Idiopathic Intracranial Hypertension

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Written by: Dr Jeremy Steinberg – created: 5 June 2024; last modified: 27 June 2024

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Idiopathic Intracranial Hypertension
Synonym Pseudotumor cerebri.
Definition A disorder characterized by increased intracranial pressure with normal CSF composition and no other cause evident on neuroimaging.
Epidemiology Primarily affects overweight females of childbearing age.
Causes The exact cause is unknown.
Pathophysiology Increased intracranial pressure without a clear structural cause.
Primary Prevention Maintaining a healthy weight.
Risk Factors Female gender, childbearing age, and obesity.
Clinical Features Headache, papilledema, vision loss, pulsatile tinnitus, and diplopia.
Diagnosis Based on clinical criteria, elevated intracranial pressure, and normal CSF composition.
Tests MRI, MRV, and lumbar puncture.
DDX Conditions causing secondary intracranial hypertension and other optic disc abnormalities.
Treatment Weight loss, medication (e.g., acetazolamide), and sometimes surgical interventions.
Prognosis Variable; risk of permanent vision loss if untreated.

Idiopathic Intracranial Hypertension (IIH) is disorder that causes clinical features related to increased intracranial pressure without any other cause found. Patients with Idiopathic Intracranial Hypertension can end up seeing a Musculoskeletal Physician because it can commonly cause neck pain. Hence it is important to keep this condition in mind especially in obese women.

Epidemiology

It is almost exclusively a disease of obese women of childbearing age. The average BMI is ~40, and average age is 29.[1]

Clinical Features

Idiopathic Intracranial Hypertension causes headache in most patients. Neck pain is very common as well. The condition can cause a myriad of different symptoms. One symptom that may help differentiate it is pulsatile tinnitus.[1]

  • Headache (84%)
  • Transient visual obscurations (68%)
  • Pulse synchronous tinnitus (52%)
  • Visual loss (32%)
  • Back pain (53%)
  • Neck pain (?52% - shown in graph format only)
  • Dizziness (?52% - shown in graph format only)
  • Photophobia (?48% - shown in graph format only)

These symptoms are very common in age and gender matched controls. Pulsatile tinnitus is the most useful distinguishing feature.[2] It is also important to be weary of the difference between correlation and causation. Back pain for example is extremely common in obese individuals.

Assessment

MRI with and without contrast plus MRV is the imaging of choice. There are several findings that are suggestive of IIH, but are not diagnostic. These are empty sella, flattening of the posterior globe, distension of the perioptic subarachnoid space, and transverse sinus stenosis.

Lumbar puncture is done after MRI. The patient should be lying on their side with their legs extended. Pressures greater than 250 mmH2O are supportive of the diagnosis. Pressures between 200-250 are equivocal. The fluid should be sent for analysis, and should be normal in the condition.

Ophalmologic assessment is required. This includes dilated fundus examination, optic nerve photographs, and visual field testing is very important.

Blood pressure should be checked to assess for malignant hypertension.

There are no highly useful blood tests, but a complete blood count can be considered.

Diagnosis

The diagnostic criteria requires all of the following:

  • Papilloedema OR sixth nerve palsy (either unilateral or bilateral)
  • Otherwise normal neurological examination
  • MRI/MRV shows normal brain parenchyma.
  • LP shows elevated opening pressure
  • Normal CSF composition

Resources

References

  1. 1.0 1.1 Wall, Michael; Kupersmith, Mark J.; Kieburtz, Karl D.; Corbett, James J.; Feldon, Steven E.; Friedman, Deborah I.; Katz, David M.; Keltner, John L.; Schron, Eleanor B.; McDermott, Michael P.; NORDIC Idiopathic Intracranial Hypertension Study Group (2014-06). "The idiopathic intracranial hypertension treatment trial: clinical profile at baseline". JAMA neurology. 71 (6): 693–701. doi:10.1001/jamaneurol.2014.133. ISSN 2168-6157. PMC 4351808. PMID 24756302. Check date values in: |date= (help)
  2. Giuseffi, V.; Wall, M.; Siegel, P. Z.; Rojas, P. B. (1991-02). "Symptoms and disease associations in idiopathic intracranial hypertension (pseudotumor cerebri): a case-control study". Neurology. 41 (2 ( Pt 1)): 239–244. doi:10.1212/wnl.41.2_part_1.239. ISSN 0028-3878. PMID 1992368. Check date values in: |date= (help)

Literature Review