Subdural hygroma in association with middle fossa arachnoid cyst: acetazolamide therapy

Intracranial arachnoid cysts are cerebrospinal fluid-filled collections between arachnoid layers. While many are silent, arachnoid cysts can become symptomatic if there is sudden expansion, haemorrhage or rupture with the development of subdural hygroma or subdural hematoma. Several studies have demonstrated the association of arachnoid cysts with subdural hygroma and subdural hematoma. We describe a 9-year-old girl with a moderate-sized middle-fossa arachnoid cyst and bilateral frontal subdural hygroma presenting with raised intracranial pressure. She was treated with acetazolamide which resulted in resolution of the subdural hygroma and relief of symptomatology.