Pseudo-subarachnoid haemorrhage: An unusual presentation of hyperviscosity syndrome.

Hyperviscosity syndrome can present with haematological, neurological or cardiovascular manifestations. The common differential diagnoses for severe headache and altered sensorium in a patient with Eisenmenger syndrome include brain abscess, meningitis, cortical venous thrombosis and subarachnoid haemorrhage (SAH). We report a patient with Eisenmenger syndrome with hyperviscosity, presenting as pseudo-SAH, which was successfully treated with phlebotomy.