Definition

Osteomyelitis is an infection that affects bone tissue. This condition involves swelling or inflammation of the bone, usually caused by bacteria or fungi. Although osteomyelitis is relatively rare, it can become serious if not treated promptly, potentially leading to permanent bone damage.

Osteomyelitis can occur in both children and adults. In children, it most commonly affects long bones such as those in the arms and legs. In adults, osteomyelitis more often affects the spine, hips, and pelvis. While osteomyelitis in children typically presents as an acute condition, in adults, it can be either acute (recently occurring) or chronic (lasting for a long period).

There are different types of osteomyelitis, which are described below:

• Acute osteomyelitis: A rapidly developing infection.
• Chronic osteomyelitis: A long-standing infection that does not heal with standard treatments and can last for months or even years. It often occurs in individuals with underlying conditions such as HIV or diabetes.
• Vertebral osteomyelitis: An infection that specifically affects the vertebrae of the spine.

Causes

Osteomyelitis is typically caused by bacteria or fungi. The most common bacterial culprit is Staphylococcus aureus. While fungal causes are less frequent, Histoplasma capsulatum and Blastomyces dermatitidis are the fungi most often associated with osteomyelitis.

The infection often originates elsewhere in the body and then spreads to the bone. The pathways for the spread of osteomyelitis are:

• Through the Blood Vessel

Bacteria from an infection in another part of the body can enter the bloodstream and travel to the bones. For example, bacteria or fungi from untreated urinary tract infections or lung infections can enter the bloodstream and infect the bones, leading to osteomyelitis.

• Through an Open Fracture

Open fractures (where the broken bone is exposed through the skin) can create an environment conducive to bacterial growth. The bacteria can then spread to the bone, causing osteomyelitis.

• Contaminated Surgical Sites

Surgery involving bone, such as hip replacement or fracture repair, that is not performed under sterile conditions can introduce bacteria and lead to bone infection.

Risk Factor

Osteomyelitis is more probable to occur if you:

• Have a fractured bone
• Use a prosthesis
• Recently underwent surgery, especially orthopedic surgery
• Have other medical conditions such as diabetes, HIV, or an autoimmune disease (a condition in which the body's immune system attacks healthy cells)
• Have a history of osteomyelitis
• Are elderly
• Are undergoing dialysis
• Experience anemia or a poor blood supply

Symptoms

Symptoms of osteomyelitis can vary depending on the cause and type of infection. Common symptoms include:

• Fever
• Chills
• Nausea and vomiting
• Loss of appetite
• Pain in the affected bone
• Irritability (in children)
• Swelling
• Redness
• Difficulty moving joints near the affected bone
• Difficulty walking
• Stiffness in the spine (in vertebral osteomyelitis)

Diagnosis

Clinical Interview and Physical Examination

The diagnosis starts with a clinical interview to gather detailed information about the patient's main complaints, associated symptoms, onset and duration of symptoms, medical history, previous surgeries, and past illnesses. A physical examination is then performed to assess the patient's overall condition and vital signs, including blood pressure, body temperature, respiratory rate, and pulse.

The physician will also examine the affected area to look for changes in shape, color, temperature, and any difficulty in moving the bone.

Diagnostic Tests

Following the physical examination, additional diagnostic tests may be performed, such as:

• Complete Blood Count

This laboratory test checks for markers of infection, such as elevated white blood cell counts, which can be detected in the blood. It also helps rule out other potential conditions.

• Blood Culture

This test identifies the type of bacteria causing the infection by cultivating it in a specialized medium. Once the bacteria are identified, the doctor can determine the most appropriate antibiotic for treatment.

• Imaging

Imaging tests such as X-rays, MRI, or bone scans can be conducted. X-rays help detect bone damage, while MRIs provide detailed images of bones and surrounding soft tissues, including muscles and fluids. Bone scans evaluate the metabolic activity of bone cells and involve injecting a specific substance into the body.

• Bone Biopsy

A bone biopsy involves taking a small sample of bone tissue for laboratory analysis to identify the type of bacteria causing the infection.

• Fine-Needle Aspiration

This procedure involves extracting a sample of fluid using a needle for laboratory analysis.

Management

The treatment for osteomyelitis depends on the patient’s age, type of osteomyelitis, any underlying conditions, and overall health status.

• Antibiotics

Since osteomyelitis is usually caused by bacteria, antibiotics are administered intravenously. If the infection is due to fungi, antifungal medications are given instead.

• Pain Management

Pain relievers are provided, especially for patients experiencing significant discomfort.

• Immobilization

Patients are often advised to rest the affected area to prevent further damage.

• Surgery

Surgical intervention may be necessary for patients with:

• Severe osteomyelitis causing bone destruction.
• Abscesses or pus-filled pockets in the bone, which need to be drained.
• Osteomyelitis that does not heal with standard treatments and affects surrounding structures.

After surgery, additional antibiotics are often prescribed to prevent further infection.

Complications

Possible complications of osteomyelitis include:

• Abscess Formation

The infection can spread to soft tissues like muscles around the bone, leading to abscesses. An abscess is a painful, pus-filled sore caused by bacterial infection and is most common in chronic osteomyelitis.

• Bone Death (Osteonecrosis)

This occurs when severe infection cuts off the blood supply to the bone, causing the bone tissue to die. Without treatment, this can lead to permanent damage and may result in the need for amputation.

• Growth Impairment

This complication is especially concerning in children with osteomyelitis.

Prevention

The best way to prevent osteomyelitis is to maintain good hygiene. For instance, if you sustain a deep cut or wound, ensure it is cleaned with running water. Once dry, cover the wound with a sterile bandage to prevent bacterial contamination.

If you have chronic osteomyelitis, it is crucial to inform your doctor about your medical history to effectively manage the condition. Inform your doctor if you have diabetes or any wounds that are slow to heal, as these could serve as potential sources for bacterial spread, leading to osteomyelitis.

When to See a Doctor?

You should see a doctor immediately if you experience a high fever or severe pain in your limbs, especially if you have recently undergone surgery. Additionally, if you have a history of osteomyelitis, seek medical attention.

For children, take them to the doctor if they seem reluctant to use a limb, as not all children with osteomyelitis will present with fever. You may start by consulting a general practitioner, who may then refer you to an orthopedic specialist if the examination results suggest osteomyelitis.

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