Unusual cause of sudden onset headache: spontaneous intracranial hypotension.

Spontaneous intracranial hypotension is a very distinctive but unusual cause of acute headache. The postural nature of the headache can be easily overlooked in the celerity to exclude subarachnoid haemorrhage. We describe the clinical and radiological features of a case that emphasizes some of the diagnostic difficulties. An approach to management and treatment for this condition is outlined.