Idiopathic intracranial hypertension

What it is

Idiopathic intracranial hypertension, also called pseudotumor cerebri or benign intracranial hypertension, is a condition of unknown etiology that manifests with chronically elevated intracranial pressure. The most common symptoms are diffuse headaches, although various visual symptoms and pulsatile tinnitus are also common.

Causes and risk

It predominantly affects obese women aged 15 to 44 years, described elsewhere as overweight women of childbearing age. The major risk factors listed are female sex, tetracyclines, obesity, excessive intake of vitamin A, and danazol; the link to medications is put as a possible one, naming tetracyclines and hypervitaminosis A.

How it presents

Diffuse headache is the commonest symptom, given at 92% of cases. Transient vision loss follows at 72%, with photopsia and retrobulbar pain. Pulsatile tinnitus, a swishing sound, is given at 60%, and diplopia at 38%. The cranial nerve disorder named is CN VI palsy, which is what produces the diplopia. On physical examination there is papilledema, a peripheral visual field defect and CN VI palsy. Headache with diplopia and papilledema in a patient whose mental status is normal is the combination that should raise this diagnosis. Two more clues are given for it. The headache is worse while lying flat, and the optic disc is bulging; a migraine, set against it, should not give papilledema. And the triad written out for the exam is hypertension with papilledema and tinnitus.