title: Hypokalemic metabolic alkalosis caused by surreptitious vomiting: report of four cases.
abstract: Four women, aged 22 to 40 years, presented with severe hypokalemia and metabolic alkalosis. Three had related neuromuscular symptoms. All four patients denied vomiting or diuretic ingestion, and a diagnosis of Bartter's syndrome was entertained. A diagnosis of surreptitious vomiting was suspected from the characteristic urine electrolyte pattern: high values for sodium and potassium, and a chloride concentration of less than 5 mmol/l. Three patients excreted sodium and potassium primarily with bicarbonate and had an alkaline urine; the fourth patient excreted these cations primarily with an organic anion and had an acid urine (pH 5.5). Since self-induced vomiting may be a common method of weight reduction in young women, recognition of this characteristic urine electrolyte pattern will assist in the rapid diagnosis of hypokalemia and metabolic alkalosis of obscure cause.
mesh_terms: D000328:Adult; D000471:Alkalosis / Q000175:diagnosis / Q000209:etiology*; D001477:Bartter Syndrome / Q000175:diagnosis; D001835:Body Weight; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007008:Hypokalemia / Q000175:diagnosis / Q000209:etiology*; D014839:Vomiting / Q000150:complications* / Q000523:psychology