chapter  21
10 Pages

Sarcoidosis Characteristics of the Disease

Sarcoidosis i s described as a disease producing granulomas resembling those of tuberculosis with the difference that the epithelioid-cell tubercles do not become caseated in sarcoid . Additionally, in general, sarcoid differs from tuberculosis in the organs invaded.25 Unlike tuberculosis, it tends to involve the skin and parotid glands and to cause cystic bone disease and uveitis . 3D It is also peculiar in causing asymptomatic granulomas in striated muscles.25 It may progres s to severe functional impairment" of various organs,9 including the nervous system. 12 S arcoid is one of the most common causes of sudden, unexpected death in young adults due to invasion of cardiac tis sue (Figure 2 1 - 1 ) and is one cause of blindness which may be preventable. There is some evidence that the di sease may be contagious and intrafamiliap·8

One well-known characteristic of sarcoid is a positive K veim test. Fifty to eighty percent of patients give a K veim reaction, a lesion developing after intracutaneous injection of a heat-sterilized suspension of sarcoid spleen or lymph tissue. When biopsied, the nodule histological ly resembles sarcoid. It appears to be a delayed reaction to some substance in sarcoid ti ssue . I '1

Another somewhat unique characteristic of the sarcoid patient is loss of the delayed-type hyper­ sensitivities which characterize normal individuals . Thus , he is usually skin test negative to tuber­ culin and to Candida antigen. Often he cannot become sensitized to dinitrochlorobenzene, employed to test for ability to develop delayed-type hypersensitivity. However, the sarcoid patient retains normal antibody responses. 3D

EVI D E N C E I NVOLV I N G A MYCOBACT E R I U M AS CAU SAT I V E AG E N T

Chapman, in an early study, showed that gel diffusion tests (Ouchterlony) gave substantial support to the theory that a certain mycobacterium is the sarcoid agent. He found, by precipitin bands, that 78% of patients have antibody for atypical mycobacteria but not for tubercle bacill i .7