Idiopathic Intracranial Hypertension (IIH)

Idiopathic intracranial hypertension is a condition in which pressure around the brain is raised for no clear reason, causing headaches and swelling of the optic nerves that can threaten vision.

Common symptoms

Persistent headaches, brief blurring or greying of vision, double vision, a whooshing noise in the ears, nausea, and enlarged blind spots or loss of side vision.

Description

In IIH, the pressure of the fluid surrounding the brain is higher than normal, although scans show no tumour or other obvious cause. This pressure pushes on the optic nerves, causing a characteristic swelling called papilloedema that can be seen at the back of the eye.

The condition most commonly affects younger women, particularly those with a higher body weight, although it can occur in others. Without treatment, the optic nerves can be damaged, leading to permanent loss of side vision or, in severe cases, blindness.

Treatment usually involves weight loss if relevant, medicines such as acetazolamide to reduce fluid production, and close monitoring of vision and visual fields. In severe or treatment-resistant cases, surgery to protect the optic nerves or drain fluid from around the brain may be considered.