Lungs.Thelungsareaffectedinmorethan50%ofcases.Thisinvolvementmaymanifestaspulmonaryhypertensionandinterstitialfibrosis.Pulmonaryvasospasmsecondarytoendothelialdysfunctionisconsideredimportantinthepathogenesisofpulmonaryhypertension.Pulmonaryfibrosis,whenpresent,isindistinguishablefromthatseeninidiopathicpulmonaryfibrosis(Chapter13).
Heart. Pericarditiswitheffusion,myocardialfibrosis,andthickeningofintramyocardialarteriolesoccurinonethirdofpatients.Becauseofthechangesinthelung,rightventricularhypertrophyandfailure(corpulmonale)arefrequent.
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Fig. 5.29 Systemicsclerosis.(A)Normalskin.(B)Skinbiopsyfromapatientwithsystemicsclerosis.Notetheextensivedepositionofdensecollageninthedermis,thevirtualabsenceofappendages(e.g.,hairfollicles),andfociofinflammation(arrow). (C)Theextensivesubcutaneousfibrosishasvirtuallyimmobilizedthefingers,creatingaclawlikeflexiondeformity.Lossofbloodsupplyhasledtocutaneousulcerations.(C,Courtesy of Dr. Richard Sontheimer, Department of Dermatology,University of Texas Southwestern Medical School,Dallas,Texas.)
Systemic sclerosis has a female-to-male ratio of 3:1 and a peak incidence in the 50to 60-year age group. Although systemic sclerosis shares features with SLE, rheumatoid arthritis (Chapter 21), and polymyositis (Chapter 22), it is distinguished by the striking cutaneous changes, notably skin thickening. Raynaud phenomenon, caused by episodic vasoconstriction of the arteries and arterioles of the extremities, is seen in virtually all patients and precedes other symptoms in 70% of cases. Progressive collagen deposition in the skin leads to increasing stiffness, especially of the hands, with eventually complete immobilization of the joints. Nailfold capillary loops are distorted early in the disease, and later disappear. Dysphagia attributable to esophageal fibrosis and its resultant hypomotility are present in more than 50% of patients. Eventually, destruction of the esophageal wall leads to atony and dilation, especially at its lower end. Abdominal pain, intestinal obstruction, or malabsorption syndrome reflect involvement of the small intestine. Respiratory difficulties caused by the pulmonary fibrosis may result in right-sided cardiac dysfunction, and myocardial fibrosis may cause either arrhythmias or cardiac failure. Mild proteinuria occurs in as many as 30% of patients, but rarely is severe enough to cause nephrotic syndrome. The most ominous manifestation is malignant hypertension, with the subsequent development of fatal renal failure (Chapter 14), but in its absence progression of the disease may be slow. In most patients the disease pursues a steady downhill course over the span of many years, although life span is improving with better treatment of the complications. The disease tends to be more severe in blacks, especially black women. As treatment of the renal complications has improved, pulmonary and cardiac complications have become the major cause of death.
Virtually all patients have ANAs that react with a variety of nuclear antigens (see