Diagnosis: Idiopathic Intracranial Hypertension, previously known as “pseudotumor cerebri”
Clinical Keywords: IIH, pseudotumor cerebri, headache, partially empty sella, papilledema
- 2.Visual changes
- 3.Ringing in the ears (tinnitus)
The brain is surrounded by a clear fluid called cerebrospinal fluid (CSF) which is also found in the nerves going to the eyes (optic nerves) and within large spaces inside the brain (ventricles).
In some people, usually obese women of childbearing age, the pressure of the fluid can become abnormally high without a specific cause. This is called idiopathic intracranial hypertension and can lead to symptoms such as headache (known as an idiopathic intracranial hypertension headache), visual changes, and ringing in the ears.
Have you recently had a brain MRI or CT scan to check for idiopathic intracranial hypertension but are confused by what your scan means? We can help.
What is idiopathic intracranial hypertension?
Idiopathic intracranial hypertension (IIH) is a condition that causes high pressure around the brain, leading to symptoms like headaches and changes in vision. “Idiopathic” means the cause is unknown; “intracranial” refers to being in the skull, and “hypertension” means high pressure.
Medical Description of IIH
Cerebrospinal fluid completely surrounds the brain and all intracranial contents within the skull as well as flowing into the optic nerves. The fluid is made in the choroid plexus within the large spaces on the inside of the brain called ventricles. For some people, the pressure of the cerebrospinal fluid can increase and result in mass effect (pushing) on the nearby parts of the brain. Imaging findings for IIH are nonspecific, but some findings that may suggest the diagnosis in combination with the right age/gender and clinical symptoms, include:
- Partially empty sella: increased CSF pressure which flattens the pituitary gland
- Increased CSF within the optic nerve sheaths with or without tortuosity
- Flattening or reversal of the optic disk (the portion of the nerve right at the globe or eyeball); seen clinically as papilledema
- Cerebellar tonsillar ectopia: downward displacement of the cerebellar tonsils through the foramen magnum
- Narrowing of the bilateral transverse dural venous sinuses
- Increased subcutaneous face of the neck and scalp
Intracranial Hypertension Symptoms
The most common symptoms include:
- Tinnitus (ringing in the ears)
- Double vision
- Temporary blindness, blind spots, or peripheral (side) vision loss
- Neck and shoulder pain
What are the best methods of diagnosing IIH?
Best Imaging Study: MRI of the Brain
Other Tests: Fundoscopic exam by an eye doctor, a lumbar puncture to measure cerebrospinal fluid pressure
It can be difficult to diagnose IIH because there are many other things that can cause a high-pressure headache. The best way to diagnose IIH is through a combination of an MRI or CT scan and a lumbar puncture (also known as a spinal tap).
In order for doctors to be able to diagnose IIH, they must find all 5 of the following:
- No other cause found on brain imaging (MRI or CT scans), including tumors or venous sinus thrombosis.
- Normal neurological exam, except for a possible sixth nerve palsy which can cause double vision.
- Normal brain fluid (CSF) analysis.
- Opening pressure of CSF during a lumbar puncture greater than 25 cmH2O.
- Papilledema (optic disk swelling) on fundoscopic (eye) exam.
What is the treatment for IIH?
- No symptoms: None
- Mild Headache: OTC pain medications
- Severe Headache and/or visual symptoms: acetazolamide
- Continued symptoms with acetazolamide: optic nerve fenestration (surgery), lumpoperitoneal shunt placement (surgery)
The treatment for IIH typically depends on the severity of the condition and the cause (if it is known). The 3 main courses of treatment include:
Losing weight is often the first line of treatment for patients who are overweight or obese and have IIH, as it can help relieve symptoms and lower the risk of complications.
Researchers have found that losing 5 to 10 percent of your body weight can help lessen symptoms. However, it is always advised to talk to your doctor before making any major changes to your diet or exercise routine.
If diet and exercise aren’t enough to reduce your symptoms, you may be prescribed a medicine called acetazolamide (Diamox) in addition to your weight loss plan. This medicine lowers the amount of CSF your body produces.
If other treatments fail to help, your doctor may recommend surgery to relieve the pressure on your brain. In shunt surgery (also called ventriculoperitoneal or VP hole placement), doctors drill a small hole in the skull and place a thin, flexible tube—called a shunt—into it. The other end of this tube drains fluid from around your brain into another part of the body, where it can be reabsorbed by capillaries; this decreases intracranial pressure.
Another form of surgery is optic nerve sheath fenestration, which involves making a small hole in the protective covering around the optic nerve.
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