Management of a severe case of Gitelman syndrome with poor response to standard treatment

Rare Case of Adult-Onset Gitelman Syndrome in a Patient With Multiple Comorbidities: A Case Report

Gitelman Syndrome (GS) is a renal tubulopathy transmitted in an autosomal recessive manner. Its primary cause is mutations Of SLC12A3 (Solute Carrier Family 12 Member 3) gene that encodes the sodium-chloride co-transporter and is characterized by hypokalemia, hypocalciuria, hypomagnesemia, and metabolic alkalosis. It appears in most cases in adolescents or early adulthood, but with end-organ disease in later adulthood with other comorbid conditions. The patient was a 55-year-old woman with refractory electrolyte disturbances comprising low potassium, calcium, and metabolic alkalosis, history of NASH (non-alcoholic steatohepatitis) cirrhosis, benzodiazepine poisoning, and gastric polyps. Persistent electrolyte abnormalities were most likely worsening renal failure before improvement with the addition of spironolactone. Urinary magnesium/creatinine ratios above 1 were indicative of GS. Electrolyte imbalances were recurring in both her and her late mother, which even existed throughout her childhood. Persistent electrolyte abnormalities in this patient's chronic NASH cirrhosis would probably worsen due to secondary hyperaldosteronism. Supplementation of potassium, calcium, and magnesium failed to address the refractory hypokalemia and hypocalcemia, and hypomagnesemia. So spironolactone was initiated, which resulted in a successful resolution of the condition. Clinical diagnosis of GS made based on biochemical markers due to an existing strong familial pattern of similar electrolyte manifestations since a genetic test for the condition was unavailable. This case shows the issue of disease synergy and how various diseases relate and need specific methods of treatment. The patient's status requires constant observation and the investigation of the possible hereditary renal -tubular disorders.

Molecular Basis, Diagnostic Challenges and Therapeutic Approaches of Bartter and Gitelman Syndromes: A Primer for Clinicians

Gitelman and Bartter syndromes are rare inherited diseases that belong to the category of renal tubulopathies. The genes associated with these pathologies encode electrolyte transport proteins located in the nephron, particularly in the Distal Convoluted Tubule and Ascending Loop of Henle. Therefore, both syndromes are characterized by alterations in the secretion and reabsorption processes that occur in these regions. Patients suffer from deficiencies in the concentration of electrolytes in the blood and urine, which leads to different systemic consequences related to these salt-wasting processes. The main clinical features of both syndromes are hypokalemia, hypochloremia, metabolic alkalosis, hyperreninemia and hyperaldosteronism. Despite having a different molecular etiology, Gitelman and Bartter syndromes share a relevant number of clinical symptoms, and they have similar therapeutic approaches. The main basis of their treatment consists of electrolytes supplements accompanied by dietary changes. Specifically for Bartter syndrome, the use of non-steroidal anti-inflammatory drugs is also strongly supported. This review aims to address the latest diagnostic challenges and therapeutic approaches, as well as relevant recent research on the biology of the proteins involved in disease. Finally, we highlight several objectives to continue advancing in the characterization of both etiologies.

A Challenging Case of Persisting Hypokalemia Secondary to Gitelman Syndrome

There are several causes of hypokalemia, including transcellular shift, renal loss, gastrointestinal loss, and decreased oral intake. Sometimes it is challenging to know the source of the problem; however, with detailed history, physical examination, and appropriate laboratory investigations, the physician should be able to narrow down the differentials diagnosis to reach the right one. One of the rare causes of hypokalemia is Gitelman syndrome, which is a salt-losing tubulopathy that manifests as renal potassium wasting, metabolic alkalosis, hypokalemia, hypomagnesemia, hypocalciuria, and hyperreninemic hyperaldosteronism. This disorder is inherited in an autosomal recessive pattern with an incidence of 25 instances per million population. We report a challenging case of persistent hypokalemia in a 30-year-old woman who presented with a history of palpitation, bilateral upper and lower limbs numbness, nausea, diarrhea, and generalized fatigue for three days. After history and physical examination, the patient was diagnosed with an episode of enteritis, and laboratory workups revealed low potassium and magnesium levels, and it was thought that these electrolyte abnormalities were secondary to gastrointestinal loss. Therefore, the patient was mainly treated supportively along with potassium and magnesium replacement. However, after one week of replacement, the patient still had low potassium and magnesium levels in spite of being diarrhea-free, so renal loss was suspected. Urine electrolytes revealed high renal potassium loss with low-normal blood pressure, arterial blood gases revealed metabolic alkalosis with a pH of 7.49 and bicarbonate level of 29 mEq/L. Repeated urine chemistry was done to check for chloride level and turned out to be high, and 24-hour urinary excretion of calcium was very low. Therefore, the patient was diagnosed with Gitelman syndrome and was managed with potassium and magnesium replacements intravenously, and was encouraged to consume a diet rich in these electrolytes. After complete resolutions of the symptoms and correction of potassium and magnesium levels, the patient was discharged home in stable condition.

Clinical and laboratory features of female Gitelman syndrome and the pregnancy outcomes in a Chinese cohort

AIM

Gitelman syndrome (GS) is a rare inherited salt-losing renal tubulopathy. Data on clinical features and the pregnancy outcome for female GS patients in a large cohort are lacking. The study was aimed to explore the phenotype and pregnant issue for female GS patients.

METHODS

GS cases from the National Rare Diseases Registry System of China (NRSC) were collected, and detailed clinical, laboratory and genetic data were analysed. Articles on pregnancy in GS were also systemically reviewed.

RESULTS

A total of 101 GS patients were included; among them, 42.6% were female and 79.2% showed hypomagnesaemia. A lower proportion of female patients presented before 18 years of age, with less frequently reported polyuria, higher serum potassium and less urine sodium and chloride excretions. There was no gender difference in the sodium-chloride cotransporter (NCC) dysfunction evaluated by hydrochlorothiazide test. Twelve of the 43 female GS patients delivered after disease symptom onset, and their pregnancies were generally uneventful. As a group, pregnant GS patients had lower potassium levels in the first-trimester (P = .002) requiring higher potassium supplementation. After delivery, serum potassium (P = .02) and magnesium (P = .03) increased significantly. Both caesarean section and vaginal delivery were safe.

CONCLUSION

Female GS patients may have a less severe phenotype with generally favourable outcomes of pregnancy. Intensive monitoring and increased potassium supplementation are necessary during pregnancy, especially in the first-trimester.

Bilateral hamstring origin calcification: rare presentation of Gitelman syndrome

This case report is the first case to our knowledge of intratendinous or peritendinous calcification reported in Gitelman syndrome (GS) patients. GS represents the clinical manifestations of inactivation of the Slc12a3 genes encoding the thiazide-sensitive sodium chloride cotransporter and the Trpm6-Mg genes encoding the magnesium transporters in the distal convoluted tubule. Hence, the biochemical findings resemble those with thiazide diuretics such as hypokalaemia, hypomagnesaemia, hypocalciuria, metabolic alkalosis and low normal blood pressure. Serum calcium and phosphate levels are usually unaffected in GS unless associated with hyperparathyroidism or other hypercalcaemic aetiologies. We report a 69-year-old male patient with a history of GS who presented with bilateral ischial tuberosity tenderness. Further investigations confirmed the calcification of bilateral hamstring origin. Chondrocalcinosis is a known association of GS; however, extra-articular calcification is rare. Literature review illustrates sclerochoroidal calcification as the only reported soft tissue calcification apart from chondrocalcinosis.

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.

Hypocalcaemia and hyponatraemia masquerading the diagnosis of Gitelman syndrome

Gitelman syndrome is the most common renal tubulopathy, recently exhibiting a dramatic rise of incidence in Asia.A 50-year-old woman presented with vomiting, fatigue and quadriparesis. Physical examination revealed a positive Trousseau sign , hypotonia and areflexia.Suspecting hypocalcaemia, she was given intravenous 10% calcium gluconate (10 mL administered slowly over 10 min) but her manifestations persisted. An exhaustive laboratory work up revealed the diagnosis of Gitelman syndrome.The peculiarity of this case however, is entailed in its coexistence with hypocalcaemia and hyponatraemia. In addition, the age of primary presentation being 50 years further culminates its atypicality.Multiple electrolyte imbalances were corrected by oral and intravenous supplementation and a high sodium-potassium diet was advocated. Administration of spironolactone imposed a pitfall in the management of our patient due to exacerbation of pre-existing hyponatraemia.On follow-up, her electrolyte profile was stable and corresponding symptoms were alleviated.

Renal physiology and fluid and electrolyte disorders in pregnancy

The majority of women are healthy entering pregnancy and do not require measurement of renal function or serum electrolytes. Clinicians must remain alert to the possibility of renal as well as fluid and electrolyte disorders in pregnancy, as the presenting complaints are often vague and mistaken for the normal physiology of pregnancy. In this chapter, our objectives are 1) to review the renal physiology from a practical/clinical standpoint; 2) to provide the clinical obstetrician a case-based approach to fluid and electrolyte disorders commonly encountered in pregnancy; 3) to consolidate knowledge on renal physiology and fluid and electrolyte disorders in pregnancy with MCQs that are directly aligned with content; and 4) to highlight key practice points and present a research agenda.

Bartter's and Gitelman's syndrome

PURPOSE OF REVIEW

The clinical presentations of Bartter's syndrome and Gitelman's syndrome will be reviewed including two most recently described hypokalemic salt-losing tubulopathies. By taking the quite heterogeneous presentations and the apparently different pathophysiologies as the basis, the applicability of the physiologic classification has been tested.

RECENT FINDINGS

According to the physiologic approach, salt-losing tubulopathies can be divided into two major groups (with completely different tubular defects): first, disorders of the thick ascending limb of Henle's loop (loop disorders); second, disorders of the distal convolute tubule (DCT disorders). A combination of these two groups with complety different tubular defects will finally lead to a third group: the combined loop/DCT disorders. On the basis of pharmacologic tests (pharmacotyping), it appears that the Bartter's syndrome V belongs to the DCT group, whereas the most recently described transient antenatal Bartter's syndrome best fits in the group with the loop and DCT combination.Besides secondary hyperaldosteronism, loop disorders present a whole spectrum of (secondary) pathophysiologic characteristics with significant diagnostic and therapeutic impact, such as polyhydramnios, hyperprostaglandinuria, nephrogenic diabetes insipidus, and nephrocalcinosis. Recent reports indicate that neonatal hyperparathyroidism has also to be added to the clinical presentation of isolated loop disorders.

SUMMARY

As long as gene therapy is not available, the overall therapeutic management follows the clinical presentation, which leads to the underlying pathophysiology of renal salt wasting. Thus, when dealing with Bartter's syndrome and Gitelman's syndrome, the correct physiologic and pharmacologic characterization appears to be essential for a sound diagnostic and therapeutic patient management.