Definition and Overview
Osteomyelitis is a type of bone infection, which causes the inflammation of both the bone and the bone marrow. The condition is classified based on the length of time since the patient has been infected, the presence of pus in the infected area, and the increasing density of the affected bone (also known as sclerosis). Osteomyelitis can be:
Suppurative osteomyelitis (where the infected area has developed pus). This classification includes acute suppurative osteomyelitis (occurring suddenly) and chronic suppurative osteomyelitis (progresses over time). Under the chronic classification are the primary phase (with no precedent) and a secondary phase (occurring after a chronic incident).
Non-suppurative osteomyelitis, which includes focal sclerosing, diffuse sclerosing, proliferative periostitis, and osteoradionecrosis.
Some medical professionals also classify osteomyelitis according to the location of the affected bone because the infection can spread out to the surrounding tissues. The severity and location of the infection can affect how it is treated because of the complications that might occur.
Children usually suffer from acute types of osteomyelitis—which features a rapid onset. Acute osteomyelitis is comparatively easier to treat, with the patient recovering well after treatment has been administered.
Research shows that the type of affected bones differs according to age group. Younger patients typically suffer from infection in the long bones (the arms and the legs), while adults typically suffer from infections in the vertebrae and the pelvic bone.
Osteomyelitis is a relatively rare condition, occurring only in two out of 10,000 people.
Cause of Condition
Bacterial infection is the main cause of all types of osteomyelitis. How the patient is infected with one of the various bacteria that cause the infection can vary. One common denominator of the majority of osteomyelitis patients is that their immune systems are weakened by different conditions, which increase their vulnerability to bacterial infections. Below are some of the factors that can increase the risk of bone infections:
- Having diabetes
- Having HIV or AIDS
- Having sickle cell disease
- Having rheumatoid arthritis
- Alcohol abuse
- Intravenous drug use
- Undergoing hemodialysis
- Having conditions that affect the level of blood supply
- Having suffered recent injury or undergone recent surgical procedures
- Having used steroids over a significant period of time
- Undergoing a root canal procedure
- Undergoing immunosuppressive therapy
Some patients get infected after undergoing bone surgery—especially during knee and hip replacements for adult patients. Though it rarely occurs, osteomyelitis can be a secondary complication of pulmonary tuberculosis. The bacteria typically travel through the patient’s circulatory system and spread to the bones. In this case, the patient’s vertebrae and long bones are usually the ones affected by the infection.
Common bacterial organisms that cause osteomyelitis include the following:
- S. aureus
- Streptococcus groups A and B
- Haemophilus influenzae
- Pseudomonas aeruginosa
- E. coli
- Serratia marcescensi
Aside from bacteria, there are also recorded cases where fungi were responsible for the infection. Common fungi species that cause osteomyelitis include Coccidioides immitis and Blastomyces dermatitidis.
Acute types of osteomyelitis are characterized by a quick onset of infection, which develops over a period of seven to ten days. Chronic osteomyelitis generally takes longer to manifest, but both types have common symptoms, including the following:
- Fever, which is the most common sign of infection
- Weakness and fatigue
- Inflammation around the infected bone
- Redness, uncharacteristic warmth, and tenderness or pain in the area of the infected bone
- Limited range of motion
When the infection sets in the patient’s vertebrae, especially in cases of chronic osteomyelitis, the patient might also experience severe back pain.
Who to See and Types of Treatment Available
Some of the signs and symptoms described above can also be associated with other conditions, which can lead to the patient ignoring them. It is best to consult a doctor once fever and pain in the bones are observed. The doctor can order laboratory test to determine the levels of white blood cells in the bloodstream; this test will only determine if the patient is suffering from an infection. Additional diagnostic tests, such as imaging procedures, will also be performed to confirm the presence of osteomyelitis.
Like other types of infection, the first line of treatment for osteomyelitis is antibiotic therapy. Depending on the severity of the infection, the doctor might prescribe a regular dosage of antibiotics over a course of several weeks or even months.
In more severe cases where the infection has gravely affected the bones and surrounding tissues—and is posing a great risk to the surrounding organ systems— amputation is performed. The infected bone will be completely removed, along with the infected tissues surrounding it.
Acute cases of osteomyelitis are often easier to treat while chronic infections might require more careful treatment plans to save healthy tissues.
Dabov GD. Osteomyelitis. In: Canale ST, Beaty JH, eds. Campbell's Operative Orthopaedics. Philadelphia, PA: Elsevier Mosby; 2012:chap 21.
Matteson EL, Osmon DR. Infections of bursae, joints, and bones. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 280.