Pseudotumor cerebri (Benign intracranial hypertension)

Pseudotumor cerebri – also known as benign intracranial hypertension / idiopathic intracranial hypertension is a condition characterised by increase in the intracranial tension in the absence of any intracranial mass lesion.

Etiology:

  • The exact etiology of benign intracranial hypertension is not known
  • Since it is seen  more in women in the childbearing age, it has been suggested that some hormonal changes may be involved in it’s pathogenesis
  • It is usually associated with recent weight gain

Pathogenesis

  • There is increase in intracranial tension
  • Signs of increased intracranial tension such as papilloedema appear
  • The clinical picture is similar to that produced by an intracranial mass lesion
  • But investigations fail to reveal a brain lesion
  • Long standing cases can result in sequelae such as blindness due to optic nerve damage

Clinical features:

  • Headache
  • Transient visual disturbance
  • Pulsatile tinnitus
  • Double vision
  • Pain behind the eye
  • Loss of vision
  • Painful eye movements

Diagnosis of Pseudotumor cerebri:

It is diagnosed from the characteristic clinical features and by measuring an increased CSF pressure by lumbar puncture. Neurological examination is normal except for papilloedema. Imaging modalities such as CT and MRI reveal a normal brain.

Conditions mimicking Idiopathic intracranial hypertension:

Some conditions can cause increased intracranial  tension in the absence of an intracranial space occupying lesion. They include:

  • blockage of the arachnoid granulations which drain the CSF into the blood
  • Block in the jugular veins
  • Withdrawal of steroids
  • Large doses of Vitamin A
  • Certain drugs such as tetracyclines and lithium

Treatment of Pseudotumor cerebri:

  • Medical treatment
    • Weight loss
    • Diuretics for decreasing intracranial tension (acetazolamide, frusemide)
    • Steroids
  • Surgical treatment
    • Optic nerve sheath fenestration operation for relieving the pressure on the optic nerve and preventing blindness
    • Lumboperitoneal shunts for draining the CSF into the peritoneal cavity – Eventhough this is helpful in decreasing the CSF pressure, the shunt may get blocked

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