USMLE Forum Archives - USMLE Step 3 - Idiopathic Intracranial Hypertension
Idiopathic Intracranial Hypertension
meduploader - 05-14-09 13:44
Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)
A headache syndrome related to chronically elevated ICP. Classically seen in young, obese women.
Associations have been noted with medications (tetracycline derivatives, steroids, vitamin A, danazol,
tamoxifen, levothyroxine, cimitidine, lithium, nitrofurontoin), endocrine disorders ( hyperparathyroidism,
hypothyroidism, adrenal insufficiency, Cushing disease) as well as with disorders such as SLE, Behçet’s
syndrome, and uremia.
Patients usually note a progressive global headache that worsens when they lie flat, often worsening at
night and upon awakening. Exacerbated by maneuvers that elevate ICP (e.g., Valsalva, cough, sneeze).
Elevated ICP can produce transient visual obscurations (blurring or blackout of vision in either or both
eyes for seconds), double vision from CN VI palsies, and/or progressive loss of peripheral vision. Total
blindness can result.
Papilledema is the key finding. Patients may also have ↓ visual acuity and/or loss of peripheral vision.
CN VI palsies may result from elevated ICP.
Following are criteria for DX:1-Presence of features of ICP in an alert pt. 2-Absence of focal
neuro signs except 6th nerve palsy. 3-Normal CSF exept icreased opening presure. 4-Absence of
any ventricular abnormality other than enlagement caused by ICP.
Patients with headache and papilledema should first undergo brain imaging, preferably with MRI. In
patients with pseudotumor, MRI is normal, including ventricular size. Most pt have empty sella in CT.
MR venography to exclude venous sinus thrombosis.
LP should be performed with the patient in the lateral decubitus position, with pressure measured after
the patient’s legs are extended and relaxed. LP reveals an opening pressure > 200 mm H2O, normal
protein and glucose, and no cells.
TX: Based on lowering ICP. Acetazolamide, a carbonic anhydrase inhibitor that reduces CSF production
and ICP, is first-line therapy. Lasix can also be used.
Serial LPs, optic nerve fenestration, and permanent shunting of CSF are used for refractory cases.
Weight loss is an important component of management in most patients.
Serial ophthalmologic evaluation is mandatory for these patients, as visual loss can be severe and permanent.
HY PC
Young, overweight female taking Vit A for acne comes with headache, double vision ---> CT done shows small ventricles ----> Benign Intracranial HT ---> next ---> stop Vit A ---> Therapeutic LP
Girl asks “when will my symptom resolve completely” ---> it can take months.
How will you monitor that increased ICP is decreasing ----> check visual acuity & visual field
meduploader - 05-14-09 13:44
Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)
A headache syndrome related to chronically elevated ICP. Classically seen in young, obese women.
Associations have been noted with medications (tetracycline derivatives, steroids, vitamin A, danazol,
tamoxifen, levothyroxine, cimitidine, lithium, nitrofurontoin), endocrine disorders ( hyperparathyroidism,
hypothyroidism, adrenal insufficiency, Cushing disease) as well as with disorders such as SLE, Behçet’s
syndrome, and uremia.
Patients usually note a progressive global headache that worsens when they lie flat, often worsening at
night and upon awakening. Exacerbated by maneuvers that elevate ICP (e.g., Valsalva, cough, sneeze).
Elevated ICP can produce transient visual obscurations (blurring or blackout of vision in either or both
eyes for seconds), double vision from CN VI palsies, and/or progressive loss of peripheral vision. Total
blindness can result.
Papilledema is the key finding. Patients may also have ↓ visual acuity and/or loss of peripheral vision.
CN VI palsies may result from elevated ICP.
Following are criteria for DX:1-Presence of features of ICP in an alert pt. 2-Absence of focal
neuro signs except 6th nerve palsy. 3-Normal CSF exept icreased opening presure. 4-Absence of
any ventricular abnormality other than enlagement caused by ICP.
Patients with headache and papilledema should first undergo brain imaging, preferably with MRI. In
patients with pseudotumor, MRI is normal, including ventricular size. Most pt have empty sella in CT.
MR venography to exclude venous sinus thrombosis.
LP should be performed with the patient in the lateral decubitus position, with pressure measured after
the patient’s legs are extended and relaxed. LP reveals an opening pressure > 200 mm H2O, normal
protein and glucose, and no cells.
TX: Based on lowering ICP. Acetazolamide, a carbonic anhydrase inhibitor that reduces CSF production
and ICP, is first-line therapy. Lasix can also be used.
Serial LPs, optic nerve fenestration, and permanent shunting of CSF are used for refractory cases.
Weight loss is an important component of management in most patients.
Serial ophthalmologic evaluation is mandatory for these patients, as visual loss can be severe and permanent.
HY PC
Young, overweight female taking Vit A for acne comes with headache, double vision ---> CT done shows small ventricles ----> Benign Intracranial HT ---> next ---> stop Vit A ---> Therapeutic LP
Girl asks “when will my symptom resolve completely” ---> it can take months.
How will you monitor that increased ICP is decreasing ----> check visual acuity & visual field
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Re: Idiopathic Intracranial Hypertension mtniharika - 09-27-09 04:26 Mechanism:
The cause of IIH is not known. The Monro-Kellie rule states that the intracranial pressure (literally: pressure inside the skull) is determined by the amount of brain tissue, cerebrospinal fluid (CSF) and blood inside the bony vault. Three theories therefore exist as to why the pressure might be raised in IIH: an excess of CSF production, increased volume of blood or brain tissue, or obstruction of the veins that drain blood from the brain.
The first theory, that of increased production of cerebrospinal fluid, was proposed in early descriptions of the disease. However, there is no experimental data that supports a role for this process in IIH.
A second theory posits that either increased blood flow to the brain or increase in the brain tissue itself may result in the raised pressure. Little evidence has accumulated to support the suggestion that increased blood flow plays a role, but both biopsy samples and various types of brain scans have shown an increased water content of the brain tissue. It remains unclear why this might be the case.
A third theory suggests that blood flow from the brain may be impaired or congested. Only in a small proportion of patients has underlying narrowing of the cerebral sinuses or veins been demonstrated. Congestion of venous blood may result from a generally increased venous pressure, which has been linked to obesity
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