Ophthalmologic Manifestations of Behcet Disease Workup

Updated: Mar 21, 2016
  • Author: Mounir Bashour, MD, PhD, CM, FRCSC, FACS; Chief Editor: Hampton Roy, Sr, MD  more...
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Workup

Laboratory Studies

Since there is no pathognomonic clinical sign or laboratory test to distinguish Behçet disease from other uveitic entities, the diagnosis must be made based on characteristic ocular and systemic findings in the absence of evidence of other disease that can explain the findings. Ancillary tests, including ocular and brain imaging studies, are used to assess the severity of intraocular inflammation and systemic manifestations of Behçet disease, to identify latent infections and other medical conditions that might worsen with systemic treatment, and to monitor for adverse effects of drugs used. There are 2 diagnostic or classification criteria in general use by the uveitis community, one from Japan and one from an international group; both rely on a minimum number and/or combination of clinical findings to identify Behçet disease. Finally, several grading schemes have been proposed to assess severity of ocular disease and response to treatment. [10]

The diagnosis of Behçet disease is based on clinical findings rather than on specific laboratory test results. Some tests are useful adjuncts in the evaluation of patients who have Behçet disease.

The pathergy test (or Behçetine test) may be useful in patient evaluation; the test result is a nonspecific inflammatory reaction to a needle prick or an intradermal injection of saline. The reaction, which varies from an indurated erythema to pustule formation, occurs in 40-60% of patients who have Behçet disease.

Several other laboratory tests may help in the evaluation of a patient who has Behçet disease. During episodes of acute inflammation, patients may have high erythrocyte sedimentation rates, high C-reactive protein levels, or an increased number of peripheral leukocytes.

In neuro-Behçet disease, an analysis of cerebrospinal fluid reveals pleocytosis and elevated protein levels. [11]

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Imaging Studies

Fundus fluorescein angiography

Fundus fluorescein angiography shows diffuse retinal vascular leakage and occlusion of retinal vessels.

Fluorescein leakage from retinal vessels may be seen before any clinical signs of vasculitis.

During acute inflammation, retinal vascular leakage is prominent, especially in the radial peripapillary area.

Affected retinal and optic nerve vessels leak fluorescein profusely during early transit and their walls stain in late transit.

Fluorescein angiography also may reveal macular ischemia and cystoid macular edema.

MRI

In neuro-Behçet disease, magnetic resonance imaging (MRI) is the imaging study of choice and often reveals iso-hypointense lesions in T1-weighted images and hyperintense lesions in T2-weighted images, mostly in the mesodiencephalic junction, cerebellar peduncles, and other parts of the brainstem. [11]

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Histologic Findings

Histopathologic changes include necrotizing, leukocytoclastic, and obliterative vasculitis, which affect arteries and veins of all sizes and are probably immune-complex mediated. Only a few eyes that have had active disease have been examined histologically. Vasculitis is the key feature of Behçet disease. Underlying changes seen in the eye are similar to those that occur in other organs of the body.

During acute inflammation, the iris, the ciliary body, and the choroid show diffuse infiltration with neutrophils. In late stages, a proliferation of collagen fibers, thickening of the choroid, formation of cyclitic membrane, and sometimes hypotonia and phthisis bulbi are noted. Lymphocytic and plasma cell infiltration occurs during remission. Of all ocular tissues, the retina suffers the most damage. In the phase of acute inflammation, severe vasculitis with marked infiltration of leukocytes in and around blood vessels is seen. Recent and old hemorrhages are present. Retinal vessels have thickened basement membranes with swollen endothelial cells, which can lead to thrombus formation and vascular obliteration.

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