these viruses and bacteria which can cause severe inflammation

Does a joint seize up? The answer is yes, literally and figuratively! An influenza virus often causes aches and pain in the joints, particularly in the hands, feet and knees. This is a symptom, like a cough, chills and fever, that disappears within a few days. But sometimes, the attack is more direct: certain viruses directly infect the joints, as do certain bacteria – this is little known.

“In the case of a viral infection, we are talking more about arthralgia, that is to say joint pain, than real arthritis with swelling in the joints,” explains Professor Jean Sibilia (UMR Inserm 1109, Strasbourg CHRU). These pathogens mainly originate from tropical regions. To cite only the best known of them, dengue or chikungunya viruses seem capable of inducing genuine arthritis, sometimes with pain lasting over time: in Makonde, a Bantu language spoken in southern Africa. , chikungunya is also translated as “who walks bent forward”. Another global viral infection: rare cases of chronic inflammatory rheumatism have been described after infection with the SARS-Cov-2 coronavirus, during the Covid-19 epidemic.

“These viral arthritis raise questions. Has the virus migrated into the joints to cause lasting inflammation? ? Or did it ignite the situation and trigger a more general inflammatory reaction? ? asks the rheumatologist, it is not always easy to decide. Because, during infection by a virus, the pathogen is not found in joint samples. It’s completely different in the case of a bacterial infection. Analyzing the joint tissue allows you to identify the micro-organism in question. » We then speak of septic arthritis when it concerns peripheral joints, and of septic spondylodiscitis (a rarer thing) when the infection affects the intervertebral discs. In France, they affect several thousand people each year, and require the prescription of antibiotics.

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These bacterial arthritis are very dangerous. “Without treatment, the bacteria diffuses and can reach the heart and other organs with a risk of sometimes fatal septicemia. ! » warns Jean Sibilia. Hence the importance of knowing the warning signs: acute inflammation resulting in pain, redness, swelling and heat of the joint, to which is added within a few hours great fatigue and high fever indicating infection. The quicker the treatment, the less damage will be to the joint. As for the culprit germs, in the majority of cases it is Staphylococcus aureus, but also streptococci and urinary germs such as E. coli, more rarely other bacteria, and exceptionally fungi.

“Contamination can also originate from an intervention in a hospital environment, where we are confronted with the presence of germs resistant to antibiotics,” acknowledged Fr Sibyl, but many occur outside the hospital, in patients with poorly treated infections. » Septic arthritis most often affects men, particularly those who are immunocompromised and weakened by diabetes or other chronic illness (such as cancer or kidney failure). They have serious consequences: around 7% of their victims lose their lives.