What is Septic Arthritis

Septic arthritis is inflammation of a joint that results from an infection. The infection occurs when bacteria or other germs get inside a joint. The knee and hip joints are most often affected, but other joints may also become infected.

Usually, just one joint is affected. Joint infections need to be treated quickly to prevent damage to the joint, and to prevent the infection from spreading to other areas of your body.

What are the causes?

This condition is most often caused by Staphylococcus bacteria. Other causes may include:

• Fungal infections.
• Sexually transmitted infections (STIs).
• Tuberculosis.

Bacteria or other germs can spread to the joint. These bacteria are usually from:

• Blood carrying germs from an infection in another part of your body to your joint. This is the most common cause of septic arthritis.
• An open wound near the joint.
• A needle put into the joint.
• Joint surgery.
• An infection in the bone (osteomyelitis) that spreads to the joint.

What increases the risk?

You may have a higher risk for this condition if you:

• Have an artificial joint.
• Have a blood or skin infection.
• Have open sores or wounds on your skin.
• Had a recent joint surgery or procedure.
• Had a recent joint injury.
• Have a long-term (chronic) disease, such as:
  • Diabetes.
  • Osteoarthritis.
  • Rheumatoid arthritis.
  • HIV (human immunodeficiency virus).
• Have a condition or take medicines that weaken your body’s defense system (immune system).
• Use IV medicines.
• Have gonorrhea.
• Have a central line for IV access.

What are the signs or symptoms?

Symptoms of this condition include:

• Swelling at the joint.
• Severe pain in the joint.
• Redness and warmth in the joint.
• Being unable to move the joint.
• Fever and chills.

How is this diagnosed?

This condition may be diagnosed based on:

• Your symptoms.
• Your medical history.
• A physical exam.
• Other tests to confirm the diagnosis. These may include:
  • Removing fluid from your joint to look for signs of infection (synovial fluid analysis).
  • Blood tests.
• Imaging studies. These may include:
  • X-rays.
  • MRI.
  • CT scan.
  • Ultrasound.

How is this treated?

This condition may be treated by:

• Draining fluid from your joint. This may be done for several days in order to relieve pain.
• Taking antibiotic medicine. This may be given by IV or by mouth. It may be done in a hospital at first. You may have to continue antibiotics at home by IV or by mouth for several weeks after that.
• Surgery to remove:
  • Infected fluid and tissue from the joint.
  • An infected artificial joint.

After the infection has started to heal, you may need physical therapy to regain strength and motion of the joint.

Follow these instructions at home:

Medicines

• Take over-the-counter and prescription medicines only as told by your health care provider.
• If you were prescribed an antibiotic medicine, take it as told by your health care provider. Do not stop taking the antibiotic even if you start to feel better.
• Follow instructions from your health care provider about how to take antibiotics at home by IV. You may need to have a nurse come to your home to give you antibiotics through IV.

Managing pain, stiffness, and swelling

• If directed, put ice on the affected area: 
  • Put ice in a plastic bag.
  • Place a towel between your skin and the bag.
  • Leave the ice on for 20 minutes, 2–3 times a day.
• Raise (elevate) the affected area above the level of your heart while you are sitting or lying down.

Activity

• Return to your normal activities as told by your health care provider. Ask your health care provider what activities are safe for you.
• Do any exercises or stretches as told by your health care provider or physical therapist.

General instructions

• Do not use any products that contain nicotine or tobacco, such as cigarettes and e-cigarettes. These can delay healing. If you need help quitting, ask your health care provider.
• Wash your hands often with soap and water. If soap and water are not available, use hand sanitizer.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if you:

• Have pain that is not controlled with medicine.
• Develop a fever or chills.
• Have redness, warmth, pain, or swelling that returns after treatment.

Get help right away if you:

• Have signs of worsening infection in your joint. Watch for:
  • Very severe pain.
  • Redness.
  • Warmth.
  • Swelling.
• Have rapid breathing or you have trouble breathing.
• Have chest pain.
• Cannot drink fluids or make urine.
• Notice that the affected area changed color or turned blue.
• Have numbness or severe pain in the affected area.

Summary

• Septic arthritis is inflammation of a joint that occurs when bacteria or other germs get inside a joint and cause an infection.
• Joint infections need to be treated quickly to prevent damage to the joint, and to prevent the infection from spreading to other areas of your body.
• Symptoms of joint infection include redness, warmth, swelling, pain, and being unable to move a joint.
• Treatment usually involves draining fluid from the joint and taking antibiotic medicine.