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For further information, see CMDT Part 24-30: Polyneuropathies & Mononeuritis Multiplex

Key Features

Essentials of Diagnosis

  • Acute or subacute progressive polyradiculoneuropathy

  • Weakness is more severe than sensory disturbances

  • Acute dysautonomia may be life-threatening

General Considerations

  • A symmetric sensory, motor, or mixed deficit, often most marked distally

  • Probably has an immunologic basis, but the mechanism is unclear

  • Sometimes follows infections, inoculations, or surgical procedures

  • There is an association with preceding Campylobacter jejuni enteritis

  • The axonal subtypes of the syndrome (acute motor axonal neuropathy [AMAN] and acute motor and sensory axonal neuropathy [AMSAN]) are caused by antibodies to gangliosides on the axon membrane, including anti-GM1, anti-GM1b, anti-GD1a, anti-GD1b, and (in AMAN) anti-GalNAC-GD1a antibodies

  • The Miller Fisher syndrome is another subtype

    • Characterized by the clinical triad of ophthalmoplegia, ataxia, and areflexia

    • Associated with anti-GQ1b antibodies

Clinical Findings

Symptoms and Signs

Motor symptoms

  • The main complaint is of weakness

    • Varies widely in severity in different patients

    • Often has a proximal emphasis and symmetric distribution

    • Usually begins in the legs, spreading to a variable extent but frequently involving the arms and often one or both sides of the face

    • The muscles of respiration or deglutition may also be affected

Sensory symptoms

  • Sensory symptoms are usually less conspicuous than motor ones, but distal paresthesias and dysesthesias are common, and neuropathic or radicular pain is present in many patients

Autonomic symptoms

  • Autonomic disturbances are common, may be severe, and are sometimes life-threatening; they include the following

    • Tachycardia

    • Cardiac rhythm irregularities

    • Hypotension or hypertension

    • Facial flushing

    • Abnormalities of sweating

    • Pulmonary dysfunction

    • Impaired sphincter control

Differential Diagnosis

  • Chronic inflammatory demyelinating polyneuropathy (CIDP)

  • Porphyria

  • Diphtheritic neuropathy

  • Toxic neuropathy, eg, lead, mercury, organophosphates, hexacarbon solvents

  • HIV infection

  • Poliomyelitis

  • Botulism

  • Tick paralysis

  • Spinal cord lesion

  • Transverse myelitis

  • West Nile virus infection

  • Periodic paralysis syndrome


Laboratory Tests

  • The cerebrospinal fluid characteristically contains a high protein concentration with a normal cell count, but this change may take up to 2 weeks to develop

  • White blood cell counts > 50 cells/mcL (0.05 × 109/L) should prompt consideration of alternative diagnoses

Diagnostic Procedures

  • Electrophysiologic (nerve conduction) studies may reveal marked abnormalities, which do not necessarily parallel the clinical disorder in their temporal course



  • Marked hypotension may respond to volume replacement or pressor agents

  • Intravenous immunoglobulin (400 mg/kg/day for 5 days) is helpful

  • Low-dose heparin to prevent pulmonary embolism should be considered

  • Prednisone is ineffective and may prolong recovery time

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