Abstract

Idiopathic Intracranial Hypertension (IIH) is a common problem in general neurological practice. It is characterised by raised intracranial pressure (ICP) in the absence of causative structural brain pathology. The usual presentation is of headache which is worse when supine and visual complications of raised ICP. We describe a patient that presented with symptoms and signs of raised intracranial pressure but also seizures and persistent CSF rhinorrhea when supine. Investigations revealed raised ICP with no structural cause and a cribriform plate defect with a large encephalocele. The defect appeared to auto-regulate intracranial pressure allowing the patient to maintain long symptom free periods but also led to the atypical presenting features. Patients rarely present with spontaneous CSF leaks but there is increasing recognition that CSF leakage from skull base defects may be a relatively common consequence of IIH. This can help to regulate ICP in these patients but can lead to atypical presenting features and further complications if untreated.