Idiopathic Intracranial Hypertension (IIH)
By: Seniha Ozudogru, MD
Headache Medicine Fellow
University of Utah Neurology Department
Idiopathic Intracranial Hypertension is a rare disease that primarily impacts women during their reproductive years. Also known as a High-Pressure Headache, the most common symptom of IIH is head pain that can be severe and long-term. Cause by raised pressure within the skull, the root reasoning behind this condition is unknown. We asked Dr. Seniha Ozudogru from the University of Utah Neurology Department to shed some light on the disease.
What is Idiopathic Intracranial Hypertension (IIH)?
Previously known as Pseudotumour cerebri, IIH is a disorder with elevated pressure inside the skull, which puts pressure on the brain. Idiopathic means the cause of the raised pressure is unknown. Most commonly, IIH occurs in obese women of childbearing age. The brain and the spinal cord are bathed in a clear, watery fluid called cerebrospinal fluid (CSF). This fluid helps to cushion the brain from contact with the skull when the head is moved vigorously. In IIH, there is too much CSF.
How Do I Know If I Have IIH?
A headache associated with IIH can mimic migraine or a tension-type headache. They are frequently worse in the morning and can even wake you up from sleep. Other symptoms accompany the headache such as temporary vision dimming, double vision, noises in the ear that may be synchronous with a heartbeat, neck pain, and migraine symptoms like nausea, photo and photophobia.
What Causes IIH?
Most people with IIH have a history of recent weight gain or obesity. Other causes include medications such as tetracycline, excessive Vitamin A, Tretinoin, steroids, growth hormone.
How is IIH Diagnosed?
The correct diagnosis is essential. First, your doctor will give you a thorough eye exam, which is the most important part of the neurological examination. It will include a funduscopic exam, a formal visual field test (not just an eye chart), and an eye movement test. He/she should then perform an MRI or CT scan to rule out the possibility of an intracranial lesion. Then, a spinal tap is required to determine if there is raised pressure. You should be lying on your side and not sitting when this is performed.
Be sure your doctor also completes imaging studies for cerebral venous sinus thrombosis (clot in brain veins) since this can present itself almost exactly like IIH.
Is There Treatment For Idiopathic Intracranial Hypertension?
Because ongoing, high intracranial pressure can damage the optic nerve and result in permanent loss of vision, the goal of treatment is to decrease the pressure and preserve the optic nerve. The most effective way is to lose weight while also taking Acetazolamide. The most common side effects are paresthesia, metallic taste and drowsiness. Acetazolamide and other diuretics can be used to reduce cerebrospinal fluid (CSF) production. Topiramate can be used for people who cannot tolerate Acetazolamide. If medical management fails, optic nerve fenestration, neurosurgical shunts, and occasionally weight loss surgery should be considered in those who are unable to lose weight.
If you believe you suffer from IIH, consult a headache specialist who can help direct you toward diagnosis and treatment options. Please visit the American Migraine Foundation website to find a doctor in your area.
Headache Classification Committee of the International Headache Society (IHS). The International Classification of Headache Disorders, 3rd edition (beta version). Cephalalgia, 2013; 33(9): 629–808
Effect of acetazolamide on visual function in patients with idiopathic intracranial hypertension and mild visual loss: the idiopathic intracranial hypertension treatment trial. NORDIC Idiopathic Intracranial Hypertension Study Group Writing Committee, Wall M, McDermott MP, Kieburtz KD, Corbett JJ, Feldon SE, Friedman DI, Katz DM, Keltner JL, Schron EB, Kupersmith MJ. JAMA. 2014 Apr 23-30;311(16):1641-51.