[Hyponatremia, rhabdomyolysis and encephalopathy after taking hydrochlorothiazide and drinking tea]

A 45-year-old women presented with muscular weakness, restlessness and blurred vision. She had been taking 25 mg hydrochlorothiazide daily and had ingested 7 liters of herbal tea during the day of admission. INVESTIGATIONS AND CLINICAL FINDINGS: Laboratory data showed severe hyponatremia (108 mmol/l, normal range 136 - 152), reduced potassium, glomerular filtration rate as well as plasma and urine osmolality, while the osmolality of the urine was lower than that of the plasma. Creatine kinase and myoglobin were elevated more than one hundredfold. CT scans of the brain was normal.

The normovolemic hyponatremia had caused encephalopathy and rhabdomyolysis resulting in temporary disorder of renal function. Despite of immediately started infusion of standard sodium solution to elevate the serum sodium level slowly the encephalopathy deteriorated initially, but ultimately recovered completely.

Patients with severe hyponatremic encephalopathy require an immediate treatment, but the sodium level should not be elevated by more than 10 mmol/l per day, in order to avoid spontaneous pontine myelinolysis. Even when the hyponatremia is carefully corrected, the encephalopathy may deteriorate in the course of treatment.