Idiopathic intracranial hypertension is a condition that causes increased pressure in the skull due to a buildup of cerebrospinal fluid.
Cerebrospinal fluid (CSF) surrounds the brain and spinal cord to provide protection from injury. This fluid is produced in the brain and absorbed into the bloodstream. This absorption allows the pressure in the brain to remain consistent.
Idiopathic intracranial hypertension (IIH) happens when the body makes too much cerebrospinal fluid, causing pressure on the optic nerve at the back of the eye and resulting in a condition known as papilledema. IIH can also happen when CSF is not adequately absorbed into the bloodstream, resulting in increased intracranial pressure.
The cause of idiopathic intracranial hypertension is unknown, thus the term “idiopathic.” If a cause is identified, however, the condition is known as secondary intracranial hypertension.
At University of Michigan Health, a multidisciplinary team of experts, including neurointerventional surgeons, neurointerventional radiologists and neuro-ophthalmologists, specializes in diagnosing and treating idiopathic intracranial hypertension. By working together, they aim to bring the most advanced diagnosis and treatment methods to patients with this condition.
Risk factors
IIH affects women more than men, particularly women of childbearing age who are overweight (BMI above 30). Recent weight gain and a family history of IIH may increase the risk of developing IIH.
Several other medical conditions and medications are often associated with elevated intracranial pressure as well, including:
- Kidney disease
- Anemia
- Systemic inflammatory diseases (e.g., systemic lupus)
- Certain medications
- Obstructive sleep apnea
Symptoms
Symptoms of idiopathic intracranial hypertension include:
- Severe headaches
- Pulsatile tinnitus (a whooshing sound in the ear)
- Transient visual loss, particularly with changes in position
- Vision loss
- Double vision
- Blind spots
- Neck and shoulder pain
- Peripheral (side) vision loss
Diagnosis
An evaluation, including a complete eye exam, by a skilled neuro-ophthalmologist is generally the first step toward a diagnosis of idiopathic intracranial hypertension.
IIH is suspected when swollen optic nerves at the back of the eye are detected. This condition is known as papilledema. Visual field tests may also be conducted to determine if there are blind spots in a patient’s vision.
Additional tests typically include:
- Brain imaging, such as an MRI or angiogram to rule out conditions that can present with similar symptoms, including a blood clot, vascular abnormality or brain tumor, among others.
- Lumbar puncture (spinal tap) to measure pressure inside the skull and to determine the amount of cerebrospinal fluid in the brain. If the pressure reading is above 20-30 cm of H2O, accompanied by swelling in the optic nerve at the back of the eye, idiopathic intracranial hypertension is often the cause, having excluded other issues.
Treatment
Treatment for IIH depends on test results that indicate too much CSF being produced in the brain or an issue with the amount of fluid being absorbed into the bloodstream.
A multidisciplinary team with expertise in IIH will determine the appropriate treatment method, which may include:
Weight loss if obesity is a factor.
Medications to help reduce the production of CSF and improve symptoms. Diuretics can also help reduce fluid retention and migraine medication may be prescribed to help reduce headaches.
Surgery if other treatment options do not improve papilledema and vision continues to worsen. Procedures to decrease pressure around the optic nerve include:
- Optic nerve sheath fenestration - An opening is made into the membrane surrounding the optic nerve, allowing excess cerebrospinal fluid to escape and reduce pressure on the optic nerve.
- Spinal fluid shunt - A thin tube, or shunt, is inserted into the brain to drain excess cerebrospinal fluid.
- Venous sinus stenting - This minimally invasive endovascular procedure is performed when imaging indicates narrowing of one of the brain venous sinuses — the large veins that return blood from the brain to the heart. The condition is known as venous sinus stenosis. The team evaluates the pressure gradient across the area of narrowing using an angiogram. When the measurement is significant (greater than 8 mm of HG), stent placement may be recommended. During the procedure, a stent is placed in the affected vein to normalize the pressure gradient. Blood thinners are needed after the procedure.
Why Choose U-M Health
The U-M Health neurointerventional team has been established in the practice of minimally invasive treatment of neurovascular disease in adult and pediatric populations for more than two decades. The team provides unparalleled expertise and the most advanced diagnosis and treatment methods for patients with idiopathic intracranial hypertension. In conjunction with our neuro-ophthalmology colleagues, the condition is diagnosed and conservatively treated.
In select cases with no improvement or with intolerance to conservative management, venous stenting may be an appropriate option to reduce intracranial pressure.
Through close collaboration, the neurointerventional and neuro-ophthalmological team at U-M Health strives to provide individualized care for each patient while helping to educate and guide patients through the pathway of diagnosis and treatment.
Make an Appointment
To make an appointment with our neuro-ophthalmology team, call 734-764-4190.