Case presentation 1
A 47-year-old male with a history of allergic asthma, osteomyelitis of the left lower third leg treated with an external fixator on April 2019 and a left bi-malleolar fracture that was orthopedically treated, 3 years ago. Twenty days before consultation, the patient was hospitalized in COVID unit of Taher Sfar University Hospital for management of Covid 19 infection. He had symptomatic treatment (oxygen therapy) with a favorable outcome. On 16th of October 2021, the patient was presented to the emergency department with acute right knee arthritis leading to significant functional impotence, impairing the ability to walk (figure 1), and occurring in a context of apyrexia. He did not report a personal or familial history of chronic rheumatism or psoriasis. He denied any recent history of physical trauma, any extra conjugal sexual relationship or infectious symptom such as dyspnea, odynophagia or urine symptoms. The patient did not report any previous episode of arthritis, dactylitis, conjunctivitis or uveitis nor inflammatory diarrhea. On biologic data, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were in the normal ranges (10 mm and 6 mg/L respectively), so was the serum uric acid. Immunologic data were negative including antinuclear anti-bodies (ANA), rheumatoid factor (RF), anti-citrullinated peptide anti-bodies (ACPA). Knees, hip, feet and hands X-rays in front and lateral views were normal without erosions or intraarticular calcifications. A joint puncture was performed showing a turbid fluid with 1500 white cells/mm3, 60% of which were neutrophils (PNN) (figure 2). Testing for microcrystals was negative, as well as the ​synovial fluid culture. An infectious investigation was conducted, including cardiac ultrasound, chest X-ray, urine cytobacteriological examination (UCE), blood cultures, Wright serology (for brucellosis infection) and viral serologies (B and C hepatitis, CMV, EBV and VIH), PCR (real-time polymerase chain reaction) for coronavirus, as well as a tuberculosis assessment, and all of which were negative. The patient’s complaints improved significantly, after immobilization and ice application associated with analgesics and non-steroidal anti-inflammatory drugs.