Intracranial hypertension in a slim young male

A 25 year old male engineering student reported to the neurological emergency department with two weeks' history of exercise-exacerbated loss of vision. At the beginning, he had noticed sudden darkening of vision when playing soccer. Episodes of vision loss had gradually increased in frequency, and now occurred even with mild physical exercise or change of posture many times per day. He did not complain of headaches at any point, and there was no double vision. Clinical examination revealed bilateral visual acuity of 0.5 c.c. Ophthalmoscopy showed marked bilateral papillary edema. Examination of this slim (BMI 17.2) patient was unremarkable otherwise. Because of moderate acne, he had been on oral tetracycline for four months.

Cranial MRI including venography was unremarkable. CSF opening pressure was 42cm H2O. CSF analysis and CSF centrifugates were normal. A preliminary diagnosis of idiopathic intracranial hypertension (IH) was made, and 40cm³ of CSF were removed. Episodes of sudden deterioration of vision were abolished.

Idiopathic IH, or pseudotumor cerebri, is a condition of unknown origin. Clinical presentation includes headaches and insidious loss of visual acuity. Sudden darkening of vision with exercise, transient obscuration, is a typical feature of the disease, when transient increase of CSF pressure restricts blood supply to the retina. If the abducens nerve is compressed, intermittent horizontal diplopia occurs. The disease is uncommon in men (f:m 9:1). Typically, the condition is associated with obesity in both genders, rendering this particular case peculiar.

Idiopathic IH is a diagnosis of exclusion. Differenzial diagnoses include mass lesion, cerebral venous sinus thrombosis, secondary IH, and obstruction of meningeal drainage by meningitis or carcinomatous meningeosis. Mass lesion and thrombosis were ruled out by MRI, and CSF analysis showed no signs of meningitis or meningeosis. A diagnosis of tetracyline-associated secondary IH was made.

Tetracycline was discontinued, and the patient was put on acetazolamide. Within 2 months, vision returned to 1.0 c.c., and CSF opening pressure declined to 24 cmH2O.

Tetracycline is an uncommon cause of secondary IH. Combination with retinoic acid or its derivatives is contraindicated, as most cases have been reported when these agents are combined. Whenever possible, acne should be treated topically, and an exact history of medication is warranted whenever assessing a case of intracranial hypertension.