Diabetes insipidus secondary to hydrocephalus.

Sir, I note with interest the recent report by Dr Menzies et al. of a patient with cranial diabetes insipidus secondary to arrested hydrocephalus.1 In his discussion he did not identify any previously reported cases of diabetes insipidus secondary to hydrocephalus. I recently reported a patient with diabetes insipidus which developed after subarachnoid haemorrhage.2 In the discussion, I noted a recent report of three cases of diabetes insipidus caused by hydrocephalus which occurred after subarachnoid haemorrhage.3 In these patients, the onset of ventricular dilatation was associated with the onset of diabetes insipidus. Furthermore, ventricular drainage resulted in an improvement of the diabetes insipidus in two of the cases. A.J. McMahon Department of Surgery, Victoria Infirmary, Glasgow, UK.