Septic arthritis is an intensely painful infection in a joint. Bacteria, or less commonly fungi, can spread from other infected areas in your body to a joint. Sometimes bacteria infect only the joint, leaving other areas of your body unharmed.
In septic arthritis, germs infiltrate your joint — usually just one — and damage it, causing severe pain, warmth and swelling. Bacteria most commonly target your knee, though other joints can be affected by septic arthritis, including your ankle, hip, wrist, elbow and shoulder.
Young children and older adults are most likely to develop septic arthritis. If treated within a week after symptoms first appear, most people make a complete recovery.
Septic arthritis typically causes extreme discomfort and difficulty using the affected joint. Signs and symptoms may include:
In children, additional symptoms may include:
If you're taking medications for other types of arthritis, you may not feel severe pain with septic arthritis because those medications may mask the pain and fever.
In adults, the joints of the arms and legs — especially the knees — are most commonly affected by septic arthritis.
In children, the hip is the joint most likely to be affected. Children with septic arthritis of the hip often hold their hip in a fixed position and try to avoid any joint rotation.
In rare cases other joints, such as those in the back, neck and head, may be affected.
When to see a doctor
Septic arthritis may develop when an infection elsewhere in your body, such as an upper respiratory tract infection or urinary tract infection, spreads through your bloodstream to a joint. Less commonly, a puncture wound, drug injection or surgery near a joint may allow bacteria into the joint space.
The lining of your joints (synovium) has little to protect itself from infection. Once bacteria reach the synovium, they enter easily and can begin destroying cartilage. Your body's reaction to the bacteria — including inflammation around the joint, increased pressure in your joint and reduced blood flow to the joint — contributes to the damage of your joint.
Types of bacteria
In the past, septic arthritis was more frequently caused by the bacterium that causes the sexually transmitted disease gonorrhea. But use of safer sex practices has led to a decline in gonorrhea and its complications, including septic arthritis. Still, in younger sexually active people, gonorrhea is a potential cause of septic arthritis.
Other infectious causes of arthritis
Risk factors for septic arthritis include:
Having a combination of risk factors usually puts you at a greater risk than having just one risk factor.
Prompt treatment with antibiotics combined with drainage of fluid from the joint usually resolves the infection. If treatment is delayed, however, the infection can quickly lead to joint degeneration and permanent damage.
Complications of septic arthritis often include:
In severe cases, the joint may need to be surgically reconstructed. If the infection affects a prosthetic joint, the prosthetic joint may need to be replaced.
Preparing for your appointment
If you have painful and inflamed joints, you're likely to start by seeing your primary care doctor or a general practitioner. However, in some cases you may be referred to an infectious disease or joint specialist. If you've been seeing a joint specialist for an existing condition such as arthritis, you may start by seeing this doctor first.
Because appointments can be brief and because there's often a lot of ground to cover, it's a good idea to be well prepared for your appointment. Here's some information to help you get ready for your appointment, and what to expect from your doctor.
What you can do
List your questions from most important to least important in case time runs out. For septic arthritis, some basic questions to ask your doctor include:
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.
What to expect from your doctor
What you can do in the meantime
Tests and diagnosis
The following tests typically help diagnose septic arthritis:
Treatments and drugs
Doctors rely on antibiotic drugs and joint drainage when treating septic arthritis.
Antibiotics carry a risk of side effects, including nausea, vomiting and diarrhea. Allergic reactions also can occur. Talk to your doctor about the side effects to expect from your specific medication.
Your doctor may be able to remove fluid from your joint with a needle (arthrocentesis). Arthrocentesis may be repeated, usually daily, until no bacteria are found in the extracted fluid. Hip joints, which are difficult to access, may require open surgery for fluid drainage. Repeat surgery is sometimes necessary.
Lifestyle and home remedies
If you've been diagnosed with septic arthritis, self-care measures may help you feel better during treatment. Here are some suggestions:
Last Updated: 2010-07-28
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