What is idiopathic intracranial hypertension?
Idiopathic intracranial hypertension (IIH) is a disorder that results from an increase in the pressure of the Cerebro-Spinal Fluid (CSF) that cushions and protects the brain and spinal cord. The CSF is constantly produced in the brain and reabsorbed back into the bloodstream at a fairly constant rate. This allows the fluid pressure around the brain to remain constant.
What are the symptoms of idiopathic intracranial hypertension?
- Headaches that are generally nonspecific in location, type and frequency and can be associated with nausea and vomiting.
- Pulsatile tinnitus is a rhythmic or pulsating ringing heard in one or both ears.
- Horizontal double vision can be a sign of pressure on the 6th cranial nerve(s).
- Nonspecific radiating pain in the arms or legs (radicular pain).
- Transient obscurations of vision (TOV), which are temporary dimming or complete blacking out of vision.
- Visual field defects. These defects can occur in the central as well as the peripheral vision.
- Loss of color vision.
What causes idiopathic intracranial hypertension?
The cause is usually not known. A common explanation for increased pressure is a problem with the reabsorption of this fluid back into the body, which causes the pressure to increase. Sometimes the cause is determined and is referred to as “secondary” intracranial hypertension.
What are the risk factors for idiopathic intracranial hypertension?
The majority of cases of IIH are adult obese females. Other risk factors include use of certain medications (oral contraceptives, steroids, vitamin A, Isotretinoin, lithium, growth hormone, nitrofurantoin, phenytoin, sulfa drugs, minocycline, Tamoxifen, naladixic acid, thyroid replacement, tetracycline, and some chemotherapeutic drugs).
Medical conditions associated with idiopathic intracranial hypertension include blockage of the brain’s venous drainage (dural sinus thrombosis), renal disease, head injuries, Lyme disease, lupus, acute sinusitis, measles, blood clotting disorders, anemia and malnutrition.
Can idiopathic intracranial hypertension affect children?
Yes, and can generally be divided into two groups. The first group includes prepubescent children and tends to be “secondary” which affects males and females equally. The second group, post pubescent teenagers, tends to fit the adult stereotype.
How is pediatric idiopathic intracranial hypertension diagnosed?
If idiopathic intracranial hypertension is suspected, an ophthalmologist usually examines the optic nerve for swelling (papilledema) and the visual field (if possible) for defects.
If MRI is unremarkable, a lumbar puncture (spinal tap) is performed to determine the pressure as well as content of the CSF. High pressure of CSF is indicative of IIH.
How is idiopathic intracranial hypertension treated?
The ophthalmologist monitors vision and the papilledema. Weight loss for the obese is recommended. The mainstay of treatment is medication to lower the CSF pressure, which decreases papilledema. The four groups of medications include carbonic anhydrase inhibitors, steroids, migraine medication, and diuretics.
Less commonly surgery of the spinal cord (shunting) or the optic nerve (fenestration of optic nerve sheath) are utilized to lower pressure.
Are there treatments besides medicine and surgery that can help?
The most important thing anyone can do to improve this condition is lose weight if they are obese. Ask your doctor about local resources and clinics designed to assist you in your weight loss.
What is the prognosis of idiopathic intracranial hypertension?
As many as 10 percent of the people with pseudotumor cerebri experience progressively worsening vision and may eventually become blind. Even if symptoms have resolved, a recurrence can occur months or even years later. It is important to have regular follow-up eye examinations.
Credits: Journal of American Association for Pediatric Ophthalmology and Strabismus