[Sarcoidosis as a multi-organ disease]

Sarcoidosis meets the criteria for multi-organ disease, which differs from systemic disease in the following points: The preferred primary organ (lungs) is known, immunological processes take place only in the organs involved (T helper lymphocyte accumulation), the clinical picture depends upon the organ involvement, and granulomas are typical of the disorder. The clinical significance of the various organ manifestations covers a broad spectrum, which can also include a threat to life (myocardium), blindness, chronic invalidism (pulmonary fibrosis, hepatopathy, nephropathy), and cosmetic impairment (cutaneous sarcoidosis). Numerous organ manifestations have no clinical significance, and some are both rare and limited (tumorous CNS involvement). So-called overlap syndromes have characteristic features common to both multi-organ and systemic diseases. In addition to characteristic sarcoidosis manifestation in an organ, signs of a generalized disorder are also detectable. Examples are primary biliary cirrhosis, Crohn's disease, coeliac disease, Whipple's disease, TASS (Thyrotoxicosis, Addison, Sjögren, Sarcoidosis) as lymphomas and inflammatory diseases (tuberculosis). Outside of the primary organ, these manifestations are often clinically latent. Selective investigations bronchoalveolar lavage), however, can demonstrate the presence of sarcoidosis alveolitis. It is demonstrated that for the clinician, differentiation of multi-organ from systemic disease is meaningful in particular with respect to therapeutic consequences. In the individual case, however, possible overlapping must always be borne in mind.