Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Septic arthritis is a serious infection of the joints caused by bacteria. The tissue of the joint reacts to the infection and fights the bacteria by filling the joint with pus and inflammation. This action can increase pressure in the joint, affect blood flow, and damage the joint structures, bone, and surrounding cartilage.


Septic arthritis develops when bacteria attaches to tissue in the joint and begins to spread. The infection may be started by bacteria:

  • That has entered the blood stream from an infection somewhere else on the body
  • That entered the bloodstream from IV drug use
  • That exists outside the body and entered through a wound, injury, or surgery to the area

Joint Damage in Knee

Knee arthitis
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Risk Factors

Septic arthritis can occur at any age, but it generally affects older adults and children aged 3 years old and younger.

Factors that may increase your chance of developing septic arthritis include:


In infants, the hip is a frequent site of infection. In toddlers, it is the shoulders, knees, and hips. In adults, it most commonly affects weight-bearing joints, such as the knees.

Symptoms may include:

  • Newborn or infants:
    • Crying when a joint is moved, such as during a diaper change
    • Inability to move the limb of a joint
    • Swelling and redness
    • Irritability
    • Fever
    • Persistent crying for any reason
  • Children and adults:
    • Intense joint pain
    • Joint swelling and redness
    • Fever
    • Chills
    • Inability to move a joint or its limb
    • Limping


You will be asked about you or your child’s symptoms and medical history. A physical exam will be done. Your doctor may refer you to a specialist.

Bodily fluids may need to be tested. This can be done with:

  • Testing joint fluids
  • Blood tests

Images may be taken of your bodily structures. This can be done with:


Antibiotic therapy is started as soon as a diagnosis is made. In the beginning, antibiotics are given by IV. This is to ensure that the infected joint receives medication to kill the bacteria. The specific medications used depend on the type of bacteria that is causing the infection. The remaining course of antibiotics may be given by mouth.

Fluid may be removed from the joint to reduce the likelihood of joint damage. This may be done either by placing a needle in the joint or through surgery.

Rest, preventing the joint from moving, and warm compresses may be used to manage pain. Physical therapy or exercises may also speed recovery.


To help reduce your chance of getting septic arthritis, get prompt treatment of infections that could lead to septic arthritis.