Pyogenic Osteomyelitis

KEY FACTS

Terminology

• Definition: Bacterial suppurative infection of vertebrae and intervertebral disc

• Synonyms: Pyogenic spondylodiscitis, disc space infection

Imaging

• Ill-defined hypointense T1 vertebral marrow with loss of endplate definition on both sides of disc

• Loss of disc height and abnormal disc signal

• Destruction of vertebral endplate cortex

• Vertebral collapse

• Paraspinal ± epidural infiltrative soft tissue ± loculated fluid collection

• Follow-up MR

  • Should focus on soft tissue findings

  • No single MR imaging parameter is associated with clinical status

Top Differential Diagnoses

• Degenerative endplate changes

• Tuberculous vertebral osteomyelitis

• Spinal neuropathic arthropathy

Pathology

• Predisposing factors

  • Intravenous drug use

  • Immunocompromised state

  • Chronic medical illnesses (renal failure, cirrhosis, cancer, diabetes)

• Staphylococcus aureus is most common pathogen

Clinical Issues

• Acute or chronic back pain

• Focal spinal tenderness

• Fever

• ↑ ESR, ↑ CRP, ↑ WBC

TERMINOLOGY