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Benign intracranial hypertension (BIH; pseudotumour cerebri; PTC; idiopathic intracranial hypertension; IIH)

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What is Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH)

Benign intracranial hypertension (BIH) is a disease of the brain. Benign intracranial hypertension is characterised by increased pressure in the brain without any evidence of any brain pathology by imaging studies. Benign intracranial hypertension is also characterised by normal cerebrospinal fluid (CSF – the fluid that surrounds the entire central nervous system, including brain and spinal cord) content.

It is known by different names, including:

  • Idiopathic intracranial hypertension (IIH); and
  • Pseudotumour cerebri (PTC).

Statistics on Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH)

Benign intracranial hypertension is an extremely rare disease. Studies from various countries estimate that the annual incidence is at the figure of 0.9 per 100,000 of general population. This figure is increased in women after puberty and in women with their weight 20% or more of the ideal weight.

Risk Factors for Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH)

Gender is a major risk factor for BIH. Before puberty, boys and girls are affected equally. After puberty, BIH affects women 9 times as often as men.

Obesity is a risk factor as well, considering that the incidence rises sharply with women 20% or more above their ideal weight.

Progression of Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH)

The pathogenesis of benign intracranial hypertension is still uncertain despite the fact that it has been described more than 100 years ago. Benign intracranial hypertension is characterised by:

  • Increased intracranial pressure;
  • Lack of ventricular dilatation (ventricles are fluid filled cavities in the middle of the brain);
  • Predilection for young, obese women;
  • Induced by various medications, including tetracyclines, vitamin A and oral contraceptive pills.

The exact mechanism of benign intracranial hypertension is still under debate at the moment. With prolonged high pressure in the brain, eye changes and brain changes may occur.

Symptoms of Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH)

Benign intracranial hypertension can produce features similar to high blood pressure at first. After a prolonged period, there might be complications from benign intracranial hypertension like visual problems.

Possible symptoms of benign intracranial hypertension include:

  • Headache;
  • Momentary visual disturbances;
  • Tinnitus (ringing noise in the ear with no external stimuli), sometimes like heart beating and whooshing sound;
  • Blindness: this can just be blurred vision, partial blindness or total blindness;
  • Double vision;
  • Other minor symptoms such as neck stiffness, painful shoulder joints, wrist joints and knees, difficulty maintaining balance, etc.

How is Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH) Diagnosed?

If a patient comes in with persistent headache and eye pathology, most likely a full physical examination will be necessary. These include looking at the blood function, kidney function, liver function, thyroid function, and the body’s iron, vitamins and electrolytes level.

The diagnosis of BIH depends upon ruling out other diseases; it is thus a diagnosis of exclusion. The following special investigations can be done:

  • Neuroimaging: these are imaging studies for the brain, including CT and MRI scan of the brain. Sometimes a more specific MRI scan called MRV (magnetic resonance venography) may be done to look at the blood flow in the veins.
  • Lumbar puncture: this test involves accessing the spinal cavity through the back using a long needle under local anaesthesia. This will help to measure the CSF pressure in the cavity, which will be raised in BIH.

Prognosis of Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH)

Benign intracranial hypertension does not increase the death rate by itself, rather, the death rate is increased by morbid obesity which is a common association with benign intracranial hypertension. However, it does cause significant inconvenience to the patients. Eye changes can be a mortal complication of untreated benign intracranial hypertension, leading to permanent blindness. As many as 96% of the patients with benign intracranial hypertension have some degree of visual changes.

How is Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH) Treated?

Treatment of benign intracranial hypertension needs multiple team approach, including neurologist, ophthalmologist, neurosurgeon and general practitioners. Treatment strategies include:

  • Diet and weight loss: This can either be achieved on patient self-discipline alone or with the help of medications and surgery. There have been positive improvement on signs and symptoms where patients have lost significant amount of weight.
  • Medications: Traditionally, diuretics (fluid tablets that removes water from the body) have been used. One such example is acetazolamide. However, it has significant side effects unpleasant taste with carbonated drinks, altered taste sensation, etc. Otherwise, other diuretics such as frusemide, thiazides, spironolactone, and triamterene can be used but with varying results. Steroids can be used to reduce the pressure in the brain rapidly but they are not suitable for long-term use.
  • Supportive care: A persistent headache can be treated by standard pain relief medications.
  • Surgery: This is indicated for visual loss or worsening visual changes due to the disease. They aim to reduce the pressure that compresses on the nerve in the eye that is responsible for normal vision.

Benign Intracranial Hypertension (BIH, Pseudotumour Cerebri, PTC, Idiopathic Intracranial Hypertension, IIH) References

  1. Durcan FJ, Corbett JJ, Wall M. The incidence of pseudotumor cerebri: Population studies in Iowa and Louisiana. Arch Neurol. 1988;45(8):875-7. [Abstract]
  2. Goodwin J. Pseudotumor cerebri [online]. Omaha, NE: eMedicine; 2005 [cited 25 October 2005]. Available from: URL link
  3. Friedman DI. Pseudotumor cerebri. Neurol Clin. 2004;22(1):99-131. [Abstract]
  4. Kesler A, Gadoth N. Epidemiology of idiopathic intracranial hypertension in Israel. J Neuroophthalmol. 2001;21(1):12-4. [Abstract | Full text]
  5. Radhakrishnan K, Ahlskog JE, Cross SA, et al. Idiopathic intracranial hypertension (pseudotumor cerebri). Descriptive epidemiology in Rochester, Minn, 1976 to 1990. Arch Neurol. 1993;50(1):78-80. [Abstract]
  6. Radhakrishnan K, Sridharan R, Ashok PP, Mousa ME. Pseudotumour cerebri: Incidence and pattern in North-Eastern Libya. Eur Neurol. 1986;25(2):117-24. [Abstract]
  7. Lee AG, Wall M. Idiopathic intracranial hypertension (pseudotumor cerebri) [online]. Waltham, MA: UpToDate; 2005 [cited 25 October 2005]. Available from: URL link
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Dates

Posted On: 26 October, 2005
Modified On: 15 May, 2018
Reviewed On: 13 November, 2006

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