Children can develop infections in their bones, joints, or muscles. Sometimes called "deep" infections, the technical names for these conditions are:

  • Osteomyelitis (bone infection)
  • Septic arthritis (joint infection)
  • Pyomyositis (muscle infection)

Deep infections are most commonly found in the joints and at the ends of long bones where they meet to form joints. These include the hip, knee, and ankle joints of the leg, and the shoulder, elbow, and wrist joints of the arm.

The large muscle groups of the thigh, groin, and pelvis are the most common locations for deep muscle infections.

The reason infections occur in these areas is due to the way blood flows to these locations. There is a strong blood flow to the ends of bone near growth centers (called growth plates), the lining of the joints, and the large muscle groups. This allows bacteria to easily find their way to these areas.

The blood supply to the spine, pelvis, and heel is similar to that of the long bones, and infections often develop in these areas, as well.

Infections pose special risks to young children for a number of reasons:

  • Children under the age of three are easily infected. Their immune systems are not fully developed and they tend to fall down a lot, opening the skin to infection.
  • Infections spread quickly through a young child's circulation system and bone structure. Damage to bones and joints caused by infection can harm a child's growth and lead to physical dysfunction. Infection of child's hip joint is a surgical emergency.

What causes infection in children?

Infections are usually caused by bacteria that are present in our normal living environment. The most common bacteria causing bone, joint, or muscle infections in children is Staphylococcus aureus (aka "Staph" infection).

Bacteria can get into the body in a variety of ways. They circulate through the bloodstream until they reach a bone, joint, or muscle. Bacteria then leave the bloodstream and multiply in the bone, joint, or muscle tissues.

What are the symptoms of infection in children?

Children who have infections of their bones, joints, or muscles often have the following:

  • Fever
  • Pain
  • Limited movement of the infected area — your child may limp or refuse to walk if the infection involves the legs or back
  • Infants may be irritable and lethargic, refuse to eat, or vomit

Many children who have bone, joint, or muscle infections have had recent injuries. The symptoms of infection are often masked by those of the injury. Because parents assume the injury will get better over time, it may take them longer to notice the infection.

It is important to bring your child to a doctor immediately if symptoms are not quickly resolving at home.