Osteomyelitis

Osteomyelitis (ah-stee-o-my-uh-LYE-tis) is a bone infection that is usually caused by bacteria. It can involve any bone in the body, but it most commonly affects the long bones of the arms and legs.

What Is Osteomyelitis?

Osteomyelitis usually is caused by infection with bacteria. Staphylococcus aureus (stah-fih-lo-KAH-kus ARE-ree-us), streptococcal (strep-tuh-KAH-kul) species of bacteria, and Pseudomonas aeruginosa (su-doe-MO-nas air-ew-jih-NO-suh) are the major organisms associated with osteomyelitis. These bacterial intruders can travel from other parts of the body, such as the ear, throat, or intestines ^* , through the bloodstream and to a bone, where they can start an infection. Bones that have been weakened or damaged, such as one that has been injured recently, are more susceptible to bacterial invasion. When there is trauma ^* to the bone, like a puncture wound from stepping on a nail, bacteria can infect the bone directly. Rarely, fungi may cause osteomyelitis, and the spread of tuberculosis (too-ber-kyoo-LO-sis), a contagious disease that typically affects the lungs, through the body also can lead to bone infection, usually in the spine.

In children, osteomyelitis occurs most often in the long bones of the leg, such as the femur (FEE-mur) and tibia (TIH-be-uh). Adults tend to have the infection in the hipbones and vertebrae ^* , where it may occur following surgery on a bone or from an infection that has spread from the skin. People with diabetes ^* can have osteomyelitis in the foot bones from ulcerations ^* on their feet. Osteomyelitis that evolves rapidly is called acute ^* osteomyelitis. If a bone infection persists because it is not treated or it does not respond to treatment, it is known as chronic ^* osteomyelitis. Over time, the infection may interfere with the blood supply to the bone, causing the bone tissue to die.

How Common Is Osteomyelitis?

Chronic osteomyelitis occurs in about 2 in 10,000 adults. Children have the acute form of the disease more often than adults do, at a rate of about 1 in 5,000. People who have diabetes, who have had a traumatic injury recently, or who use intravenous ^* drugs are at greatest risk for chronic infection.

Is It Contagious?

Bone infections are not contagious. However, some types of bacteria that cause the infections that can progress to osteomyelitis are passed from person to person.

What Are the Signs and Symptoms of Osteomyelitis?

The first sign of acute infection may be a fever that begins suddenly. The area over the infected bone may become warm, red, and swollen, and the joints next to the bone may swell as well. As the infection progresses, it can cause pain in the affected bone and may limit the person's movement in that area. Some people with osteomyelitis feel irritable, nauseated, and generally sick. Patients with long-term bone infection may experience drainage of pus ^* through the skin covering the affected bone.

How Is the Disease Diagnosed?

To help make the diagnosis, a doctor may order an X ray of the suspect area to look for signs of bone inflammation or damage, but changes in the bone may not show up for weeks after the infection begins. Magnetic resonance imaging ^* (MRI) or a computerized tomography ^* (CT) scan may show changes that reflect osteomyelitis sooner than X rays will. Radionuclide scans ^* may help pinpoint the location of the infection early in the course of the disease. Blood cultures ^* or, less commonly, a bone biopsy ^* may identify the infectious agent.

What Is the Treatment for Osteomyelitis?

Patients with osteomyelitis usually need to be hospitalized. They typically receive antibiotics for 4 to 6 weeks to combat the infection. At first, the medication is given intravenously, but patients may be switched to oral (by mouth) medicine as the treatment continues and their condition improves. In more serious and chronic cases, patients may need an operation to remove bits of bone that have died. To help new bone grow, surgeons may perform a bone graft, in which bone from another part of the body is placed in the spot where dead bone has been removed; doctors may use packing material to fill in the open area temporarily.

How Long Does the Disease Last?

Patients with osteomyelitis often need several weeks or months of treatment before the infection clears up. Acute cases may resolve after as little as 1 month of antibiotic therapy, but chronic cases can linger much longer.

What Are the Complications?

In children, osteomyelitis can damage growing bones permanently, especially if it is not promptly and adequately treated. Infection may spread to the blood, overlying skin, or nearby joints. Bones may be weakened and break more easily. Movement of nearby joints or limbs may become limited. Occasionally in chronic cases, severe infection or damage to the bone may result in the need to amputate, or remove, part or all of a limb.

How Can Osteomyelitis Be Prevented?

Quick, thorough treatment of any infection, particularly those from deep wounds, can lower the risk of osteomyelitis. It is recommended that patients who are more susceptible to osteomyelitis, such as those with diabetes, contact a doctor promptly if they notice signs of infection.