A 25-year-old man comes to the physician with a 4-day history of fever and malaise followed by the onset of severe joint pain yesterday. This morning, his body felt unusually stiff. He works as a social media expert and went to Puerto Rico on a business trip 10 days ago. He is in a polyamorous relationship and reports that he was sexually active with one female partner during the business trip; he uses condoms. He appears lethargic but is alert and oriented. His temperature is 39.1°C (102.4°F), pulse is 64/min, respirations are 14/min, and blood pressure is 123/76 mm Hg. Physical examination shows tender deltoid muscles bilaterally as well as tenderness in proximal interphalangeal joints, metacarpophalangeal joints, radiocarpal joints, and tarsophalangeal joints bilaterally. The left first metatarsophalangeal joint is swollen with no erythema or tenderness. A diffuse nonpruritic maculopapular rash is visible. Laboratory testing reveals lymphopenia. Which of the following is the most likely cause of this patient's symptoms?

Question

A 25-year-old man comes to the physician with a 4-day history of fever and malaise followed by the onset of severe joint pain yesterday. This morning, his body felt unusually stiff. He works as a social media expert and went to Puerto Rico on a business trip 10 days ago. He is in a polyamorous relationship and reports that he was sexually active with one female partner during the business trip; he uses condoms. He appears lethargic but is alert and oriented. His temperature is 39.1°C (102.4°F), pulse is 64/min, respirations are 14/min, and blood pressure is 123/76 mm Hg. Physical examination shows tender deltoid muscles bilaterally as well as tenderness in proximal interphalangeal joints, metacarpophalangeal joints, radiocarpal joints, and tarsophalangeal joints bilaterally. The left first metatarsophalangeal joint is swollen with no erythema or tenderness. A diffuse nonpruritic maculopapular rash is visible.   Laboratory testing reveals lymphopenia.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

Eductional Objective: This patient's acute onset of fever, malaise, myalgia, symmetric polyarthralgia affecting distal joints, morning stiffness, and maculopapular rash in combination with leukopenia and thrombocytopenia after traveling to Puerto Rico are suggestive of Chikungunya virus infection. This condition most commonly occurs in tropical and subtropical regions and is transmitted via Aedes aegypti and Aedes albopictus mosquito bites; the incubation period ranges from 1 to 14 days (usually 3 to 7 days). The diagnosis is confirmed via RT-PCR or serology. Treatment is supportive. Although many patients fully recover, some develop chronic arthritis, which can be severe and often incapacitating, as a complication of Chikungunya virus infection.
Because infections with Chikungunya virus, Dengue virus, and Zika virus can have similar clinical presentations, including arthralgia, fever, and a diffuse maculopapular rash, a single PCR that simultaneously tests for all three viruses should be performed.

A 25-Year-Old Man Comes to the Physician with a 4-Day