*2.2.4.2 Relapsing polychondritis*

*Aortic Aneurysm and Aortic Dissection*

*2.2.3.1 Treponema pallidum*

rarity of the disease presentation [46, 50].

showing a relationship with AoD.

*2.2.4 Inflammatory disorders*

*2.2.4.1 Ankylosing spondylitis*

*2.2.3.2 Tuberculosis*

*2.2.3.3 HIV*

*tuberculosis* and *Treponema pallidum*, which will be discussed below, and more rare causes include *Listeria*, *Bacteroides*, *Clostridium septicum*, and *Campylobacter jejuni* [46]. With the majority of bacterial aortitis, aneurysm development is generally saccular, and *Salmonella* has been reported in case studies to predominantly affect the abdominal aorta than the thoracic [46, 48]. Infections with Staphylococcal species generally are related to underlying aortic valve infections, but have been

*Treponema pallidum*, a sexually transmitted spirochete which is the causative organism of syphilis, is a well characterized cause of aortitis [46, 50, 51]. Cardiovascular involvement is limited to late stage, or tertiary syphilis, and generally occurs 5 to upwards of 40 years after primary infection [50, 51]. Aortitis, and aneurysm development is due to invasion of the vasa vasorum, resulting in obliterative endarteritis that leads to degradation of the aortic media [50, 51]. The chronic inflammation results in fibrosis of the intima, a phenomenon known as "treebarking" that ultimately progresses to aneurysm development. In an autopsy study in 1960 of 51 aortic aneurysms secondary to syphilitic aortitis, 7.8% were found at the sinuses of Valsalva and 29.4% involved the ascending aorta, representing a majority of the sample [52]. This predominance to the ascending thoracic aorta have been further corroborated in later studies, however the detailed echocardiographic analysis of syphilitic aortitis, specifically in relation to AoD is limited due to the

Tuberculosis is a relatively common infection especially in developing countries [53]. *Mycobacterium tuberculosis*, the causative pathogen, is a known cause of mycotic aortic aneurysms [46, 50]. Pathogenesis of tuberculous mycotic aneurysm is believed to be due to lymphatic spread or hematogenous seeding, and mortality rates are reported as high as 60% in patients who develop this complication [50]. While more commonly affecting the distal aortic arch and descending aorta, there are case reports detailing aortic root aneurysms due to tuberculosis [50, 54].

There have been case reports proposing an association between aortic aneurysms and HIV [50]. In a variety of these cases the causes are generally multifactorial, as the majority of cases have reported coinfections (Q fever and leishmaniasis) or comorbid autoimmune conditions (giant cell arteritis) [55, 56]. It is still an area of investigation as to whether there is a true association, and there is sparse data

Ankylosing spondylitis, a seronegative spondyloarthropathy, is a chronic, progressive rheumatologic disorder, and was one of the first found to be associated with aortitis [50, 57]. The proposed mechanism of AoD in ankylosing spondylitis is fibrous growth development along the intima, which leads to subsequent weakening [57]. Prior TEE studies further evaluated the prevalence of AoD in ankylosing

reported to progress into aneurysms of the aortic root [46, 49].

**6**

Relapsing polychondritis is another autoimmune disorder, which is a multisystem inflammatory disorder that primarily affects the cartilaginous structures of the body [59]. Cardiovascular involvement is common, estimated to be the second most frequent cause of death and can result in aneurysm development in 5% of cases of both thoracic and abdominal aorta [50, 59]. AoD has been known to occur, albeit rare, with cases of requiring surgical revision after the development of aortic regurgitation [60, 61].
