Idiopathic Intracranial Hypertension - IIH - is a condition that consists of high pressure in the head. IIH is most prevalent in the female population of ages 20 to 45 years old and the prevalence of IIH is 0.5-2.0 per 100,000 in the general population of the United States. “Idiopathic” means that a specific cause is often not identified.
IIH was formerly called “pseudotumor cerebri”. The name ‘pseudotumor” comes from the symptoms caused by this condition which can be similar to having a brain tumor. But pseudotumor cerebri/IIH is not a brain tumor — the presence of a tumor or other condition must be excluded in order to make the diagnosis.
The classic symptoms of IIH include headaches, vision changes and pulsatile tinnitus.
The headaches are typically worse when lying down and patients often wake from sleep with headache.
Visual changes include blurry vision, double vision (called “diplopia”), transient vision loss lasting a few seconds (called “transient visual obscurations”) and loss of peripheral vision.
Pulsatile Tinnitus is the symptoms of hearing a rhythmic sound in the ear, in sync with the heartbeat.
Other symptoms include neck pain, nausea and brain fogginess.
Patients with possible IIH should be evaluated by expert physicians. Evaluation by an ophthalmologist is imperative as IIH can manifest with swelling of the optic nerves, a condition called “papilledema”). Neurological exam is essential also.
Brain imaging, typically MRI, is necessary to exclude conditions (such as tumors) which could have the same symptoms as IIH.
Finally, a procedure called spinal tap or lumbar puncture is often required. The spinal tap is a minimally invasive procedure during which a thin needle is inserted in the skin in the lower back and navigated into a sack of fluid. This fluid is called CSF (cerebrospinal fluid) and exists around the brain and spine. Once the needle tip is in the fluid, we can measure the intracranial pressure and also sample fluid for more tests. At the same time, we can remove some of the CSF and decrease the pressure in the head.
Venous Sinus Stenosis
Today we know that the majority of patients with IIH have severe stenosis (“narrowing”) of the large veins in the brain. This condition is called Venous Sinus Stenosis . This condition can be easily demonstrated with a non-invasive test called MRV (MRI for the Veins).
The large veins of the brain (“venous sinuses”) facilitate removal of CSF from the brain. Once a patient has venous sinus stenosis, the removal of CSF from the brain is impaired. As CSF is constantly produced, impaired removal of CSF leads to excessive CSF in the brain and leads to increased intracranial pressure.
If the patient is overweight, the initial recommendation will be weight loss. Achieving a healthy weight may help alleviate headache and other symptoms.
There are medications that can help reduce intracranial pressure, including diuretics (which reduce fluids in body tissue) and migraine drugs. Medicines used to treat glaucoma can also be effective, since they reduce pressure by suppressing production of cerebrospinal fluid (CSF).
Traditional Surgical Options
Traditional surgical treatments include:
- Shunt surgery: placement of a shunt in the brain to drain excess CSF and relieve the pressure.
- Optic Nerve Sheath Fenestration: surgery around the optic nerve to relieve pressure around the optic nerve and protect the vision.
Venous Sinus Stenting
A new minimally invasive procedure called Venous sinus stenting has been performed by Dr. Patsalides since 2012 has been shown to be effective in the treatment of patients with IIH. Clinical trials conducted at Weill Cornell have shown that venous sinus stent is effective in decreasing intracranial pressure and alleviating symptoms of IIG in carefully selected patients with IIH. The procedure is minimally invasive and is performed via a tiny incision in the arm or leg. For more details of the procedure please refer to the Venous Sinus Stenting section.
(Figure 1) The illustration shows normal veins draining blood from the brain towards the neck (blue arrows)
(Figure 2) The illustration shows venous sinus stenosis (red circles). As a result of the narrowed veins, blood flow from the brain to the neck is compromised, leading to build of pressure in the veins (blue arrows) and subsequently increased intracranial pressure and IIH.
(Figure 3) The venous sinus narrowing has been treated with placement of a stent (circle). After stenting, the blood flow from the brain to the neck is restored (blue arrows), leading to normalized intracranial pressure and improvement of the symptoms of IIH.