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Idiopathic intracranial hypertension (IIH)

Patient information A-Z

Information for patients with IIH and their families/ carers attending the Neuro-ophthalmology Clinic

What is IIH?

The space around the brain is filled with water-like fluid known as cerebrospinal fluid (CSF). Idiopathic Intracranial Hypertension (IIH) is a neurological condition in which the CSF is at a higher pressure than normal. This causes headaches, swelling of the optic nerves (papilloedema) and can result in loss of vision or blindness. Idiopathic Intracranial Hypertension (IIH) is a rare condition affecting about one to five in every 100,000 people, most of them women, but men and children can also be affected.


‘Idiopathic’ is a medical term which means that the cause is not known. However, we do know that there are important factors that increase the risk of getting the condition:

  • The most common risk factor is gaining weight or being overweight.
  • Certain medications increase a person’s chance of suffering from IIH. These include tetracycline antibiotics, steroids, high doses of vitamin A and growth hormone.

What are the symptoms of IIH?

The most common symptoms of IIH are:

  • Headache.
  • Loss of field of vision and, rarely, of central vision.
  • Transient blurred vision.
  • Double vision.
  • Pulsatile tinnitus (‘whooshing noise’ in the ears in time with the pulse).
  • Nausea/vomiting


Weight loss:

  • Weight loss is the most important treatment for IIH. Many medical research studies have shown that losing weight and maintaining that weight loss is effective at reducing the fluid pressure, headaches and problems with vision.


Medications can be used alongside weight loss.

  • The most commonly prescribed medication is a water tablet called acetazolomide (Diamox).
  • Other medications include topiramate, furosemide and bendroflumethiazide.


Surgery is a last resort and is only considered when weight loss and medications have failed and there are significant visual problems arising from the condition. There are a few surgical options available, but these all carry their own risks and potential complications.

  • Neurosurgical CSF ’shunting’ is the most commonly used procedure. This is where a plastic tube is placed permanently inside the body with one end draining the fluid, and the other end depositing it into the abdomen. There are two types of shunt commonly used:

- Lumbo-peritoneal shunt: the shunt is placed into your lower back to drain CSF from there into the abdomen. (is this draining from the spinal fluid or back tissues?)

- Ventricular peritoneal shunt: one end of the tube is placed directly into one of the fluid compartments of the brain (called ventricles) and drains the fluid directly from the brain into the abdomen.

  • Venous sinus stenting: This is where a small tube (stent) is placed inside a blood vessel (vein) in the brain. This helps reduce the CSF pressure by improving drainage of fluid from the brain via these veins. A special x-ray of the blood vessels called an angiogram is done first to see if there is evidence of narrowing in any veins. This procedure is only suitable for a small proportion of people with a specific type of IIH (called venogenic IIH). Your neurologist will tell you if this applies to you.
  • Bariatric (weight loss) surgery: Surgery to the stomach (such as a gastric band) to reduce weight may be offered to patients with IIH who are very overweight (with a body mass index or BMI over 35).

Long-term outlook for IIH

The main risk of IIH, if untreated, is permanent damage to the vision. Fortunately, this is rare but if you are concerned that your vision has deteriorated you should seek medical attention urgently.

Some patients’ symptoms improve quickly with weight loss alone. If medications are required, most people are able to do without these after a few years. Some patients with IIH continue to be prone to headaches even after the high CSF pressure is effectively treated and remains normal. These headaches are often similar to migraines and are treated in a similar way. You can seek advice from your neurologist or GP about treatments available for headaches.

What will happen at my appointment in the Eye Clinic?

You will have a series of tests including:

  • Humphrey Visual Field test. This is a peripheral vision test.
  • Orthoptist assessment including: visual acuity using a letter chart test colour vision, pupil reactions and eye movements. This will include the opportunity to report symptoms. It is helpful if you keep a record of any symptoms as you notice them.
  • OCT scan and optic disc photographs. This is a non-invasive scan and photographs of the back of the eye.
  • You may need to have dilating eye drops during the appointment so please do not drive to or from the appointment.
  • If you wear glasses, please bring them with you to the appointment.
  • Please allow two hours for the appointment.

How will I get the results of the vision tests?

The results from your visit to the Eye Clinic will be sent in a letter to your neurosurgery/neurology team (if applicable) and to your GP You will be sent a copy of the letter. Please keep hold of your clinic letter as it may be helpful to show it to other professionals involved in your care.


Orthoptic Department: 01223 216528

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Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151