Guillain-Barré Syndrome: Diagnostic Work-Up and First-Line Treatment

Immediate Life-Threatening Assessment

All patients with suspected Guillain-Barré syndrome require immediate assessment of respiratory function and autonomic stability, as these determine mortality risk and need for ICU-level care. 1

Respiratory Monitoring

Measure vital capacity, negative inspiratory force (NIF), and maximum inspiratory/expiratory pressures at presentation and serially. 1
Apply the "20/30/40 rule": Patient is at risk of respiratory failure if vital capacity <20 ml/kg, maximum inspiratory pressure <30 cmH₂O, or maximum expiratory pressure <40 cmH₂O. 1, 2
Single breath count ≤19 predicts need for mechanical ventilation. 1
Approximately 20-30% of patients develop respiratory failure requiring mechanical ventilation, which can occur rapidly and sometimes without obvious dyspnea. 1, 2

Cardiovascular Monitoring

Perform electrocardiography at presentation and continuously monitor heart rate and blood pressure for arrhythmias and blood pressure instability. 1, 3
Up to two-thirds of deaths occur during the recovery phase from cardiovascular and respiratory dysfunction. 2, 3

Diagnostic Work-Up

Clinical Criteria

The diagnosis is primarily clinical, based on rapidly progressive bilateral ascending weakness with diminished or absent reflexes. 1, 2

Key clinical features to assess:

Bilateral ascending weakness typically starting in legs and progressing to arms and cranial muscles (though not universal). 1, 2
Diminished or absent deep tendon reflexes, typically beginning in lower limbs. 1, 2
Distal paresthesias or sensory loss often precede or accompany weakness. 1, 2
Assess for cranial nerve involvement, particularly bilateral facial palsy—the most frequently affected cranial nerve due to its longest intracranial course and extensive myelin coverage. 1
Recent infection history (within 6 weeks) is present in about two-thirds of patients. 1
Back and limb pain is often an early symptom, affecting approximately two-thirds of patients. 1

Neurological Examination Specifics

Grade muscle strength using Medical Research Council scale in neck, arms, and legs. 1, 2
Test swallowing and coughing ability to identify aspiration risk. 1, 2
Assess for facial weakness and ophthalmoplegia. 1
Check for corneal reflex in patients with facial palsy to prevent corneal ulceration. 1

Laboratory and Diagnostic Testing

Obtain neurology consultation for all suspected GBS cases. 1, 2

Cerebrospinal Fluid Analysis

Perform lumbar puncture to look for albumino-cytological dissociation (elevated protein with normal cell count). 1, 2
Do not dismiss GBS based on normal CSF protein in the first week—this may be absent early in the disease course. 1, 2
Analyze CSF for cell count and differential, cytology for malignant cells, glucose, and viral/bacterial cultures. 1

Electrodiagnostic Studies

Perform nerve conduction studies and EMG to support diagnosis and classify the neuropathy pattern (AIDP, AMAN, or AMSAN). 1, 2
Look for sensorimotor polyradiculoneuropathy with reduced conduction velocities, reduced amplitudes, temporal dispersion, or conduction blocks. 1
"Sural sparing pattern" (normal sural sensory nerve action potential with abnormal median/ulnar responses) is typical for GBS. 1
Electrodiagnostic measurements might be normal when performed early (within 1 week)—repeat testing in 2-3 weeks if clinical suspicion remains high. 1

Initial Laboratory Tests

Complete blood count, glucose, electrolytes, kidney function, liver enzymes to exclude metabolic or electrolyte dysfunction as causes of weakness. 1
Serum creatine kinase (CK) is sensitive though nonspecific; elevation suggests muscle involvement and may indicate AMAN variant. 1
Screen for reversible neuropathy causes: HbA1c, vitamin B12, TSH, vitamin B6, folate. 1

Additional Testing

MRI of spine with and without contrast to rule out compressive lesions and evaluate for nerve root enhancement/thickening. 1, 2
Serum antiganglioside antibody tests for GBS subtypes (e.g., anti-GQ1b for Miller Fisher variant). 1, 2

Red Flags Requiring Diagnostic Reconsideration

Marked persistent asymmetry, bladder dysfunction at onset, or marked CSF pleocytosis should prompt reconsideration of the diagnosis. 1
Bilateral simultaneous facial weakness is extremely rare in Bell's palsy and should immediately raise suspicion for GBS. 1

First-Line Treatment

Initiate immunotherapy immediately in patients unable to walk unaided within 2-4 weeks of symptom onset—do not wait for antibody test results. 1, 2

Immunotherapy Options (Equally Effective)

Option 1: Intravenous Immunoglobulin (IVIg)

Dose: 0.4 g/kg/day for 5 consecutive days (total dose 2 g/kg). 1, 2

Option 2: Plasma Exchange

Dose: 200-250 ml/kg over 4-5 sessions. 1, 2

IVIg is usually the preferred treatment for practical reasons. 4

What NOT to Use

Corticosteroids alone are NOT recommended for idiopathic GBS—they have shown no significant benefit. 1, 2, 5, 6, 7

Admission and Monitoring Criteria

Admission Guidelines

Admit patients with Grade 3-4 disease (severe weakness limiting self-care, any dysphagia, facial weakness, respiratory muscle weakness, or rapidly progressive symptoms) to inpatient unit with capability for rapid transfer to ICU-level monitoring. 1
Even patients with moderate symptoms (Grade 2) require neurology consultation and close monitoring. 1
All grades of GBS warrant workup and intervention given potential for progressive disease leading to respiratory compromise. 1

Ongoing Monitoring

Frequent pulmonary function assessment with serial vital capacity and NIF measurements. 1
Daily neurologic evaluation. 1
Monitor for autonomic dysfunction including blood pressure/heart rate instability, pupillary dysfunction, bowel/bladder dysfunction. 1, 2

Managing Treatment Response

Expected Timeline

Approximately 40% of patients do not improve in the first 4 weeks following treatment—this does not necessarily mean treatment failed, as progression might have been worse without therapy. 1, 2
Disease progression typically reaches maximum disability within 2 weeks of symptom onset. 1, 2

Treatment-Related Fluctuations (TRFs)

TRFs occur in 6-10% of patients within 2 months following initial treatment-induced improvement or stabilization. 1, 2
Repeating a full course of IVIg or plasma exchange is common practice for TRFs. 1

When to Reconsider Diagnosis

Consider changing diagnosis to acute-onset CIDP if progression continues after 8 weeks from onset or if patient has three or more TRFs—this occurs in approximately 5% of patients initially diagnosed with GBS. 1, 4

Supportive Care

Pain Management

Use gabapentinoids (gabapentin, pregabalin) or duloxetine for neuropathic pain. 1, 2
Gabapentin can be used alongside IVIg—there is no contraindication or interaction. 1
Do not delay gabapentin initiation waiting for IVIg to "work first"—pain control should begin immediately. 1

Medications to Avoid

Avoid medications that can worsen neuromuscular transmission: β-blockers, IV magnesium, fluoroquinolones, aminoglycosides, and macrolides. 1, 3

Standard Preventive Measures

Treatment of constipation/ileus. 1
Standard preventive measures for pressure ulcers, hospital-acquired infections, and deep vein thrombosis. 1, 2

Rehabilitation

Arrange a rehabilitation programme with a rehabilitation specialist, physiotherapist, and occupational therapist. 1
Exercise programmes, including range-of-motion exercises, stationary cycling, walking, and strength training, can improve physical fitness, walking ability, and independence. 1

Prognosis

80% of patients regain independent walking ability at 6 months. 1
Mortality is 3-10%, primarily from cardiovascular and respiratory complications. 1, 3, 8
Recovery can continue for more than 3 years, with improvement possible even more than 5 years after onset. 1
Advanced age and severe disease at onset are risk factors for poor outcome. 1, 3
Use the modified Erasmus GBS outcome score (mEGOS) to predict probability of regaining walking ability. 1

Critical Pitfalls to Avoid

Do not dismiss GBS based on normal CSF protein in the first week—repeat testing if clinical suspicion remains high. 1
Do not dismiss GBS based on absent sural sparing in the first week—repeat electrodiagnostic studies in 2-3 weeks. 1
Recognize that patients with GBS, even those with complete paralysis, usually have intact consciousness, vision, and hearing—be mindful of what is said at bedside and explain procedures to reduce anxiety. 1
Screen for anxiety, depression, and hallucinations, which are frequent complications. 1, 2
The plateau and early recovery phases are particularly dangerous for cardiovascular events, including sudden arrhythmias and blood pressure shifts. 3

What is the recommended diagnostic work‑up and first‑line treatment for an adult with suspected Guillain‑Barré syndrome?

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