STI screening and management — KFP-style written assessment

KFP 1 (10 marks)

A 29-year-old gay man attends for a routine quarterly screen. He reports receptive anal and oral sex with two regular partners, no condoms. He is well, asymptomatic. ^[1]

1. List every site you test and the specimen type for each. (3) ^[1]
2. Justify extragenital testing quantitatively. (4) ^[1]
3. His rectal chlamydia NAAT returns positive. State first-line therapy and its trial evidence. (3) ^[2]

Model answers

1. First-catch urine, self-collected rectal swab, self-collected oropharyngeal swab for chlamydia/gonorrhoea NAAT; serum for HIV and syphilis serology. ^[1]
2. In this population anal positivity exceeded genital (chlamydia 9.3% vs 3.5%; gonorrhoea 8.5% vs 5.2%), and genital-only screening would have missed 71.4% of chlamydia and 67.3% of gonorrhoea infections. Extragenital infections are usually asymptomatic yet sustain transmission and reinfect index patients after treatment. ^[1]
3. Doxycycline 100 mg twice daily for seven days: randomised cure 96.9% versus 76.4% for azithromycin 1 g (adjusted risk difference 19.9 percentage points), and meta-analysis pooled efficacy 99.6% versus 82.9%. Doxycycline also caused fewer adverse events. ^[2]