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

• Tends to occur in young, obese women
• Headache
  • Tend to be worse at night or first thing in the morning
  • Frequently starts as dull occipital pain, may become diffuse and throbbing
  • Typically worse with maneuvers to increase ICP
• Nausea and Vomiting
• Vision blurring
• Papilledema
  • can be visualized with ultrasound
• Irregular menses or amenorrhea
• Neuro exam often normal
  • May have cranial nerve palsies if severe, most often abducens nerve palsy

Differential Diagnosis

Headache

Common

• Migraine headache
• Tension headache
• Cluster headache

Killers

• Meningitis/encephalitis
  • Neoplastic meningitis
• Myocardial ischemia
• Retropharyngeal abscess
• Intracranial Hemorrhage (ICH)
  • SAH / sentinel bleed
• Acute obstructive hydrocephalus
• Space occupying lesions
• CVA
• Carbon monoxide poisoning
• Basilar artery dissection
• Preeclampsia
• Cerebral venous thrombosis
• Hypertensive emergency
• Depression

Maimers

• Giant cell arteritis of temporal artery (temporal arteritis)
• Idiopathic intracranial hypertension (Pseudotumor Cerebri)
• Acute Glaucoma
• Acute sinusitis
• Cavernous sinus thrombosis or cerebral sinus thrombosis
• Carotid artery dissection

Others

• Mild traumatic brain injury
• Trigeminal neuralgia
• TMJ pain
• Post-lumbar puncture headache
• Dehydration
• Analgesia abuse
• Various ocular and dental problems
• Herpes zoster ophthalmicus
• Herpes zoster oticus
• Cryptococcosis
• Febrile headache (e.g. pyelonephritis, nonspecific viral infection)
• Ophthalmoplegic migraine
• Superior Vena Cava Syndrome

Aseptic Meningitis

• Viral
  • Varicella
  • Herpes
  • Enterovirus
  • West Nile
• Tuberculosis
• Lyme disease
• Syphilis
• Leptospirosis
• Fungal (AIDS, transplant, chemotherapy, chronic steroid use)
• Noninfectious
  • Sarcoidosis
  • Vasculitis
  • Connective tissue disease
  • Drug induced aseptic meningitis

Evaluation

• CT (negative or slit-like ventricles)
• LP (Opening pressure >25)
  • CSF lab studies by lumbar puncture are negative
  • No special CSF studies need to be sent, unless differential includes etiologies for infection, hemorrhage, etc
• CT or 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