Idiopathic intracranial hypertension
A syndrome of raised intracranial pressure without obvious cause.
A condition mainly affecting overweight young women. A similar condition is seen secondary to endocrine abnormalities, polycystic ovaries, vitamin A toxicity, steroids and other drugs.
Patients present with headache, visual obscurations and may have tinnitus. On fundoscopy they have papilloedema. In more advanced cases an enlarged blind spot, visual field loss or a sixth cranial nerve palsy may occur. Severe untreated disease may result in ischaemia of the optic nerve presenting with progressive blindness.
CT brain is normal (there are no mass lesions or ventricular dilatation). CSF examination is normal although there is increased CSF pressure. MRI may be performed to exclude intracranial venous thrombosis. Repeated formal visual field assessment is required.
No treatment is of proven benefit; however, therapies aim to conserve vision.
The acute stages can be managed with repeated lumbar puncture and diuretics.
If the pressure is severe and vision threatened optic nerve sheath decompression/fenestration may be indicated.
Recurrence prevention includes weight reduction; however, a lumboperitoneal shunt may be appropriate in patients requiring repeated CSF drainage.