Vertebral Osteomyelitis

By admin Last updated Mar 17, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Vertebral Osteomyelitis

Vertebral Osteomyelitis

Henry Boateng MD

Damien Doute MD

A. Jay Khanna MD

Basics

Description

Infection of the vertebral bony elements, not including the disc space

General Prevention

Prevention of HIV and hepatitis
Early treatment of hematogenous infection
Postoperative wound care, including dressing changes and prophylactic postsurgical antibiotics

Epidemiology

Bimodal distribution:
- Small peak in youth (10–20 years old)
- Largest peak in adults >50 years old
Increasing rates in young adults with HIV or other immunocompromise
Males affected more than females (60–80% of cases) (1,2)

Incidence

Rare: 1 per 250,000 (1)

Prevalence

2–8% of all osteomyelitis cases (1)

Risk Factors

HIV
Diabetes
Organ transplant recipient
Spine surgery
Intravenous drug use
Immunosuppression
Alcoholism (3)

Genetics

No known Mendelian genetic association

Pathophysiology

Thought to be primarily secondary to vascular spread of pathogens:
- Most spinal infections originate from a hematogenous source.
- The spine’s large venous and arterial circulation at both endplates and body facilitates hematogenous spread (3).
In postoperative patients with hardware, bacteria may adhere to instrumentation via glycocalyx and develop into osteomyelitis.

Etiology

Staphylococcus aureus: Most common pathogen
Pseudomonas: Seen in immunocompromised patients and those with a history of intravenous drug use
Klebsiella, Escherichia coli, and Proteus may be seen in patients with previous genitourinary infection and subsequent vertebral osteomyelitis.
Postoperative infections usually are caused by S. aureus and have a higher rate of antibiotic resistance than do infections from other organisms (3).
Mycobacterium tuberculosis (Potts
disease) is now rare, but it can occur in developing countries and in
immunocompromised patients.

Associated Conditions

Epidural abscess
HIV
Intravenous drug abuse
Discitis
Paravertebral abscess
Meningitis
Myelitis
Sepsis

Diagnosis

Signs and Symptoms

Back pain is the most common presenting symptom.
Constitutional symptoms of infection, including fever, anorexia, night sweats, chills
Spinal deformity in late cases secondary to bony destruction
Postoperative infections may show discharge and purulence from incision.

History

Back pain: Insidious but may be acute
Fever
Chills, night sweats
Irritability and fussiness in children
Neurologic deficits may occur in rare cases.

Physical Exam

Paraspinal tenderness and muscle spasm
Torticollis
Generalized weakness
Kernig sign and symptoms of meningitis
Hamstring spasm
Many clinical findings of infection may be reduced or absent in immunocompromised patients.

Tests

Lab

Complete blood count with differential may be elevated in 50% of patients (1).
ESR is the most sensitive marker for infection.
- Normal rate is 0–20
- Elevated in 90% of patients with
  infection, but also elevated postoperatively and thus lacks the
  specificity on its own for confident diagnosis
C-reactive protein is a more specific marker of acute infection.
- Returns to normal 6–10 days postoperatively
- Thus, an elevated rate for >10 days is suspicious for infection.
Blood cultures
Fungal cultures
History-driven specific labs such as exposure to tuberculosis

Imaging

Conventional radiography:
- Changes on radiographs occur late, and initial radiographs may be normal.
- If clinically suspicious, obtain MRI.
MRI:
- Best study: Low on T1-weighted scans, high on T2-weighted scans
- Post-gadolinium images show ring-enhanced areas of signal intensity.
CT scan: Osteolysis (3)

P.479

Diagnostic Procedures/Surgery

Nuclear medicine studies are useful in MRI-contraindicated patients (e.g., those with pacemakers)
Bone scan
Indium-labeled white blood cell count:
- High false-negative rate
- Do not use as stand-alone test.
Biopsy: Percutaneous or open at the time of surgery (1)

Pathological Findings

Biopsy material may contain organisms:
- Inflammatory cells
- Caseating necrotic granulomas in patients with tuberculosis

Differential Diagnosis

Fracture
Tumor
Disc herniation
Infections:
- Typically cross the endplate
- Tumor usually spares the endplate (per MRI).

Treatment

Initial Stabilization

Intravenous antibiotics:
- Initially, broad spectrum until organism sensitivities are obtained, and the specific antibiotics can be administered.
Spine immobilization

General Measures

Obtain cultures of blood and, if possible, bone before starting antibiotics.
Biopsy is critical for treatment: Should attempt percutaneously if possible.
Immobilize spine.

Activity

Bed rest
Thoracolumbosacral orthotic for immobilization, if needed

Nursing

Patients may be critically ill and may require intensive care.
Patients should be hospitalized for
intravenous administration of antibiotics and for observation and
management of medical comorbidities.

Special Therapy

Physical Therapy

No role for physical therapy in acute infection
Increased pain postoperatively with physical therapy may be a signal of infection.

Medication

First Line

Broad-spectrum antibiotics

Second Line

After biopsy, culture-specific antibiotics:
- Vancomycin for methicillin-resistant organisms
Zosyn (piperacillin and tazobactam) for Pseudomonas and Gram-negative organisms

Surgery

Indications for surgical management (4):
- Failure of nonoperative treatment
- Need for open biopsy
- Presence of spinal abscess
- Sepsis
- Progressive spinal deformity
- Refractory pain
- Spinal Instability
- Neurologic deficit
Surgical treatment principles in infection are (1):
- Adequate débridement
- Neurologic decompression if needed
- Rigid fixation

Follow-up

Continue intravenous antibiotics for 6–8 weeks.
Follow-up with infectious-disease specialist.
Early and progressive mobilization

Complications

Abscess formation
Vertebral collapse
Neurologic compromise
Paralysis
Cauda equina syndrome
Untreated infections may lead to sepsis and possible death.

Patient Monitoring

Repeat radiographs every 4–8 weeks until radiographically and clinically stable.
Follow-up ESR and C-reactive protein
Repeat MRI if pain or fever continues.

References

1. Carragee EJ. Pyogenic vertebral osteomyelitis. J Bone Joint Surg 1997;79A:874–880.

2. Sapico FL, Montgomerie JZ. Vertebral osteomyelitis. Infect Dis Clin North Am 1990;4:539–550.

3. Eastlack
RK, Kauffman CP. Pyogenic infections. In: Bono CM, Garfin SR, Tornetta
P, et al., eds. Spine. Philadelphia: Lippincott Williams & Wilkins,
2004:73–80.

4. Emery
SE, Chan DPK, Woodward HR. Treatment of hematogenous pyogenic vertebral
osteomyelitis with anterior debridement and primary bone grafting. Spine 1989;14:284–291.

Additional Reading

Stone DB, Bonfiglio M. Pyogenic vertebral osteomyelitis: a diagnostic pitfall for the internist. Arch Intern Med 1963;112:491–500.

Miscellaneous

Codes

ICD9-CM

730.28 Vertebral osteomyelitis

Patient Teaching

Early treatment of infectious processes, especially in immunocompromised patients.
It is essential that patients complete the course of intravenous antibiotics.

Activity

Immobilization in acute phase with brace
Early mobilization after surgical stabilization

FAQ

Q: Is emergent surgery indicated once the diagnosis of vertebral osteomyelitis is suspected?

A:
The 1st-line treatment for this condition is intravenous antibiotics
and immobilization. Surgery is indicated in the presence of neurologic
deficit, worsening pain, deformity, or the presence of an epidural
abscess.

Q: Is neurologic compromise the most common presenting symptom in patients with vertebral osteomyelitis?

A:
No. Neurologic compromise actually is quite rare. One should suspect
possible vertebral osteomyelitis in immunocompromised or postsurgical
patients with worsening back and spine pain. Appropriate imaging and
laboratory studies should be obtained.