Ophthalmologic Manifestations of Behcet Disease

Updated: Aug 17, 2018
  • Author: Mounir Bashour, MD, PhD, CM, FRCSC, FACS; Chief Editor: Hampton Roy, Sr, MD  more...
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Overview

Background

Behçet disease is a systemic disorder characterized by recurrent aphthous ulcers and intraocular inflammation. The clinical triad of uveitis with recurrent oral and genital ulcers bears the name of Hulusi Behçet, a Turkish dermatologist who described 3 patients who had this triad.

The Behçet's Disease Research Committee of the Ministry of Health and Welfare of Japan first proposed formal diagnostic criteria in 1972. This set of criteria, which has been used throughout the world, classifies disease findings into 4 major criteria and 5 minor criteria. When all 4 major criteria are met, the disease is said to be of the complete type, whereas the incomplete type consists of various combinations of major and minor criteria, with added weight given to ocular disease.

In 1990, The International Study Group (ISG) for Behçet's Disease proposed a separate set of diagnostic criteria for Behçet disease. Based on these criteria, a diagnosis of Behçet disease requires recurrent oral ulceration and at least 2 additional criteria, including recurrent genital ulcers, ocular lesions, skin lesions, and a positive pathergy test. The ISG criteria for Behçet disease have excellent specificity, but lack sensitivity. The International Criteria for Behçet’s Disease (ICBD) was created in 2006, as a replacement to the ISG criteria. For ICBD, vascular lesions were added, while oral aphthosis is no longer mandatory. Accruing 3 or more points is an indication of the diagnosis of Behçet disease (genital aphthosis, 2 points; eye lesions, 2 points; and the remaining each are 1 point).

A recent study compared the performance of the ISG and ICBD criteria. Their sensitivity, specificity, and accuracy (percent agreement), were tested in 3 independent cohorts of patients from the Far East (China), Middle East (Iran), and Europe (Germany). The sensitivity for ISG criteria was, respectively, 65.4%, 78.1%, and 83.7%, and, for ICBD, was 87%, 98.2%, and 96.5%. The specificity for ISG was, respectively, 99.2%, 98.8%, and 89.5%, and, for ICBD was 94.1%, 95.6%, and 73.7%. The accuracy for ISG was 74.2%, 85.5%, and 85.5%, and, for ICBD was 88.9%, 97.3%, and 89.5%. The conclusion is that ICBD has better sensitivity and accuracy than ISG. [1]

Other Medscape Reference articles on Behçet disease include Behcet disease (Dermatology) and Behcet disease (Rheumatology).

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Pathophysiology

The cause and the pathogenesis of Behçet disease remain unknown. More than one mechanism seems to be operative in the pathogenesis of Behçet syndrome, including genetic and environmental factors, causing different manifestations of the syndrome. Several clues suggest the role of environmental factors and, especially, microorganisms, in the pathogenesis. These include clinical findings such as a decrease in the frequency of a positive pathergy reaction with surgical cleaning of the skin before the procedure, the acne-arthritis association carrying similar features to acne-associated reactive arthritis, a higher rate of tonsillectomy, cold sores, late birth order, higher number of siblings, history of travel to countries with a high incidence of Behçet syndrome, and earlier age at first sexual intercourse. Moreover, basic research on both viruses and bacteria suggests that microorganisms may be playing a role, possibly through heat-shock proteins and T-cell hypersensitivity. [2]

The tumor necrosis factor-alpha (TNF-alpha) pathway is likely involved in the pathophysiology of Behçet disease. The frequency of the R92Q TNFRSF1A mutation in patients with Behçet disease is significantly higher than that in control subjects (P = .006 by the Fisher exact test) and is associated with an increased risk of extracranial venous thrombosis.

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Epidemiology

Frequency

United States

The prevalence of Behçet disease is estimated to be only 1 case per 300,000 persons per year.

In a university hospital setting, Behçet disease was responsible for 12-20% of cases of uveitis in Japan, compared with only 0.2-0.4% in the United States.

International

Behçet disease occurs worldwide, with a predominance among Asians, North Africans, and Europeans who live between the latitudes of 30-45°N.

Behçet disease is one of the main causes of endogenous uveitis in Japan and Turkey, with prevalence rates of 1 case per 10,000 population and 8-30 cases per 10,000 population, respectively.

Race

The prevalence of Behçet disease exhibits a strong geographic variation and has a unique geographic distribution, being most prevalent along the ancient Silk Road linking Rome with China, which was used for centuries as a trade passage. [3]

The prevalence of Behçet disease is highest in Turkey, in the countries bordering the Mediterranean, in the Mideast, in the Far East, and in Japan, where it is 1 case per 1000 population.

Behçet disease occurs less frequently in northern Europe, the United States, and the United Kingdom.

The prevalence of Behçet disease in African Americans is 1 case per 100,000 population.

Sex

The male-to-female ratio varies with ethnic origin; androtropism is still observed in Arabian countries, with a ratio of 2.3:1, whereas female predominance is seen in some European countries and in the United States. [3]

Age

The mean age at onset is in the third decade of life. However, when Behçet disease occurs in males aged 15-25 years, it takes a more serious form.

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Prognosis

Spontaneous remissions and relapses characterize the natural history of ocular Behçet disease.

Visual prognosis in countries (ie, Japan, Turkey) that have the highest prevalence of Behçet disease is poor.

In Japan and Turkey, more than 50% of cases result in legal blindness within 4 years of onset.

The prevalence of blindness in Behçet disease patients in North America is 25%.

Possible explanation for this discrepancy includes genetic heterogeneity, with the occurrence of more severe disease in the Mideast and the Far East.

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