A bacterial infection of a joint can cause a severe and potentially destructive form of joint inflammation, which can have permanent joint changes even after healing if proper intervention is delayed. Bacterial joint infections can be caused by a number of different organisms and can occur in both natural and artificial joints (for example, after a joint replacement surgery).
A joint infection happens when a bacterial infection occurs inside a joint space (a joint is the connection between to bones). Joints include the knee, hip, shoulder, dozens of joints in the spine and many others. Any joint can become infected, but some are more commonly infected than others.
The bacteria get into the joint in different ways. Most often, the bacteria travel to the joint through the blood from another part of the body.
The most common type of joint infection is caused by an organism called N. gonorrhoeae, the sexually transmitted bacteria that causes gonorrhea. This type of joint infection is called a gonococcal joint infection.
A person who becomes infected with gonorrhea but does not receive early treatment can develop joint pain, especially in the wrist, fingers, ankles, and toes.
Symptoms of this gonococcal joint infection can also include fever (temperature >100.4ºF or 38ºC), chills, and feeling ill. A skin rash can develop and may be mild.
In other people, the knees, wrists, and/or ankles become painful and swollen due to collections of pus inside the joint. Multiple joints can be affected at the same time.
Joint infections can also be caused by other types of bacteria not related to gonorrhea. These can cause a more aggressive form of joint infection (also called septic arthritis) which is a potentially dangerous form of arthritis that can destroy a joint if not treated promptly.
This form of bacterial joint infections are most common in infants and young children, patients with decreased immune system (decreased immunity could be due to conditions such as HIV, diabetes, cancers or certain forms of medications such as steroid medications). People who had a joint replacement done are also at an increased risk.
Symptoms usually start suddenly and can include; joint pain, joint swelling, and warm skin around the joint, trouble moving the joint and fever.
Unlike the joint infection related to gonorrhea, this usually affects only one joint, although sometimes can affect more than one joint. Joints commonly involved are the knee, wrist, ankle, and hip.
The diagnosis of a joint infection and the specific cause is done after the physician has taken history of the patient, examined the patient as well as done some medical tests.
The doctor may use a needle and syringe to withdraw fluid from the joint. The fluid will be analysed in a laboratory for bacteria and other features of infection. This can be done in the doctor’s room or in some cases in the operating theatre room.
Some blood tests can be done to look for features of the infection. Radiology imaging might be done, such as ultrasound scan of the suspected joint, to look for any fluid collections or features of early joint infection.
After the diagnosis of a bacterial joint infection, treatment will include appropriate antibiotics, thorough surgical drainage of the joint fluid, and physical therapy to maintain joint motion.
In most cases, the antibiotics are given into a vein initially and then later by mouth. Intravenous therapy is usually started in the hospital and then, depending on the doctor’s assessment, the treatment can be continued at home with close monitoring through regular medical follow ups.
Dr Ian Shyaka,
Resident in plastic surgery, Rwanda Military Hospital