Acute hyponatraemia and 'ecstasy': insights from a quantitative and integrative analysis.

A 20-year-old woman attended a 'rave party' where she took the drug 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy'). She had used this drug previously without serious adverse effects. On this occasion, while both she and her friends drank a large quantity of water, only she became seriously ill. The initial manifestation was an altered sensorium; several hours later she had a grand mal seizure. In the Emergency Department, the most striking features were the severe degree of hyponatraemia (112 mmol/l) and cerebral oedema. To explain the basis for this life-threatening clinical presentation, an imaginary consultation was sought with Professor McCance. Using both a deductive and a quantitative analysis that involved several medical subspecialties, he illustrated that a simple story of water ingestion and vasopressin release was not sufficient to explain her hyponatraemia. It was only after events in her gastrointestinal tract were analysed that a plausible hypothesis could be constructed.