Lessons to be learned: a case study approach diuretic therapy and a laxative causing electrolyte and water imbalance, loss of attention, a fall and subsequent fractures of the tibia and fibula in an elderly lady.

Abstract

The case is described of a hitherto well, alert and intelligent lady of 85 years of age, who commenced medication with diuretics--prescribed for mild congestive cardiac failure; she developed constipation consequent upon the diuresis and dehydration thereby provoked. As a result she began to take, unknown to her general practitioner, regular and increasing amounts of laxatives. At about this time she was noted by her son to become "rapidly senile"--with the result that she fell on account of losing her normally good concentration and attention; she sustained fractures of the right tibia and fibula. Shortly after admission to hospital she was premedicated, anaesthetised and operated upon, following which there was a postoperative regimen comprising several litres of low sodium isotonic infusions, all given intravenously. She was found at this point to be severely hyponatraemic with a low serum osmolality, but following the institution of water restriction rapidly improved as her serum sodium rose again; there was an accompanying massive diuresis as the previously retained water was voided. Concomitant with the serum sodium rise her mental concentration and attention regained their former levels. The biochemical and cellular mechanisms underlying this patient's symptoms are discussed.