Acute Inflammatory Demyelinating Polyradiculoneuropathy (AIDP)

KEY FACTS

Terminology

• Acute inflammatory demyelinating polyradiculoneuropathy (AIDP)

  • a.k.a. Guillain-Barré syndrome (GBS)

• Autoimmune postinfectious or postvaccinial acute inflammatory demyelination of peripheral nerves, nerve roots, cranial nerves

Imaging

• Smooth pial enhancement of cauda equina and conus medullaris

  • Nerve roots often slightly enlarged

  • Conus not enlarged

• Axial T1WI C+ MR shows preferential contrast accentuation of ventral roots in cauda

Top Differential Diagnoses

• Miller-Fischer syndrome

• Chronic polyneuropathies

  • Subacute inflammatory demyelinating polyradiculoneuropathy

  • Chronic inflammatory demyelinating polyradiculoneuropathy

  • Hereditary polyneuropathies

• Carcinomatous or lymphomatous meningitis

• Anterior lumbar radiculopathy

Pathology

• Antecedent event or “trigger” in 70% of GBS cases

  • Usually follows recent viral illness

• Campylobacter jejuni infection can be trigger

Clinical Issues

• Classically presents with “ascending paralysis”

  • If ascends to brainstem, may involve cranial nerves, require ventilator

  • Sensory loss common but less severe

• Cerebrospinal fluid shows albuminocytologic dissociation (↑ protein in absence of elevated WBCs)

TERMINOLOGY

IMAGING