Osteomyelitis of the spine, also known as vertebral osteomyelitis, is an infection of the vertebrae, which are the bones of the spine. It can be caused by bacteria or other microorganisms that enter the spine through the bloodstream or from nearby infected tissue. Symptoms of vertebral osteomyelitis include back pain, fever, chills, and weakness. Treatment typically involves a combination of antibiotics to kill the infection and surgery to remove any infected tissue.
What is Osteomyelitis of the Spine?
Osteomyelitis of the spine, also known as vertebral osteomyelitis, is an infection of the vertebrae, which are the bones of the spine. The infection is typically bacterial but can be from other microorganisms including fungi.
A vertebra is one of the small bones that make up the spine.There are a total of 33 vertebrae in the human spine, arranged into four regions: the cervical spine, the thoracic spine, the lumbar spine, and the sacrum. The vertebral column serves as a support structure for the body and protects the spinal cord.
Causes of Osteomyelitis
Osteomyelitis of the spine is usually caused by one of three things:
- Spread through the bloodstream (hematogenous spread): This is when the infection is spread through the bloodstream, from a source elsewhere in the body. This can occur when pneumonia or a urinary tract infection, for example, makes its way into the bloodstream and is “seeded” in the vertebrae.
- Spread through nearby structures (contiguous spread): This is when the infection is spread from a nearby structure, such as skin or an infected intervertebral disc.
- Direct inoculation of bacteria: This is when there is direct injection of bacteria or other mico-organism into the vertebra. This can occur from trauma or as a complication from surgery.
There are several risk factors that can increase a person’s risk of developing osteomyelitis, including:
- Age: Osteomyelitis is more common in older adults
- Weakened immune system: People with compromised immune systems, such as those with HIV/AIDS or cancer, are at increased risk of infection.
- Chronic medical conditions: Certain medical conditions, such as diabetes and end stage renal disease, can increase the risk of infection.
- IV drug use: IV drug use can introduce bacteria from the skin into the bloodstream
- Previous surgery: People who have had surgery, particularly spine surgery, may be at increased risk of developing osteomyelitis.
- Injections or spinal procedures: Procedures that involve injecting substances into the spine or manipulating the spine can increase the risk of infection.
- Use of certain medications: Some medications, such as corticosteroids and immunosuppressants, can weaken the immune system and increase the risk of infection.
Incidence
The incidence of vertebral osteomyelitis varies worldwide, with rates ranging from 1 case per 100,000 people to 7 cases per 100,000 people. In the United States, the estimated incidence is 4.8 cases per 100,000 people. The incidence increases with age and is slightly more common in males than females.
Symptoms of Vertebral Osteomyelitis
The symptoms of osteomyelitis of the spine can vary depending on the severity of the infection and the location of the infected vertebra. Common symptoms may include:
- Back pain
- Fever
- Weakness
- Weight loss
- Numbness or tingling
- Difficulty walking or standing
If you experience any of these symptoms, it is important to seek medical attention as soon as possible. Early diagnosis and treatment can help prevent the infection from spreading and reduce the risk of long-term complications.
Diagnosis of Osteomyelitis
Vertebral osteomyelitis is usually diagnosed through a combination of medical history, physical examination, labs, and imaging tests.
History and Physical Examination
During the examination, the healthcare provider will ask about the symptoms and the location and severity of the pain. They will ask about your medical history and any risk factors for developing osteomyelitis.
Physical exam findings may include
- Tenderness in the affected area
- Decreased range of motion: Osteomyelitis may cause stiffness and decreased range of motion in the affected area of the spine.
- Numbness or tingling: The infection may cause numbness or tingling in the back, legs, or arms if nearby nerves are affected.
Laboratory Tests
Lab tests may be used to help diagnose osteomyelitis and determine the cause of the infection. Some common lab tests that may be ordered include:
- Complete blood count (CBC): This test measures the number and types of cells in the blood, including red blood cells, white blood cells, and platelets. An elevated white blood cell count may indicate an infection.
- C-reactive protein (CRP) test: This test measures the level of CRP, a protein produced by the liver in response to inflammation. An elevated CRP level may indicate an infection or inflammation.
- Erythrocyte sedimentation rate (ESR): This test measures the rate at which red blood cells settle to the bottom of a tube. An elevated ESR may indicate inflammation or infection.
- Blood culture: This test involves taking a sample of blood and culturing it in a laboratory to identify the specific type of bacteria causing the infection.
Imaging Studies
Imaging studies are often used to confirm the diagnosis of osteomyelitis and to determine the location and extent of the infection. Some common imaging studies that may be used to diagnose osteomyelitis include:
- X-ray: X-rays use radiation to produce images of the bones in the spine. X-rays may show signs of infection, such as bone destruction or bone abnormalities.
- Computed tomography (CT) scan: CT scans use X-rays and a computer to produce detailed images of the spine. CT scans may show signs of infection, such as abscesses or areas of inflammation.
- Magnetic resonance imaging (MRI): MRI is the modality of choice to diagnose osteomyelitis. MRI uses a strong magnetic field and radio waves to produce detailed images of the spine. MRI is particularly useful for identifying soft tissue abnormalities, and infection in bone and discs.
Treatment of Osteomyelitis
The treatment for osteomyelitis typically involves antibiotics, often IV, for several weeks. In some cases, surgery may be necessary to remove the infected tissue. Physical therapy may also be recommended to help strengthen the muscles in the back and improve mobility.
The specific treatment plan for osteomyelitis will depend on the severity of the infection, the location of the infected vertebra, and the overall health of the patient.
Antibiotics
Antibiotics are the main treatment for osteomyelitis. The specific type of antibiotic and the duration of treatment will depend on the specific type of bacteria causing the infection. However, treatment is typically for 6 weeks and is often administered intravenously.
Surgery
In severe cases of osteomyelitis, surgery may be necessary to remove the infected tissue and stabilize the spine. This may involve removing the infected bone and fusing the adjacent vertebrae together for stability.
Physical Therapy
Physical therapy may be recommended to help strengthen the muscles in the back and improve mobility. Physical therapy may include exercises to stretch and strengthen the muscles, as well as techniques to reduce pain and improve function.
It is important to complete the full course of treatment as prescribed by the healthcare provider to ensure that the infection is fully cleared and to reduce the risk of recurrence.
Prognosis
The prognosis for vertebral osteomyelitis depends on a number of factors, including the severity of the infection, the underlying cause of the infection, and the patient’s overall health. In most cases, early diagnosis and treatment can lead to a good outcome. However, if the infection is not treated promptly or if the patient has a weakened immune system, the prognosis may be less favorable.
Sources
Berbari, Elie F et al. “2015 Infectious Diseases Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adults.” Clinical infectious diseases : an official publication of the Infectious Diseases Society of America vol. 61,6 (2015): e26-46. doi:10.1093/cid/civ482
Zimmerli, Werner. “Clinical practice. Vertebral osteomyelitis.” The New England journal of medicine vol. 362,11 (2010): 1022-9. doi:10.1056/NEJMcp0910753
Graeber, Adam. and Nathan D. Cecava. “Vertebral Osteomyelitis.” StatPearls, StatPearls Publishing, 3 October 2022.
