DESCRIPTION 
- Buildup of CSF pressure without mass lesion or clear etiology
- Also known as idiopathic intracranial hypertension
- 2 proposed mechanisms:
- Increased abdominal pressure or intracranial venous stenosis may decrease venous drainage from the head
- Vitamin A levels above the saturation of the liver can damage cell membranes in the arachnoid granulations
- Associated with obesity
- Average age of onset 30 yr
- Female predominance (7:1)
- Uncommon, ~1–5 cases per 100,000
ETIOLOGY
Proposed causative agents:
- Obesity
- Obstruction of intracranial venous drainage
- Hypervitaminosis A
- Steroids/steroid withdrawal
- Tetracycline antibiotics
- Oral contraceptive pills
- Hypertension
- Recent weight gain
- Chronic carbon dioxide retention with elevated intracranial pressure
[Outline]
SIGNS AND SYMPTOMS
History
- Headache:
- Typically described as constant, bilateral
- Pressure like
- Worse in the morning
- Worse with Valsalva maneuver
- Nausea and vomiting
- Tinnitus or pulsatile intracranial noise
- Diplopia
- Dizziness
- Scotoma
- Transient visual obscurations lasting seconds
- Blind spots
- Constriction of vision
Physical Exam
- Visual field defects (in up to 90%):
- Typically inferior nasal visual field loss
- Papilledema
- Lumbar puncture improves symptoms
- 6th cranial nerve palsy
- Loss of visual acuity
- Otherwise normal neurologic exam except:
- Visual changes
- Abducens palsy
- Rarely 7th cranial nerve palsy
Pediatric Considerations
- Usually presents with strabismus as opposed to headache and visual field loss
- Also associated with obesity and medications (tetracycline antibiotics, steroids)
ESSENTIAL WORKUP
- Thorough history and physical exam
- Detailed neurologic assessment and fundoscopic exam
DIAGNOSIS TESTS & INTERPRETATION
Lab
- Lumbar puncture: CSF normal or low protein with a normal cell count
- Opening pressure > 25 cm H2O or > 20 cm H2O in nonobese, relaxed patient
- Consider CBC, coagulation studies prior to lumbar puncture
- Improvement of symptoms with lumbar puncture
Imaging
- Head CT/MRI to rule out mass lesions (prior to lumbar puncture)
- Classically, the head CT will demonstrate slitlike frontal horns of the lateral ventricles
- MRI recommended in the full workup:
- Can be done as an outpatient
- Cerebral venous thrombosis can mimic pseudotumor cerebri in all regards including normal head CT
Diagnostic Procedures/Surgery
- Modified Dandy criteria for diagnosis:
- Symptoms of raised intracranial pressure
- No localizing symptoms with exception of 6th nerve palsy
- Patient is awake and alert
- Normal CT/MRI findings without evidence of thrombosis
- Lumbar puncture opening pressure > 25 cm H2O (some suggest > 20 cm H2O in nonobese, relaxed patients)
- Lumbar puncture
- Opening pressure should be performed in lateral decubitus position with neck and legs straight
- Observing respiratory variation ensures good transmission of pressure
- Improvement of symptoms may occur with lumbar puncture
DIFFERENTIAL DIAGNOSIS
[Outline]
PRE-HOSPITAL
Pain control as appropriate
INITIAL STABILIZATION/THERAPY
- Airway and circulation management as indicated
- IV fluid hydration
ED TREATMENT/PROCEDURES
- Large-volume lumbar puncture of 20–30 mL of CSF:
- Only if confident of correct diagnosis and head CT demonstrates open basilar cisterns and 4th ventricle
- Acetazolamide
- Pain control
- Neurology consult
- Ophthalmology consult
- Neurosurgery consult for acute or impending visual loss unresponsive to diuretics (for lumboperitoneal shunt)
- Optic nerve fenestration is another surgical option
- Venous sinus stenting if stenosis is present
- Weight loss
- Discontinue any drugs that could be causative
- Typically resolves spontaneously
MEDICATION
- Acetaminophen: 500 mg PO (peds: 10–15 mg/kg; do not exceed 5 doses/24 h) PO q6h; do not exceed 4 g/24 h
- Acetazolamide: 500 mg slow-release PO BID (peds: 25 mg/kg/d div. TID/QID) PO/IV
- Ibuprofen: 600–800 mg (peds: 10 mg/kg) PO q8h
- Lasix: 0.5–1 mg/kg IV/PO
- Morphine: 0.1 mg/kg IV/IM
- Prednisone: Helpful when severe visual symptoms present, 5-day course recommended (longer treatment not recommended)
First Line
Second Line
Topiramate has been suggested as a 2nd-line agent but is not FDA approved for this use
[Outline]
DISPOSITION
Admission Criteria
Acute or impending visual loss
Discharge Criteria
- Consultation obtained from neurology and ophthalmology
- Appropriate follow-up arranged
- Tolerating oral diuretics
- Pain under control
Issues for Referral
Timely referral and return precautions:
- Visual loss
- Focal neurologic deficit
- Worsening headache
FOLLOW-UP RECOMMENDATIONS
Follow-up is recommended with neurology and ophthalmology
[Outline]
ICD9
348.2 Benign intracranial hypertension
ICD10
G93.2 Benign intracranial hypertension
[Outline]
- Bradley WG, Daroff R, Fenichel G, et al., eds. Neurology in Clinical Practice. 5th ed. Philadelphia, PA: Butterworth-Heinemann, 2008.
- Galgano MA, Deshaies EM. An update on the management of pseudotumor cerebri. Clin Neurol Neurosurg. 2013;115:252–259.
- Lee AG, Wall M. Idiopathic Intracranial hypertension. In: UpToDate, Basow DS, eds. UpToDate: Waltham, MA, 2013.
- Randhawa S, Van Stavern GP. Idiopathic intracranial hypertension (pseudotumor cerebri). Curr Opin Ophthalmol. 2008;19:445–453.
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