Osteomyelitis is bacterial infection. Actually it is a swelling of bone tissue that is usually caused by pyogenic bacteria or mycobacteria. Depending on how the bone becomes infected and the age of the person, other types of bacteria can cause it, too. In kids and teens, osteomyelitis usually affects the long bones of the arms and legs.

Causes

It can be caused by a variety of microbial agents and situations including:
An open injury to the bone, such as an open fracture with the bone ends piercing the skin.
An infection from elsewhere in the body, such as a urinary tract infection that has spread to the bone through the blood.
Bacteria in the bloodstream, which is deposited in a focal (localized) area of the bone. This bacterial site in the bone then grows, resulting in destruction of the bone. However, new bone often forms around the site.
A chronic open wound or soft tissue infection can eventually extend down to the bone surface, leading to a secondary bone infection.

In children, the long bones are usually affected. In adults, the vertebrae and the pelvis are most commonly affected. Bone infection can be caused by bacteria or by fungus. When the bone is infected, pus is produced within the bone, which may result in an abscess. The abscess then deprives the bone of its blood supply.

Symptoms

Infections of the leg and arm bones cause fever and, sometimes days later, pain in the infected bone. The area over the bone may be sore, warm, and swollen, and movement may be painful. The person may lose weight and feel tired.
The child may complain of nausea, vomit or feel lethargic and weak. In chronic osteomyelitis, pus may drain through the skin.

Treatment

A child with suspected osteomyelitis should be investigated in hospital. A sample of blood must be tested to find out which bacteria are causing the infection. X-rays can help to pinpoint infection, but may be normal for the first seven to ten days. Bone scans and ultrasound scans are also used.
If a fungal infection is identified or suspected, antifungal drugs are required for several months. If the infection is detected at an early stage, surgery is usually not necessary. If the infection has become chronic, surgical removal of dead and infected bone is usually necessary, to allow the infection to clear. The space left by the bone that has been taken out may be filled with a bone graft to encourage new bone tissue to grow. Sometimes plastic surgery is also needed to cover the wound.