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Spinal infections, an umbrella term covering osteomyelitis, diskitis, and spinal epidural abscess, are a rare but serious cause of back pain. They are caused by bacteria (most commonly Staphylococcus aureus) introduced during surgery or via hematogenous or contiguous spread from other infections, which leads to inflammation and abscess formation. Risk factors include immunosuppression, bacteremia, and recent surgery. Patients typically present with nonspecific symptoms such as back pain and fever; however, the presentation depends on the location and extent of the infection and may include signs of cord compression. Diagnosis is often delayed due to the nonspecific nature of symptoms, as well as the overlap between symptoms of spinal infection and those of the underlying source of infection, e.g., skin and soft tissue infection or urinary tract infection. Diagnosis is based on blood cultures, inflammatory markers, and advanced imaging of the spine; the first-line imaging modality is MRI with and without contrast. If initial studies are negative, a CT-guided biopsy may be appropriate. Patients with hemodynamic instability or signs of neurologic compromise should be started on antibiotics immediately and urgently referred to a neurosurgeon. For stable patients, antibiotic therapy is typically deferred until the causative organism is known. Additional surgical management should be considered for patients with complications such as abscesses or spinal deformity, or who have ongoing severe pain or fail to respond to antibiotic therapy.
(spondylitis): an infection of the vertebral body. Subtypes include:
- Granulomatous vertebral osteomyelitis: most commonly caused by tuberculosis (Pott disease). Risk factors include immigration from countries with high TB prevalence and coinfection with HIV. 
- Pyogenic vertebral osteomyelitis: most common form; typically occurs secondary to infection with Staphylococcus aureus
- Diskitis: an infection of the intervertebral disk space
- Spondylodiskitis: an infection of both the vertebral body and intervertebral disk space
- : a suppurative infection in the epidural space
Routes of infection
- Spinal infection may arise from: 
- Frequently, a primary source of infection cannot be identified. 
In special patient groups
- After spinal surgery, usually: 
- In areas of high endemicity or in patients emigrating or traveling from those areas, also consider:
- In patients with immunosuppression, long-term indwelling venous catheters, or IV drug use, also consider fungal species.
Risk factors 
- Age > 50 years 
- Sickle cell disease 
- Immunocompromise: e.g., steroid use, HIV infection
- Intravenous drug use
- Recent bacteremia
- Infective endocarditis
- Recent spinal surgery and instrumentation
- Intravascular devices
- Chronic medical conditions:
All types of spinal infections have similar clinical features. In cases of hematogenous spread, features of the primary infection (e.g., urinary tract infection, skin and soft tissue infection) may dominate the clinical presentation. 
Back or neck pain 
- Onset is typically insidious, worsening over several weeks to months.
- Occurs in a localized area
- Worse during physical activity and at night
- May radiate to the abdomen, hip, leg, scrotum, groin, and/or perineum
- Severe, sharp back pain may indicate an epidural abscess.
- Examination findings
- Pain is exacerbated by palpation or percussion of the area.
- Palpation of paravertebral muscles can cause tenderness and spasm.
- Spinal mobility is reduced.
- Neurological signs and symptoms may be present: See “Complications.”
- Fever: present in up to 45% of patients. 
The diagnosis of spinal infection is often delayed because back pain is a common and nonspecific symptom, while spinal infections are rare.
- Obtain the following tests in all patients with suspected spinal infections:
- If all initial tests are negative but clinical suspicion remains high, consider:
- Suspected hematogenous or contiguous spread: Identify and treat the underlying cause.
- ↑ CRP, ↑ ESR 
- CBC: typically elevated 
- Blood cultures: two sets, aerobic and anaerobic, from two separate peripheral venipuncture sites
- Additional testing when less common pathogens are suspected, e.g.:
- If initial testing shows no signs of infection, consider checking serum protein electrophoresis to evaluate for multiple myeloma.
Imaging studies 
MRI spine with and without IV gadolinium contrast 
- Indication: first-line imaging modality for suspected spinal infection (highest sensitivity) 
- Pyogenic vertebral osteomyelitis
- Granulomatous vertebral osteomyelitis: See “Diagnostics” in “Pott disease.”
- Spinal epidural abscess 
Additional imaging studies
- CT spine with IV contrast 
- Nuclear medicine scans: adjunct to MRI if initial MRI results are negative or equivocal
- Indications: not used to diagnose spinal infections but a potential initial study in a patient presenting with back pain
- Findings 
If imaging is inconclusive but suspicion for spinal infection persists, repeat after 1–3 weeks. 
CT-guided aspiration biopsy 
- A biopsy of the affected area is performed and material is sent for microbiologic and pathologic examination.
- Indications to repeat the biopsy include:
In patients with a nondiagnostic workup and negative CT-guided aspiration biopsy in whom the clinical suspicion of spinal infection remains high, a repeat biopsy (CT-guided or surgical) should be obtained. 
The differential diagnoses listed here are not exhaustive.
The following recommendations pertain to the treatment of suspected pyogenic vertebral osteomyelitis and spinal epidural abscess. Involve specialists (infectious disease, neurosurgery) early. For treatment of tubercular vertebral osteomyelitis, see “Pott disease.”
Initial management: Assess the need for empiric antibiotic therapy and invasive treatment.
- Initiate empiric antibiotic therapy and obtain cultures and an urgent neurosurgical consult if any of the following criteria are met:
- If none of the criteria are fulfilled, antibiotic therapy can be delayed until the causative organism is identified.
- If mobility is limited, start .
- Identify and treat underlying causes.
- Regularly reassess for new neurologic signs and symptoms.
- Tailor antibiotic therapy based on culture and susceptibility results.
Empiric antimicrobial therapy for spinal infections
- Coverage: : must include Staphylococcus spp., including MRSA, Streptococcus spp., and gram-negative bacilli
- Recommended regimens
Tailored antimicrobial therapy
- Initiate IV antimicrobial treatment based on culture and susceptibility results.
- Consider switching to oral antibiotics if symptoms improve and inflammatory markers trend downward.
|Culture-specific antibiotic therapy for vertebral osteomyelits |
|Staphylococcus species||Methicillin-susceptible Staphylococcus aureus|
|Methicillin-resistant Staphylococcus aureus|
|With associated endocarditis|
|Mycobacterium tuberculosis|| |
Spinal infections are usually treated with 6 weeks of antibiotics, but the duration may vary based on the causative organism and patient response to treatment. Consult an infectious disease specialist prior to stopping treatment.
CT-guided drainage and irrigation 
- Indication: epidural and paraspinal abscesses
- Contraindications: anterior abscess, spinal instability, associated osteomyelitis or spondylodiskitis
- Epidural abscesses and paraspinal abscesses, particularly those large in size (e.g., ≥ 2.5 cm) 
- Spinal instability or deformity
- New or progressive neurologic impairment
- Intractable pain
- Need for open biopsy 
- Infections associated with spinal implants
- Persistent or recurrent bloodstream infection
- Objectives 
- Neurologic 
- Motor weakness or paralysis 
- Sensory loss
- Meningitis 
- Abscess in the surrounding soft tissues
- Psoas abscess
- Infectious aortitis 
Severe complications can occur if the diagnosis or treatment of spinal infections is delayed.
We list the most important complications. The selection is not exhaustive.