All About IIH

To date there is no direct medical evidence to indicate weight as a causal factor for IIH. Weight loss has been shown to be the only treatment to date to modify the underlying condition. Statistically over 90% of patients diagnosed with IIH are overweight women. Recent studies have shown that weight loss is an effective treatment to reduce papilloedema and headaches and for many, putting IIH in to remission. The IIH:WT has shown that a 24% reduction in body weight is required to normalise Intracranial Pressure (ICP) reduce headache and improve quality of life. Men and women of normal weight and children of both sexes both overweight and of normal weight are diagnosed with IIH every year, suggesting that weight is not the only risk factor.

Doctors will always recommend losing weight for patients who are overweight. There are many ways of losing weight and it is advisable to try and report any difference in symptoms (if any) to your Doctors. Remember, losing weight has far reaching health benefits sometimes beyond ‘curing’ IIH.

CT and MRI scans are usually performed to rule out other reasons for your symptoms such as a brain tumour, blood clot, lesions, venous sinus stenosis or other abnormality with your brain. The MRI is reported as ‘normal’ if none of these have been found. If you have papilloedema and your MRI is ‘normal’ your Doctor should book you in for a lumbar puncture as quickly as possible in order to diagnose IIH correctly.

Intracranial pressure, the pressure of the cerebrospinal fluid that surrounds the brain and spinal cord is measured in mm/H₂O or cm/H₂O. Normal intracranial pressure in IIH is considered to be up to 25cm H₂O (250mm). Between 25 and 30 is considered a 'grey' area as people who are overweight without IIH can have readings in this area. If an LP reading is between 25-30 then other symptoms of IIH should be taken into account. 30 and over is indicative of IIH.

While most people with IIH have some degree of papilloedema, you can have IIH without papilloedema. (IIHWOP) The Dandy Criteria for IIH includes papilloedema so some hospitals will not diagnose you with IIH if you present without it. Many patients who are diagnosed without papilloedema go on to develop it. High intracranial pressure can still damage the optic nerves without papilloedema being present, which is why it is so important that you have your vision monitored regularly. In IIHWOP people report blurred vision and when tested in the eye clinic often the field of vision test may not be normal. This is not thought to be a permanent problem. You can find our IIHWOP leaflet here.

It is well documented that although severe headache is a classic symptom of IIH for some people headache never occurs. Visual problems, papilloedema (swelling of the optic nerves), pulsatile tinnitus, back and neck pain and many other symptoms can indicate raised intracranial pressure.

In treating IIH the daily dosage of Diamox® varies widely between patients. The dosage that is prescribed by your doctor depends on many factors, including your intracranial pressure, how seriously your vision is being affected, the severity of your symptoms and your tolerance of any side effects.

When starting patients on Diamox® (Acetazolamide) the doctor may prescribe a relatively low dosage. This may be taken in divided doses at intervals throughout the day. There is also a sustained release capsules Diamox SR® and Eytazox PR® which many patients find are more easily tolerated. You can read our Acetazolomide leaflet here.

One of the main side effects of Diamox® is tingling of the hands and feet. You should read the leaflet that came with your medicine and speak to your Doctor if you are worried about any side effect you are experiencing.

It is important that patients taking Diamox® have a blood test about 4 weeks after starting to determine whether their body is tolerating the medication or not. Speak to your Doctor about making blood test appointments whilst taking Diamox®/Acetazolamide or any other medication prescribed for your IIH.

Often patients who have IIH will have papilloedema (swelling of the optic nerve) and enlarged blind spot (where the optic nerve enters the back of the eye). Visual problems are common with IIH and people with IIH report a wide variety of vision problems including: changes in colour vision or after-images; diplopia (double vision); blurred vision; photophobia (pain and discomfort caused by bright light); reduced or fluctuating visual fields (loss of peripheral vision); ‘greying out’ of vision (transient visual obscurations).

Many of these visual problems are transient meaning they come and go, and sometimes will improve with treatment. None of these symptoms mean that you will lose your sight because of IIH if you are treated promptly. All of these symptoms are due to the high pressure of CSF on the optic nerve.

The most important thing to do is to make sure you attend ophthalmic appointments to have your vision checked regularly.

Everyone is different and vision loss may not be permanent. It can improve with medication and or surgery. It is important that you attend ophthalmic follow-ups regularly as the earlier vision loss is detected, the better chance of treating it. Sadly for some treatment comes too late and permanent vision loss is possible. Speak to your Ophthalmologist about any concerns you have with your vision.

For some people with IIH their symptoms of IIH may resolve spontaneously, however IIH can be a chronic condition. Sometimes symptoms are controlled with medication, some may need surgical intervention to protect their sight. People may find that their symptoms go into 'remission', they disappear. In some cases symptoms do come back, in others they don't. It is important if your symptoms improve significantly or disappear that you still have regular sight tests.

Some hospitals will only perform lumbar punctures as a diagnostic procedure. This is because CSF is replenished 3 times in a 24 hour period so the pressure can very quickly return to pre-lumbar puncture levels. Some hospitals still perform lumbar punctures as a therapeutic procedure, i.e. to help relieve severe symptoms of IIH although there is little evidence that this works longer than a few hours or days. When having a lumbar puncture it is important that you make sure you are comfortable and that if the procedure does not work the first time, you ask to stop and try again another day. Having multiple attempts at lumbar punctures in one day will result in a huge amount of stress and may have no benefit to the patient whatsoever.

Approximately a third of people after a lumbar puncture will experience an epidural, or post lumbar puncture low pressure headache. Symptoms include nausea and vomiting and a severe headache which is worsened by sitting or standing. If the pain is relieved by lying flat, then the headache is more than likely a low pressure headache. These can occur within 1 to 3 days after the LP. The treatment for a post lumbar puncture low pressure headache is to rest, lying down as flat as possible, to drink plenty of fluids.

The amount of fluid that is drained off during a lumbar puncture varies, but due to possible 'leaking' of the puncture site, additional CSF may be lost which can lead to low pressure headache.

If the headache is very severe, consult your Doctor or the ward that performed the LP. Occasionally a procedure called a ‘blood patch’ can be performed. A small amount of your own blood is injected into the site where the lumbar puncture was performed forming a clot and stopping the leaking of CSF.

On occasion a post LP headache can be caused by the pressure returning to the same high level it was before the procedure. If your headache is not relieved by lying flat and in fact this increases the pain, then it is likely that your ICP is high again and you should contact your Doctor to discuss treatments.

Yes - it is safe to fly with or without a shunt if you have IIH. Some people find that flying causes a temporary worsening of their symptoms especially on take-off and/or landing. Any worsening of symptoms should be short lived once the aircraft has landed. If you are at all concerned or you've had recent surgery, you should check with your doctor whether you are fit enough to fly. You should inform your travel insurer that you have IIH, as not doing so will invalidate your policy.