Spinal Meningitis

KEY FACTS

Imaging

• MR

  • Diffuse, extensive subarachnoid enhancement

  • Smooth or irregular meningeal enhancement

Top Differential Diagnoses

• Carcinomatous meningitis

  • Focal or diffuse, sheet-like or nodular enhancement along cord or nerve roots

• Sarcoidosis

  • Leptomeningeal + nerve root enhancement mimics spinal meningitis

• Lumbar arachnoiditis

  • Empty-sac sign (nerve roots stuck to inside of thecal sac)

• Guillain-Barré syndrome

  • Inflammatory demyelination typically following recent viral illness

• Intracranial hypotension (spontaneous or iatrogenic)

  • Engorged epidural venous plexi, not dura/arachnoid or pia

Pathology

• Infection of cerebrospinal fluid (CSF), pia covering spinal cord/roots

• Associated findings

  • Spondylodiscitis

  • Spinal epidural abscess

  • Blocked CSF flow → increased pressure in cord → syrinx

Clinical Issues

• Acute fever, chills, headache ± altered consciousness

Diagnostic Checklist

• Imaging often negative early, so lumbar puncture necessary

  • Positive in advanced bacterial meningitis or granulomatous infection

• Intravenous gadolinium increases sensitivity in detecting meningeal disease

TERMINOLOGY

IMAGING