Intercranial Hypertension (pseudotumor cerebri)

Intracranial hypertension is increased pressure (hypertension) inside the cranium, or skull. Inside the cranium sits the brain, surrounded by cerebrospinal fluid (CSF) and the various blood vessels that supply the brain.

What is Intracranial Hypertension?

CSF is a liquid the surrounds the brain and the spinal cord, existing in what is called the subarachnoid space. In addition to providing cushioning for the brain and spinal cord, CSF transports nutrients to the brain and removes waste. About one pint of CSF is produced and reabsorbed in one day, with 140 mL around the skull at any given time.(1)

Cerebrospinal fluid can build up in the brain because either too much is being produced or because not enough is being reabsorbed. The skull is made of bone and can't expand, and the brain and related vasculature can only compress so much, so the intracranial pressure rises when there's too much CSF.

There are various names and types of intracranial hypertension. Some of them are just different names for the same condition while others have specific features that differentiate them from the others.

Increased intracranial pressure headache is a symptom of intracranial hypertension--usually the most prominent and most severe.(2)

Acute intracranial hypertension usually happens suddenly because of an accident to the head or neck, an aneurysm, bleeding in the brain, brain tumors and abscesses, or a stroke. Once the underlying cause of the intracranial hypertension is resolved, the intracranial hypertension resolves as well.(3)

Chronic intracranial hypertension develops over time, due to a condition like blood clots, encephalitis, meningitis, certain medications, or chronic conditions Chiari malformation and high blood pressure. The source of the intracranial hypertension is known, and it is a chronic condition, so the intracranial hypertension is likely to be chronic as well.(3)

Secondary intracranial hypertension develops as the results of a medication or other condition.(8) Both acute and chronic intracranial hypertension can be secondary intracranial hypertension.

Benign intracranial hypertension(4) and idiopathic intracranial hypertension don't have an identifiable cause. "Idiopathic" is medical-speak for "we don't know what's causing it." Benign intracranial hypertension is a misnomer as there is nothing benign about intracranial hypertension--it causes a lot of pain, associated symptoms, and, depending on the cause, if left untreated, death. This is also called primary intracranial hypertension.

Pseudotumor cerebri is an older name for intracranial hypertension. "Pseudotumor cerebri" means "false brain tumor" as the symptoms of intracranial hypertension are similar to those of a brain tumor. Pseudotumor cerebri is "[a]n outdated name for idiopathic intracranial pressure," according to Cleveland Clinic, but it is still used in some medical settings.(5)

"Schematic Drawing of Cerebrospinal Fluid Circulation. Elevated CSF pressure is transmitted around the brain and along the optic nerve (sub-arachnoid space) producing papilledema."(1)

The blue in the diagram above is the cerebrospinal fluid. It is produced at the star (*) in the center of the brain. It then flows through the subarachnoid space, including around the optic nerve, and is absorbed out into the venous blood that is leaving the brain.

Left untreated, intracranial hypertension can cause seizures, strokes, neurological damage, optic nerve damage, permanent vision loss, and death.

Symptoms of Idiopathic Intracranial Hypertension (IIH) (2,4,5,6,7)

Most Common Symptoms:

A severe, throbbing or pulsing headache above the eyes or at the back of the head and neck. This headache may be worse in the morning, when lying down, when coughing, or when straining (like when having a bowel movement.) It may improve when standing up or be so painful as to cause a patient to wake from sleep. It may be accompanied by nausea and vomiting.
Temporary loss of vision, double vision, or blind spots. Vision can become dark for a few seconds, especially when coughing, sneezing, or bending down.
Symptoms usually get worse with exertion or exercise.

Other Symptoms:

Pain behind the eye and with eye movement
Photophobia--looking bright lights can cause pain.
Decreased depth perception and peripheral vision
Feeling and being sick (nausea, vomiting, fatigue)
Feeling sleepy and/or irritable
Feeling "spaced out" or less alert than usual; brain fog
Lack of energy; sleepiness
Shoulder and neck pain
Loss of feeling or weakness
Pulsatile tinnitus--a pulsing or rhythmic sound in the ears in time with the pulse or heartbeat
Problems with coordination, balance, and spatial awareness
Mental issues including confusion, aphasia, disorientation, loss of short-term memory, sometimes loss of long-term memory
Depression
Problems with walking or talking

SOMETIMES SYMPTOMS OF INTRACRANIAL HYPERTENSION ARE MEDICAL EMERGENCIES (6)

Go to the nearest emergency room or call 911 (or local emergency services) if you experience any of the above symptoms, and…

…they come on quickly, like a sudden, severe headache; sudden vision changes for no reason; confusion or weakness with no apparent cause.

…you've recently had a head injury (even if you feel well otherwise or feel it was a minor injury).

…you have a seizure, especially without the history of previous seiziures.(2)

…you have a high temperature or feel generally unwell.

Diagnosis of and Treatment for Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is a rare condition that mainly affects women in their 20s and 30s. The reason for this is unknown. It is also more likely affect people who:

live in large bodies (BMI over 30.)
are between the ages of 20 and 50.
are taking certain medicines, including birth control pills, certain antibiotics, chemotherapy medicines, steroids, some acne medications, lithium, and some thyroid medication.

Have any of the following conditions:

hormone conditions, like hypothyroidism, hyperthyroidism, Cushing syndrome, and Addison’s disease
high level of vitamin A
lack of red blood cells (iron deficiency anemia) or too many blood cells (polycythemia vera)
lupus
chronic kidney disease
head injuries
severe sinus or ear infections
measles
blood clotting disorders
malnutrition(8)
blood vessel irregularities
sleep apnea
CSF rhinorrhea(9)
CSF otorrhea(9)
nasal meningoceles/encephaloceles(9)

Diagnosing idiopathic intracranial hypertension requires seeing both a neurologist and ophthalmologist to make sure other conditions aren’t causing IIH-like symptoms.(7)

An ophthalmologist is involved because the excessive cerebrospinal fluid can cause swelling of the optic nerve. The optic nerve is wrapped in a sheath. When more CSF is present, the sheath tries to make room for the extra fluid, but only has so far it can swell. This then puts pressure on the optic nerve which becomes less effective at doing its job.

An eye exam can show swelling near the optic nerve, and a visual field test can check for blind spots.(5) An ophthalmologist will also perform a dilated eye exam.(10) They may also order an optical coherence tomography which is an imaging test to measure the thickness of the layers of the retina. Photos of the patient’s eyes may be taken as well.(8)

Image from Nationwide Children’s (13)

To make certain what the patient has is IIH, a neurologist will gather the patient’s medical history and do a physical exam, including a neurological exam to check muscle strength, reflexes, balance, and other signs that there could be an issue with the brain. They will often have a magnetic resonance imaging (MRI) or computed tomography (CT) scan of the head and brain performed. In addition, the neurologist may also perform an assessment of the patient's eyes and vision to assess any visual changes that may have occurred. A lumbar puncture (also called a spinal tap) may be done to check for high pressure in the CSF.

The following five things differentiate idiopathic intracranial hypertension from other conditions. If all five are present, it will often result in a diagnosis of IIH.(7)

Papilledema (swelling of the eye nerves—though there is a type of IIH without papilledema(11))
A normal neurological evaluation
Normal brain imaging using a magnetic resonance imaging (MRI) or computed tomography (CT) scan. A scan of the veins of the brain (MRA) can be useful to rule out venous sinus thrombosis (brain aneurysm.)
Normal cerebrospinal fluid analysis
Elevated lumbar puncture opening pressure about 25 cm

Treatment for idiopathic intracranial hypertension can include*: (2,4,6,8)

Stopping medicine that may be causing symptoms
Limiting fluids or salt in the diet
Diuretics—medicine to remove excess fluid from the body
Medicine to reduce the production of CSF in the brain (acetazolamide or topiramate)
Medicine to reduce swelling (some migraine medications can sometimes help with the severe headaches)
Draining extra CSF fluid or bleeding around the brain
A short course of steroid medication to relieve the headaches and reduce the risk of vision loss
Regular lumbar punctures to remove excess fluid from the spine and relieve the pressure on the brain

Surgery: there are four types of surgery for idiopathic intracranial hypertension

Shunt surgery--a thin flexible tube is inserted into the fluid-filled space in the skull or spine to divert excess fluid to another part of the body
Optic nerve sheath fenestration--the protective layer surrounding the optic nerve (the one that connects the eye to the brain) is opened to relieve pressure on the nerve and allow fluid to drain away. This is especially protective against vision loss.
A relatively new procedure which is rarely used, venous sinus stenting, involves placing a stent (a small device that keeps the vein open) into one of the larger veins in the head to increase the blood's ability to flow. More research needs to be done on the effectiveness of this procedure.8
A craniotomy, a procedure that removes part of the skull to ease swelling (though this is rare).(9)

After treatment, regular checkups with an ophthalmologist to check for vision changes is recommended.(5) The best treatment for IIH is one that fits with the patient’s symptoms, severity, goals, and lifestyle.

*Some studies say that losing 5% to 10% of body weight can help relieve idiopathic intracranial hypertension symptoms(12) and that people who live in larger bodies (a BMI greater than 30) are at a higher risk for idiopathic intracranial hypertension. It has not been proven that living in a larger body does not cause idiopathic intracranial hypertension as people in smaller bodies get it, too. Researchers have known for years that sustained weight loss is not an ethical, evidence-based medical treatment.(15,16,17) For a weight-neutral method of treating idiopathic intracranial hypertension, see the IIH Health at Every Size® Health Sheet.(14)

1. https://ihrfoundation.org/what-is-ih

2. https://www.hopkinsmedicine.org/health/conditions-and-diseases/headache/increased-intracranial-pressure-icp-headache

3. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/idiopathic-intracranial-hypertension

4. https://www.cedars-sinai.org/health-library/diseases-and-conditions/i/pseudotumor-cerebri.html#:~:text=Idiopathic%20intracranial%20hypertension%20(IIH)%20is,called%20cerebrospinal%20fluid%20or%20CSF.

5. https://my.clevelandclinic.org/health/diseases/21968-idiopathic-intracranial-hypertension

6. https://www.nhs.uk/conditions/intracranial-hypertension/

7. https://www.iih.org.uk/product/4/diagnosis

8. https://www.mayoclinic.org/diseases-conditions/pseudotumor-cerebri/diagnosis-treatment/drc-20354036

9. https://uvahealth.com/services/benign-brain-tumor/pseudotumor-cerebri

10. https://www.nei.nih.gov/learn-about-eye-health/healthy-vision/get-dilated-eye-exam

11. https://www.iih.org.uk/shopimages/pdfs/What-is-IIH-WOP.pdf

12. https://ihrfoundation.org/what-is-ih/idiopathic-ih-and-weight