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HANDBOOK OF PHYSIOL! )( ;Y 



CIRCULATION II 



major shock organs of these 

 diseases. It is likely that the 

 vasculitis is responsible for a 

 great portion o f the mani- 

 festations of the various dis- 

 ease entities. Any type of 

 vessel may be involved, but 

 the fine blood vessels are 

 usually major participants. 

 Pathological changes in- 

 clude subendothelial fibrin- 

 oid degeneration, fibro- 

 blastic proliferation, intimal 

 thickening, varied inflam- 

 matory responses, and 

 thromboses. 



From the pathophysio- 

 logic standpoint the vascular 

 manifestations probably re- 

 sult in greatest part from 

 organic structural change 

 and occlusion. That a func- 

 tional vasospastic compo- 

 nent may be superimposed, 



however, has been proposed. It has been stated that 

 angiitis of the fine acral vessels is particularly apt 

 to give rise to vasoconstriction both reflexly and 

 by direct stimulation of the vessel network (21). 

 The organic changes plus the "spastic" factors lead 

 to agglutination of the cellular elements of blood in 

 the fine vessels in the distal reaches of the circulation, 

 which is an effective precursor of tissue necrosis. It 

 is impossible to quantitate the degree to which func- 

 tional vasospasm contributes to the pathogenesis of 

 these diseases. Vasospasm probably exists to some 

 degree as suggested (but not proved) from the fre- 

 quent association of secondary Raynaud's phenom- 

 enon (as high as 25% in some series). 



Scleroderma {progressive systemic sclerosis). The terms 

 sclerodactylia, acrosclerosis, and scleroderma (pro- 

 gressive systemic sclerosis) have been introduced in 

 the section on Raynaud's phenomenon; the collagen 

 diseases in general have been discussed above. Be- 

 cause of its importance, scleroderma or progressive 

 systemic sclerosis is discussed further. 



Scleroderma is a systemic disorder which involves 

 connective tissue of skin, muscles, tendons, fascia, and 

 all internal organs. Its outstanding manifestation is 

 a generalized increase in collagen fibers (97). 



As with other collagen diseases, the etiology of 

 scleroderma is unknown. It affects both the white 

 and Negro races (74), is more common in females, 



fig. 6. Severe scleroderma. 



and usually occurs during early adult life and middle 

 age. 



Many organs of the bodv may be involved. Thicken- 

 ing of the skin with tightening, increased rigidity, 

 and reduced distensibility, involving the face, ex- 

 tremities, and trunk produce a characteristic ap- 

 pearance (fig. 6). In the early stages of the disease 

 the skin may be edematous, but later it characteris- 

 tically becomes firm and nondistensible, with areas 

 of hyperpigmentation and hypopigmentation, and 

 the joints become stiff and contracted. Calcification 

 of tissues, absorption of the terminal phalanges, 

 atrophy of the fingertips, deformed nails, and cutane- 

 ous ulcers may occur. The face may offer a striking 

 appearance being tight, expressionless, and masklike 

 without wrinkles. The features are pinched, the nose 

 is pointed, and there is difficulty in smiling and open- 

 ing the mouth. Acral vasomotor disturbances such 

 as color changes, coldness, hyperhidrosis, and Ray- 

 naud's phenomenon are not infrequent. 



Histologic sections through affected skin show that 

 the Malpighian layer is atrophic. The deep layers of 

 the skin show increased fibrosis which extends into 

 the subcutaneous tissues. It may extend into muscles 

 of the limbs and may bind the skin of the fingers to 

 bone. Blood vessels are entrapped in the dense fibrotic 

 change. The feet may be involved but the hands 

 show by far the most extensive change. 



