Idiopathic Intracranial Hypertension (IIH)

What is IIH?

IIH (old term: pseudotumor cerebri) is a condition mostly affecting young and obese resulting in high intracranial pressure (pressure in the CSF or the spinal fluid), usually from no other obvious reason. Normal intracranial or CSF pressure in adults is up to 6-20cm or 60-200mm of H₂O, and probably up to 25-28cm in children, depending upon their age.

 

What are risk factors for IIH?

Obesity in young age (15-44 years) is the leading risk factor. With obesity (BMI 30 or more), it is much more common in women than in men.  Blacks are more affected and the risk of complications from IIH is also higher in black population. It is also higher in patients with poor socioeconomic status or those living in rural areas.

 

What are symptoms of IIH?

 Following are common symptoms:

1. Headache: Severity of headache ranges from debilitating 24/7 pain to minimal pressure type feeling. Patient may also complain of sensitivity to light and noise, nausea, and dizziness. Headache may be worse upon waking up, with coughing or sneezing, or with activities that may raise pressure in the head, such as straining while passing bowels, or having an orgasm.
2. Vision problems: Blurred vision or visual obscurations is a common symptom, and if the pressure is high enough, patient may also have episodes of double vision, or complete loss of vision.
3. Ear symptoms: There may be a feeling of ear popping, or heart beat type of feeling in the ear, the so-called pulsatile tinnitus.
4. Rarely, there may be facial numbness or weakness.
5. Finally, many patients have no symptoms at all, and the condition is discovered on a routine eye examination.

 

What are typical signs or the finding on examination of IIH?

Most patients are obese, usually with history of recent significant weight gain. BMI is usually significantly elevated, 30 or higher. The more specific finding on examination is the swelling inside the eyes, the disc edema. Rarely, an eye muscle may not work well. There may be evidence of visual loss on bedside examination. Rarely, there may be facial weakness. Other than that, there is no particular finding on examination.

 

How is the diagnosis of IIH confirmed?

Confirmation of IIH requires confirmation of high intracranial pressure. Theoretically, one can measure intracranial pressure in three different ways: a. directly within the skull (almost never done), b. accessing the CSF cavity in the neck (doable but risky, and not the procedure of choice), and the c. accessing the CSF cavity in the lower back, the lumbar puncture. Lower back is a relatively safe area, as there is no risk of direct injury to either brain or the spinal cord.

 

What tests are required to investigate IIH?

1. MRI of brain: If patient’s history and examination is suggestive of high intracranial pressure, the first next step is to have a brain scan done. MRI of brain is preferred, unless for some reason patient cannot have an MRI, in which case a CT scan is performed. This is to make sure that there is no obvious structural reason for the high pressure, such as a tumor. MRI may also provide some clues for the high pressure, but the MRI findings are not definitive.
2. Lumbar Puncture: This is done to check CSF pressure. Please review the details of this procedure on the post titled, The Lumbar Puncture.
3. Visual field testing: This is done in ophthalmology office. It can be a useful way to monitor visual dysfunction, and indirectly, the severity of CSF pressure. On one hand, it is not a very sensitive test, but on the other, it is easily available and provides opportunity to take visual pictures for comparison.
4. Optical Coherence Tomography or OCT: This is much more sensitive test to monitor a patient, especially after treatment. But it requires experience to avoid technical errors.
5. If a problem with venous sinus is suspected, an MRV or a CTV of brain is performed.
6. Other ophthalmological measures such as Fluorescein Angiography may also help to rule out alternate optic nerve pathologies, or to assess the extent of nerve injury.

 

What are different causes of high CSF pressure?

1. Anything blocking the CSF-flow, like a tumor
2. Certain medications: such as minocycline, retinoids (vitamin A derivatives), lithium, growth hormones, anabolic steroids, methotrexate, cyclosporine, and few other.
3. Corticosteroid withdrawal
4. Cerebral venous sinus thrombosis
5. Venous sinus compression by a mass, like a meningioma
6. Congenital stenosis or tightening of cerebral venous sinus
7. AVM (arteriovenous malformation or fistula) resulting in leakage of arterial blood (high pressure area) in a venous sinus (low pressure area).

 

Are there different levels of IIH?

Following division is based upon my own observations and experience:

            . Mild: CSF pressure 20-25 cm. In this range, patients may or may not have any symptom. An eye doctor on a routine eye examination may pick it up.

            . Moderate: CSF pressure 26-30 cm. In this range, patients usually complain of headaches.

            . Severe: CSF pressure: 31-40 cm. In this range, patients complain of continuous headache, blurred vision, and other symptoms described above.

            . Critical: CSF pressure >40 cm. In this range, patients usually have severe symptoms, including episodes of complete loss of vision, and quickly progressive visual loss. 

 

How is IIH treated?

The goal of treatment in IIH is to:

. Alleviate pressure to avoid permanent visual loss

. Alleviate symptoms

. Measures to prevent its recurrence.

Following measures can be useful, with some limitations:

1. Lumbar puncture (LP). It can help to confirm the diagnosis of high pressure, and remove some CSF to lower the pressure, at least temporarily.
2. Acetazolamide: a diuretic or a water-pill. It is a temporary solution until the more definitive measures start to work. Many patients do not tolerate its side effects, especially in higher doses where it is more effective.
3. Weight loss, in many cases the best of all solutions. Even 10% of weight loss can make a significant difference. For more difficult cases, aggressive medical management, or bariatric surgery should be considered.
4. Topiramate: It works similar to acetazolamide, though not that effective to lower CSF pressure. It has a weight reducing side effect but usually in high doses.
5. CSF shunting procedures: Usually, for patients not responsive to other measures, or with critically high CSF pressure. Shunting procedure involves putting a plastic tube with one end in the central brain cavity, and the other in the belly (the ventriculo-peritoneal shunting). It can also be achieved by putting a tube between the CSF cavity in the back and the belly (the lumbo-peritoneal shunt). Shunts can malfunction, get infected, or obstructed, and many times require replacement. This treatment is effective in about 90% of patients but severe complications may affect 9% of patients, and shunt failure may occur in more than 40% of patients.
6. Eye surgery: In this procedure, an ophthalmologist performs a surgical procedure and approaches the back of the eye, from the side, and makes a hole in the covering of the optic nerve. This suddenly takes away the pressure on the optic nerve, with resolution of eye symptoms and the nerve protected from high-pressure injury. The procedure may have to be done on both sides. The risks may include injury to the optic nerve, other nerves in the vicinity, or the small blood vessels. It can be a useful option for patients with significant eye involvement, a permanent incurable reason (such as venous sinus disease), and not responsive to other measures. This treatment is also effective in about 90% of patients.
7. Transverse sinus stenting: It is an option for some patients with venous sinus stenosis. Complications may include restenosis, blockage of the stent, and subdural hemorrhage.

Formal investigational data to compare different types of treatment is lacking, and the decision for the procedure is made based upon clinical experience and common sense. It depends upon the exact cause of high pressure, if known, severity of symptoms, and the extent of ophthalmological complications. IIH is best managed by close collaboration between a primary care provider, a neurologist, an ophthalmologist (ideally a neuro-ophthalmologist), and at times a neurosurgeon and a bariatric medicine physician. Most patients require long-term follow-up and care.

 

How is the progression of IIH followed?

Headache may be the leading symptom of IIH, but it is not a good parameter to follow as patients might continue to have significantly high intracranial pressure with minimal headaches. The main concern in IIH is visual loss from permanent injury to the neurological parts of eyes. The best way to monitor progress is through regular interval eye exam and some tests usually offered in an ophthalmology office. An ophthalmologist can check for visual acuity, take a picture of the disc and compared it to the previous pictures, perform automated visual field test (which can help detect subtle or peripheral visual dysfunction), and might also perform OCT (optical coherence tomography). All tests, including OCT, are carefully analyzed to make sure there is no technical or computerized error or any discrepancy, which may happen in some patients with psychological disorder. Input from ophthalmologist is critical for a neurologist to make decisions about management.

 

Should I have another lumbar puncture after treatment to find if the pressure has dropped?

Role of lumbar puncture is initial diagnosis and especially to quickly lower CSF pressure to avoid injury to the visual apparatus. After initial lumbar puncture, it is better to monitor progression through eye examination and testing as described above. CSF pressure does not correspond well with papilledema or the visual loss.  

 

Can I take contraceptive hormone if I have IIH?

Despite some reports suggesting that there might be a link between oral contraception and IIH, formal study to address this question has not confirmed this notion. Based upon this finding, present day oral contraception treatment is not contraindicated in patients with IIH. Patients should be told to monitor their weight to avoid any worsening of IIH because of weight gain.

 

Can I get pregnant if I have IIH?

Yes, if you can avoid gaining too much weight other than the additional weight of pregnancy, it can be managed. If the baseline pressure was not too high and eye exam close to delivery only show mild disc edema, you may deliver vaginally. In doubtful or more severe case, epidural anesthesia is a reasonable option.

 

Is there a relationship between IIH and depression?

Yes. Patients with IIH are at greater risk of anxiety, low self-esteem, depression, and self-harm compared to the larger population. Rate of suicide is many times higher in patients with IIH. Exact reasons for these associations are unclear. It might be partly due to unmanageable obesity.

 

Can topiramate or acetazolamide be used during pregnancy?

Topiramate no. I educate patients to avoid topiramate if they were even thinking about getting pregnant or if that was a possibility (unprotected sex). Acetazolamide can be used but it is best to avoid it during first trimester.

 

What headache pain medicines are safe to take with IIH and pregnancy?

Ideally, all chemicals should be avoided during pregnancy, especially during the first trimester. If that is not possible, acetaminophen (Tylenol, Panadol), naproxen, or sumatriptan can be used. Excessive use of headache pain meds should be avoided as it may result in worsening instead of improving the headache due to analgesic-rebound headaches. Small amount of caffeine is also safe and a cup of tea or coffee with a painkiller might be a better option. Sedatives like butalbital or habit-forming meds like oxycodone are not safe to take.

 

Is IIH a genetic disorder?

There is not enough data to answer that question. With that said, many times obesity is a familial trait, which may put multiple generations at risk of having this condition.

 

What medicines to avoid with IIH?

If possible, medicines that carry higher risk of weight gain or create a difficulty losing weight should be avoided. There are many meds in this list including anti-psychotics, some anti-depressants, some mood stabilizers, some seizures medicines, and steroids.

 

Where can get more information about IIH?

American Academy of Neurology

American Ophthalmology Association