Blood Culture-Negative Cardiovascular Syphilis in an Untreated HIV-Positive Man

Area of Science:

• Infectious Diseases
• Cardiology
• Genitourinary Medicine

Background:

• Blood culture-negative endocarditis (BCNE) is a serious heart infection.
• Cardiovascular syphilis, caused by Treponema pallidum, is a rare BCNE affecting the aorta and occasionally the aortic valve.
• Coinfection with human immunodeficiency virus (HIV) is common, and lack of antiretroviral therapy may worsen syphilis progression.

Purpose of the Study:

• To report a rare case of syphilis endocarditis in a patient with untreated HIV.
• To emphasize the diagnostic challenges and treatment implications of this condition.
• To highlight the unusual presentation of valvular syphilis without significant aortic involvement.

Main Methods:

• Case report of a 44-year-old male with heart failure and untreated HIV.
• Diagnostic workup included transesophageal echocardiogram, rapid plasma reagin (RPR) test, and blood cultures.
• Causative agent (T. pallidum) identified via 16S rRNA sequencing on explanted aortic valve tissue.

Main Results:

• Patient presented with aortic valve lesion, negative blood cultures, and high RPR titer (1:128).
• Diagnosis of syphilis endocarditis confirmed by genetic sequencing of the aortic valve.
• Successful treatment with aortic valve replacement and antibiotics (penicillin and ceftriaxone).

Conclusions:

• Syphilis endocarditis is a rare but life-threatening diagnosis.
• HIV positivity and non-adherence to antiretroviral therapy likely accelerated disease progression and treatment complexity.
• The absence of typical aortic involvement in this valvular syphilis case was highly unusual.