IIH / Pseudotumor Cerebri

What is IIH / Pseudotumor Cerebri?

Idiopathic intracranial hypertension (IIH), formerly known as pseudotumor cerebri, is a condition in which the pressure of the cerebrospinal fluid (CSF) inside the skull is elevated without an identifiable cause such as a tumor. It most commonly affects women of childbearing age, particularly those who are overweight. Left untreated, IIH can lead to permanent vision loss due to damage to the optic nerves from chronic elevated pressure.

Symptoms

• Headaches, often severe and daily, sometimes worse in the morning
• Transient visual obscurations — brief episodes of dimming or graying of vision lasting seconds
• Pulsatile tinnitus — a whooshing sound in the ears that matches the heartbeat
• Double vision due to sixth cranial nerve palsy
• Neck and shoulder pain
• Progressive visual field loss if untreated

Diagnosis

Evaluation includes a comprehensive eye examination with dilated fundoscopy to look for papilledema (swelling of the optic disc). Visual field testing documents any peripheral vision loss. An MRI of the brain with MR venography rules out structural causes and venous sinus thrombosis. A lumbar puncture (spinal tap) measures the opening pressure of the CSF — an elevated opening pressure above 25 cm H2O, with normal CSF composition, confirms the diagnosis.

Treatment

Treatment focuses on protecting vision and reducing intracranial pressure. Weight loss is the most effective long-term treatment — even a 5-10% reduction in body weight can significantly improve symptoms. Acetazolamide (Diamox) is the first-line medication, which reduces CSF production. In severe or rapidly progressing cases, surgical options include optic nerve sheath fenestration (to directly protect the optic nerve) or CSF shunting procedures. Regular monitoring of visual fields and optic nerve health is essential.