Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)

Key Features

Essentials of Diagnosis

• Headache, worse on straining

• Visual obscurations or diplopia may occur

• Examination reveals papilledema

• Abducens palsy is commonly present

General Considerations

• Idiopathic intracranial hypertension

  • No specific cause can be found in many cases

  • Occurs most commonly among overweight women aged 20–44

  • Screening for space-occupying lesion of brain is important

• Thrombosis of the transverse venous sinus as a complication of otitis media or chronic mastoiditis is one cause of intracranial hypertension, and sagittal sinus thrombosis may lead to a clinically similar picture

• Other causes of intracranial hypertension

  • Chronic pulmonary disease

  • Systemic lupus erythematosus

  • Uremia

  • Endocrine disturbances such as hypoparathyroidism, hypothyroidism, or Addison disease

  • Vitamin A toxicity

  • Use of tetracycline or oral contraceptives

• Cases have also followed withdrawal of corticosteroids after long-term use

Clinical Findings

Symptoms and Signs

• Symptoms

  • Headache

  • Diplopia

  • Other visual disturbances due to papilledema and abducens nerve dysfunction

• Physical examination reveals

  • Papilledema

  • Some enlargement of the blind spots

  • Patients otherwise look well

Differential Diagnosis

• Venous sinus thrombosis

• Dural arteriovenous malformation

• Space-occupying lesion, eg, brain tumor

• Meningitis

• Systemic hypertension

• Migraine

• Glaucoma

• Associated conditions

  • Hypoparathyroidism

  • Addison disease

  • Hypothyroidism

  • Chronic pulmonary disease

  • Systemic lupus erythematosus

  • Uremia

• Associated drugs

  • Vitamin A

  • Tetracycline

  • Minocycline

  • Oral contraceptives

  • Corticosteroid withdrawal

  • Isotretinoin

  • Danazol

Diagnosis

Laboratory Tests

• Lumbar puncture is necessary to confirm intracranial hypertension (elevated opening pressure), but the cerebrospinal fluid is normal

Imaging Studies

• CT or MRI may show

  • Small or normal ventricles

  • An empty sella turcica

  • Tortuous optic nerves

  • Distension of the optic nerve sheath

  • Posterior globe flattening

• MR venography is important in screening for thrombosis of the intracranial venous sinuses

Treatment

Medications

• Acetazolamide (250–500 mg orally three times daily, increasing slowly to a maintenance dose of up to 4000 mg daily, divided two to four times daily) reduces formation of cerebrospinal fluid

• Topiramate

  • See Table 24–2

  • Has been shown to be effective

  • Has added benefit of causing weight loss

• Furosemide (20–40 mg/day) may be helpful as adjunctive therapy

• Corticosteroids (eg, prednisone 60–80 mg/day) are sometimes prescribed but side effects and the risk of relapse on their discontinuation have discouraged their use

• Any specific cause of intracranial hypertension requires appropriate treatment

  • Hormone therapy should be initiated if there is an underlying endocrine disturbance

  • Discontinue the use of tetracycline, oral contraceptives, or vitamin A

  • If corticosteroid withdrawal is responsible, the medication should be reintroduced and then tapered more gradually