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| Pseudotumor Cerebri |
| Overview |
 | Synonyms: Idiopathic Intracranial Hypertension, Benign Intracranial
hypertension |
| Epidemiology
 | 3.5/100,000 in women 15-44 years |
| 19.3/100,000 in women ages 20-44 years who are 20% or more above ideal
body weight. |
| Rare in patients over 45 years of age, men and slim adults, need to
consider a secondary cause or another disease. |
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| Symptoms |
| Headache: worsen by bending forward. cough, sneezing.
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| Neck and back pain are often prominent. |
| Brief episodes of monocular or binocular visual loss that may be partial
or complete. |
| Pulsatile tinnitus, may be unilateral or bilateral, described as a
heartbeat or whooshing sound. |
| May have VI nerve palsy. |
|
| Differentiate papilledema from
pseudopapilledema |
| Difficult to differentiate with a direct ophthalmoscope. |
| Tilted optic nerves and optic disc drusen, both benign conditions, can
simulate optic nerve head swelling. |
| Infiltrative optic neuropathies can produce elevation of the optic disc.
|
| Stereoscopic viewing using indirect ophthalmoscopy can distinguish these
entities. |
| When in doubt, fluorescein angiography, stereoscopic fundus photography
and orbital ultrasound/CT scanning to look for buried drusen are employed. |
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| Diagnosis |
| No lateralizing signs on neuro exam besides a lateral rectus palsy. |
| Papilledema from increased intracranial pressure, not pseudopapilledema. |
| Neuroimaging studies such as MRI normal. |
| Lumbar puncture shows an elevated CSF pressure
| > 200 mm of water in non-obese |
| > 250 mm water in obese patients |
| normal or low CSF protein, normal glucose and cell count. |
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| Predisposing factors |
Female, overweight, menstrual irregularities
Other: Head trauma, hypoparathyroidism, Addison's disease
Medications: see below |
| Differential diagnosis |
| Real tumor, including spinal cord tumor |
| Leptomeningeal inflammation, infection or neoplasia.
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| Venous sinus thrombosis, antiphospholipid antibody syndrome and systemic
lupus erythematosis |
| Increased CSF pressure in patients with chronic daily headaches and no
papilledema, may have analgesic rebound headaches . |
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| Lumbar puncture |
| Radiologist performs LP with the patient prone, attaches the manometer to
the needle vertically and reads the pressure. Since the base of the manometer is not
aligned with the cisterna magna, the pressure reading will be falsely low. |
| Reposition the patient in the lateral decubitus position may resolve this
problem. |
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| Medical treatment |
| Avoid medication that may cause the disease |
| Follow up Fundi exam & visual field testing by Ophthalmologist. |
| Lose weight. |
| Acetazolamide (Diamox)
| The usual dose to treat patient with visual loss is 1.5 to 3.0
grams daily in three to four divided doses. |
| Diamos sequel (sustained release) 500 mg is better tolerated. |
| Warn patient of side effects: metallic taste, intolerance of carbonated
beverages, tingling around lips and limbs, fatigue, mild anorexia, some gastrointestinal
symptoms or diarrhea. |
| Some patients develop renal stones, presumably due to alkalization of
urine and reduction of renal secretion of citrate.
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| Furosemide (Lasix)
| Reduces CSF production, a second line agent.
|
| Usual dose: 40 - 160 mg per day in two divided doses. |
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| Steroid
| Brief course of high dose steroid: may be useful when there is rapidly
deteriorating visual loss. |
| This may buy some extra time to consider other options. |
| Long term steroid not used routinely, due to:
 | Weight gain and fluid retention |
| Numerous long-term side effects: glucose intolerance, osteoporosis,
fracture, capillary fragility and gastric ulcer. |
| Withdrawal of steroid may cause intracranial hypertension. |
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| Surgical treatment |
| Indication for surgical treatment: is progressive visual failure despite
maximally tolerated medical therapy |
| Additional relative surgical indications:
| Severe visual loss at initial presentation |
| Inability to reliably follow a patient with severe or progressing visual
loss |
| Inability to reliably follow a patient with superimposed non-organic
visual loss |
| Anticipated systemic hypotension in a patient with severe papilledema
(e.g., patient with severe hypertension about to be aggressively treated, patient with
uremia about to undergo dialysis) |
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| Optic sheath fenestration:
| Recommended procedure |
| In the nonoperated eye: improvement of papilledema in roughly 50%
of patients. It is rational to operate on one eye first and wait to see if the papilledema
and vision in the other eye improves before proceeding with contralateral fenestration. |
| Complications:
| Double vision and tonic pupil.
|
| More serious complications: visual loss, tend to be vascular in nature,
and include retrobulbar hemorrhage, hemorrhage into the optic nerve sheath, central and
branch retinal artery occlusion, choroidal ischemia, and injury of the optic nerve. |
| Long-term deterioration in visual function occurs in as many as one-third
of operated eyes in 10 months following an initially successful procedure. |
| Failure of vision can occur at anytime, even a few years later. |
| Patients treated surgically still need to undergo serial follow-up to
detect papilledema and visual loss, & signs of optic nerve sheath shunt failure. |
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| Lumbar peritoneal shunt
| Initially effective in most patients. |
| High failure rate and need for revision. |
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| Conditions that may contribute to the disease |
| Obstruction to venous drainage
| Cerebral venous sinus thrombosis |
| Bilateral radical neck dissection with jugular vein ligation |
| Superior vena cava syndrome |
| Increased right heart pressure |
| Cerebral arterial-venous sinus shunts |
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| Medical conditions
| Overweight, recent weight gain |
| Orthostatic edema |
| Antiphospholipid antibody syndrome |
| Chronic obstructive pulmonary disease |
| HIV infection |
| Iron deficiency anemia |
| Polycystic ovary syndrome |
| Sleep apnea |
| Systemic lupus erythematosis |
| Turner syndrome |
| Addison's disease |
| Hypoparathyroidism |
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| Medications:
| Vitamin A and related compounds: Acutane, Vitamin supplements, liver,
All-trans-retinoic acid (for acute promyelocytic leukemia) |
| Tetracycline and related compounds: Minocycline,
Doxycycline |
| Sulfa antibiotics, |
| Hormones: Corticosteroids (particularly withdrawal), Growth hormone,
Norplant, Leuprorelin acetate (LH-RH analogue) |
| Other medications: Amiodarone. Chlordecone (kepone),
Cyclosporine, Lithium, Nalidixic acid |
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| References & further reading |
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