Syphilitic Aortitis and Non-Atherosclerotic Aortic Disease
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Direct answer
Syphilitic aortitis is inflammation of the vasa vasorum of the ascending aorta in tertiary syphilis, which destroys the media and leads to aneurysm and aortic regurgitation. It typically appears a decade or more after the original infection, and the classic tree-bark aorta is seen at pathology. Serology with both a non-treponemal and a treponemal test confirms the diagnosis, and penicillin treats the infection while the aneurysm needs surgical assessment.
What you must remember
- Mechanism: endarteritis of the vasa vasorum causes medial necrosis, which weakens the ascending aorta and dilates the aortic annulus.
- Site: the ascending aorta and arch are most affected, with the root especially vulnerable, and aortic regurgitation is the typical valve lesion.
- Tree-bark aorta: a wrinkled, scarred intima with longitudinal ridging gives the bark-like pattern at pathology, and linear calcification may show on imaging.
- Coronary ostial stenosis: narrowing of the coronary ostia is a recognised complication of syphilitic aortitis.
- Serology: a non-treponemal test such as VDRL or RPR reflects activity, and a treponemal test confirms infection.
- Treatment: penicillin treats the infection, but the aneurysm and aortic regurgitation still need surgical review.
- Marfan syndrome: a fibrillin-1 defect causes cystic medial degeneration and root dilatation, with ectopia lentis and a tall habitus as clues.
- Takayasu arteritis: granulomatous aortitis of young Asian women involves the arch and its branches, often with a raised ESR and CRP.
Working up a dilated ascending aorta
A dilated ascending aorta in a younger patient should trigger a search for the cause, because the treatment differs. The approach starts with the history and ends with imaging and serology.
- Take the history: Ask about prior genital ulcers or rash, previous syphilis treatment, family history of aneurysm or sudden death, and features such as eye or joint involvement.
- Check serology: A reactive non-treponemal test indicates activity, and a treponemal test confirms infection, so both are ordered together.
- Image the aorta: CT or MRI measures the root and ascending diameter, and shows calcification, aneurysm shape and the arch.
- Assess the valve: Echocardiography grades aortic regurgitation, checks for annular dilatation and looks for a bicuspid valve.
- Screen for genetic syndromes: Look for ectopia lentis and skeletal features of Marfan syndrome, or thin translucent skin and arterial rupture in Ehlers-Danlos type IV.
- Plan the treatment: Penicillin is given for syphilis, blood pressure is controlled, and surgical referral follows when the diameter reaches the guideline threshold, around 5.5 cm in the general population and lower in Marfan syndrome.
Where the aortic diagnosis gets missed
Errors usually come from attributing every aneurysm to atherosclerosis, which is most common in older patients.
- Trap: attributing every ascending aneurysm to atherosclerosis Correct: syphilis, Marfan syndrome, bicuspid valves and arteritis cause non-atherosclerotic dilatation, often in younger patients.
- Trap: treating syphilitic aortitis with antibiotics alone Correct: penicillin treats the infection, but the aneurysm and aortic regurgitation still need surgical review.
- Trap: labelling Takayasu arteritis as a disease of older men Correct: it classically affects young Asian women and involves the arch and its branches, not the older atherosclerotic population.
Frequently asked questions
What is the tree-bark appearance in syphilitic aortitis?
The tree-bark appearance is the wrinkled, scarred intima of the ascending aorta, which resembles the bark of a tree at autopsy, with linear calcification sometimes visible on imaging. It is a classic feature of syphilitic aortitis, and it prompts a search for serological evidence of syphilis.
Which serology is used to diagnose syphilitic aortitis?
A non-treponemal test such as VDRL or RPR assesses disease activity, and a treponemal test confirms infection. Both are needed in syphilitic aortitis, because a treponemal test usually stays reactive after successful treatment.
Which genetic aortopathy causes cystic medial degeneration?
Marfan syndrome, caused by fibrillin-1 mutations, causes cystic medial degeneration and aortic root dilatation. Ectopia lentis and a tall habitus are common clues in Marfan syndrome.
Which arteritis causes aortic regurgitation in young Asian women?
Takayasu arteritis causes aortic regurgitation in young Asian women, usually through aortitis and root dilatation. It also involves the arch and its branches, which can produce pulse deficits and asymmetric blood pressure.