What is Pseudotumor Cerebri?
Pseudotumor cerebri (PTC), also known as idiopathic intracranial hypertension, is a condition that causes an increase in the pressure inside the skull (intracranial pressure or ICP). This increase in pressure can lead to headaches, changes in vision, a swollen optic nerve (papilledema), and a pulsating noise in the ears (pulsatile tinnitus). This condition persistently exists even after all brain and spinal cord scans and fluid tests appear normal.
PTC most commonly affects overweight women during their childbearing years, although anyone, including men, women of all ages, and children of both genders can also develop this disease. The exact cause of PTC remains unknown, but it’s believed to be due to either a decrease in the absorption of spinal fluid (CSF) by the body, an increase in the production of this fluid, or both.
It’s crucial to highlight that if left untreated, PTC can become a disabling condition, potentially leading to permanent loss of vision. Therefore, it’s of the utmost importance to diagnose and start treatment for PTC as soon as possible.
What Causes Pseudotumor Cerebri?
The main cause of this condition is the build-up of a fluid called cerebrospinal fluid (CSF) due to its reduced absorption or increased production in the body. This causes an increase in pressure inside the skull, which results in symptoms associated with this condition.
Interestingly, there’s no recognized cause for why the absorption might decrease or the production might increase. That’s why this condition is sometimes called ‘idiopathic intracranial hypertension,’ where ‘idiopathic’ refers to diseases with unknown causes. However, there are some proposed possible reasons for this, which are discussed in the section on pathophysiology (the study of how disease processes affect the body).
Risk Factors and Frequency for Pseudotumor Cerebri
This condition usually strikes women between the ages of 20 to 44. Especially, those who weigh 20% or more above their ideal body weight are commonly affected. On average, there are 19.3 cases per 100,000 women in this weight bracket recorded every year. In general, all women between the ages of 15 and 44 have an annual rate of 3.5 cases per 100,000. However, the condition’s annual frequency in the general population is comparatively lower, at 0.9 cases per 100,000.
Interestingly, after puberty, women are significantly more predisposed to this condition – 90 percent of all cases are in females. There seems to be a link between being female, having a higher Body Mass Index (BMI), and the risk of developing this condition. However, before the age of 12 – considered the pre-puberty stage – both boys and girls have an equal chance of getting this condition. Interestingly, in this age bracket, being overweight is less likely to be associated with this condition.
- Males aged 12 to 15 years have an annual rate of 0.8 cases per 100,000.
- Females aged 12 to 16 years have an annual rate of 2.2 cases per 100,000.
Signs and Symptoms of Pseudotumor Cerebri
If someone has a history of the certain symptoms, it might indicate a specific medical issue. Some of the tell-tale signs include:
- Headache: This could occur anywhere and is often a daily occurrence. It could be severe in the morning or when trying to push air out from the lungs (Valsalva). Associated symptoms might include nausea, vomiting, sensitivity to light and neck and back pain. Roughly 98% of patients may report headaches.
- Temporary loss of vision: This can happen in one or both eyes, be partial or complete, and typically only last for a few seconds at a time. It’s caused by swelling of the optic nerve, which temporarily stops blood flow. About 70% of patients might experience this.
- Seeing double (diplopia): This happens when the 6th cranial nerve gets paralyzed.
- Pulsatile tinnitus: This is described as hearing a heartbeat or a whooshing sound in the ears. It’s thought to be due to increased pressure causing blood flow patterns to vibrate against the walls of the veins in the sinuses. About 60% of patients might experience this.
There are other signs that clinicians might look for during a physical examination. These include:
- Papilledema: This is caused by increased pressure in the brain.
- Cranial nerve VI palsy or problems with the lateral rectus muscle can manifest as seeing double horizontally.
- Vision loss: This happens more frequently than changes in visual clarity, and about 96% of patients may experience this to different degrees. It’s commonly presented as enlarged blind spots or the loss of lower, inner quadrant of the field of vision.
Testing for Pseudotumor Cerebri
If you are experiencing symptoms of Pseudotumor Cerebri (PTC), several tests can help to diagnose the issue. Doctors usually conduct neuroimaging, lumbar punctures, eye examinations, visual acuity testing, perimetry testing, and a complete blood count.
Neuroimaging involves making a detailed image of your brain and is carried out using Magnetic Resonance Imaging (MRI) and computed tomography (CT scan). An MRI can rule out other causes of increased pressure in the head. However, if an MRI isn’t suitable, then a CT scan might be used, but it’s not as accurate.
A lumbar puncture, also known as spinal tap, measures the pressure of the cerebrospinal fluid (CSF) – the fluid that surrounds your brain and spinal cord. In adults, a pressure greater than 25 cm H2O and in children aged between 1 to 18 years, greater than 28 cm H2O could suggest PTC. The CSF is then analyzed for things like cell count, sugar levels, protein, harmful bacteria, etc.
The doctor may perform an eye examination using an ophthalmoscope to check for optic disc edema, which is a swollen optic nerve; other vision tests assess the impact of the disease on eyesight. The severity of vision loss is usually related to the grade of optic disc edema.
A complete blood count is performed to rule out other conditions like anemia that might cause optic nerve swelling.
The Modified Dandy Criteria is widely used to diagnose PTC. The criteria stipulate that one must exhibit signs of increased pressure in the skull without any specific neurological signs, have no deformity or obstruction in the ventricles of the brain, and be fully conscious. The person with the suspected condition should also demonstrate no other causes of intracranial hypertension while showing any one of the following: hearing a rhythmical ringing sound, impaired eye movement, nervous tissue swelling, negative echography for drusen, or stenosis or collapse of the lateral sinus as confirmed by Magnetic Resonance Venography.
Treatment Options for Pseudotumor Cerebri
There are many ways doctors can treat this condition. Below are some common methods:
First, there’s something called a diagnostic lumbar puncture. This procedure involves inserting a needle into the lower part of the spine to drain some of the cerebrospinal fluid (CSF). CSF is a clear liquid that supports the brain and spinal cord. This process can provide temporary relief from symptoms and sometimes, it can even stop all symptoms.
Another crucial part of treatment can be weight loss. If a patient reduces their total body weight by 5% to 10%, this has been shown to sometimes stop symptoms completely.
A key part of the treatment for this condition can be medication. There are a few types of drugs doctors can prescribe:
- Acetazolamide, a type of drug known as a carbonic anhydrase inhibitor, can be used to reduce the production of CSF by up to 50%. It also works as a diuretic, which is a medicine that helps your body get rid of excess water.
- Topiramate, a medication often used to prevent migraines, may be helpful as it can also reduce CSF and even lead to some weight loss.
- Diuretics like furosemide or chlorthalidone may not reduce symptoms as effectively as carbonic anhydrase inhibitors, but they can still help. But be aware, if used with carbonic anhydrase inhibitors, they can lead to very low potassium levels.
- Steroids, a type of anti-inflammatory medication, can quickly lower inter-cranial pressure (pressure inside the brain). But these drugs can have side effects such as weight gain and can cause pressure to rise again when you stop taking them, so they are usually used in severe cases or when other treatments don’t work.
For those who don’t respond to these treatments, surgery may be an option. Doctors can relieve pressure on the optic nerve through a procedure called optic nerve sheath defenestration. This surgical technique is typically used in severe cases or when other treatments don’t work.
Another surgical option would be a CSF diversion, which uses a device called a shunt to move CSF from the brain or spine to another area of the body where it can be absorbed so that it doesn’t cause pressure. The objective of this procedure is primarily to reduce headache symptoms and it’s less effective at correcting vision loss.
What else can Pseudotumor Cerebri be?
When trying to diagnose pseudotumor cerebri (PTC), doctors would look at other conditions that can cause a rise in the pressure inside the skull (ICP). These conditions could include:
- Cerebral venous sinus thrombosis (a blood clot in the brain’s veins)
- Intracranial mass (an abnormal growth within the brain)
- Obstructive hydrocephalus (a condition caused by a blockage in the brain’s ventricles)
- Jugular vein compression (pressure on the vein in the neck)
- Superior vena cava syndrome (blockage of the main vein in the upper body)
- Decreased cerebrospinal fluid (CSF) absorption (this can be caused by meningitis or if you’ve had a particular type of stroke called a subarachnoid hemorrhage)
- Malignant hypertension (extremely high blood pressure)
It’s important for a doctor to rule out these possibilities and conduct the necessary tests to ensure an accurate diagnosis.
What to expect with Pseudotumor Cerebri
The chances of recovering from this disease depend on several things, including:
* The speed at which symptoms start: a quicker appearance of symptoms suggests a need for faster, more intense treatment.
* The amount of vision lost at the time it is first detected: a significant loss of sight right from the beginning suggests a higher chance of permanent vision loss.
* The severity of ‘papilledema’ (swelling of the optic disc at the back of the eye) at the time it is first identified: a more severe grade indicates a greater chance of permanent vision loss.
It’s not unusual for this condition to cause symptoms for months or even years, even after immediate treatment. Some patients may still experience swelling of the optic disc, increased inner ocular pressure (pressure within the eye), and ongoing issues with their field of vision.
Possible Complications When Diagnosed with Pseudotumor Cerebri
The most serious problem related to PTC (Pseudotumor Cerebri) is the potential for permanent loss of vision. This can occur if there’s compression of the optic nerve, caused by high pressure inside the skull. Other issues that arise are mostly side effects from the treatments used to manage the condition.
- Acetazolamide (a type of medication): Low levels of potassium in the blood, tingling in the hands or feet, and altered taste sensations.
- Steroids: Weight gain, increased intracranial pressure that does not improve when dose is reduced, and more fluid in the body.
- Diuretics (furosemide, chlorthalidone – a type of medication that reduces fluids in the body): Low levels of potassium and magnesium in the blood, and potential harm to the ears.
- Lumbar puncture (a procedure where fluid is drawn from the spine): Risk of infection, injury to nearby body parts, and headache following the procedure.
- Surgery: Risk of infection, double vision (which can be temporary or permanent), and chance of transient or permanent loss of vision due to blockage or damage to blood vessels that supply the eye.
Preventing Pseudotumor Cerebri
Idiopathic intracranial hypertension, also known as PTC, often impacts women who are at their childbearing age and people who are overweight. This condition can cause various symptoms such as headaches, vision loss (which may be either temporary or permanent), a rushing sound in the ears (also known as pulsatile tinnitus), and blurry or double vision (referred to as diplopia).
The treatment approach usually combines weight loss methods with medications that help reduce the production of cerebrospinal fluid (CSF), the fluid that surrounds your brain and spinal cord. A typical medication is acetazolamide. Some drugs like loop diuretics (for example, furosemide or chlorthalidone) reduce overall body fluids. In severe cases, your doctor might consider steroids and even surgery.
Prevention strategies often include weight loss and avoiding specific medications such as vitamin A (retinoic acids), certain antibiotics (tetracyclines), growth hormones, corticosteroids, and lithium.
