Diagnosis of Osteomyelitis (Infection of the Bone)

What is Osteomyelitis?
Osteomyelitis is the infection of bone. It can occur in any bone in the body but long bones such as of the arms and legs are more commonly affected particularly in children. In adults, generally it affects bones of the feet, spine, and hips. Common symptoms of osteomyelitis are pain in the bone with redness, fever, and weakness.

The infection is usually caused by bacteria and rarely by fungus. It may spread through the blood or from surrounding tissue. Certain medical conditions can increase the risk of developing osteomyelitis such as diabetes, removal of the spleen, and trauma to the area.

Read about jaw bone infection.

How is osteomyelitis diagnosed?
Diagnosis of osteomyelitis is generally done based on the symptoms of the disease. The doctor may ask for blood tests, medical imaging, or biopsy of the affected bone.

Blood tests may show elevated levels of white blood cells (WBCs) and other factors that may indicate that there is something that the body is fighting with. If the osteomyelitis is caused by an infection in the blood, tests may reveal the germs for the infection as well.

However, no blood test can tell whether you do or do not have osteomyelitis. Blood tests only give clues that your doctor can use to decide what tests are needed further for the confirming of the infection and whether there is a suspicion of the infection.

The diagnosis of bone infection is complex and is done through a combination of clinical analysis of the symptoms and laboratory markers such as a high white blood cell count and fever. The confirmation of the physical examination and blood tests is done with imaging and biopsy generally. Radiographs and CT scans are preferred methods for the diagnosis of osteomyelitis. Confirmation is most often done by magnetic resonance imaging tests (MRI) and bone biopsies.

A bone biopsy is the gold standard for diagnosing osteomyelitis. It can show even particular type of germ that has infected the bone.

Read about foot infection.

Osteomyelitis in diabetes patients: White blood cell counts and temperature may not be reliable indicators of the presence of osteomyelitis in patients with diabetes. Studies show that white blood cell count was increased in about half of the patients with positive bone cultures. Fever was also found to be present in about 20 percent of the same population. According to this study, ESR was found to be a valuable method in the initial evaluation of the patient with diabetes as it was found increased in about 96 percent of these patients.

Procalcitonin is comparatively a new laboratory marker for the diagnosis of osteomyelitis. It is secreted by the thyroid gland and is a precursor peptide to calcitonin. Procalcitonin is increased during an acute infective process and studies have found its utility in the prediction of soft tissue infection such as certain bone infections. However, there is one study that does not confirm these findings. The study suggests procalcitonin is not useful in diagnosing osteomyelitis within the diabetic population. Therefore, this cannot be considered as a reliable indicator.