[Fluorescein angiography in the diagnosis of periarteritis nodosa].
Periarteritis Nodosa (P.A.N.) is a systemic connective tissue disease with a variety of manifestations that includes ocular involvement in 20% of cases. The diagnosis of this condition is difficult due to the absence of any specific clinical signs or laboratory findings. However, histologic studies have demonstrated a segmental vasculitis that is often necrotic. Ocular findings frequently include choroidal involvement that is characteristic. Nevertheless, angiographic studies of this disease are extremely rare. The findings in three patients suspected of having P.A.N. are presented. Fluorescein angiography established the diagnosis of P.A.N. in two cases and ruled-out its presence in the third case. In the first case angiography demonstrated a retinal vasculitis with multiple arteriolar and capillary occlusions. There was also ischemic involvement of the choriocapillaris and a mild anterior optic nerve vasculitis. All findings resolved, leaving numerous Elschnig spots. In the second case the angiogram showed acute multifocal ischemia of the choriocapillaris. The ocular examination and fluorescein angiogram in the third case were entirely normal, thereby ruling-out P.A.N. on the basis of insufficient criteria. Acute multifocal choroidal ischemia is present in a variety of rare conditions: Toxemia of pregnancy, Disseminated Intravascular coagulopathy, Moskowitz Disease (T.T.P.), Leukemia and Malignant Hypertension. However, the presence of multifocal choroidal ischemia in the presence of a systemic connective tissue disorder strongly favors the diagnosis of P.A.N. The relative contributions of co-existent Malignant Hypertension and P.A.N. in producing choroidal ischemia are discussed. The spectrum of clinical manifestations and laboratory findings in P.A.N. as well as hypotheses concerning pathogenesis (immune-complex deposition) are described. Among all systemic vasculitis , only P.A.N., and rarely Scleroderma, feature choroidal involvement. This is possibly due to the fact that the degree of vasculitis in P.A.N. is sufficiently severe to cause clinically significant choroidal involvement.