Objective: We present an uncommon case of surreptitious diuretic usage mimicking Gitelman syndrome. Case Presentation: A 31 year old Caucasian female who works as a pharmacy technician presented with fatigue, polyuria, polydipsia, intermittent leg cramps and tingling in her feet. She reports that she was diagnosed with hypertension two months before admission and was started on metoprolol succinate. This was discontinued several weeks later and she was started on spironolactone as her potassium was noted to be decreased. Her serum potassium had been persistently low for a month prior to admission and was receiving potassium supplementation. Interestingly her serum potassium was noted to be low (2.8 mmol/L) ten years ago but had normal values until one month prior to admission. On admission, the patient was noted to be normotensive with the following lab values: serum sodium 130 mmol/L(136-145); potassium 2.2 mmol/L(3.5-5.3); bicarbonate 35mmol/L(23-33); BUN 42 mg/dL(5-25); creatinine 1.4 mg/dL(0.6-1.3); uric acid 10.4 mg/dL(2.7-6.8); calcium 10.6 mg/dL(8.3-10.1); renin 92.56 ng/ml/hr(1-4) and aldosterone 74.9ng/dL(0.0- 30.0). Twenty four hour urine potassium and calcium were 58 mmol (25-150) and 84mg (42-353) respectively. Serum magnesium was normal. Serum metanephrines, cortisol, TSH and PTH were normal. The patient denied self-induced vomiting and licorice consumption. She persistently denied surreptitious diuretic usage. Renal arteriogram and MRI abdomen ruled out renal artery stenosis and renin secreting tumor respectively. Her potassium normalized with supplementation and she remained normotensive without antihypertensive medications. Urine analysis performed by high performance liquid chromatography showed hydrochlorothiazide 14mcg/ml and furosemide 5.4mcg/ml. Spironolactone was discontinued and was discharged without any potassium supplementation. Discussion: The diagnosis of surreptitious diuretic usage is largely one of exclusion, made in someone who presents with unexplained hypokalemia and metabolic alkalosis with a normal or low blood pressure. This condition mimics Gitelman syndrome except that urine diuretic screen will be positive. High urine chloride variability suggests the possibility of diuretic usage whereas urine chloride persistently greater than 25 meq/L suggests Gitelman syndrome. The diagnosis is usually made with a careful history, physical examination, measurement of the urine chloride concentration, and a urine diuretic screen. Conclusion: In patients who present with unexplained hypokalemia, metabolic alkalosis, and an index of suspicion for surreptitious diuretic use should undergo a urine diuretic screen to provide the most cost-effective care.
Shaik, S. Abichandani, A. Gayner, R. Arastu, M. (2013, May). A case of Hypokalemic Hypertension...Primum non Nocere. Poster Presented at: (AACE) The American Association of Clinical Endocrinologists, Phoenix, AZ.