Microangiopathy of progressive systemic sclerosis. Evaluation by dynamic fluorescence videomicroscopy.

Morphologic changes of the nail-fold capillaries have been studied extensively in progressive systemic sclerosis (PSS). With videomicroscopy after intravenous injection of fluorescein sodium as a tracer, a more accurate morphologic description became possible, including data on the pericapillary interstitial space and the measurement of transcapillary diffusion of dye (videodensitometry). The results in 13 patients with PSS and Raynaud's phenomenon were compared with those obtained in 12 healthy volunteers. The diameters of the patients' nail-fold capillaries were significantly increased. The normal barriers for diffusion of the dye are located at the capillary wall and at the outer border of the skin papilla (halo). Both were less effective in PSS, with significantly enhanced fluorescent light intensities in the juxtacapillary region and outside of the halo. "Streetlike" or "lakelike" areas are stained in the remote parts, demonstrating abnormal architecture of the interstitial space. The technique could facilitate early detection of PSS.