A -year-old man comes to the clinic for a scheduled follow-up evaluation. Six months ago, he presented with a painless penile ulcer and a diffuse maculopapular rash involving his palms and soles. At that time, a rapid plasma reagin (RPR) test was reactive with a titer of , and a Treponema pallidum particle agglutination (TP-PA) test was positive. He was diagnosed with secondary syphilis and successfully treated with a single intramuscular injection of million units of benzathine penicillin G. Today, the patient reports feeling well and notes that his rash resolved completely within a few weeks of treatment. He has no new sexual partners and has been consistently using condoms. Vital signs are within normal limits. Physical examination reveals clear skin with no active lesions, rashes, or lymphadenopathy. Neurologic examination shows no abnormalities. Which of the following is the most appropriate next step to evaluate the efficacy of this patient's treatment?
- ARepeat the Treponema pallidum particle agglutination test to ensure it has become nonreactive
- BProvide routine reassurance with no further laboratory testing since his clinical symptoms have resolved
- Repeat the rapid plasma reagin test to confirm at least a four-fold reduction in the titerCevap
- DPerform a lumbar puncture to analyze cerebrospinal fluid to rule out asymptomatic neurosyphilis
- EOrder magnetic resonance imaging of the brain to screen for central nervous system involvement