A mosquito-borne virus called Chikungunya could mimic symptoms of rheumatoid arthritis, potentially leading to misdiagnosis. Chikungunya often causes joint pain and swelling similar to what is seen in rheumatoid arthritis patients.
Researchers found the blood tests of patients with Chikungunya virus and those with rheumatoid arthritis can produce similar results, Washington University in St. Louis reported. The findings highlight the need for doctors to make sure they have obtained detailed medical and travel records on their patients being evaluated for rheumatoid arthritis.
"For now, good travel histories of patients are among the best diagnostic tools for physicians," said senior author Dr. Wayne Yokoyama, the Sam and Audrey Loew Levin Professor of Medicine at the university. "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."
The phenomenon is potentially problematic because rheumatoid arthritis is generally treated with immune system-suppressing drugs, and it is not yet known if these treatments could harm Chikungunya patients.
To make their findings the researchers studied 10 St. Louis-area residents who traveled in June 2014 to Haiti and were infected with the Chikungunya virus. The subjects were evaluated between seven and 10 weeks after symptom onset; during this follow-up, eight of the patients developed persistent arthritis characterized by severe joint pain. It has been estimates about percent of those infected with Chikungunya will develop these types of symptoms, and they can last for up to three years.
"All eight patients with Chikungunya-related arthritis met the American College of Rheumatology's criteria for a diagnosis of rheumatoid arthritis," said lead author Jonathan Miner, a rheumatology fellow. "Their recent travel to Haiti led us to suspect they had Chikungunya virus infections."
The study also included healthy subjects and patients newly diagnosed with rheumatoid arthritis. In laboratory tests the researchers measured levels of specialized immune cells in the blood, revealing deceptive similarities between Chikungunya virus infections and 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," said co-author Deborah Lenschow, associate professor of medicine and of pathology and immunology.
The findings were published in the January edition of the journal Arthritis and Rheumatology.
