6.1.11.3 Ocular Manifestations

Ocular involvement may be the presenting manifestation of ABD. It also may correlate with systemic exacerbations of the disease, particularly with central nervous system complications [366]. Ocular disease usually begins in one eye but eventually involves both; inßammation is more severe in one eye when it is bilateral. Sterile hypopyon, occurring in one-third of cases, is the classic ocular Þnding described by both Adamantiadess and Beh•et. It may be a late sign and tends to disappear quickly. Sterile hypopyon in ABD can be distinguished from an infectious hypopyon in that it does not coagulate; it moves with gravity, changing with position. Anterior uveitis and vasculitic involvement of the retina and optic nerve are much more common than hypopyon in ABD. Anterior uveitis may lead to cataract as well as synechia formation and subsequent glaucoma. Retinal vasculitis can involve small vessels of both the arterial and venous systems and can produce vascular ÒsheathingÓ with intraretinal hemorrhages, edema, and exudates, branch and central retinal vein occlusion, arteriolar attenuation, and venous dilatation and tortuosity. Serous retinal detachment is sometimes seen. Optic nerve vasculitis leads to disk hyperemia or edema and eventual optic atrophy [369]. Retinal or optic nerve vasculitis may lead to blindness.

Although much less common, involvement of the anterior segment of the eye may lead to conjunctivitis, keratitis, scleritis, and episcleritis.

Scleritis

Scleritis is rare in ABD [366]. ABD is also rare in patients with scleritis; the reported incidence of ABD in patients with scleritis is about 0.68% [123, 124]. Occasionally, however, it may be the presenting symptom that prompts the patient to seek medical advice and whose study leads to the ABD diagnosis. Scleritis may appear as an isolated ocular Þnding or may be part of a complex ocular involvement with retinal vasculitis and papillitis. ABD must be strongly considered in a young patient with recurrent, bilateral retinal vasculitis associated with scleritis. A careful review of systems and dermatologic examination are essential in establishing the diagnosis. Scleritis may correlate with systemic disease activity.

In our series of 500 patients with scleritis, two patients had ABD (0.4%). They were two females with a mean age of 46 years (range, 38Ð54 years) with unilateral diffuse anterior scleritis. One of the two patients had mild anterior uveitis-associated scleritis. There were no posterior pole abnormalities, keratitis, or glaucoma, and visual acuity was not decreased. Review of systems disclosed oral ulcers, genital ulcers, erythema nodosum, and arthritis.

Episcleritis

Episcleritis is also rare in ABD and often appears after other ocular manifestations, such as retinal vasculitis or disk edema. ABD must be strongly considered in a young patient with recurrent, bilateral retinal vasculitis associated with episcleritis. Mucosal and skin examination may be helpful in determining the diagnosis of BD. Like other ocular abnormalities in ABD, episcleritis may appear during episodes of active disease. Only one patient of our 85 patients with episcleritis had BD (1.18%). The patient was a 47-year- old White female who had nodular episcleritis as well as retinal vasculitis and disk edema in the left eye. Vision in the left eye was reduced to the level of counting Þngers. The patient had already been diagnosed with ABD because of oral ulcers, genital ulcers, papulopustular eruptions in skin, arthritis, gastrointestinal complaints, retinal vasculitis, and optic neuritis.

6.1.11.4 Laboratory Findings

Numerous immunological abnormalities in patients with BD have been detected, but none is diagnostic. These abnormalities include elevated CICs and decreased complement components, leukocytosis, cryoglobulins, elevated interferon g, increased chemotactic activity of neutrophils, and elevation of serum immunoglobulins A, G, and M. Furthermore, T-cell subsets CD4+ (helper) and CD8+ (suppressor), which are normally in serum in a 2:1 ratio, change to a 1:1 ratio in ABD.

6.1.11.5 Diagnosis

The diagnosis of ABD is based on a constellation of clinical Þndings that may occur simultaneously or sequentially [365, 378]. The International Study Group (ISG) for ABD [379] established in