Medicines for Septic arthritis

What it is

Septic arthritis is an infection inside a joint, usually caused by bacteria. It is a serious condition and a medical emergency, because infection within a joint can rapidly damage the joint (the cartilage and bone) if it is not treated quickly, and the infection can also spread. The bacteria can reach the joint in several ways: spreading through the bloodstream from an infection elsewhere; spreading from a nearby infection; or entering directly, for example through a wound, injection, or joint surgery. It can affect any joint, but often affects a large joint such as the knee or hip, and usually affects a single joint. People at higher risk include those with existing joint problems (such as rheumatoid arthritis) or a joint replacement, older people, young children, people with diabetes or a weakened immune system, and those who inject drugs. The symptoms of septic arthritis usually come on quickly (over hours to a day or two) and can include: a joint that becomes very painful, hot, red, and swollen; being unable or very reluctant to move the joint or bear weight (in a child, they may not use the limb); a high temperature and feeling generally unwell or shivery. Because septic arthritis can rapidly damage a joint and is serious, a hot, swollen, very painful joint — particularly with a fever or feeling unwell — needs urgent medical assessment. Treatment is in hospital and usually involves draining the infected fluid from the joint (sometimes repeatedly, or by surgery) and giving antibiotics (usually started into a vein), along with supportive care. Prompt treatment gives the best chance of clearing the infection and preventing lasting joint damage. The key messages are that a hot, swollen, very painful joint (especially with fever or feeling unwell) is a medical emergency needing urgent assessment, and that septic arthritis is treated with joint drainage and antibiotics.

How it is treated

Septic arthritis is a medical emergency and is treated urgently in hospital, because prompt treatment is needed to clear the infection and prevent rapid joint damage. If septic arthritis is suspected — a joint that has become very painful, hot, red, and swollen, with difficulty moving it, particularly with a fever or feeling unwell — urgent medical assessment is essential; this is especially important in people at higher risk, in those with a joint replacement, and in children (who may simply refuse to use the limb). In hospital, assessment includes examination, blood tests, and, crucially, taking a sample of the fluid from the affected joint (joint aspiration) to look for infection and identify the bacteria; imaging may also be used. Treatment usually involves: draining the infected fluid (pus) from the joint — which relieves pressure, removes infected material, and is important for clearing the infection, and may need to be repeated, or done surgically (for example by washing out the joint, particularly for certain joints like the hip, or if the infection is not settling); and antibiotics, usually started into a vein and then continued (often for a number of weeks), tailored to the bacteria identified. Pain relief and supportive care are given, and the joint is rested initially and then gently mobilised and rehabilitated (with physiotherapy) as it recovers, to restore movement and function. Treating any source of infection is also important. For an infected joint replacement, specialist orthopaedic input is needed, and treatment may be more involved. Prompt treatment gives the best chance of clearing the infection and preserving the joint; delay increases the risk of lasting joint damage. Because of this, the key message is urgency: a hot, swollen, very painful joint, especially with fever or feeling unwell, needs urgent assessment and should not be dismissed. It is worth noting that a hot, swollen joint can have other causes (such as gout or a flare of arthritis), but because septic arthritis is serious and time-critical, it must be considered and assessed urgently. The reassuring message is that, although septic arthritis is a serious emergency, prompt treatment with joint drainage and antibiotics is usually effective at clearing the infection, and preserving the joint, when treatment is not delayed.