What are the diagnostic criteria and treatment options for Guillain-Barré Syndrome (GBS)?

Guillain-Barré Syndrome: Diagnostic Criteria and Treatment

Diagnostic Criteria

GBS diagnosis requires bilateral progressive limb weakness with reduced or absent reflexes, typically reaching maximum disability within 2 weeks of onset. 1

Core Clinical Features

• Bilateral ascending weakness starting in the legs and progressing to arms and cranial muscles, with distal paresthesias or sensory loss often preceding or accompanying weakness 2
• Diminished or absent reflexes beginning in the lower limbs (though normal or exaggerated reflexes may occur in pure motor variants with AMAN subtype) 1, 2
• Acute or subacute onset with progression to maximum disability typically within 2 weeks; if progression occurs within 24 hours or after 4 weeks, consider alternative diagnoses 1, 2
• Monophasic course with recovery expected, though treatment-related fluctuations occur in ~10% and 5% may actually have acute-onset CIDP 3, 4

Preceding Events

• Recent infection history (within 6 weeks) is present in approximately two-thirds of patients 1, 2
• Six pathogens have been temporally associated with GBS in case-control studies: Campylobacter jejuni, cytomegalovirus, hepatitis E virus, Mycoplasma pneumoniae, Epstein-Barr virus, and Zika virus 1
• Absence of antecedent illness does not exclude GBS, as infections may be subclinical 1

Laboratory Investigations

CSF examination should be performed during initial evaluation to rule out alternative diagnoses and support the GBS diagnosis 1

• Albumino-cytological dissociation (elevated CSF protein with normal cell count) is the classic finding 1, 5
• Normal protein levels occur in 30-50% of patients in the first week and 10-30% in the second week, so normal CSF does not rule out GBS 1, 5
• Marked pleocytosis (>50 cells/μl) suggests alternative pathologies such as leptomeningeal malignancy or infectious/inflammatory disease 1

Electrodiagnostic Studies

Electrodiagnostic testing should be performed to support the diagnosis and classify GBS subtypes (AIDP, AMAN, AMSAN) 5, 3

• Normal electrophysiological findings early in the course do not rule out GBS; repeat studies 3-8 weeks after symptom onset may help classify initially unclassifiable cases 5
• "Sural sparing pattern" (normal sural SNAP with abnormal median/ulnar SNAPs) is characteristic, seen in 67% of patients under 60 years 5

Antibody Testing

• Anti-ganglioside antibody testing has limited diagnostic value and should not delay treatment 1, 3
• Anti-GQ1b antibodies are found in up to 90% of Miller Fisher syndrome cases and should be tested when MFS is suspected 1, 3
• Nodal-paranodal antibodies should be tested when autoimmune nodopathy is suspected 3

Diagnostic Criteria Systems

Use the NINDS criteria (1978, revised 1990) for clinical practice, as they present typical and atypical GBS features more clearly than Brighton Collaboration criteria 1

Clinical Variants

The classic sensorimotor form (30-85% of cases) presents with rapidly progressive symmetrical weakness and sensory signs with absent or reduced reflexes 1, 2

Major Variants

• Pure motor variant (5-70%): Motor weakness without sensory signs 1
• Miller Fisher syndrome (5-25%): Ophthalmoplegia, ataxia, and areflexia 1, 2
• Paraparetic variant (5-10%): Paresis restricted to the legs 1
• Pharyngeal-cervical-brachial (<5%): Weakness of pharyngeal, cervical and brachial muscles without lower limb weakness 1
• Bilateral facial palsy (<5%): Bilateral facial weakness with paresthesias and reduced reflexes 1

Atypical Presentations

Young children (<6 years) can present with nonspecific features including poorly localized pain, refusal to bear weight, irritability, meningism, or unsteady gait 1

Back and limb pain affects approximately two-thirds of patients and can be muscular, radicular, or neuropathic, often preceding weakness 2

Treatment Options

Immunotherapy

For patients unable to walk unaided within 2 weeks of symptom onset, administer intravenous immunoglobulin (IVIg) 0.4 g/kg daily for 5 consecutive days. 2, 3

Plasma exchange (PE) is an equally effective alternative: 200-250 mL/kg total volume over 4-5 exchanges (12-15 L) within 1-2 weeks, for patients within 4 weeks of onset who cannot walk unaided 2, 3

Treatment Recommendations and Contraindications

• Do not use PE followed immediately by IVIg, as this combination is not recommended 3
• Do not administer a second IVIg course in GBS patients with poor prognosis, as this is not recommended 3
• Do not use oral corticosteroids; the EAN/PNS guideline recommends against their use 3
• Weakly recommend against IV corticosteroids 3

Symptomatic Treatment

For pain management, use gabapentinoids, tricyclic antidepressants, or carbamazepine (weak recommendation) 3

No specific treatment is recommended for fatigue 3

Treatment-Related Fluctuations

Approximately 10% of GBS patients have secondary deterioration within the first 8 weeks after starting IVIg, requiring repeated IVIg treatment 4

Consider changing diagnosis to acute-onset CIDP (A-CIDP) if progression continues after 8 weeks from onset, which occurs in around 5% of patients initially diagnosed with GBS 3, 4

Prognosis Assessment

Use the modified Erasmus GBS Outcome Score (mEGOS) to assess outcome and the modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess risk of requiring artificial ventilation 3

Expected Outcomes

• Full recovery expected in approximately 90% of cases, though recovery may take up to 2 years or continue for more than 3 years after onset 2, 6
• About 25% of patients require artificial ventilation during a period of days to months 4, 6
• Approximately 20% of patients are still unable to walk after 6 months 4
• Mortality is 3-10% 4
• Recurrence is rare, occurring in only 2-5% of cases 2

Common Pitfalls

Do not delay treatment while waiting for antibody test results or confirmatory CSF findings, as early treatment improves outcomes 1, 3

Do not rule out GBS based on normal CSF protein in the first week or normal electrophysiological studies early in the disease course 1, 5

Recognize that dysautonomia is common and can include blood pressure or heart rate instability, pupillary dysfunction, and bowel or bladder dysfunction, requiring intensive monitoring 1, 2