A 35-year-old, previously healthy woman comes to the office due to 3 days of fever and malaise. The patient's symptoms started after she returned from a 2-week vacation in the Caribbean islands. For the past day, she has also had marked pain in her hand and wrist joints. The patient does not use tobacco, alcohol, or illicit drugs and is in a monogamous relationship with her fiancé. Temperature is 39.4 C (103 F), blood pressure is 110/70 mm Hg, and pulse is 98/min. Examination reveals clear lung fields, normal heart sounds, and no murmurs. The abdomen is soft and nontender with no hepatosplenomegaly. She has a macular skin rash on her trunk and extremities and mild cervical lymphadenopathy. There are no oral ulcers. Musculoskeletal examination is notable for swelling and tenderness of bilateral hand, wrist, and ankle joints. Laboratory results are as follows:
| Hematocrit | 38% |
| Platelets | 120,000/mm3 |
| Leukocytes | 2,900/mm3 |
| Neutrophils | 82% |
| Lymphocytes | 10% |
| Creatinine, serum | 0.8 mg/dL |
| Aspartate aminotransferase (SGOT) | 32 U/L |
| Alanine aminotransferase (SGPT) | 24 U/L |
Which of the following is the most likely diagnosis?
Chikungunya virus infection | |
Epidemiology |
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Manifestations |
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Management |
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This patient visited the Caribbean islands and subsequently developed fever, rash, and severe polyarthritis, likely indicating chikungunya, an alphavirus infection transmitted by Aedes mosquitoes. Outbreaks are common in tropical and subtropical regions (eg, Caribbean, Africa, Asia, Indian/Pacific Oceanic islands) during the rainy seasons, and travelers may return to their home countries with the illness.
Manifestations typically include high fever; diffuse maculopapular rash; and symmetric, progressive joint pain that is severe enough to interfere with daily activities. Joint symptoms begin in the distal small joints of the hands and feet but may affect proximal joints over time. Transient lymphopenia and thrombocytopenia often occur.
Although fever and rash resolve spontaneously in a few days, up to 70% of patients with chikungunya develop chronic arthralgia/arthritis that lasts months or years. Treatment is mainly supportive, but patients with severe, long-lasting joint symptoms sometimes require disease-modifying antirheumatic drugs (eg, methotrexate).
(Choice B) Disseminated gonococcus infection can cause rash and joint symptoms (eg, tenosynovitis, polyarthralgia). However, the rash is marked by a few scattered pustules or vesicopustules, not a diffuse maculopapular rash.
(Choice C) Infectious mononucleosis often causes fever, cervical lymphadenopathy, and generalized rash. However, most patients have pharyngitis and atypical lymphocytosis; in addition, polyarticular arthralgia/arthritis would be atypical.
(Choice D) Reactive arthritis typically causes asymmetric oligoarthritis, conjunctivitis, and oral lesions 1-4 weeks after a gastrointestinal or genitourinary tract infection. The presence of symmetric polyarthritis and a lack of conjunctivitis and oral lesions make reactive arthritis less likely.
(Choice E) Systemic lupus erythematosus can cause constitutional symptoms (eg, fever, myalgias), symmetric arthritis (usually hands), and rash. However, the rash is typically in sun-exposed areas (eg, malar), not diffuse; in addition, this patient's high fever and symptom onset shortly after traveling make an infectious etiology more likely.
Educational objective:
Chikungunya is a mosquito-borne viral illness endemic to tropical and subtropical regions. It typically presents with high fever, diffuse maculopapular rash, and severe polyarthralgia/arthritis. Although most initial symptoms resolve spontaneously within days, polyarthralgia/arthritis may persist for months or years.