Overview
Definition:
Guillain-Barré syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy characterized by rapid onset of symmetrical limb weakness and areflexia
in children, it is the most common cause of acute flaccid paralysis.
Epidemiology:
Incidence in children is approximately 0.4-1.0 per 100,000 person-years, with a bimodal age distribution peaking in early childhood and adolescence
it can occur at any age, following infections (most commonly Campylobacter jejuni) or vaccinations.
Clinical Significance:
GBS is a pediatric emergency due to the potential for rapid progression of respiratory muscle weakness, leading to respiratory failure
timely diagnosis, aggressive respiratory monitoring, and appropriate immunosuppressive therapy (IVIG or plasma exchange) are crucial for improving outcomes and preventing mortality.
Clinical Presentation
Symptoms:
Ascending symmetrical weakness, typically starting in the legs and progressing upwards
Sensory symptoms like paresthesias, pain (often disproportionate to motor deficit), and gait ataxia
Cranial nerve involvement leading to dysphagia, facial diplegia, ophthalmoplegia
Autonomic dysfunction including labile blood pressure, cardiac arrhythmias, urinary retention
Respiratory distress due to weakness of respiratory muscles.
Signs:
Decreased or absent deep tendon reflexes (areflexia or hyporeflexia) in affected limbs
Muscle weakness, often greater distally than proximally
Cranial nerve palsies
Tachycardia or bradycardia
Hypotension or hypertension
Respiratory rate may be normal initially, but paradoxical breathing patterns may emerge
Decreased lung volumes on auscultation.
Diagnostic Criteria:
The Brighton Collaboration case definition for GBS includes: progressive muscle weakness in at least two limbs
symmetrical weakness
areflexia or hyporeflexia
absence of other identifiable causes
support from CSF and/or nerve conduction study findings
Most subtypes require progression of symptoms for less than 4 weeks.
Diagnostic Approach
History Taking:
Detailed history of preceding illness (viral prodrome, diarrhea, respiratory infection) within 1-4 weeks of symptom onset
Vaccination history
Onset and progression of weakness, sensory symptoms, and cranial nerve deficits
Presence of autonomic symptoms
History of any conditions causing acute flaccid paralysis.
Physical Examination:
Systematic neurological examination to assess motor strength (MRC scale), sensation (light touch, pinprick, proprioception), reflexes, and cranial nerves
Assess respiratory effort, use of accessory muscles, vital capacity, and negative inspiratory force
Auscultation of lungs
Cardiovascular assessment for autonomic dysfunction.
Investigations:
Cerebrospinal fluid (CSF) analysis: typically shows albumino-cytologic dissociation (elevated protein with normal or mildly elevated white blood cell count) after the first week
Nerve conduction studies (NCS) and electromyography (EMG): demonstrate demyelination (prolonged distal motor latencies, reduced conduction velocities, conduction block) or axonal loss depending on the subtype
Baseline blood tests: CBC, electrolytes, renal and liver function tests, creatine kinase (CK) to rule out rhabdomyolysis or myositis
Electrocardiogram (ECG) to monitor for cardiac arrhythmias.
Differential Diagnosis:
Other causes of acute flaccid paralysis in children include: transverse myelitis, poliomyelitis and other enteroviruses, botulism, tick paralysis, spinal muscular atrophy, myasthenia gravis, toxic neuropathies, critical illness polyneuropathy.
Management
Initial Management:
Admission to hospital, preferably a pediatric intensive care unit (PICU) or high-dependency unit, for close monitoring
Prompt neurological and respiratory assessment
Secure airway if necessary
Intravenous access
Pain management
Hydration.
Medical Management:
Treatment options include: Intravenous Immunoglobulin (IVIG): 2 g/kg total dose, divided over 2-5 days
Plasma Exchange (PLEX): 4-5 exchanges of 20-25 mL/kg body weight
PLEX is generally considered as effective as IVIG but may be preferred in certain situations (e.g., severe autonomic dysfunction, limited IV access, contraindications to IVIG)
Supportive care is paramount, including mechanical ventilation if respiratory failure occurs.
Supportive Care:
Intensive respiratory monitoring: vital capacity, negative inspiratory force, arterial blood gases, oxygen saturation
Mechanical ventilation is indicated if vital capacity falls below 15-20 mL/kg or negative inspiratory force is less than -25 cm H2O
Nutritional support via nasogastric or gastrostomy tube if dysphagia persists
Deep vein thrombosis (DVT) prophylaxis
Bladder care
Physiotherapy and occupational therapy for rehabilitation and prevention of contractures.
Monitoring:
Continuous monitoring of respiratory function (vital capacity, negative inspiratory force, end-tidal CO2, SpO2, ABGs)
Frequent assessment of neurological status, motor strength, and reflexes
Cardiovascular monitoring for autonomic instability (heart rate, blood pressure)
Fluid balance and electrolyte monitoring.
Complications
Early Complications:
Respiratory failure requiring mechanical ventilation
Autonomic dysfunction (cardiac arrhythmias, labile blood pressure, ileus)
Deep vein thrombosis and pulmonary embolism
Pressure sores
Corneal abrasions due to ophthalmoplegia.
Late Complications:
Chronic fatigue
Pain
Residual weakness or sensory deficits
Psychological sequelae (anxiety, depression).
Prevention Strategies:
Proactive and continuous respiratory monitoring to anticipate and manage respiratory failure
Early mobilization and physiotherapy to prevent DVT and contractures
Regular skin care to prevent pressure ulcers
Careful management of autonomic dysfunction.
Prognosis
Factors Affecting Prognosis:
Severity of initial weakness
Rapid progression
Presence of respiratory failure
Degree of autonomic dysfunction
Age (younger children tend to have a better prognosis)
Promptness and adequacy of treatment
Presence of specific GBS subtypes (e.g., AIDP generally has better prognosis than AMAN/AMSAN).
Outcomes:
Most children with GBS recover well, with over 80% achieving functional recovery within months to a year
Some may have residual symptoms
Mortality is low (around 2-5%) but can be reduced with optimal intensive care and management of complications.
Follow Up:
Regular follow-up with a pediatric neurologist and rehabilitation team for monitoring of neurological recovery, functional status, and management of any long-term sequelae
Physiotherapy and occupational therapy may be required for extended periods.
Key Points
Exam Focus:
GBS is an immune-mediated demyelinating polyneuropathy
Key features: ascending paralysis, areflexia
CSF shows albumino-cytologic dissociation
Management involves IVIG or PLEX
Critical complication is respiratory failure requiring vigilant monitoring.
Clinical Pearls:
Always consider GBS in a child with acute onset of flaccid paralysis, especially if preceded by an infection
Measure vital capacity and negative inspiratory force frequently in suspected or confirmed GBS
Autonomic dysfunction is common and can be life-threatening
monitor BP and HR closely.
Common Mistakes:
Delaying diagnosis and treatment
Underestimating the risk of respiratory failure
not monitoring respiratory parameters adequately
Inadequate management of autonomic instability
Failing to initiate rehabilitation early enough.