Examkin

Question

Difficulty: MediumPediatric Neurologic Disorders

A 5-month-old boy is brought to the pediatric emergency department due to a 3-day history of weak crying, poor feeding, and progressively decreased spontaneous movements. His parents report that he has not had a bowel movement for the past 4 days. The infant was previously healthy and exclusively breastfed, but the parents recently began giving him homemade fruit purees sweetened with a small amount of honey. On physical examination, temperature is 37.1°C (98.8°F), heart rate is 130/min, and respiratory rate is 32/min. The infant appears lethargic with profound generalized hypotonia, a weak gag reflex, and poor head control. Pupils are dilated and sluggishly reactive to light. Deep tendon reflexes are diminished bilaterally. Which of the following statements regarding the diagnosis and management of this patient's condition are correct? (Select all that apply)

  1. Immediate administration of human-derived botulism immune globulin is indicated.Answer
  2. The underlying pathophysiology involves the prevention of presynaptic acetylcholine release.Answer
  3. C
    The loss of head control at this age represents a normal, transient developmental regression requiring only observation.
  4. D
    Intravenous broad-spectrum antibiotics should be initiated promptly to eradicate the causative bacteria.
  5. E
    The clinical presentation is highly suggestive of a severe adverse reaction to a recently administered live-attenuated vaccine.

Answer

The correct statements are that immediate administration of human-derived botulism immune globulin is indicated, and the underlying pathophysiology involves the prevention of presynaptic acetylcholine release.
The infant is presenting with classic signs of infant botulism, characterized by initial constipation followed by bulbar palsies (sluggish pupils, weak gag reflex, poor feeding) and descending flaccid paralysis (generalized hypotonia, poor head control, weak crying). This condition is caused by the ingestion of Clostridium botulinum spores, which are classically found in honey and environmental dust. Upon ingestion, these spores colonize the infant's intestinal tract and produce botulinum neurotoxin. The toxin is absorbed into the bloodstream and irreversibly binds to presynaptic nerve terminals at the neuromuscular junction, where it cleaves SNARE proteins and prevents the release of acetylcholine. This direct inhibition of neurotransmission leads to flaccid paralysis. Because the toxin binds irreversibly, the primary treatment is the immediate administration of human-derived botulinum immune globulin (BabyBIG). This neutralizes any freely circulating toxin in the bloodstream and halts the progression of the disease, although recovery relies on the regeneration of new nerve terminals.

Step-by-Step Solution

1
Identify the clinical syndrome based on the infant's presentation of constipation followed by descending flaccid paralysis.
The infant's hypotonia, poor head control, weak gag reflex, and sluggish pupils point to a neuromuscular junction disorder, classic for infant botulism.
Recognizing the pattern of descending paralysis and bulbar palsies is the first step in diagnosing infant botulism.
2
Correlate the clinical findings with the patient's dietary history.
The recent consumption of honey is the primary risk factor for the infant's current condition.
Honey frequently contains Clostridium botulinum spores, which can colonize an infant's immature intestinal tract and produce neurotoxin.
3
Determine the appropriate management and understand the mechanism of disease.
Management requires rapid administration of human-derived botulism immune globulin to counteract the toxin, which causes paralysis by blocking presynaptic acetylcholine release.
Because the toxin binds irreversibly to nerve terminals, prompt neutralization of freely circulating toxin is critical to prevent respiratory failure.

Key Concept

Infant botulism: pathophysiology and management
Rate this question

Topics

Pediatric Neurologic Disorders

More questions from this topic