Idiopathic intracranial hypertension (IIH) is a disorder of increased pressure in the brain. When a condition is idiopathic, that means its exact cause is unknown.
Increased pressure in the brain usually causes severe headaches and changes in vision. When IIH is discovered and treated early, patients gradually improve. If untreated, the changes in vision may be permanent. Long-term vision loss is rare. It is the major concern associated with IIH.
IIH is also known as pseudotumor cerebri.
Like the heart, the brain requires a certain level of pressure to function properly. In IIH, the pressure in the brain is increased. Increased pressure in the brain leads to:
- Swelling in the optic nerves (the nerves of the eyes; this is also known as papilledema)
Optic nerve swelling can lead to changes in vision or even vision loss. In some cases, these vision changes or losses can be permanent. However, permanent vision loss is rare when IIH is treated early.
IIH mostly affects overweight adolescent females. Other risk factors include:
- Rapid weight gain
- Being of childbearing age
IIH can also occur in males and older people. IIH is a rare diagnosis, but it tends to affect teenagers and young adults. Two of every three IIH cases are among youth under eighteen.
The exact mechanisms of how and why IIH develops are unknown. However, some ideas as to why IIH occurs include:
- Changes of blood flow within the veins of the brain
- Problems with how spinal fluid is draining
- Increased pressure within the veins of the head
IIH can be caused by certain medical conditions or treatments. These include:
- Vitamin and mineral deficiencies or overdoses
- Anemia, or low numbers of red blood cells
- Medications, such as:
- Growth hormones
- Tetracycline and minocycline antibiotics
- High-dose vitamin A
- Some acquired or inherited autoimmune and blood disorders
Obesity and rapid weight gain are strongly associated with IIH.
SIGNS AND SYMPTOMS
There are two major symptoms associated with IIH: headaches and vision changes.
Headaches are the most common symptom of IIH. Each patient may experience the headaches differently. Sometimes patients have nausea and vomiting with the headaches. The headaches tends to be worse when lying down, whether at night or first thing in the morning. It is rare for a patient to have IIH without headaches.
Vision changes can include:
- Seeing floaters or shapes
- Dimming or blurring of vision
- Double vision
- Loss of vision, which can be temporary or permanent
Vision loss can:
- Affect the sides of vision (peripheral vision)
- Make central vision blurry
Other Signs of IIH
Other signs of high pressure in the brain include:
- Whooshing, heartbeat-like sounds in the ears (pulsatile tinnitus)
- Pain behind the eyes
- Hearing abnormal noises
- Neck pain
- Back pain
IIH is investigated when a patient shows the signs and symptoms of increased pressure within the brain. A physical exam will often reveal swelling within the optic nerves, which are the nerves of the eyes. (This is also known as papilledema.)
There are several steps to making an IIH diagnosis:
1. Eye exam.
First, a patient should have a complete eye exam.
2. Magnetic resonance imaging (MRI).
Next, images of the brain taken with MRI can look for other causes of increased pressure in the brain. Imaging of the brain vessels with magnetic resonance venography (MRV) may be helpful as well.
3. Lumbar puncture (spinal tap).
Finally, doctors need to obtain fluid from around the spine. This is done using a procedure known as a lumbar puncture or spinal tap. While the patient is lying down and relaxed, fluid from around the spine is drawn into a small tube. The pressure at which the fluid comes out is measured. If it is higher than normal, this is consistent with a diagnosis of IIH. Additional tests on the cerebral spinal fluid may be done.
The goals of treatment are to improve headaches and prevent vision loss.
Several types of treatments may be used for IIH. They can include removing the underlying cause of the disorder or treating the symptoms of IIH.
In patients with obesity, weight loss is the main treatment for IIH. The goal of weight loss treatment is to bring down a patient’s weight by 5% to 10%. A low-sodium weight reduction program may be recommended in consultation with a dietician or nutritionist. Some patients over eighteen years old may undergo gastric bypass surgery.
One of the first steps to treating IIH is reviewing the patient’s medication and vitamin list. Any medications or vitamins linked to IIH may be stopped.
Many times, the treating physician will prescribe a medication called acetazolamide. Acetazolamide reduces the amount of cerebral spinal fluid that the brain produces. This then reduces the pressure within the brain. Research shows that this medication can improve:
- Quality of life
Other medications may be used in cases where the headaches are not responding to other treatments or if vision is not improving.
In rare cases, further treatments are necessary:
Repeat spinal taps.
These may be needed to reduce the pressure in the brain.
Surgery on the optic nerve.
Surgery is sometimes needed to allow fluid to drain out from behind the eye. This is known as an optic nerve fenestration. The procedure creates a window in the coating around the optic nerve to help relieve pressure.
Surgical placement of a shunt.
If pressure remains elevated, a shunt (a special tube) can drain fluid from the brain. This can be placed by neurosurgeons.
Symptoms can last for months or years in some patients and be life-long in others. With treatment, there is typically a gradual improvement in vision with minimal, if any, vision loss. Cases where vision loss is significant or permanent are uncommon in IIH.
IIH can appear again months or years after treatment. It is important for patients to have yearly follow-up eye exams.
The mission of the Bobby Jones Chiari & Syringomyelia Foundation (Bobby Jones CSF) is to advance knowledge through research and to educate the medical, allied sciences and lay communities about Chiari, syringomyelia and related disorders, including Idiopathic Intracranial Hypertension (IIH). Patient information includes the Chiari Malformation & Syringomyelia Handbook which is an excellent resource for patients and medical professionals. Join the online community to connect with patients, families, friends and caregivers for support and inspiration.
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ClinicalTrials.gov for Idiopathic Intracranial Hypertension (birth to 17 years).
These are clinical trials that are recruiting or will be recruiting. Updates are made daily, so you are encouraged to check back frequently.
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Pseudotumor cerebri information page [Internet]. National Institute of Neurological Disorders and Stroke. National Institutes of Health [cited 2022 Mar 24]. Available from: https://www.ninds.nih.gov/Disorders/All-Disorders/Pseudotumor-Cerebri-Information-Page/
Pseudotumor cerebri: Q & A [Internet]. Neurology and Neurosurgery. Johns Hopkins Medicine [cited 2022 Mar 24]. Available from: https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/cerebral-fluid/pseudotumor_cerebri/pseudotumor_cerebri_qa.html/
Friedman DI. The pseudotumor cerebri syndrome. Neurol Clin. 2014 May;32(2):363-96. https://doi.org/10.1016/j.ncl.2014.01.001. Epub 2014 Feb 28. PMID: 24703535.
Gillson N, Jones C, Reem RE, Rogers DL, Zumberge N, Aylward SC. Incidence and Demographics of Pediatric Intracranial Hypertension. Pediatr Neurol. 2017 Aug;73:42-47. https://doi.org/10.1016/j.pediatrneurol.2017.04.021. Epub 2017 Apr 27. PMID: 28668233.