Vertebral Osteomyelitis: Symptoms, Types, Causes and Treatment

Vertebral osteomyelitis is a serious infection affecting the bones of the spine. Once considered rare, its incidence is rising due to better diagnostics, aging populations, and increasing numbers of patients with risk factors such as diabetes and immunosuppression. Early recognition and treatment are critical, as delayed diagnosis can result in irreversible neurological damage or even death. In this article, we'll comprehensively explore the symptoms, types, causes, and treatment options for vertebral osteomyelitis, synthesizing the latest research to provide a clear, practical guide for understanding this challenging condition.

Symptoms of Vertebral Osteomyelitis

Recognizing the symptoms of vertebral osteomyelitis is often the first, and sometimes the most difficult, step toward diagnosis. The signs can be subtle, overlap with common back problems, or be masked in elderly and immunosuppressed individuals. However, certain features tend to stand out and should raise clinical suspicion, especially in patients with risk factors.

Symptom	Frequency/Context	Clinical Relevance	Source(s)
Back pain	Most common, often persistent	Key presenting symptom	1, 2, 3, 5, 6, 7
Fever	Present in 30–70% of cases	May be absent, esp. in elderly	1, 2, 5, 13
Neurological deficits	Up to 32% of cases	Paresis, paralysis, sensory loss	1, 2, 9, 13
Local tenderness	Common, esp. on palpation	Aids in localizing infection	2, 6
Weight loss	Sometimes present, subacute/chronic	Suggests chronic/advanced disease	5, 9
Elevated CRP/ESR	Nearly always elevated	Important diagnostic clue	2, 6

Table 1: Key Symptoms

Overview of Key Symptoms

Back pain is the most prevalent symptom, reported in almost all patients with vertebral osteomyelitis. It is usually persistent and can be severe, often unrelieved by rest. Fever, though a classical sign of infection, may be absent, particularly in elderly or immunocompromised individuals, making diagnosis more challenging 1, 2, 13.

Neurological Symptoms

Neurological deficits—such as muscle weakness, sensory changes, and even paralysis—occur when the infection causes compression or destruction of spinal structures. These can develop insidiously or abruptly and are a red flag for urgent intervention 1, 2, 9.

Systemic and Local Signs

Other signs include local tenderness over the affected vertebrae and, in some cases, visible swelling or deformity. Systemic symptoms like weight loss, malaise, and night sweats often point toward a more chronic or advanced infection, such as those caused by tuberculosis or non-tuberculous mycobacteria 5, 9.

Laboratory Findings

Laboratory markers of inflammation, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), are almost universally elevated and serve as key diagnostic clues, especially when combined with persistent back pain and risk factors 2, 6.

Types of Vertebral Osteomyelitis

Vertebral osteomyelitis is not a single disease but a spectrum of disorders, distinguished by their causative organisms, routes of infection, and clinical behavior. Understanding these types is crucial for tailored therapy and prognosis.

Type	Typical Cause/Organism	Distinguishing Features	Source(s)
Pyogenic	Bacterial (S. aureus, others)	Acute/subacute, rapid progression	1, 2, 6, 7, 13
Tuberculous	Mycobacterium tuberculosis	Chronic, systemic symptoms	6, 7, 9, 13
Brucellar	Brucella species	Endemic regions, systemic features	6, 7
Non-tuberculous Mycobacterial (NTM)	NTM (e.g., M. abscessus)	Rare, indolent, often in immunosuppressed	9, 11
Fungal	Aspergillus, others	Immunocompromised hosts	10
Nonbacterial (CNO/CRMO)	Auto-inflammatory	Children/adolescents, multifocal	8

Table 2: Types of Vertebral Osteomyelitis

Pyogenic (Bacterial) Osteomyelitis

Pyogenic vertebral osteomyelitis (PVO) is the most common type, often caused by Staphylococcus aureus, but also by streptococci, gram-negative bacteria (e.g., E. coli), and others. It typically presents acutely or subacutely, progresses rapidly, and may be linked to urinary tract infections, skin infections, or invasive procedures 1, 2, 5, 13.

Tuberculous Osteomyelitis

Tuberculous vertebral osteomyelitis, also known as Pott's disease, is caused by Mycobacterium tuberculosis. It tends to have a more insidious onset, with chronic back pain, constitutional symptoms (weight loss, night sweats), and is more common in endemic regions or immunosuppressed individuals 6, 9, 13.

Brucellar Osteomyelitis

Brucellar vertebral osteomyelitis is seen in areas where Brucella infection is endemic, often associated with exposure to unpasteurized dairy products or livestock. It may be difficult to distinguish from other forms but often presents with systemic symptoms and specific epidemiological clues 6, 7.

Non-tuberculous Mycobacterial and Fungal Osteomyelitis

NTM and fungal vertebral osteomyelitis are rare and primarily affect immunocompromised patients. They usually have a chronic, indolent course and may be missed without a high index of suspicion. Fungal infections, such as those caused by Aspergillus, are particularly seen in patients with hematologic malignancy or immunosuppression 9, 10, 11.

Nonbacterial/Auto-inflammatory Osteomyelitis

Chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO) are auto-inflammatory bone disorders, mostly seen in children and adolescents. They are not caused by infection, exhibit multifocal lesions, and can lead to significant morbidity if not recognized and managed appropriately 8.

Causes of Vertebral Osteomyelitis

The underlying causes of vertebral osteomyelitis are diverse, influenced by the patient's age, immune status, comorbidities, and exposure risks. Understanding these helps clinicians anticipate potential pathogens and tailor diagnostic and therapeutic strategies.

Cause/Pathogen	Common Risk Factors	Notable Features	Source(s)
Hematogenous spread	UTI, skin infection, IVDU, endocarditis	Most common route, especially in elderly	1, 5, 7, 13
Staphylococcus aureus	Diabetes, healthcare exposure	Most frequent overall pathogen	1, 2, 13
E. coli and Gram-negatives	UTI (esp. elderly women)	Often linked to urinary tract source	1, 5, 12
Mycobacterium tuberculosis	Immunosuppression, endemic regions	Chronic, insidious onset	6, 9, 13
Brucella spp.	Animal exposure, unpasteurized dairy	Systemic illness, endemic regions	6, 7
Fungi (Aspergillus)	Immunosuppression, malignancy	Unusual, often severe	10
Non-tuberculous mycobacteria	Immunosuppression	Rare, slow-growing, difficult to diagnose	9, 11
Auto-inflammatory	Pediatric/autoimmune background	CNO/CRMO, not infectious	8

Table 3: Causes and Risk Factors

Hematogenous Seeding

The majority of vertebral osteomyelitis cases result from hematogenous spread—bacteria or other pathogens enter the bloodstream and localize in the vertebral bodies. The lumbar spine is most frequently affected, followed by thoracic and cervical regions, although intravenous drug users (IVDU) may have more frequent cervical involvement 1, 13.

Direct Inoculation and Contiguous Spread

In some cases, infection arises from direct inoculation during spinal surgery, procedures, or trauma. Contiguous spread from adjacent infections—such as pressure sores or retroperitoneal abscesses—can also lead to vertebral involvement. These are more likely to be polymicrobial, including anaerobes 13.

Patient Risk Factors

• Diabetes mellitus is a major risk factor, associated with higher morbidity and mortality 1, 13.
• Elderly patients are particularly susceptible, often with atypical presentations 2.
• Immunosuppression (due to cancer, chemotherapy, HIV, or corticosteroids) increases the risk of unusual pathogens, such as fungi and NTM 9, 10, 11.
• IVDU is associated with younger patients and a broader range of pathogens, including Pseudomonas aeruginosa and S. aureus 13.

Unusual Causes

Brucella, NTM, and fungi are rare but important causes, particularly in certain geographic or patient populations 6, 7, 9, 10, 11. Auto-inflammatory causes (CNO/CRMO) are unique to pediatric populations and are not infectious in origin 8.

Treatment of Vertebral Osteomyelitis

Effective management of vertebral osteomyelitis requires a nuanced, often multidisciplinary approach, combining targeted antimicrobial therapy, supportive measures, and, when necessary, surgical intervention. Treatment must be individualized based on the causative organism, patient risk factors, and the presence of complications.

Intervention	Indication/Context	Key Points/Outcomes	Source(s)
Antibiotics	All cases (pathogen-directed)	6–12 weeks; shorter possible if low risk	14, 15, 16, 18
Surgery	Neurologic deficits, instability, abscess	40–50% cases may need surgery	2, 7, 13, 17
Supportive care	All patients	Bed rest, pain management	13, 15
Monitor response	All patients	Repeat imaging, labs	15, 17

Table 4: Main Treatment Modalities

Antimicrobial Therapy

The cornerstone of treatment is targeted antibiotic therapy. Empiric antibiotics are started after obtaining blood cultures and, when possible, biopsy specimens. Once the pathogen is identified, therapy should be tailored accordingly.

• Duration: Recent evidence supports that 6 weeks of antibiotics may be as effective as 12 weeks in patients at low risk of recurrence or complications, but high-risk patients (e.g., with MRSA, undrained abscess, end-stage renal disease) may benefit from at least 8 weeks or longer 14, 18.
• Route: Intravenous antibiotics are commonly started, with transition to oral therapy depending on response and organism 15, 16.
• Special cases: Treatment of TB, brucellosis, NTM, and fungal infections requires prolonged and specific regimens 6, 9, 10, 11.

Surgical Management

Surgery is reserved for patients with significant neurological deficits, spinal instability, failure of medical therapy, or large abscesses. Procedures may include debridement, drainage of abscesses, or spinal stabilization. Advances have made surgery safer, and in select patients, it can lead to faster recovery and improved quality of life 2, 7, 13, 17.

Supportive and Adjunctive Measures

Patients require immobilization (bed rest or bracing), pain management, and close monitoring for complications. Repeat imaging and laboratory markers (CRP, ESR) are used to track treatment response 13, 15, 17.

Special Considerations

• Immunosuppressed/Comorbid patients: May need longer therapy, close monitoring, and multidisciplinary care 9, 10.
• Pediatric/nonbacterial cases: Management of CNO/CRMO involves nonsteroidal anti-inflammatory drugs, sometimes steroids or immunomodulators—not antibiotics 8.

Conclusion

Vertebral osteomyelitis is a complex, potentially devastating condition that requires a high index of suspicion, especially in at-risk populations. Early recognition, appropriate diagnostics, and individualized therapy are essential to optimize outcomes and prevent permanent disability.

Key points:

• Back pain is the most common presenting symptom, but fever and neurological signs may be absent, especially in the elderly or immunosuppressed.
• Types of vertebral osteomyelitis include pyogenic, tuberculous, brucellar, non-tuberculous mycobacterial, fungal, and auto-inflammatory forms, each with unique risk factors and presentations.
• The primary route of infection is hematogenous spread, with S. aureus as the most common pathogen; diabetes, immunosuppression, and advanced age increase risk.
• Treatment is based on targeted antimicrobial therapy, often lasting 6–12 weeks, with surgery reserved for selected cases.
• Prognosis is generally good with prompt diagnosis and appropriate management, but delays can lead to irreversible neurologic deficits or death.

By appreciating the varied presentations and evolving management strategies, clinicians can improve patient outcomes and reduce the burden of this serious spinal infection.