A 35-year-old woman from Mumbai presents with a 2-month history of fever, maculopapular rash on the trunk and extremities (including palms and soles), and oral ulcers. She reports a history of an ulcer on the vulva 3 months ago that healed spontaneously. Examination reveals generalized lymphadenopathy and hepatosplenomegaly. RPR titre is 1:128 and FTA-ABS is positive. What is the most appropriate next step in management?