Symptom Similarities in Rheumatoid Arthritis, Chikungunya Lead to Misdiagnosis

Mosquito-borne virus causes joint pain and swelling similar to rheumatoid arthritis.

Similarities in the symptoms caused by both Chikungunya virus and rheumatoid arthritis may cause difficulties in the diagnosis of either condition, a recent study finds.

Published in the January issue of Arthritis and Rheumatology, the study emphasizes the need for physicians to obtain detailed travel and medical histories from patients who are being evaluated for rheumatoid arthritis in order to help in distinguishing the 2 conditions, which both cause joint pain and swelling. The mosquito-borne virus, which has spread to the Caribbean, Central and South America, has also recently been reported in Florida.

"For now, good travel histories of patients are among the best diagnostic tools for physicians," senior author Wayne Yokoyama, MD, said in a press release. "Recent travel to the Caribbean, Central and South America, Africa, India or other areas where the virus is prevalent should raise suspicions of Chikungunya infection. In addition, the disease typically starts with high fever and abrupt onset of severe pain in the joints, which are not usually seen with rheumatoid arthritis."

Rheumatoid arthritis is typically treated with drugs that suppress the immune system, but it has yet to be determined whether that treatment will help or harm Chikungunya virus patients.

More than 2000 people in the United States last year contracted the Chikungunya virus after traveling to a foreign country. Meanwhile, 11 cases of the infection were reported among people living in Florida who had not traveled outside the country, which indicates the virus is being spread by mosquitoes in that state.

Chikungunya causes a fever, rash, and severe joint pain in the hands, feet, knees, neck, and elbows of most patients. While symptoms like fever and rash typically subside within 10 days, arthritis symptoms have been found to persist for up to 15 months in up to 60% of patients, however, in some patients the symptoms may persist for up to 3 years.

The researchers evaluated 10 residents of the St. Louis area infected with Chikungunya virus after traveling to Haiti in June 2014. Patients were evaluated 7 to 10 weeks after symptom onset. Eight of the patients developed persistent arthritis and several reported difficulty walking after developing severe joint pain.

"All 8 patients with Chikungunya-related arthritis met the American College of Rheumatology's criteria for a diagnosis of rheumatoid arthritis," lead author Jonathan Miner, MD, PhD, said in a press release. "Their recent travel to Haiti led us to suspect they had Chikungunya virus infections."

The study also included healthy subjects and newly diagnosed rheumatoid arthritis patients who had not received treatment.

Testing to measure levels of specialized immune cells in the blood showed other similarities between Chikungunya infection and rheumatoid arthritis, including elevated levels of specialized T-cells. This finding indicates the immune system recognizes and actively fights the infection. The results of specialized immune system testing showed antibodies that fight the Chikungunya virus in the blood of patients.

The authors concluded that learning more about Chikungunya may also lead to a greater understanding of rheumatoid arthritis.

"We're anticipating that Chikungunya virus will spread broadly in the United States, so it's important to develop better tools for diagnosis, prevention and treatment,” co-author Deborah Lenschow, MD, PhD, said in a press release.