Syphilitic aneurysms commonly occur in ascending aorta (50%), aortic arch (30%), descending aorta (15%) and abdominal aorta in 5%. Most aneurysms are saccular and less commonly fusiform. [3]
The diagnosis of tertiary syphilis may be difficult because clinical features may be similar with other granulomatous disease and serologic titers specially the nontreponemal one could be low or negative [10, 11]. The approach of using treponomal test as screening test, first described in 2008 by the US CDC is gaining popularity because it can detect syphilis in some patients with syphilis who would not have been identified if a nontreponemal test was used initially. However, it results in higher rate of false positivity as well. [12, 13] To settle the diagnosis of confirmed cardiovascular tertiary syphilis, on top of a clinically compatible case it requires either identification of treponemes in tissue sections with silver or immunohistochemical staining or detection of T. palladium DNA in tissue with PCR. Our patient had positive serologic tests in the background of an abdominal aneurysm and no classic risk factors for atherosclerotic aneurysm like diabetes, hypertension or obesity which makes syphilitic aneurysm highly likely. [14] A possible limitation is that we did not have a histologic confirmation which may not be mandatory since mesoaortitis by itself is not diagnostic in the absence of serology. [15] Many case reports clinically diagnosed syphilitic aneurysm with an appropriate clinical presentation and high serum TPHA. [14, 16]
Cardiovascular syphilis left untreated it can lead to rupture of aneurysm, coronary ostial necrosis with sudden death and embolization. [3] Treatment of syphilitic AAA involves medical treatment with intramuscular penicillin and surgical intervention. Symptomatic AAA (abdominal, back, flank pain and limb ischemia) has increased risk of aneurysmal rupture, hence most require repair. Urgent or emergent repair is indicated for patients with ruptured AAA and symptomatic non ruptured AAA, provided the risk of repair is not prohibitive. [17, 18]
Conclusion