Intracranial hypertension: was it really idiopathic?

A healthy 44-year-old slim female presented with a constant, non-specific dull headache of subacute onset. The examination showed papilloedema but no other problem. On further questioning she revealed transient visual obscurations and pulsatile tinnitus. The CT scan of the brain was normal, the lumbar puncture showed increased pressure but normal cerebrospinal fluid, and the MR scan and MR venogram was reported showing a small area of developmental venous anomaly in the left parietal region but no venous thrombosis. Benign intracranial hypertension (BIH) was diagnosed but later in the course further tests were done as the patient was atypical for BIH, which revealed essential thrombocythaemia. A CT venogram was arranged which showed partly recanalised chronic sigmoid sinus thrombosis with dilation of collaterals. The patient was treated with acetazolamide, wafarin and hydroxycarbamide. The headache resolved quickly and the papilloedema reduced significantly over 6 months.