Hypokalemic rhabdomyolysis in a child with Gitelman's syndrome

Gitelman syndrome with Graves' disease leading to rhabdomyolysis: a case report and literature review

A 14-year-old male patient who suffered from limb numbness, fatigue, and hypokalemia was considered Graves' disease (GD) complicated with thyrotoxic periodic paralysis (TPP) at the first diagnosis. Although with the treatment of antithyroid drugs, he developed severe hypokalemia and rhabdomyolysis (RM). Further laboratory tests revealed hypomagnesemia, hypocalciuria, metabolic alkalosis, hyperrenin, and hyperaldosteronemia. Genetic testing revealed compound heterozygous mutations in the SLC12A3 gene (c.506-1G > A, c.1456G > A) encoding the thiazide-sensitive sodium-chloride cotransporter, which presented a definitive diagnosis of Gitelman syndrome (GS). Moreover, gene analysis revealed his mother diagnosed with subclinical hypothyroidism due to Hashimoto's thyroiditis carried the c.506-1G > A heterozygous mutation in the SLC12A3 gene and his father carried the c.1456G > A heterozygous mutation in the SLC12A3 gene. His younger sister who had hypokalemia and hypomagnesemia carried the same compound heterozygous mutations as the proband and was diagnosed with GS as well, but with a much milder clinical presentation and better treatment outcome. This case suggested the potential relationship between GS and GD, clinicians should strengthen the differential diagnosis to avoid missed diagnosis.

A Family with Gitelman Syndrome with Asymptomatic Phenotypes while Carrying Reported SLC12A3 Mutations

Gitelman syndrome (GS) is an autosomal recessive disorder characterized by alkalosis, hypokalemia, and hypomagnesemia. Although hundreds of genetic variants associated with GS have been reported, many of them are categorized as of uncertain significance in ClinVar. Here, we describe a pediatric GS patient from a three-generation family whose mother and maternal grandmother were asymptomatic. The proband was a 16-year-old Japanese girl with muscle weakness and continuous hypokalemic metabolic alkalosis. The patient, her mother, and her maternal grandmother were compound heterozygous for, and each expressing a different combination of, previously reported SLC12A3variants in GS patients. The mother and the maternal grandmother had no symptoms related to GS, and blood gas tests showed that the blood potassium levels and venous pH were within normal limits; however, the venous blood HCO₃- levels were slightly elevated. The phenotypic effect of missense mutations is difficult to evaluate, and accumulation of genotypic data with accurate phenotyping, including those of “healthy” and “asymptomatic” individuals in various ethnic populations, will improve the genetic diagnosis of GS.

The challenges of diagnosis and management of Gitelman syndrome

Gitelman syndrome is an inherited tubulopathy characterized by renal salt wasting from the distal convoluted tubule. Defects in the sodium chloride cotransporter (encoded by SLC12A3) underlie this autosomal recessive condition. This article focuses on the specific challenges of diagnosing and treating Gitelman syndrome, with use of an illustrative case report. Symptoms relate to decreased serum potassium and magnesium levels, which include muscle weakness, tetany, fatigue and palpitations. Sudden cardiac deaths have been reported. Making a diagnosis may be difficult given its rarity but is important. A knowledge of the serum and urine biochemical picture is vital to distinguish it from a broad differential diagnosis, and application of genetic testing can resolve difficult cases. There is a group of Gitelman syndrome heterozygous carriers that experience symptoms and electrolyte disturbance and these patients should be managed in a similar way, though here genetic investigations become key in securing a difficult diagnosis. Potassium and magnesium replacement is the cornerstone of treatment, though practically this can be hard for patients to manage and often does not fully relieve symptoms even when serum levels are normalized. Challenges arise due to the lack of randomized controlled trials focussing on treatment of this rare disease; hence, clinicians endorse strategies in line with correction of the underlying pathophysiology such as sodium loading or pharmacological treatments, which seem to help some patients. Focussed dietary advice and knowing the best tolerated preparations of potassium and magnesium medications are useful tools for the physician, as well as an awareness of the specific burdens that this patient group face in order to signpost appropriate support.

A case of Gitelman syndrome: our experience with a patient treated in clinical practice on a local island

Background: Gitelman syndrome (GS) is an autosomal recessive salt-losing renal tubulopathy resulting from mutations in the thiazide-sensitive Na-Cl cotransporter (NCC) gene. Notably, lack of awareness regarding GS and difficulty with prompt diagnosis are observed in clinical practice, particularly in rural settings.

Case presentation: We report a case of a 48-year-old man with GS who presented to a local clinic on a remote island. Occasional laboratory investigations incidentally revealed a reduced serum potassium level of 2.6 mmol/L. A careful medical interview revealed episodes of intermittent paralysis of the lower extremities and muscular weakness for >30 years. Subsequent laboratory investigations revealed hypomagnesemia, hypocalciuria, and hypokalemic metabolic alkalosis. Based on the patient’s history, clinical presentation, and laboratory investigations, we suspected GS. Genetic testing revealed a rare homozygous in-frame 18 base insertion in the NCC gene that might have resulted from the founder effect, consequent to his topographically isolated circumstances.

Conclusion: More case studies similar to our study need to be added to the literature to gain a deeper understanding of the functional consequences of this mutation and to establish optimal management strategies for this condition, particularly in rural clinical settings.

Liquorice-induced severe hypokalemic rhabdomyolysis with Gitelman syndrome and diabetes: A case report

BACKGROUND

Licorice-induced severe hypokalemic rhabdomyolysis is clinically rare. Gitelman syndrome (GS) is the most common inherited renal tubular disease, while diabetes is one of the most prevalent diseases in the world. Recently, some studies have found that GS patients had higher diabetic morbidity. However, the coexistence of these three diseases has yet to be reported.

CASE SUMMARY

We report the case of a 62-year-old Chinese man who was admitted with weakness in the extremities, muscle pain, and dark-colored urine. He had consumed liquorice water daily for seven days prior to admission. The laboratory tests revealed a serum potassium level of 1.84 mmol/L, magnesium 0.68 mmol/L, creatinine phosphokinase (CK) 10117 IU/L, and marked hemoglobinuria. Fractional chloride excretion and fractional magnesium excretion were increased. Plasma renin activity and aldosterone concentration were within the normal ranges. Sequence analysis of the SLC12A3 gene revealed that he had compound heterozygous mutations. The diagnosis of liquorice-induced severe hypokalemic rhabdomyolysis with GS and diabetes was thus genetically confirmed. Serum potassium and CK quickly improved with potassium replacement therapy, hydration, and discontinuation of liquorice ingestion. Upon follow-up at 3 mo, the levels of CK, myoglobin, and potassium remained normal, and magnesium was above 0.6 mmol/L.

CONCLUSION

This case emphasizes that liquorice consumption and GS should be considered causes of hypokalemia and that the diabetic status of GS patients should be noted in the clinic.

Gitelman Syndrome: A Rare Cause of Seizure Disorder and a Systematic Review

Gitelman syndrome is one of the few inherited causes of metabolic alkalosis due to salt losing tubulopathy. It is caused by tubular defects at the level of distal convoluted tubules, mimicking a thiazide-like tumor. It usually presents in late childhood or in teenage as nonspecific weakness, fatigability, polyuria, and polydipsia but very rarely with seizures. It is classically associated with hypokalemia, hypomagnesemia, hypocalciuria, hyperreninemia, and hyperaldosteronism. However, less frequently, it can present with normal magnesium levels. It is even rarer to find normomagnesemic patients of GS who develop seizures as the main complication since hypomagnesemia is considered the principal etiology of abnormal foci of seizure-related brain activity in GS cases. Interestingly, patients with GS are oftentimes diagnosed during pregnancy when the classic electrolyte pattern consistent with GS is noticed. Our case presents GS with normal serum magnesium in a patient, with seizures being the main clinical presentation. We also did a comprehensive literature review of 122 reported cases to show the prevalence of normal magnesium in GS cases and an overview of clinical and biochemical variability in GS. We suggest that further studies and in-depth analysis are required to understand the pathophysiology of seizures in GS patients with both normal and low magnesium levels.

Gitelman syndrome in a South African family presenting with hypokalaemia and unusual food cravings

BACKGROUND

Gitelman syndrome (GS) is an autosomal recessive renal tubular disorder characterised by renal salt wasting with hypokalaemia, metabolic alkalosis, hypomagnesaemia and hypocalciuria. It is caused by mutations in SLC12A3 encoding the sodium-chloride cotransporter on the apical membrane of the distal convoluted tubule. We report a South African family with five affected individuals presenting with hypokalaemia and unusual food cravings.

METHODS

The affected individuals and two unaffected first degree relatives were enrolled into the study. Phenotypes were evaluated through history, physical examination and biochemical analysis of blood and urine. Mutation screening was performed by sequencing of SLC12A3, and determining the allele frequencies of the sequence variants found in this family in 117 ethnically matched controls.

RESULTS

The index patient, her sister, father and two aunts had a history of severe salt cravings, fatigue and tetanic episodes, leading to consumption of large quantities of salt and vinegar. All affected individuals demonstrated hypokalaemia with renal potassium wasting. Genetic analysis revealed that the pseudo-dominant pattern of inheritance was due to compound heterozygosity with two novel mutations: a S546G substitution in exon 13, and insertion of AGCCCC at c.1930 in exon 16. These variants were present in the five affected individuals, but only one variant each in the unaffected family members. Neither variant was found in any of the controls.

CONCLUSIONS

The diagnosis of GS was established in five members of a South African family through clinical assessment, biochemical analysis and mutation screening of the SLC12A3 gene, which identified two novel putative pathogenic mutations.

Hypokalemia causing rhabdomyolysis in a patient with short bowel syndrome

BACKGROUND

Rhabdomyolysis, usually in the setting of trauma or drug use, is frequently seen in the emergency setting, and often leads to hyperkalemia at presentation. Hypokalemia, however, is a potentially underrecognized cause of rhabdomyolysis.

CASE REPORT

We present a case of rhabdomyolysis likely due to hypokalemia in the setting of short bowel syndrome. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although less common, hypokalemia can be a significant cause of rhabdomyolysis via its effects on muscle. This scenario should be considered in the differential diagnosis of patients at risk for hypokalemia who present with weakness. Rapid recognition of this relationship and rapid correction of hypokalemia may prove very important in preventing the deleterious effects of rhabdomyolysis.

Cardiac arrhythmias and rhabdomyolysis in Bartter-Gitelman patients

Recent data demonstrate that patients affected with hypokalemic salt-losing tubulopathies are prone to acute cardiac arrhythmias and rhabdomyolysis. The tendency to these potentially fatal complications is especially high if chronic hypokalemia is severe, in patients with diarrhea, vomiting or a prolonged QT interval on standard electrocardiography, in patients on drug management with compounds prolonging the electrocardiographic QT interval (including antiarrhythmic agents, some antihistamines, macrolides, antifungals, psychotropics, beta2-adrenergic agonists or cisapride), following acute alcohol abuse and during exercise. Cardiac arrhythmias and rhabdomyolysis occur with sufficient frequency in hypokalemic salt-losing tubulopathies to merit wider awareness of their presence and the preparation of specific prevention and management recommendations.