Learn about this painful infection in a joint and why prompt treatment can help minimize joint damage.
Septic arthritis is a painful infection in a joint that can come from germs that travel through your bloodstream from another part of your body. Septic arthritis can also occur when a penetrating injury, such as an animal bite or trauma, delivers germs directly into the joint.
Infants and older adults are most likely to develop septic arthritis. People who have artificial joints are also at risk of septic arthritis. Knees are most commonly affected, but septic arthritis also can affect hips, shoulders and other joints. The infection can quickly and severely damage the cartilage and bone within the joint, so prompt treatment is crucial.
Treatment involves draining the joint with a needle or during surgery. Antibiotics also are usually needed.
Septic arthritis typically causes extreme discomfort and difficulty using the affected joint. The joint could be swollen, red and warm, and you might have a fever.
If septic arthritis occurs in an artificial joint (prosthetic joint infection), signs and symptoms such as minor pain and swelling may develop months or years after knee replacement or hip replacement surgery. Also, a loosening of the joint may occur, which causes pain while moving the joint or while putting weight on the joint. Typically, the pain goes away when at rest. In extreme cases, the joint may become dislocated.
See your doctor if you have severe pain in a joint that comes on suddenly. Prompt treatment can help minimize joint damage.
If you have an artificial joint, see your doctor if you experience pain while using the joint.
Septic arthritis can be caused by bacterial, viral or fungal infections. Bacterial infection with Staphylococcus aureus (staph) is the most common cause. Staph commonly lives on even healthy skin.
Septic arthritis can develop when an infection, such as a skin infection or urinary tract infection, spreads through your bloodstream to a joint. Less commonly, a puncture wound, drug injection, or surgery in or near a joint — including joint replacement surgery — can give the germs entry into the joint space.
The lining of your joints has little ability to protect itself from infection. Your body's reaction to the infection — including inflammation that can increase pressure and reduce blood flow within the joint — contributes to the damage.
Risk factors for septic arthritis include:
Having a combination of risk factors puts you at greater risk than having just one risk factor does.
If treatment is delayed, septic arthritis can lead to joint degeneration and permanent damage. If septic arthritis affects an artificial joint, complications may include joint loosening or dislocation.
The following tests typically help diagnose septic arthritis:
Imaging tests. X-rays and other imaging tests of the affected joint can assess damage to the joint or loosening of an artificial joint.
A specialized scan that involves swallowing or injecting a small amount of a radioactive chemical may be used if your doctor suspects you have a prosthetic joint infection and it's been more than a year since you've had surgery.
Doctors rely on joint drainage and antibiotic drugs to treat septic arthritis.
Removing the infected joint fluid is crucial. Drainage methods include:
To select the most effective medication, your doctor must identify the microbe causing your infection. Antibiotics are usually given through a vein in your arm at first. Later, you may be able to switch to oral antibiotics.
Typically, treatment lasts from two to six weeks. Antibiotics carry a risk of side effects, including nausea, vomiting and diarrhea. Allergic reactions also can occur. Ask your doctor about what side effects to expect from your medication.
If an artificial joint is infected, treatment often involves removing the joint and temporarily replacing it with a joint spacer — a device made with antibiotic cement. Several months later, a new replacement joint is implanted.
If a replacement joint can't be removed, a doctor may clean the joint and remove damaged tissue but keep the artificial joint in place. Intravenous antibiotics are followed by oral antibiotics for several months to prevent the infection from coming back.
If you have painful and inflamed joints, you're likely to start by seeing your family doctor. He or she may refer you to an orthopedic surgeon, infectious disease specialist or joint specialist (rheumatologist).
Here's some information to help you get ready for your appointment.
When you call to make the appointment, ask if you need to do anything in advance, such as fasting for certain tests. Make a list of:
Take a family member or friend along, if possible, to help you remember information you're given.
For septic arthritis, questions to ask your doctor include:
Don't hesitate to ask other questions.
Your doctor is likely to ask you questions, such as:
February 5th, 2021