What are the causes of ascending paralysis in pediatric patients?

Causes of Ascending Paralysis in Children

Primary Etiology: Guillain-Barré Syndrome

Guillain-Barré syndrome (GBS) is the most important and common cause of acute ascending paralysis in pediatric patients, typically presenting as bilateral symmetric weakness that progresses over 12 hours to 28 days, accompanied by hyporeflexia or areflexia. 1

Clinical Presentation of GBS in Children

• Progressive ascending weakness starting in the lower extremities and moving upward, with most patients developing generalized hyporeflexia or areflexia (though reflexes can initially be normal or even exaggerated in early stages) 1
• Cranial nerve involvement occurs in more than half of patients, including bilateral facial weakness, bulbar weakness, or extraocular motor dysfunction 1
• Atypical presentations in children may include pain, refusal to walk, or inability to stand, which can complicate early diagnosis 1
• Respiratory insufficiency can develop rapidly, requiring close monitoring for impending respiratory failure 1, 2

Preceding Infections

• Campylobacter jejuni is the strongest documented infectious trigger, with 1 in 1,058 Campylobacter infections resulting in GBS (and 1 in 158 for type O:19 strains) 3
• Viral illnesses including enterovirus, Zika virus, dengue, and chikungunya have been associated with GBS outbreaks 1
• Recent respiratory or gastrointestinal infection precedes 50-75% of GBS cases 4, 3

Diagnostic Approach

• Cerebrospinal fluid analysis typically shows cytoalbuminologic dissociation (elevated protein with normal cell count), though this may not be present initially and requires repeat sampling if clinical suspicion is high 4, 5
• Nerve conduction studies support the diagnosis but should not delay treatment if clinical presentation is consistent with GBS 1
• Anti-GQ1b IgG antibody is present in Miller-Fisher syndrome, a GBS variant presenting with ataxia, ophthalmoplegia, and areflexia 1

Other Important Causes

Infectious Etiologies

• Poliomyelitis presents with flaccid paralysis, disturbances in consciousness, and seizures, primarily in unvaccinated children in Africa and Asia 1
• Enterovirus 71 can cause rhombencephalitis with myoclonus, tremors, ataxia, and cranial nerve defects, with MRI showing increased signal in midbrain, pons, and medulla 1
• Rabies virus (paralytic form) causes ascending paralysis followed by cerebral involvement, though this is rare in the United States 1
• Meningitis should be considered, particularly if fever or altered mental status is present 6

Neuromuscular Disorders

• Spinal muscular atrophy presents with fasciculations (especially in the tongue) and carries high risk of rapid deterioration during acute illness, requiring urgent referral 1, 2
• Muscular dystrophies (Duchenne, Becker) should be suspected if creatine kinase is elevated >3× normal, requiring immediate pediatric neurology referral 1, 2
• Botulism can present with descending paralysis but may have ascending features in infants 5

Central Nervous System Causes

• Acute transverse myelitis can present with ascending sensory and motor deficits 7
• Spinal cord compression from tumor, abscess, or hematoma requires urgent neuroimaging 1
• Post-traumatic ascending myelopathy is rare but can occur within weeks after spinal cord injury, progressing more than four neurological levels 7
• Cerebellar stroke is rare (3 of 364 children with acute ataxia in one series) but critical to diagnose 1

Metabolic and Toxic Causes

• Tick paralysis causes ascending flaccid paralysis that resolves after tick removal 1
• Heavy metal poisoning (lead, arsenic) can cause peripheral neuropathy with ascending features 1
• Diphtheria causes demyelinating neuropathy, though rare in vaccinated populations 1

Critical Red Flags Requiring Immediate Action

• Respiratory insufficiency with generalized weakness requires consideration of inpatient evaluation for neuromuscular disorders with high respiratory failure risk 2
• Fasciculations (especially tongue) indicate lower motor neuron disorders like spinal muscular atrophy with risk of rapid deterioration 1, 2
• Loss of previously achieved motor milestones suggests neurodegenerative process requiring urgent neurology referral 2
• Elevated creatine kinase >3× normal indicates muscle destruction requiring immediate referral 1, 2

Diagnostic Algorithm

1. Obtain detailed history of preceding infections (gastrointestinal, respiratory, viral illness), recent vaccinations, tick exposure, travel history, and medication/toxin exposure 1

2. Perform focused neurological examination assessing pattern of weakness (ascending vs. descending), reflexes, cranial nerve function, sensory deficits, and respiratory effort 1

3. Order initial laboratory studies including creatine kinase, complete blood count, electrolytes, and thyroid function tests 1, 2

4. Obtain cerebrospinal fluid analysis with cell count, protein, glucose, and consider repeat sampling if initial results are normal but clinical suspicion remains high 4, 5

5. Neuroimaging (MRI brain and spine with contrast) is indicated if focal neurological signs, altered mental status, or concern for structural lesion exists 1

6. Initiate treatment empirically for GBS with intravenous immunoglobulin if clinical presentation is consistent, without waiting for confirmatory testing 4

Management Priorities

• Early recognition and treatment of GBS with IVIG or plasmapheresis can prevent life-threatening complications including respiratory failure 4
• Respiratory monitoring is essential, with low threshold for intubation in patients with bulbar weakness or declining respiratory parameters 1, 2
• Immediate referral to early intervention services should occur regardless of whether definitive diagnosis is established, as therapy improves outcomes 2
• Avoid misdiagnosis as conversion disorder in patients with psychiatric history, as this can delay critical treatment 4