Idiopathic intracranial hypertension (IIH) is a disorder of increased intracranial pressure in an alert and oriented patient. The most popular hypothesis is that IIH is a syndrome of reduced cerebrospinal fluid absorption.
Clinical features include headaches, pulse-synchronous tinnitus, transient visual obscurations, visual loss, neck and back pain, and diplopia.
Signs include papilledema, sixth nerve paresis, and disturbances in sensory visual function. Visual field loss is ubiquitous, and the prototype pattern for early loss is enlargement of the blind spot and inferonasal loss. Diagnostic criteria are the modified Dandy criteria.
In all patients with IIH, treatment consists of eliminating causal factors, such as drugs and other conditions known to cause increased intracranial pressure, and instituting a low-sodium weight-reduction diet plus acetazolamide when indicated. Therapy can be given to reverse and prevent loss of vision.
IIH, also known as pseudotumor cerebri, is a disorder of increased intracranial pressure that occurs mainly in overweight women of childbearing years, often in the setting of weight gain. Its cause is unknown. It is characterized by increased intracranial pressure and its associated signs and symptoms in an alert and oriented patient, but without localizing neurologic ﬁndings. There is no evidence of deformity or obstruction of the ventricular system, and neurodiagnostic studies are normal except for increased cerebrospinal fluid pressure and the related neuroimaging signs. Furthermore, no secondary cause of intracranial hypertension is apparent. IIH can either be self-limited or have a life-long chronic course.
History and exam
Key diagnostic factors
- visual field loss
Other diagnostic factors
- transient visual obscurations
- pulse-synchronous tinnitus
- retrobulbar pain
- optical disk swelling
- decreased visual acuity
- ocular motility disturbances
- relative afferent pupillary defect
- female sex
- obesity and weight gain
- certain medication use
- associated causal diseases
- sleep apnea
- family history
1st investigations to order
- visual field testing (perimetry)
- dilated fundoscopy
- visual acuity
- MRI of brain with or without contrast
- lumbar puncture at spinal L3/L4
Investigations to consider
- magnetic resonance venogram of head
- optical coherence tomography
- Intracranial structural anomalies
- European Headache Federation guideline on idiopathic intracranial hypertension
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