eMedicine Specialties > Ophthalmology > Neurologic Disorders

Idiopathic Intracranial Hypertension: Differential Diagnoses & Workup

Author: Mark S Gans, MD, Associate Professor, Director of Neuro-Ophthalmology, Department of Ophthalmology, McGill University; Clinical Director, Department of Ophthalmology, Adult Sites, McGill University Hospital Center, Interim Chairman of the Department of Ophthalmology, McGill University
Contributor Information and Disclosures

Updated: Aug 18, 2009

Differential Diagnoses

Papilledema

Other Problems to Be Considered

Bilateral optic nerve head edema is presumably due to increased intracranial pressure secondary to an intracranial tumor until proven otherwise. However, malignant hypertension may also cause bilateral optic nerve edema and is easily ruled out by taking the blood pressure.

If the patient's blood pressure is normal or minimally to moderately elevated, obtaining urgent neuroimaging studies to rule out a space-occupying lesion or a dural sinus thrombosis is essential. If the neuroimaging study does not demonstrate any pathology and if a lumbar puncture demonstrates a raised opening pressure, then one of the above-mentioned causes of increased intracranial pressure must be considered (see Risk factors in Causes). 

In the absence of a specific offending agent, the diagnosis of the patient is presumably idiopathic intracranial hypertension.

Other causes of bilateral raised discs include the following:

Workup

Imaging Studies

  • Neuroimaging studies
    • A patient with bilateral disc swelling should undergo urgent neuroimaging studies to rule out an intracranial mass or a dural sinus thrombosis.
    • CT scan is adequate to rule out an intracranial lesion in most instances; however, MRI/venography are more effective in ruling out both a mass lesion and a dural sinus thrombosis, respectively.  Although magnetic resonance venography was once considered an elective imaging study for atypical patients, it is becoming increasingly accepted as a routine study for all patients with idiopathic intracranial hypertension.
    • In the setting of idiopathic intracranial hypertension, the findings on neuroimaging studies include normal or small slit-like ventricles, enlarged optic nerve sheaths, and, occasionally, an empty sella. 
  • Ultrasonography
    • Standardized A-scan orbital ultrasonography precisely measures the diameter of the optic nerve sheath.
    • If this diameter increases in primary gaze and diminishes by 25% in eccentric gaze (30° test), then increased subarachnoid fluid surrounding the optic nerve is presumably present. This finding is consistent with papilledema if it is bilateral.
    • The drawback of this noninvasive technique is that it requires a highly skilled clinician to obtain reproducible results.

Procedures

  • Lumbar puncture
    • Once an intracranial mass lesion is ruled out, a lumbar puncture is indicated. The opening pressure should be measured with the patient relaxed in the decubitus position to avoid a falsely elevated pressure reading.
    • The clinician performing the procedure must indicate to the ophthalmologist if any specific difficulty was encountered that may have falsely elevated the pressure reading.
    • Unfortunately, some patients demonstrate a transiently normal pressure despite their harboring idiopathic intracranial hypertension. Confirming the disease in these patients is difficult.
    • Besides the value of the opening pressure, the clarity and the color of the cerebrospinal fluid should be noted. In addition, the cerebrospinal fluid should be forwarded for assessment of the cell count, cytology, culture, glucose, protein, and electrolyte concentration. All of these findings are normal in patients with idiopathic intracranial hypertension.

More on Idiopathic Intracranial Hypertension

Overview: Idiopathic Intracranial Hypertension
Differential Diagnoses & Workup: Idiopathic Intracranial Hypertension
Treatment & Medication: Idiopathic Intracranial Hypertension
Follow-up: Idiopathic Intracranial Hypertension
References
Further Reading
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References

  1. Friedman DI, Jacobson DM. Idiopathic intracranial hypertension. J Neuroophthalmol. Jun 2004;24(2):138-45. [Medline].

  2. Friedman DI, Jacobson DM. Diagnostic criteria for idiopathic intracranial hypertension. Neurology. Nov 26 2002;59(10):1492-5. [Medline].

  3. Miller NR, Newman NJ. Pseudotumor cerebri (benign intracranial hypertension). In: Walsh and Hoyt's Clinical Neuro-Ophthalmology. Vol 1. 5th ed. 1999:523-38.

  4. Bateman GA, Stevens SA, Stimpson J. A mathematical model of idiopathic intracranial hypertension incorporating increased arterial inflow and variable venous outflow collapsibility. J Neurosurg. Mar 2009;110(3):446-56. [Medline].

  5. Wall M. Idiopathic intracranial hypertension (pseudotumor cerebri). Curr Neurol Neurosci Rep. Mar 2008;8(2):87-93. [Medline].

  6. Corbett JJ. The first Jacobson Lecture. Familial idiopathic intracranial hypertension. J Neuroophthalmol. Dec 2008;28(4):337-47. [Medline].

  7. Daniels AB, Liu GT, Volpe NJ, et al. Profiles of obesity, weight gain, and quality of life in idiopathic intracranial hypertension (pseudotumor cerebri). Am J Ophthalmol. Apr 2007;143(4):635-41. [Medline].

  8. Digre KB, Nakamoto BK, Warner JE, Langeberg WJ, Baggaley SK, Katz BJ. A comparison of idiopathic intracranial hypertension with and without papilledema. Headache. Feb 2009;49(2):185-93. [Medline].

  9. Corbett JJ, Savino PJ, Thompson HS, et al. Visual loss in pseudotumor cerebri. Follow-up of 57 patients from five to 41 years and a profile of 14 patients with permanent severe visual loss. Arch Neurol. Aug 1982;39(8):461-74. [Medline].

  10. Ney JJ, Volpe NJ, Liu GT, Balcer LJ, Moster ML, Galetta SL. Functional Visual Loss in Idiopathic Intracranial Hypertension. Ophthalmology. Jul 28 2009;[Medline].

  11. Bruce BB, Kedar S, Van Stavern GP, et al. Idiopathic intracranial hypertension in men. Neurology. Jan 27 2009;72(4):304-9. [Medline].

  12. Jiraskova N, Rozsival P. Idiopathic intracranial hypertension in pediatric patients. Clin Ophthalmol. Dec 2008;2(4):723-6. [Medline].

  13. Gonzalez-Hernandez A, Fabre-Pi O, Diaz-Nicolas S, Lopez-Fernandez JC, Lopez-Veloso C, Jimenez-Mateos A. [Headache in idiopathic intracranial hypertension]. Rev Neurol. Jul 1-15 2009;49(1):17-20. [Medline].

  14. Mollan SP, Ball AK, Sinclair AJ, et al. Idiopathic intracranial hypertension associated with iron deficiency anaemia: a lesson for management. Eur Neurol. 2009;62(2):105-8. [Medline].

  15. Lin A, Foroozan R, Danesh-Meyer HV, De Salvo G, Savino PJ, Sergott RC. Occurrence of cerebral venous sinus thrombosis in patients with presumed idiopathic intracranial hypertension. Ophthalmology. Dec 2006;113(12):2281-4. [Medline].

  16. Johnson LN, Krohel GB, Madsen RW, March GA Jr. The role of weight loss and acetazolamide in the treatment of idiopathic intracranial hypertension (pseudotumor cerebri). Ophthalmology. Dec 1998;105(12):2313-7. [Medline].

  17. Brazis PW. Clinical review: the surgical treatment of idiopathic pseudotumour cerebri (idiopathic intracranial hypertension). Cephalalgia. Dec 2008;28(12):1361-73. [Medline].

  18. Spoor TC, McHenry JG. Long-term effectiveness of optic nerve sheath decompression for pseudotumor cerebri. Arch Ophthalmol. May 1993;111(5):632-5. [Medline].

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Keywords

idiopathic intracranial hypertension, IIH, papilledema, pseudotumor cerebri, PTC, benign intracranial hypertension, BIH, elevated intracranial pressure, increased intracranial pressure, ICP, optic neuropathy

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Contributor Information and Disclosures

Author

Mark S Gans, MD, Associate Professor, Director of Neuro-Ophthalmology, Department of Ophthalmology, McGill University; Clinical Director, Department of Ophthalmology, Adult Sites, McGill University Hospital Center, Interim Chairman of the Department of Ophthalmology, McGill University
Mark S Gans, MD is a member of the following medical societies: American Academy of Ophthalmology, Canadian Medical Association, Canadian Ophthalmological Society, and North American Neuro-Ophthalmology Society
Disclosure: Nothing to disclose.

Medical Editor

Edsel Ing, MD, FRCSC, Assistant Professor, Department of Ophthalmology & Vision Sciences, University of Toronto: Consulting Staff, Toronto East General Hospital
Edsel Ing, MD, FRCSC is a member of the following medical societies: American Academy of Ophthalmology, American College of Physician Executives, American Society of Contemporary Ophthalmology, Canadian Ophthalmological Society, Contact Lens Association of Ophthalmologists, North American Neuro-Ophthalmology Society, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Brian R Younge, MD, Professor of Ophthalmology, Mayo Clinic School of Medicine
Brian R Younge, MD is a member of the following medical societies: American Medical Association, American Ophthalmological Society, and North American Neuro-Ophthalmology Society
Disclosure: Nothing to disclose.

CME Editor

Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri
Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology
Disclosure: Nothing to disclose.

 
 
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