idiopathic intracranial hypertension
Dayton Children’s neurology department offers a specialty clinic for care for idiopathic intracranial hypertension syndrome (IIH) that brings together a team of experts in one convenient appointment.
The child meets with a neurologist as well as an ophthalmologist, a psychologist and a dietitian to provide a customized, well-rounded plan. This multidisciplinary approach is beneficial for clear communication and holistic care, leading to the best clinical outcomes for the child.
During this visit, the child will be evaluated by each specialist within the clinic. Discussions will include appropriate testing and management of the condition and staff will answer any questions you may have.
what is idiopathic intracranial hypertension (IIH)?
IIH is a condition in which there is an elevated pressure in the brain. In the past, this condition was called pseudotumor cerebri, because the signs and symptoms mimic those that a brain tumor would cause. With IIH, there is an increase of CSF (cerebral spinal fluid) in the brain. CSF is a clear, watery fluid that helps cushion the brain from contact with the skull. Too much CSF in the brain causes an increase in pressure in the head, which can lead to headaches. It also puts pressure on the optic nerve, behind the eyes which helps us to see. This results in swelling of the optic nerves, called papilledema. This can lead to blurry vision, blind spots, and even vision loss. There are many things that can cause an increase of CSF pressure in the brain, such as a brain tumor, certain medications, or even a blood clot. When the increase in CSF pressure is due to any of these above causes, it is called secondary intracranial hypertension(SIH). When these causes are ruled out, patients are diagnosed with IIH. In patients with IIH, it is unknown why they have an increase in CSF pressure.
why is it called idiopathic intracranial hypertension?
Idiopathic means unknown, intracranial means inside the head and hypertension means increased pressure. Idiopathic intracranial hypertension translates to unknown increased pressure within the head.
who is at risk for idiopathic intracranial hypertension?
IIH affects between 1-2 people in 100,000. There is no known cause for developing IIH. Anyone can start showing signs and symptoms at any point in their life. There are certain factors that put some people at an increased risk of developing IIH.
- It has been found that women who have an unhealthy weight (overweight or obese) and are of childbearing age are the highest population affected by IIH. Overweight is defined as a body mass index (BMI) between the 85thand 95th percentile. Obesity is defined as a BMI greater than the 95th percentile.
- A recent gain of 5-15 percent of total body weight is also considered a risk factor, even for people whose weight is below the 85th percentile.
- It can also be seen in women with healthy weight, or less frequently, men of healthy or unhealthy weight.
- IIH has also been associated with taking certain medications (some steroids, antibiotics, and oral contraceptive pills), as well as certain medical conditions, and even pregnancy. In these patients, it is termed as secondary intracranial hypertension as it is secondary to a known cause.
how is idiopathic intracranial hypertension diagnosed?
There is currently no way to screen for IIH. It is diagnosed only after you begin to start having the signs and symptoms of IIH (such as headaches and vision problems). If IIH is suspected, there are several tests that may be performed.
- An in-depth eye exam will be done by the eye doctor (ophthalmologist). They will look for swelling behind the eyes (papilledema) and perform other tests to assess for vision changes.
- Brain imaging will be completed to rule out other causes that can result in an increase in CSF pressure, such as a tumor or hydrocephalus (enlargement of the CSF containing structures in the brain).Some imaging that might be ordered:
- CT scan – this scan only takes a few minutes, and uses x-ray technology to take several pictures of the brain. A CT scan is effective in looking for hydrocephalus or any bleeding within the head.
- MRI – this imaging often takes 30 minutes or more and the patient must lie still during the whole procedure. The MRI gives a more detailed pictures of the brain and helps to rule out other causes.
A lumbar puncture (LP), also known as a spinal tap, will be performed. For this procedure, a needle is inserted into the lower back. When the needle is first inserted, the doctor is able to measure the amount of pressure in the head (intra-cranial pressure or ICP). Traditionally, normal CSF pressure was thought to be less than 20 mmHg, but recent studies have shown that the normal ICP in children is considered to be less than 28 mmHg, with anything above 28 considered high. In adults, ICP greater than 25 is considered high. Measuring the pressure will let us know if the signs and symptoms are being caused by an increased CSF pressure. Also, while the needle is inserted, the doctor is able to remove some of the extra CSF, which then lowers the pressure in the head and temporarily helps relieve the signs and symptoms. We might also take a sample of CSF and check it to make sure there is no underlying infection. The procedure is usually done by a radiologist under X-ray guidance and with sedation.
treatment of idiopathic intracranial hypertension
weight loss
Since the majority of IIH patients have an unhealthy weight, weight loss is recommended. Healthy eating and exercise are a critical part of treatment for these patients. Losing weight can reduce CSF intracranial pressure, optic nerve swelling and headaches, and can help lead to remission. Studies have shown that patients have reported improvement in their symptoms after losing as low as 5-10 percent of their total body weight.
medical treatment
The doctor might also prescribe a medicine to lower the CSF pressure and improve the symptoms while you continue to make efforts to lose weight. One of these medications is called Acetazolamide (Diamox), which helps lower CSF production. Common side effects of this medication are tingling in the hands and feet, increase in urination, metallic taste in the mouth – often with carbonated beverages, fatigue, and irritability. Topiramate (Topamax) is another frequently prescribed medication, that is commonly used to treat headaches and seizures. Some common side effects of this medication are drowsiness, complaints of feeling “foggy” and forgetful, weight loss, and numbness or tingling in hands and feet. In some patients, if Acetazolamide or Topiramate is not helpful or if they are allergic to these medications, Furosemide(Lasix) is used. Furosemide is a water pill (diuretic) and helps to lower CSF production.
As stated, it is thought that some medications may cause IIH. If you are on one of these medications, simply stopping it might help the IIH. Always talk with the doctor before stopping any medication.
A small number of patients find they need to have regular lumbar punctures to help relieve the pressure and remove the excess CSF.
surgical treatment
In some IIH patients, if the CSF pressure is too high with concern for an impending vision loss, the eye doctor (ophthalmologist) will perform an eye surgery to release the pressure on the optic nerves (optic nerve sheath fenestration) and to prevent permanent vision loss.
In some patients, if the medications are not helping to reduce the pressure, they will need a surgery that creates a way for the extra CSF fluid to drain from the brain. Neurosurgeons will place a shunt device, which goes in the fluid-filled space inside the brain. It is connected to a tube that is placed under the skin and empties into the abdomen, which helps drain the extra CSF fluid from the brain and reduce the CSF pressure.
how does idiopathic intracranial hypertension effect everyday life?
At first, the diagnosis of IIH might seem overwhelming. A diagnosis where the body produces too much CSF, and might potentially lead to blindness sounds scary. The good news is, as long as you are compliant with treatment, IIH can be managed. Most people with IIH lead relatively normal lives. The only change for most patients is a daily medication and regular eye exams. Sometimes, for those patients who are an unhealthy weight, losing weight is all that is needed to control their IIH.
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