Idiopathic intracranial hypertension

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 11 Aug 2025

Last updated: 04 Feb 2022

Idiopathic intracranial hypertension (IIH) is a disorder of increased intracranial pressure in an alert and orientated 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 papilloedema, 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.

Definition

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.[1] Its cause is unknown. It is characterised by increased intracranial pressure and its associated signs and symptoms in an alert and orientated patient but without localising neurological 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 lifelong chronic course.[1][2]

History and exam

Key diagnostic factors

presence of risk factors
visual field loss

Full details

Other diagnostic factors

headache
transient visual obscurations
pulse-synchronous tinnitus
photophobia
retrobulbar pain
optical disc swelling
decreased visual acuity
ocular motility disturbances
relative afferent pupillary defect

Full details

Risk factors

female sex
obesity and weight gain
certain medication use
associated causal diseases
sleep apnoea
family history

Full details

Diagnostic investigations

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

Full details

Investigations to consider

magnetic resonance venogram of head
optical coherence tomography

Full details

Treatment algorithm

ACUTE

all patients

Contributors

Authors

Michael Wall, MD

Professor

Department of Neurology and Department of Ophthalmology & Visual Sciences

University of Iowa Hospitals & Clinics and Iowa City VA Health Care System

Iowa City

Disclosures

MW is an author of a number of references cited in this topic.

Mansoor Mughal, MD

Retina Fellow

Rutgers University

Robert Wood Johnson University Hospital

New Brunswick

Disclosures

MM declares that he has no competing interests.

Peer reviewers

Paul W. Brazis, MD

Consultant in Neurology and Neuro-Ophthalmology

Mayo Clinic Florida

Jacksonville

Disclosures

PWB declares that he has no competing interests.

Tim D. Matthews, MBBS

Consultant Neuro-ophthalmologist

Birmingham Neuro-ophthalmology Unit

University Hospital Birmingham

Birmingham

Disclosures

TDM declares that he has no competing interests.

Peer reviewer acknowledgements

BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.

Disclosures

Peer reviewer affiliations and disclosures pertain to the time of the review.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Wall M. Idiopathic intracranial hypertension. Neurol Clin. 2010 Aug;28(3):593-617.Full text Abstract

Johnson LN, Krohel GB, Madsen RW, et al. The role of weight loss and acetazolamide in the treatment of idiopathic intracranial hypertension (pseudotumor cerebri). Ophthalmology. 1998 Dec;105(12):2313-7. Abstract

Hayreh SS. Pathogenesis of oedema of the optic disc (papilloedema): a preliminary report. Br J Ophthalmol. 1964 Oct;48:522-43.Full text Abstract

Smith JL. Whence pseudotumor cerebri? J Clin Neuroophthalmol. 1985 Mar;5(1):55-6. Abstract

Frisen L. Swelling of the optic nerve head: a staging scheme. J Neurol Neurosurg Psychiatry. 1982 Jan;45(1):13-8.Full text Abstract

NORDIC Idiopathic Intracranial Hypertension Study Group Writing Committee; Wall M, McDermott MP, Kieburtz KD, et al. Effect of acetazolamide on visual function in patients with idiopathic intracranial hypertension and mild visual loss: the idiopathic intracranial hypertension treatment trial. JAMA. 2014 Apr 23-30;311(16):1641-51.Full text Abstract

Sinclair AJ, Burdon MA, Nightingale PG, et al. Low energy diet and intracranial pressure in women with idiopathic intracranial hypertension: prospective cohort study. BMJ. 2010 Jul 7;341:c2701.Full text Abstract

Hoffmann J, Mollan SP, Paemeleire K, et al. European Headache Federation guideline on idiopathic intracranial hypertension. J Headache Pain. 2018 Oct 8;19(1):93.Full text Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Intracranial structural anomalies
More Differentials
Guidelines
- European Headache Federation guideline on idiopathic intracranial hypertension
More Guidelines
Patient information
Obesity - drugs and surgery
Obesity - diet and exercise
More Patient information
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Idiopathic intracranial hypertension

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

all patients

Contributors

Authors

Michael Wall, MD

Disclosures

Mansoor Mughal, MD

Disclosures

Peer reviewers

Paul W. Brazis, MD

Disclosures

Tim D. Matthews, MBBS

Disclosures

Peer reviewer acknowledgements

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Patient information

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice