Third-degree atrioventricular block as a rare complication of disseminated gonococcal infection (DGI): A case report

Third-degree atrioventricular (AV) block is characterised by complete dissociation between atrial and ventricular activity. It is commonly caused by degenerative conduction disease, ischaemia, medications, or in this case – an infective process. We report a rare case of third-degree AV block caused by disseminated gonococcal infection (DGI). Rates of Neisseria gonorrhoeae are increasing, and DGI remains an important but often under-recognised complication. While DGI typically presents with tenosynovitis, polyarthralgia, and skin lesions - cardiac involvement is uncommon. A 36-year-old cis-male who has sex with men presented with polyarthralgia, tenosynovitis, maculopapular rash, and exertional dyspnoea. Electrocardiogram (ECG) demonstrated third-degree AV block. Mucosal swabs were positive for N. gonorrhoeae at both rectal and pharyngeal sites, though blood cultures were likely negative due to prior antibiotic usage before obtaining cultures. Cardiac imaging showed no structural abnormality or evidence of endocarditis. In the absence of an alternative cause, a diagnosis of presumptive DGI was made. After treatment with intravenous ceftriaxone for seven days, cardiac conduction normalised. Follow-up ECG and cardiac magnetic resonance imaging (MRI) at later time points confirmed complete recovery. This case highlights a novel cardiac manifestation of DGI and reinforces the importance of recognising systemic complications of gonorrhoea.