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Diagnosis
How is IIH diagnosed?
To diagnose IIH you may see a neurologist and an ophthalmologist. Doctors need to talk to you about what you have been experiencing and perform a physical examination. It is important that other conditions are ruled out before diagnosing IIH.
It is essential that other conditions such as venous sinus thrombosis (blood clot in brain), anaemia (lack of red blood cells) and certain drugs such as some antibiotics or vitamin A containing drugs are ruled out, as they require different treatment.
To be diagnosed with IIH you will need brain scans and a lumbar puncture(LP), sometimes called a spinal tap. It is vital that lumbar puncture reading is performed with you relaxed and lying on your side for the reading to be accurate. For more information, see the IIHUK Information on Lumbar Puncture Leaflet.
For doctors to be able to diagnose IIH all the following 5 things need to be present:
- Papilloedema (swelling of the eye nerves).
- Normal neurological examination (sixth nerve palsy causing double vision is allowed).
- Normal brain imaging. This is usually with computerized tomography(CT) or magnetic resonance imaging (MRI) scans. They should also include a scan of the veins of the brain to exclude venous sinus thrombosis.
- Normal brain fluid (CSF) analysis.
- Elevated lumbar puncture opening pressure above 25cm (for some people a pressure above 25cm may be normal for them)
(For the criteria for IIH without papiloedema, see the IIHWOP leaflet)
Diagnosis of IIH is made by identifying the typical symptoms of the condition and ruling out others which can cause similar symptoms. Neurological examination is usually reported as normal, with the exception of cases where papilledema (swelling of the optic disc of the eye) is present. Imaging procedures such as CAT/CT scans and MRI scans are also reported as normal. Definitive diagnosis of IIH is made by performing a lumbar puncture which shows an above 'normal' CSF pressure of above 25cm/H2O.
Possible causes
Blood clots: in the veins draining CSF from the brain can cause increased ICP (intracranial pressure). Withdrawal of steroids, large doses of vitamin A, use of body building–type steroids, hormonal changes (including possible links to human growth hormone) and certain medications may also cause raised ICP. There is also some unresolved medical debate about the possibility that the inflow of CSF may be too high even though the outflow mechanism is working correctly.
Weight issues: There is now definitive evidence that weight and IIH are related. Leading-edge research is being undertaken during 2014/15 including an examination of links between obesity and female hormones and obesity enzyme abnormalities (11 beta Hydroxysteroid dehydrogenase metabolism). Research supports that a 6% decrease in bodyweight can help to resolve papilledema associated with IIH. Some women find that their IIH symptoms go when they are pregnant and then come back after childbirth.
Weather/Climate Issues: Some people with IIH report that they have bad headaches and feel ill when the atmospheric pressure is low as storms cross the UK – but some report that they feel bad when the atmospheric pressure is high in good summer weather or prolonged cold spells in winter. Some people with IIH keep a log of their symptoms in relation to the weather along-side the pressure readings from their properly calibrated home barometers.
Symptoms of IIH: The most common symptoms of IIH are: severe headache, papilledema, transient visual obscurations (temporary loss of vision), diplopia (double vision) and decreased visual acuity, pulsatile tinnitus ("whooshing noise" in the ears in time with the pulse), pain behind the eye and with eye movement.
Other symptoms reported by sufferers include but are not limited to: nausea, vomiting, fatigue, photophobia (dislike of and pain caused by bright light), problems with balance and spatial awareness, aphasia (difficulty using or understanding words), disorientation, loss of short-term memory (sometimes also long-term memory loss), confusion, feeling 'spaced out', decreased depth perception and peripheral vision. Some children are often too young to report their symptoms adequately and can present with many nonspecific symptoms such as mood swings and more. Although many people with IIH have symptoms in common, each person is an individual and should be treated accordingly.
