Journal Article

An unusual cause of hypokalaemia

Yao, Jianping, Liu, Bo, Pan, Yunfei, Huang, Cao

2024

Overview

Table 1 Blood test results one year previously, and on admission Test Results (1 year previously) Results on admission Reference range Sodium, mmol/L 142.5 140.5 135.0–145.0 Potassium, mmol/L 1.78 2.59 3.50–5.50 Calcium, mmol/L 2.60 2.49 2.25–2.75 Magnesium, mmol/L 0.61 0.63 0.75–1.25 Urinary potassium excretion, mmol/24 h - 76.23) <25 (for patient with hypokalaemia) Urinary calcium excretion, mmol/24 h - 1.6 2.5–7.5 PH 7.525 7.46 7.35–7.45 Renin, ng/mL/h - 19.64 0.15–2.33 Aldosterone, pg/mL - 193.6 30.00–160.0 Thyroid stimulating hormone, μIU/mL 0.003 7.283 0.350-4.940 Free triiodothyronine, pg/mL 5.16 2.23 1.58-3.91 Free thyroxine, ng/dL 1.99 0.90 0.70-1.48 Thyroid stimulating hormone receptor antibody, IU/L 3.41 - 0.00-1.75 SLC12A3 gene mutation - Positive - Questions 1. Common causes of hypokalaemia include inadequate intake, increased gastrointestinal losses, excessive renal excretion, drug induced (eg, diuretics, antibiotics, beta-agonists), genetic causes (eg, Bartter’s and Gitelman’s syndromes), and iatrogenic (table 2).12 Table 2 Causes of hypokalaemia Reason Related diseases Inadequate intake or increased gastro-intestinal losses Digestive tract obstruction, anorexia nervosa, partial eating, long term fasting, gastroenteritis, inflammatory bowel disease, gastrointestinal drainage, fistula Excessive potassium excretion from the kidney Renal diseases: acute renal failure polyuria stage, renal tubular acidosis, Fanconi syndrome Hyperaldosteronism: primary aldosteronism, Bartter/Gitelman syndrome, renin tumour, renal artery stenosis, etc Excessive glucocorticoids: stress such as trauma, surgery, hypoxia, infection; Cushing syndrome, ectopic adrenocorticotropin secretion syndrome Drugs Diuretics, eg, furosemide, hydrochlorothiazide, acetazolamide, mannitol and sorbitol; excessive sodium supplementation; antibiotics, eg, penicillin, gentamicin, and carbenicillin; beta-agonists, eg, albuterol, epinephrine, and salbutamol; mineralocorticoids and glucocorticoids, eg, hydrocortisones, fludrocortisones, and prednisolone; laxatives, eg, sorbitol, phenophtalein, and sodium polysterene fulfonate; xanthines, eg, theophylline and caffeine; other drugs, including insulin overdose Iatrogenic causes Infusion of large glucose solutions, medication induced (as above), dilute hypokalaemia Genetic disorders Hypokalaemic periodic paralysis, congenital adrenal hyperplasia (11-beta hydroxylase or 17-alpha hydroxylase deficiency), Liddle/Bartter/Gitelman/Gullner syndrome, thyrotoxic periodic paralysis, SeSAME syndrome (seizures, sensorineural deafness, ataxia, mental retardation and electrolyte imbalance), glucocorticoid remedial hypertension, glucocorticoid receptor deficiency Other Discharge of ascites, peritoneal dialysis, haemodialysis, extensive burns 2. Gitelman syndrome is a rare genetic disorder with a global prevalence of approximately 1/400 00 to 1/4000.34 The disorder typically presents clinically with systemic manifestations of hypokalaemia and hypomagnesaemia, including salt craving, muscle weakness, palpitation, and low blood pressure.56 Patients with Gitelman syndrome have an increased urinary potassium excretion, while those with hypokalaemic periodic paralysis have a lower 24 hour urinary potassium excretion owing to the absence of renal losses of potassium.7 Clinical diagnosis of Gitelman syndrome is based on biochemical changes, whereas a definitive diagnosis relies on genetic testing which reveals a positive mutation for SLC12A3.8 Diagnostic criteria are listed below: Heterozygous mutations of the sodium chloride cotransporter in Chinese children: prevalence and association with blood pressure.

• Publisher: British Medical Journal Publishing Group,BMJ Publishing Group LTD
• Subject: Acetazolamide / Acidosis / Agonists / Aldosterone / Alkalosis / Anorexia / Antibiotics / Ascites / Ataxia / Blood pressure / Caffeine / Calcium (urinary) / Carbenicillin / Collaboration / Creatinine / Deafness / Diagnosis / Disease / Diuretics / Drug addiction / Drugs / Eating disorders / Endgames / Endocrine disorders / Endocrinology / Gastrointestinal tract / Genetic disorders / Genetic screening / Genetic testing / Hemodialysis / Humans / Hyperplasia / Hyperthyroidism / Hypokalemia / Hypokalemia - etiology / Hypoxia / Iatrogenesis / Metabolism / Mutation / Paralysis / Patients / Penicillin / Potassium / Potassium - therapeutic use / Renal failure / Sodium / Thyroid gland