Hyponatraemia must be treated with low water input

EDITOR,—S M Matthai and colleagues have rightly brought our attention again to hyponatraemia as a complication of ingesting 3, 4-methylenedioxy-methamphetamine (MDMA or “ecstasy”), adding two cases1 to at least four previously described. The syndrome of inappropriate secretion of antidiuretic hormone has been proposed as the cause in five of these six cases.1

I am unconvinced that the clinical and biochemical details presented in these cases point indisputably to the syndrome of inappropriate secretion of antidiuretic hormone. In this syndrome the inappropriateness is not that the urine is concentrated in the presence of dilute plasma, because this can occur in other diseases such as …