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Difficulty: HardPediatric Neurologic Disorders

An infant, aged 4 months, is brought to the emergency department by her parents due to a three-day history of a progressively weakened cry and diminished spontaneous movements. The parents note she has been feeding poorly and has not passed a bowel movement for the last five days. The infant was born at term without complications and had been meeting early developmental milestones appropriately. The family recently relocated to a rural agricultural community and is renovating an old farmhouse, exposing the home to significant environmental dust. Vital signs are within normal limits. Physical examination reveals a lethargic infant with profound generalized hypotonia and severe head lag. Bilateral ptosis, sluggishly reactive pupils, and a markedly weak gag reflex are present. Deep tendon reflexes are diffusely diminished. Which of the following is the most appropriate next step in management?

  1. Administration of human-derived botulism immune globulinAnswer
  2. B
    Administration of equine-derived heptavalent botulinum antitoxin
  3. C
    Lumbar puncture and administration of intravenous ceftriaxone and vancomycin
  4. D
    Electromyography and genetic testing for the SMN1 gene
  5. E
    Intravenous administration of pyridostigmine

Answer

Administration of human-derived botulism immune globulin
The infant's presentation of constipation followed by acute-onset descending flaccid paralysis, bulbar weakness (ptosis, weak gag, sluggish pupils), and severe hypotonia is classic for infant botulism. The most common source of Clostridium botulinum spores in the United States is environmental dust or soil, often associated with rural areas or construction. Ingestion of spores leads to colonization of the infant's gastrointestinal tract and subsequent in vivo toxin production. The toxin irreversibly inhibits presynaptic acetylcholine release at the neuromuscular junction. The most appropriate initial step in management is the prompt administration of human-derived botulism immune globulin. Treatment should be initiated immediately based on clinical suspicion to neutralize unbound toxin and halt the progression of paralysis; clinicians should not wait for confirmatory stool studies.

Step-by-Step Solution

1
Identify the clinical syndrome
The combination of acute severe constipation followed by descending flaccid paralysis, bulbar palsies (ptosis, poor gag), and autonomic dysfunction (sluggish pupils) in an infant indicates infant botulism.
Recognizing this specific triad of symptoms separates botulism from other causes of infant hypotonia like spinal muscular atrophy or sepsis.
2
Identify the epidemiological risk factor
The exposure to significant environmental dust in a rural agricultural area suggests inhalation or ingestion of Clostridium botulinum spores.
While honey is the classically taught risk factor, environmental soil/dust is actually the most common source of infant botulism in the United States.
3
Determine the definitive, age-appropriate treatment
Select human-derived botulism immune globulin (BabyBIG) as the immediate next step.
Treatment must be initiated based on clinical suspicion to halt paralysis progression. Infants must receive the human-derived formulation to avoid the severe hypersensitivity reactions associated with the equine-derived formulation used in adults.

Key Concept

Diagnosis and specific pharmacotherapy of infant botulism
Estimated Time:1m 30s
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Topics

Pediatric Neurologic Disorders

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