseases. This article summarizes the causes, pathophysiologic mechanisms and diagnostic procedures as well as treatment recommendations. The main focus is on hypercalcaemia in primary hyperparathyroidism (PH), complemented by a case report. An elevated total calcium level should generally be investigated and verified by measurement of ionized calcium concentration. The further diagnostic approach depends on the phosphate level. Tumour screening, measurement of parathormone and parathromone-related protein and sonography of parathyroid glands may be necessary. If the calcium-phosphate-product exceeds 60 mg/dl, there is a risk of tissue mineralisation and a rapid treatment of hypercalcaemia is required. For acute therapy, sodium chloride infusion, furosemide and glucocorticoids can be used. Glucocorticoids should only be given after strict indication and after a definite diagnosis. For long-term management, bisphosphates, particularly alendronate, are increasingly used successfully. Causal therapy of PH can be performed by parathyreoidectomy, heat ablation or ethanol ablation. Thereafter, particularly in cases of severe preoperative hypercalcaemia, hypocalcaemia can occur. Treatment is performed using vitamin D₃ (calcitriol), which may also be given preoperatively in cases of severe hypercalcaemia. A concomitant oral calcium supplementation using calcium carbonate as medication of choice is contentious. Due to a potential relapse after successful excision of the affected parathyroid gland in PH, the serum calcium level should be monitored periodically.

Thiazide Treatment in Primary Hyperparathyroidism-A New Indication for an Old Medication?

CONTEXT

There is no therapy for control of hypercalciuria in nonoperable patients with primary hyperparathyroidism (PHPT). Thiazides are used for idiopathic hypercalciuria but are avoided in PHPT to prevent exacerbating hypercalcemia. Nevertheless, several reports suggested that thiazides may be safe in patients with PHPT.

OBJECTIVE

To test the safety and efficacy of thiazides in PHPT.

DESIGN

Retrospective analysis of medical records.

SETTING

Endocrine clinic at a tertiary hospital.

PATIENTS

Fourteen male and 58 female patients with PHPT treated with thiazides.

INTERVENTIONS

Data were compared for each patient before and after thiazide administration.

MAIN OUTCOME MEASURES

Effect of thiazide on urine and serum calcium levels.

RESULTS

Data are given as mean ± standard deviation. Treatment with hydrochlorothiazide 12.5 to 50 mg/d led to a decrease in mean levels of urine calcium (427 ± 174 mg/d to 251 ± 114 mg/d; P < 0.001) and parathyroid hormone (115 ± 57 ng/L to 74 ± 36 ng/L; P < 0.001), with no change in serum calcium level (10.7 ± 0.4 mg/dL off treatment, 10.5 ± 1.2 mg/dL on treatment, P = 0.4). Findings were consistent over all doses, with no difference in the extent of reduction in urine calcium level or change in serum calcium level by thiazide dose.

CONCLUSION

Thiazides may be effective even at a dose of 12.5 mg/d and safe at doses of up to 50 mg/d for controlling hypercalciuria in patients with PHPT and may have an advantage in decreasing serum parathyroid hormone level. However, careful monitoring for hypercalcemia is required.

Thiazide-Associated Hypercalcemia: Incidence and Association With Primary Hyperparathyroidism Over Two Decades

CONTEXT

Thiazide diuretics, the antihypertensive agent prescribed most frequently worldwide, are commonly associated with hypercalcemia. However, the epidemiology and clinical features are poorly understood.

OBJECTIVE

To update the incidence of thiazide-associated hypercalcemia and clarify its clinical features.

PATIENTS AND METHODS

In a population-based descriptive study, Olmsted County, Minnesota, residents with thiazide-associated hypercalcemia were identified through the Rochester Epidemiology Project and the Mayo Clinic Laboratory Information System from 2002-2010 and were added to the historical cohort beginning in 1992.

MAIN OUTCOME

Incidence rates were adjusted to the 2010 United States white population.

RESULTS

Overall, 221 Olmsted County residents were identified with thiazide-associated hypercalcemia an average of 5.2 years after initiation of treatment. Subjects were older (mean age, 67 years) and primarily women (86.4%). The incidence of thiazide-associated hypercalcemia increased after 1997 and peaked in 2006 with an annual incidence of 20 per 100,000, compared to an overall rate of 12 per 100,000 in 1992-2010. Severe hypercalcemia was not observed in the cohort despite continuation of thiazide treatment in 62.4%. Of patients discontinuing thiazides, 71% continued to have hypercalcemia. Primary hyperparathyroidism was diagnosed in 53 patients (24%), including five patients who underwent parathyroidectomy without thiazide discontinuation.

CONCLUSIONS

Many patients with thiazide-associated hypercalcemia have underlying primary hyperparathyroidism. Additionally, a sharp rise in thiazide-associated hypercalcemia incidence began in 1998, paralleling the increase observed in primary hyperparathyroidism in this community. Case ascertainment bias from targeted osteoporosis screening is the most likely explanation.

Potentiation of the effect of thiazide derivatives by carbonic anhydrase inhibitors: molecular mechanisms and potential clinical implications

BACKGROUND

Carbonic anhydrase inhibitors (CAI) are mild diuretics, hence not widely used in fluid overloaded states. They are however the treatment of choice for certain non-kidney conditions. Thiazides, specific inhibitors of Na-Cl cotransport (NCC), are mild agents and the most widely used diuretics in the world for control of mild hypertension.

HYPOTHESIS

In addition to inhibiting the salt reabsorption in the proximal tubule, CAIs down-regulate pendrin, therefore leaving NCC as the major salt absorbing transporter in the distal nephron, and hence allowing for massive diuresis by the inhibitors of NCC in the setting of increased delivery of salt from the proximal tubule.

EXPERIMENTAL PROTOCOLS AND RESULTS

Daily treatment of rats with acetazolamide (ACTZ), a known CAI, for 10 days caused mild diuresis whereas daily treatment with hydrochlorothiazide (HCTZ) for 4 days caused hardly any diuresis. However, treatment of rats that were pretreated with ACTZ for 6 days with a combination of ACTZ plus HCTZ for 4 additional days increased the urine output by greater than 2 fold (p<0.001, n = 5) compared to ACTZ-treated animals. Sodium excretion increased by 80% in the ACTZ plus HCTZ group and animals developed significant volume depletion, metabolic alkalosis and pre-renal failure. Molecular studies demonstrated ∼75% reduction in pendrin expression by ACTZ. The increased urine output in ACTZ/HCTZ treated rats was associated with a significant reduction in urine osmolality and reduced membrane localization of AQP-2 (aquaporin2).

CONCLUSIONS

These results indicate that ACTZ down-regulates pendrin expression and leaves NCC as the major salt absorbing transporter in the distal nephron in the setting of increased delivery of salt from the proximal tubule. Despite being considered mild agents individually, we propose that the combination of ACTZ and HCTZ is a powerful diuretic regimen.

Recent finding and new technologies in nephrolitiasis: a review of the recent literature

This review summarizes recent literature on advances regarding renal and ureteral calculi, with particular focus in areas of recent advances in the overall field of urolithiasis. Clinical management in everyday practice requires a complete understanding of the issues regarding metabolic evaluation and subgrouping of stone-forming patients, diagnostic procedures, effective treatment regime in acute stone colic, medical expulsive therapy, and active stone removal. In this review we focus on new perspectives in managing nephrolitihiasis and discuss recentadvances, including medical expulsive therapy, new technologies, and refinements of classical therapy such as shock wave lithotripsy, give a fundamental modification of nephrolithiasis management. Overall, this field appears to be the most promising, capable of new developments in ureterorenoscopy and percutaneous approaches. Further improvements are expected from robotic-assisted procedures, such as flexible robotics in ureterorenoscopy.

Unrecognized and unappreciated secondary causes of osteoporosis

There are a substantial number of secondary causes of osteoporosis that can be identified through appropriate evaluation. Unrecognized celiac disease, Monoclonal gamopathy of undetermined significance (MGUS), impaired renal function, diabetes mellitus, and renal tubular acidosis are just a few of the more common secondary causes of osteoporosis. Through targeted laboratory tests, many secondary causes of osteoporosis can be identified.

Drug-induced alterations in Mg2+ homoeostasis

Magnesium (Mg2+) balance is tightly regulated by the concerted actions of the intestine, bone and kidneys. This balance can be disturbed by a broad variety of drugs. Diuretics, modulators of the EGFR (epidermal growth factor receptor), proton pump inhibitors, antimicrobials, calcineurin inhibitors and cytostatics may all cause hypomagnesaemia, potentially leading to tetany, seizures and cardiac arrhythmias. Conversely, high doses of Mg2+ salts, frequently administered as an antacid or a laxative, may lead to hypermagnesaemia causing various cardiovascular and neuromuscular abnormalities. A better understanding of the molecular mechanisms underlying the adverse effects of these medications on Mg2+ balance will indicate ways of prevention and treatment of these adverse effects and could potentially provide more insight into Mg2+ homoeostasis.