The pseudotumor cerebri syndrome (PTCS) may be primary (idiopathic intracranial hypertension) or arise from an identifiable secondary cause. Characterization of typical neuroimaging abnormalities, clarification of normal opening pressure in children, and features distinguishing the syndrome of intracranial hypertension without papilledema from intracranial hypertension with papilledema have furthered our understanding of this disorder. We propose updated diagnostic criteria for PTCS to incorporate advances and insights into the disorder realized over the past 10 years.

Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children.

Idiopathic intracranial hypertension is a disorder characterised by raised intracranial pressure that predominantly affects young, obese women. Pathogenesis has not been fully elucidated, but several causal factors have been proposed. Symptoms can include headaches, visual loss, pulsatile tinnitus, and back and neck pain, but the clinical presentation is highly variable. Although few studies have been done to support evidence-based management, several recent advances have the potential to enhance understanding of the causes of the disease and to guide treatment decisions. Investigators of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) reported beneficial effects of acetazolamide in patients with mild visual loss. Studies have also established weight loss as an effective disease-modifying treatment, and further clinical trials to investigate new treatments are underway. The incidence of idiopathic intracranial hypertension is expected to increase as rates of obesity increase; efforts to reduce diagnostic delays and identify new, effective approaches to treatment will be key to meeting the needs of a growing number of patients.

https://www.thelancet.com/pdfs/journals/laneur/PIIS1474-4422(15)00298-7.pdf

Understanding idiopathic intracranial hypertension: mechanisms, management, and future directions

PTC is a clinical entity of uncertain etiology characterized by intracranial hypertension. The syndrome classically manifests with headaches and visual changes in women with obesity. Traditionally, imaging ruled out secondary causes of elevated CSF pressure but now may reveal findings frequently seen in patients with PTC, including the following: flattening of the globe, an empty sella, an enlarged ONS, protrusion and enhancement of the optic nerve head, and increased tortuosity of the optic nerve. Novel imaging methods, including MR venography, have additionally identified sinovenous stenosis as a potential indicator of PTC.

http://www.ajnr.org/content/ajnr/32/11/1986.full.pdf

Pseudotumor cerebri: brief review of clinical syndrome and imaging findings.

Idiopathic intracranial hypertension is a disease of unknown aetiology, typically affecting young obese women, producing a syndrome of increased intracranial pressure without identifiable cause. Despite a large number of hypotheses and publications over the past decade, the aetiology is still unknown. Vitamin A metabolism, adipose tissue as an actively secreting endocrine tissue and cerebral venous abnormalities are areas of active study regarding the pathophysiology of idiopathic intracranial hypertension. There continues to be no evidence based consensus or formal guidelines regarding management and treatment of the disease. Treatment studies show that the diagnostic lumbar puncture is a valuable intervention beyond its diagnostic importance, and that weight management is critical. However, many questions remain regarding the efficacy of acetazolamide, CSF shunting procedures and cerebral transverse venous sinus stenting.

https://jnnp.bmj.com/content/jnnp/83/5/488.full.pdf

Update on the pathophysiology and management of idiopathic intracranial hypertension

The cause of idiopathic intracranial hypertension (IIH) remains unknown, and no consensus exists on how patients should be monitored and treated. Acetazolamide is a common treatment but has never been examined in a randomised controlled trial. The objectives of this pilot trial are to prospectively evaluate the use of acetazolamide, to explore various outcome measures and to inform the design of a definitive trial in IIH. Fifty patients were recruited from six centres over 23 months and randomised to receive acetazolamide (n = 25) or no acetazolamide (n = 25). Symptoms, body weight, visual function and health-related quality-of-life measures were recorded over a 12-month period. Recruited patients had typical features of mild IIH and most showed improvement, with 44% judged to have IIH in remission at the end of the trial. Difficulties with recruitment were highlighted as well as poor compliance with acetazolamide therapy (12 patients). A composite measure of IIH status was tested, and the strongest concordance with final disease status was seen with perimetry (Somers' D = 0.66) and optic disc appearance (D = 0.59). Based on the study data, a sample size of 320 would be required to demonstrate a 20% treatment effect in a substantive trial. Clinical trials in IIH require pragmatic design to involve sufficiently large numbers of patients. Future studies should incorporate weighted composite scores to reflect the relative importance of common outcome measures in IIH.

A randomised controlled trial of treatment for idiopathic intracranial hypertension.

Objective: To compare the characteristics of idiopathic intracranial hypertension (IIH) in men vs women in a multicenter study. Methods: Medical records of all consecutive patients with definite IIH seen at three university hospitals were reviewed. Demographics, associated factors, and visual function at presentation and follow-up were collected. Patients were divided into two groups based on sex for statistical comparisons. Results: We included 721 consecutive patients, including 66 men (9%) and 655 women (91%). Men were more likely to have sleep apnea (24% vs 4%, p p = 0.02). As their first symptom of IIH, men were less likely to report headache (55% vs 75%, p p = 0.005). Men continued to have less headache (79% vs 89%, p = 0.01) at initial neuro-ophthalmologic assessment. Visual acuity and visual fields at presentation and last follow-up were significantly worse among men. The relative risk of severe visual loss for men compared with women was 2.1 (95% CI 1.4–3.3, p = 0.002) for at least one eye and 2.1 (95% CI 1.1–3.7, p = 0.03) for both eyes. Logistic regression supported sex as an independent risk factor for severe visual loss. Conclusion: Men with idiopathic intracranial hypertension (IIH) are twice as likely as women to develop severe visual loss. Men and women have different symptom profiles, which could represent differences in symptom expression or symptom thresholds between the sexes. Men with IIH likely need to be followed more closely regarding visual function because they may not reliably experience or report other symptoms of increased intracranial pressure.

R. A. Braswell

Papers

Idiopathic intracranial hypertension in men.