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Idiopathic intracranial hypertension (IIH)

What is IIH?

IIH or Idiopathic Intracranial Hypertension is a condition associated with raised pressure (hypertension) in the brain (intracranial). Idiopathic means there is no structural cause identified and it is diagnosed when other abnormalities causing raised pressure in the brain have been ruled out. It is therefore important to recognise that in IIH, there is no brain swelling nor is cerebrospinal fluid (CSF) getting blocked in the brain.

IIH most commonly affects women of childbearing age who are already overweight or who have gained weight. It has also been known, although rare to affect males and those who have an average BMI (Body Mass Index).


 Patients diagnosed with IIH can present with a multitude of symptoms however the most common are:

  • New onset of headaches
  • Visual symptoms typically present as brief episodes of loss of vision in one eye or both, double vision and decreased visual acuity.
  • Papilloedema—a swelling of the optic nerve which connects the eye to the brain. This is picked up when opticians or doctors examine the back of the eyes. This is the most significant finding in IIH which if not treated could lead to visual loss.
  • Pulsatile tinnitus - usually a whooshing noise in the ear in line with one’s heartbeat.

How is IIH diagnosed?

Diagnosis of IIH is made by identifying the typical symptoms of the condition and ruling out other conditions which can cause similar symptoms. You will have a scan of your brain and the veins of the brain in the form of a CT/MRI scan. These will often be reported as normal or as showing certain expected features found in raised pressure conditions  like mild narrowing of the veins  or a thin pituitary gland ( referred to as ‘empty sella’ ). Such findings are not cause for concern.  You will also receive a formal ophthalmology review to check for papilledema or any other change to your vision.

If your symptoms and ophthalmology assessment are suggestive of IIH and your scan does not show any abnormalities to cause raised pressure, you will then undergo a lumbar puncture to measure the opening pressure of CSF. If your opening pressure is more than 25cm of water, then the diagnosis is likely to be IIH and you will be advised about further management/treatment. You will also be referred to a neurologist (if you have not already) for further review.

Lumbar Punctures: what to expect?

Lumbar Punctures are a crucial diagnostic test for IIH and currently are the only practical way of measuring the opening pressure of CSF. It involves passing a fine needle into a lower spinal space under local anaesthetic. It is understandable that you may feel nervous about undergoing a lumbar puncture but the health professional performing the procedure will explain the procedure and ensure you are comfortable. There are some risks involved such as requiring multiple attempts or a low-pressure headache which will often resolve within a few days. In a lumbar puncture, some CSF may be removed to lower your pressure temporarily. Lumbar punctures are not a long-term treatment of IIH.

Treatment of IIH

One of the most effective ways of treating IIH is by losing weight and maintaining an average BMI. Weight loss can result in your IIH going into remission; however, should you re-gain significant weight in the future you could see a return of some of your symptoms.

You may also be prescribed a drug called Acetazolamide (Diamox) which is used to protect your vision. Acetazolamide often causes transient side-effects such as tingling in your fingers and toes, and this will be discussed further by your neurologist.

We often find that patients with IIH can suffer with continuous headaches that are migrainous in nature rather than from raised pressure. These headaches can be associated with other symptoms such as sensitivity to light and noise, feeling sick, difficulty in concentration etc. We would aim to manage your headache symptoms along the same principles as managing chronic migraine. There are multiple medications we can use to treat headache, and these will be discussed with you at your clinic appointment.

Here at the Walton Centre, we have an MDT (Multi-Disciplinary Team) meeting three times per month to discuss patients with IIH. The team consists of consultant neurologists, consultant neurosurgeons, consultant ophthalmologists, interventional radiologists, nurse specialists and orthoptists. The purpose of this meeting is for the whole team to review symptoms, assessments and investigation results to ensure that the correct treatment path is followed.

Surgical Management

Surgical interventions like CSF diversion shunts and cerebral venous stents are only indicated in patients with severe papilledema which is sight threatening. Decisions to proceed with surgical intervention will be discussed and decided on a case-by-case basis by the MDT and appropriate information will be provided to the patient.

It is important to note that lumbar punctures are not used in the treatment of headaches in IIH. Lumbar punctures are used as a diagnostic investigation or as a short-term measure in a sight threatening emergency.


It is important that you stay up to date with all your ophthalmology appointments as part of your IIH management. Should you notice any changes to your vision this should be treated as an emergency, and you should either get in touch with your local ophthalmology department or attend your nearest A&E. You can also contact the nurse specialists for advice Mon-Fri 08:30—17:00 on 0151 525 3611 bleep 5340 or 0151 556 3178.

Further Information

Although IIH is not a life-threatening condition the symptoms can be disabling and affect people in different ways. Should you require any further information on your condition or wish to speak to people who have been diagnosed with IIH then please consider visiting

  • Last Updated:
    01 July 2023
  • Review Date:
    01 July 2025
  • Author:
    Louise Wainwright
  • Summary:

    IIH or Idiopathic Intracranial Hypertension is a condition associated with raised pressure (hypertension) in the brain (intracranial)

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