Bacteria can "infect" the bone or joint in a process similar to how they cause infections in the throat, lungs, urinary system, or any other tissue. These conditions are medically referred to as "Osteomyelitis" (when it affects the bone) and "Septic Arthritis" (when it affects the joint).
There are two main ways through which bacterial infection can reach these tissues. The most common route is through the bloodstream. Bacteria enter the bloodstream for various reasons, such as wounds in the throat, dental infections, or via the digestive tract, and when they are present in the blood, they can settle in different tissues. The unique blood supply to the joints and bones in children increases the risk of bacterial infection in these tissues. Another way for infection to occur is through "direct contamination" when bacteria directly reach the bone or joint from the external environment, for example, due to a deep wound that reaches the bone or joint.
A septic process in the joints can damage the joint cartilage, causing pain and limited movement throughout life. In bones, an infection usually develops slowly, affecting the bone's normal growth and potentially spreading to nearby tissues. In both types of infections, there is a risk of the infection spreading back into the bloodstream and spreading to other tissues.
Typical symptoms of these processes include pain, high fever, sensitivity, or swelling at the site of infection, along with blood test results indicating an infectious process. In some cases, these signs may be very mild, and limping or difficulty moving the limb might be the only indication.
X-rays taken in the first few days after the appearance of infection will usually be normal. Characteristic changes in bone structure (see image) appear only after about two weeks. Ultrasound can detect fluid in the joint and the accumulation of pus around the bone. MRI can be used mainly to visualize the bone marrow and help detect the infection in its early stages.
X-ray demonstrating bone infection
In most cases, the contaminating bacteria are common and can be eliminated with regular antibiotics. The treatment will be based on intravenous antibiotics initially, and once the child starts showing signs of improvement, we will switch to oral antibiotics. Local treatment, such as draining the joint or bone and irrigating the accumulated pus, is also added. The treatment of these infections is very prolonged (several weeks and sometimes months) due to the tendency of infections to become chronic if all bacteria are not eradicated. In some cases, we may not identify the infecting bacteria. In such cases, the diagnosis will be based on the overall picture of the sick child, and treatment will be targeted against the common bacteria in this disease.
The complications of infection depend mainly on the timing of treatment. An infection left untreated, treated late, or not treated fully can lead to severe damage to the joint or bone, including impairing bone growth, constant bending of the joint, and limitation of its movement.
To avoid complications and assist in the treatment's success, parents should ensure that the child receives the prescribed antibiotic treatment as required. It is essential that the child takes all prescribed antibiotics and does not spit or vomit the medication. It is crucial not to stop the treatment before the recommended period by the medical team. Additionally, it is vital to undergo all the necessary follow-up tests during the medical follow-up. Only then can we determine that the treatment is effective, and the child is recovering. If during treatment there is a resurgence of symptoms (fever, decreased ability to move the limb, new swelling, or anything else), the medical team should be informed promptly to identify any issues.
This page provides general explanations of the phenomenon and does not replace personalized medical examination and treatment. The information is intended to help parents better understand the diagnostic and therapeutic process and be more involved.