Idiopathic intracranial hypertension

Background

• Also known as pseudotumor cerebri/benign intracranial hypertension (BIH)
• Cause is idiopathic, but believed be due to impaired CSF absorption at arachnoid villi
• Associated with OCPs, vitamin A, tetracycline and thyroid disorders

Clinical Features

• Headache
• Nausea and Vomiting
• Vision blurring
• Irregular menses

Differential Diagnosis

• Aneurysm rupture and Subarachnoid Hemorrhage
• Brain tumor
• Encephalitis
• Head Injury
• Hydrocephalus (increased CSF)
• Hypertensive brain hemorrhage
• Intraventricular hemorrhage
• Cerebral venous sinus thrombosis
• Meningitis
• Subdural Hematoma
• Status epilepticus
• Stroke

Evaluation

• Young, obese women
• Headache (worse in AM / with manuvers increasing ICP)
• Papilledema (optic atrophy/vision loss)
  • can be visualized with ultrasound
• Neuro Exam frequently normal
  • May have cranial nerve palsies in severe, most often CN 6

Work-Up

• CT scan (negative or slit-like ventricles)
• LP (Opening pressure >25)
• MR venogram (to rule out cerebral venous sinus thrombosis)

Management

• Repeat LPs (decrease CSF pressure) - large volume LPs on the order of 30-40 cc of CSF
• Acetazolamide 500mg BID (decrease CSF production)
• Furosemide 20mg PO BID, give potassium supp as needed
• Weight loss
• CSF Shunt
• Optic nerve sheath fenestration

Disposition

• Admit for:
  • Severe pain
  • Focal findings
  • Vision changes
• Otherwise, discharge with ophtho follow up for formal visual field monitoring

External Links

• Induction to EM: An approach to headache in the ED. St.Emlyn’s

See Also

• Ocular ultrasound