Septic arthritis: symptoms, causes, treatment and recovery

The NHS lists the main symptoms of septic arthritis, and says they usually develop over a few days and need to be checked straight away. Arthritis UK adds that the symptoms can be slower to develop after joint replacement surgery or if you have tuberculosis, and that at first pain and fever may be mild but gradually get worse.

• Sudden severe pain in a joint, usually just one joint.

• Not being able to move or put weight on the affected joint.

• Hot, swollen or red skin over the joint, with redness harder to see on black or brown skin.

• A high temperature or fever, although not everyone has one.

• Feeling generally unwell, sick or unable to eat.

• In children, irritability, crying when the joint is moved, avoiding movement or being unable to walk if the hip is affected.

The NHS says you need urgent medical help if you think you have septic arthritis. Ask for an urgent GP appointment or get help from NHS 111 if you have severe joint pain that started suddenly, swelling around a joint, a change in the colour of the skin around a joint, difficulty moving a joint, or joint pain with feeling generally unwell and a high temperature or feeling hot, cold or shivery. If you cannot get an urgent GP appointment, call 111.

Arthritis UK is firmer: if you think you may have septic arthritis, see your GP or go to your nearest A&E as soon as possible to stop the infection spreading, and if you cannot see your doctor take yourself to A&E. A GP who suspects it will refer you immediately to A&E for tests.

Septic arthritis happens when germs, usually bacteria, get into a joint and cause infection. The NHS says this can happen after an injury or accident affecting a joint, when germs from somewhere else in the body spread into the blood and then into a joint, or as a complication of joint surgery.

Arthritis UK describes it as extremely painful, a very serious condition that can affect people of any age and needs to be treated in hospital as soon as possible as an emergency. It is most commonly caused by bacteria from an infected cut or wound that travel through the blood to a joint. It is sometimes called bacterial or infectious arthritis, and a virus, a skin infection or bacteria entering through an injection or surgery site can also be responsible.

Arthritis UK says the infection needs treating as soon as possible to prevent long-term damage to the joint and other complications to your general health, because a delay lets the infection quickly damage parts of the joint.

Arthritis UK says septic arthritis can affect people of any age. In children it can be harder to spot because a young child cannot always say where it hurts. Arthritis UK says children become irritable and may cry when the affected joint is moved. They may try to avoid moving it, or may not be able to walk, particularly if it is the hip that is affected.

The NHS advice on urgent help applies to children too: sudden severe joint pain, swelling around a joint, a change in skin colour, difficulty moving a joint, or joint pain with feeling unwell and a high temperature are reasons to ask for an urgent GP appointment or get help from NHS 111. If you cannot get an urgent GP appointment, the NHS says to call 111 or use 111 online.

A child who suddenly refuses to use a limb or put weight on a leg, particularly with a fever, should be seen urgently. Do not wait to see whether it settles.

The NHS says anyone can get septic arthritis but some people are more at risk, including people with rheumatoid arthritis, a weakened immune system, recent joint surgery, an artificial joint such as a knee or hip replacement, who inject drugs such as heroin, who have diabetes, or who have gonorrhoea.

Arthritis UK gives a wider list: injury or an infected wound, joint surgery, injections into or near a joint, injecting non-prescription drugs, infections such as gonorrhoea, abscesses, urine infections, food poisoning, sinus or skin infections, tuberculosis or a bone infection close to a joint, and long-term conditions such as rheumatoid arthritis, diabetes, treatment that reduces immune activity, cancer, HIV, and liver or kidney failure.

Arthritis UK says that in hospital a blood test and sometimes a needle inserted into the joint to take a sample of the infected fluid are used to identify the germ and choose antibiotics. An X-ray or MRI scan gives a better picture of what is happening to the joint, and these tests may show that the inflammation has a different cause and that you do not have septic arthritis.

It stresses that the sooner it is diagnosed the better, because a delay allows the infection to damage the joint quickly, which may lead to long-lasting pain and loss of mobility, and in some cases, if left untreated, to blood poisoning, known as septicaemia.

The NHS says septic arthritis is usually treated in hospital with antibiotics given straight into a vein, a procedure to drain fluid from the joint and antibiotic tablets for several weeks after you leave hospital. The average stay is about 2 weeks, and most people start feeling better quickly once given antibiotics.

There is no single recovery time because it depends on the joint, the germ and how early treatment started. The NHS gives these anchors: an average hospital stay of about 2 weeks, antibiotic tablets for several weeks after leaving hospital, and a referral to a physiotherapist to help the joint get moving again and prevent long-term stiffness. Arthritis UK says a stay may be two weeks or more.

Arthritis UK says that in most cases early hospital treatment and antibiotics successfully treat septic arthritis, leaving little or no lasting effect, although some people may still struggle to get full use out of the affected joint. Completing the full course of antibiotics matters: the NHS warns that stopping treatment too soon could lead to the infection coming back.

Once the infection has settled, gentle movement is important to prevent stiffness, and a physiotherapist may advise specific exercises. Resting the joint from time to time, raising it above the heart and applying an ice pack for around 20 minutes can ease swelling and pain, according to Arthritis UK.

Septic arthritis is an emergency and is managed through NHS 111, GPs and hospital emergency departments. The NHS says you will usually be admitted to hospital for treatment. Arthritis UK says a GP who suspects it will refer you immediately to A&E for tests, and that if you cannot see a doctor you should go to your local A&E. It should not wait for an appointment with a private clinic.

Follow-up is different. The NHS says you may be referred to a physiotherapist to get the joint moving again, and private physiotherapy or surgical follow-up may be used later if you prefer. Whichever route you use, make sure the antibiotic plan, its end date and the signs that the infection may be returning are written down and shared with your GP.