Background Since 2013, Chikungunya fever (CHIK) has become a re-emerging disease, with an important number of cases imported in Europe, mainly from South America. At chronic stage (after third month) it can develop a chronic inflammatory rheumatism (CIR), in some cases indistinguishable from rheumatoid arthritis (RA) or spondyloarthritis (SpA).
Objectives The aim of this study was to investigate the ultrasound (US) alteration in patients with persistent arthralgia at chronic stage of CHIK.
Methods Observational study of patients with persistent arthralgias at the chronic stage of CHIK. We designed a protocol of derivation patients from the Tropical Diseases Unit to the Rheumatology Department which included patients had persistent arthritis after 6 weeks who did not respond to steroids, presence of bone erosion or any diagnosis doubt. In the basal rheumatological visit, we made the clinical history, physical examination, blood analysis, X-ray and US examination. A Mylab Twice equipment (Esaote, Geneve, Italy) was used, with a 5–13 MHz frequency for grey scale and 5–12.5 MHz for Power Doppler (PD). Wrist, metacarpophalangeal (MCP), interphalangeal (IP), knee, ankle and metatarsophalangeal joint were assesed and also enthesis if symptomatic. Three patterns of post-CHIK CIR were defined: 1) Post-CHIK RA (if meet RA ACR/EULAR 2010 criteria). 2) post-CHIK SpA (if meet ASAS criteria) and 3) post-CHIK undifferentiated arthritis (arthritis without meeting the previous criteria). Post-CHIK musculoskeletal disorders were defined as chronic polyarthralgia without objective physical signs of inflammation (without arthritis, tendinitis or enthesitis).
Results 59 patients were included, 76.3% women, mean age of 46.08±13.65 years. 6 patients (10.2%) were derived to the Rheumatology Department, 5 women and 1 man. In one rheumatoid factor and anti-cyclic citrullinated peptide antibodies were detected. HLA B27 and antinuclear antibodies were negative in all patients. The physical and US data of these patients are shown in the table. 5 of these patients were diagnosed with post-CHIK CIR: 1 post-CHIK RA, 1 non-radiographic axial SpA with peripheral affectation (arthritis and enthesitis) and 3 patients with post-CHIK undifferentiated arthritis. The other patient was diagnosed with post-CHIK musculoskeletal disorder. All 59 patients received NSAIDs and steroids. In addition, post-CHIK CIR received methotrexate (2 patients) and sulfasalazine (1 patient), all with improvement. In the full cohort, only 5.9% of patients had arthralgias prior to CHIK infection, vs. 33.3% in the post-CHIK CIR (p=0.081). 3 patients (5.08%) had a family history of arthritis, all in the post-CHIK CIR.
Conclusions Arthralgias are a frequent symptom even at chronic stage of CHIK. Sometimes it is true arthritis and in others cases edema. For this reason US is very useful in doubtful cases. In our cohort, patients that developed post-CHIK CIR were more frequently women, with a higher percentage of family history of arthritis. To the best of our knowledge, this is the first US study in patients with post-CHIK CIR.
Disclosure of Interest None declared