Persistent Cerebrospinal Fluid Leukocytosis: Could this be Idiopathic Intracranial Hypertension?

A 37-year-old female, a known epileptic, presented to the neurology clinic with a seven-day history of persistent bilateral headache not improving with analgesics. Her neurological and systemic examinations were unremarkable except for right optic disc edema. Magnetic resonance imaging (MRI) brain and magnetic resonance venography (MRV) were normal but her cerebrospinal fluid (CSF) opening pressure was 280 mm of water with a CSF white cell count of 214. The patient showed improvement following treatment with intravenous antibiotics and acyclovir. She returned a week later with double vision and blurring in both eyes. Examination showed bilateral sixth nerve palsies and bilateral optic disc edema with left fundal hemorrhages. The spinal tap was repeated again, which showed a CSF opening pressure of 500 mm of water and the white cell count was 48. Extensive investigations for etiologies were mostly unrevealing. The patient was started on acetazolamide and topiramate combined with a large-volume therapeutic CSF tap. She continued to improve subsequently and was at the baseline functional state at three months, with complete resolution of hemorrhages and optic disc edema. Idiopathic intracranial hypertension (IIH) may present with persistent abnormal CSF with a high white cell count. Therefore, this must be diagnosed with caution, as it may be misdiagnosed and wrongly treated for other causes.