subject: Syphilitic endocarditis and its pathogenesis [print this page] Pathogenesis Pathogenesis
Syphilis is now much less common as a cause of heartdisease. Cardiac involvement is a manifestation of the tertiarystage of the disease, which often follows a prolongedquiescent period. An endarteritis obliterans of the vasavasorum of the aorta weakens the media, which undergoesa slow necrosis and causes thickening and scar formationin the intima. The changes are irregular, and complicatedby fibrosis and calcification. Dilatation of the aorta occursand can be localized, giving a fusiform or saccular aneurysm;it often also involves the valve ring, causing progressive,and often severe, aortic regurgitation. There maybe damage to the aortic valve cusps leading to retraction,but never stenosis. Intimal scarring of the aorta can lead tocoronary ostial stenosis. The changes do not always lead toovert heart disease. There is a higher percentage of casesof aortic regurgitation and aortic aneurysms in manuallabourers with aortitis, than in sedentary men and womenwith necropsy evidence of aortitis. Thus, it may be thatphysical activity produces additional loads on the aorta,578 which induce these changes.
Clinical features
The patient is usually a man (there is a 3:1 sex ratio foruncomplicated aortitis, but this rises to 10:1 for aorticaneurysm) in late middle age.
Aortic regurgitationThe presentation may be with pure aortic regurgitationwith evidence (best shown echocardiographically) of adilated aortic valve ring, and serological proof of previousTreponema pallidum infection. If untreated, the regurgitation tends to be progressive and severe; indeed, the classic19th century physical signs described for aortic regurgitation are almost all based on patients with severe symphilitic aortic regurgitation (water hammer pulse, head rocking etc.). With a dilated aortic root, the early diastolicmurmur is louder in the third right interspace than thethird left inter space. If there is coronary ostial stenosissevere angina is usually present, often leading to status anginosus (continuous pain), heart failure and death,unless there is early surgical intervention.
Aortic aneurysm
Aortic aneurysm is much less common than regurgitation.It usually occurs in the ascending aorta or arch rather thanthe descending aorta, where aneurysms are much morelikely to be arteriosclerotic. The clinical features dependon the position of the aneurysm. Classically, the ascending aortic aneurysm produces signs of aortic regurgitation, thearch aneurysm symptoms such as dysphagia, cough, painand dyspnoea, and the descending aneurysm pain from erosion of the spine.
