Spinal Infections

Types of Spinal Infections

1. Vertebral Osteomyelitis:
   • Infection of the vertebrae itself.
   • Usually caused by bacteria, such as Staphylococcus aureus, that enter the body through the bloodstream (hematogenous spread) or from an adjacent infected area (e.g., skin or urinary tract).
   • Symptoms: Fever, back pain, tenderness over the affected vertebrae, and sometimes neurological deficits.
2. Spinal Epidural Abscess:
   • A collection of pus that forms in the epidural space surrounding the spinal cord and nerve roots.
   • Can compress the spinal cord, leading to severe neurological symptoms such as paralysis, sensory loss, and bladder/bowel dysfunction.
   • Most commonly caused by bacterial infections, although fungi can also be involved in immunocompromised patients.
   • Symptoms: Severe back pain, fever, weakness, sensory changes, and in severe cases, paralysis.
3. Discitis:
   • Infection of the intervertebral discs, which can involve the surrounding vertebrae.
   • More common in children, but can occur at any age.
   • Often caused by bacteria, but tuberculosis (TB) is a significant cause in certain populations.
   • Symptoms: Localized back pain, fever, and sometimes limping or difficulty moving in children.
4. Spinal Infections Following Surgery or Trauma:
   • Postoperative spinal infections can occur after spine surgery or trauma, such as a spinal fracture.
   • These infections may be caused by hospital-acquired bacteria or other pathogens introduced during the surgical procedure.

Causes and Risk Factors

Spinal infections can be caused by a variety of microorganisms, including bacteria, fungi, and, more rarely, viruses. Common causes include:

• Bacteria: The most common bacteria that cause spinal infections are Staphylococcus aureus and Streptococcus species, but Escherichia coli and other gram-negative bacteria can also be involved.
• Tuberculosis: Mycobacterium tuberculosis can infect the spine, particularly in immunocompromised individuals or in areas where TB is more prevalent.
• Fungi: In immunocompromised individuals (e.g., those with HIV/AIDS, diabetes, or on immunosuppressive medications), fungal infections like Candida or Aspergillus may cause spinal infections.

Risk factors for developing spinal infections include:

• Immunosuppression (e.g., due to HIV, diabetes, cancer, or immunosuppressive medications).
• Recent surgery or trauma involving the spine.
• Intravenous drug use, which can introduce bacteria directly into the bloodstream.
• Chronic conditions, such as diabetes or renal disease, which can impair the body’s ability to fight infection.
• Poor hygiene or infections elsewhere in the body (e.g., urinary tract infections or skin infections) that spread to the spine.

Symptoms

The symptoms of a spinal infection can vary depending on the type, location, and severity of the infection, but they generally include:

• Severe back pain that is often worse at night or with movement.
• Fever and chills, indicating an active infection.
• Neurological symptoms, such as numbness, tingling, weakness, or paralysis, if the infection compresses the spinal cord or nerve roots.
• Inability to move or walk, which is a serious complication that requires immediate medical attention.
• Localized tenderness over the spine or specific vertebrae.

Diagnosis

Diagnosis of spinal infections usually involves a combination of clinical evaluation, imaging studies, and microbiological testing:

1. Clinical History and Physical Exam: Doctors will assess symptoms, medical history, and risk factors.
2. Imaging:
   • MRI is the gold standard for diagnosing spinal infections, as it can identify abscesses, discitis, osteomyelitis, and other soft tissue infections.
   • CT scan or X-rays may also be used, but they are less sensitive than MRI in detecting early or subtle spinal infections.
   • Bone scans or positron emission tomography (PET) scans can sometimes be used for additional evaluation.
3. Blood Tests:
   • Blood cultures are essential to identify the causative organism.
   • C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) can be elevated in the presence of infection but are nonspecific.
4. Biopsy: In some cases, a biopsy of the infected tissue may be needed to identify the microorganism causing the infection, especially in cases of tuberculosis or fungal infections.

Treatment

Treatment of spinal infections depends on the specific type and severity of the infection but generally involves:

1. Antibiotic Therapy:
   • Intravenous antibiotics are usually the first line of treatment, followed by oral antibiotics for a longer period. The choice of antibiotics depends on the microorganism identified and its sensitivity to specific drugs.
   • In cases of tuberculosis or fungal infections, specific antifungal or antitubercular medications are needed.
2. Surgical Intervention:
   • Surgery may be required in cases where there is an abscess that needs to be drained or if the infection is causing compression of the spinal cord or nerve roots.
   • Surgery may also be necessary if the infection involves hardware placed during previous spinal surgery.
3. Pain Management:
   • Pain management, including nonsteroidal anti-inflammatory drugs (NSAIDs) or opioids in more severe cases, may be necessary during the treatment process.
4. Rehabilitation:
   • Physical therapy and rehabilitation may be required after the infection is controlled, especially if there has been any neurological damage.

Complications

If spinal infections are not treated promptly or effectively, they can lead to serious complications, including:

• Permanent neurological deficits (paralysis, sensory loss).
• Sepsis, a life-threatening systemic infection.
• Deformities or spinal instability if the infection weakens the vertebrae.
• Recurrence of the infection, especially in patients who do not complete their antibiotic regimen.

Prognosis

The prognosis for spinal infections varies depending on the promptness of diagnosis and treatment. Early intervention typically leads to a better outcome. However, if left untreated, spinal infections can cause severe complications and long-term disability. In severe cases, they can be fatal, particularly if the infection leads to sepsis or significant spinal cord damage.

Prevention

While not all spinal infections can be prevented, some strategies can reduce the risk:

• Proper wound care and hygiene after spine surgery or trauma.
• Prompt treatment of any infections elsewhere in the body (e.g., urinary tract or skin infections).
• Use of prophylactic antibiotics before spine surgery in high-risk patients.

Spinal infections are serious conditions, and anyone experiencing symptoms such as unexplained back pain, fever, or neurological symptoms (e.g., numbness or weakness) should seek medical attention immediately for evaluation and treatment.