Diagnosis of Botulism in Infants
Infant botulism is diagnosed clinically based on characteristic neurologic findings and should be distinguished from foodborne botulism in infants, as they require different antitoxin treatments. 1
Distinguishing Infant Botulism Syndrome from Foodborne Botulism in Infants
Critical distinction: A single sporadic case of suspected botulism in an infant is usually presumed to be infant botulism syndrome (intestinal colonization with in situ toxin production). However, if an infant is affected as part of a group of botulism cases, the infant has likely been exposed to preformed toxin from food or the environment, representing foodborne botulism in an infant rather than infant botulism syndrome. 1
Clinical Diagnostic Criteria
The CDC's evidence-based clinical criteria tool can be applied to infants and requires all three of the following categories to be met: 1
1. Temperature Status
- Afebrile (<100.4°F [<38°C]) 1
- Note: Fever is rare in infants and young children with botulism but may be slightly more common than in adults 1
2. Acute Onset of at Least One Symptom
- Blurred vision or double vision 1
- Difficulty speaking, including slurred speech 1
- Any change in sound of voice, including hoarseness 1
- Dysphagia, pooling of secretions, or drooling 1
- Thick tongue 1
3. At Least One Objective Sign
- Ptosis 1
- Extraocular palsy or fatigability (manifested by inability to avert eyes from light shone repeatedly into eye—typically used in infants) 1
- Facial paresis (manifested by loss of facial expression, pooling of secretions, poor feeding, poor suck on breast or pacifier, or fatigue while eating) 1
- Fixed pupils 1
- Descending paralysis, beginning with cranial nerves 1
Additional Key Features
- Intact mental status is expected; altered mental status suggests other causes (respiratory failure, concurrent infection, or preexisting condition) 1
- Descending paralysis pattern with prominent bulbar palsies 1
Common Presenting Symptoms in Infants
Infant botulism frequently presents with vague, nonspecific symptoms that can delay diagnosis: 2, 3
- Poor feeding and lethargy are the most common chief complaints 2
- Constipation (often preceding other symptoms) 4
- Weak cry 4, 2
- Hypotonia ("floppy baby") 4, 2
- Loss of head control 4
Common pitfall: Infants may initially be misdiagnosed with sepsis, intussusception, or other conditions due to the nonspecific presentation. 2 The diagnosis is frequently omitted from the differential in very young neonates (<30 days) exclusively due to age, leading to costly and prolonged workups. 3
Treatment Based on Diagnosis Type
For Infant Botulism Syndrome (Sporadic Single Case)
The indicated treatment is human-origin anti-A, anti-B botulinum antitoxin (BabyBIG), available after consultation from the California Department of Public Health Infant Botulism Treatment and Prevention Program. 1
- BabyBIG was developed in 2003 and has substantially decreased both morbidity and hospital costs 4
- Infant botulism syndrome caused by other toxin types (not A or B) may be treated with BAT 1
For Foodborne Botulism in an Infant (Part of Outbreak)
The infant should receive heptavalent botulinum antitoxin (BAT) at 10% of the adult dose, regardless of weight. 1
- This represents a public health emergency requiring immediate investigation 5
- The FDA-approved BAT dose for infants (<1 year) is 10% of the adult dose, regardless of weight 1
Supportive Care
All infants with suspected botulism require:
- Admission to a unit with close neurologic and respiratory monitoring 6
- Serial complete neurologic examinations including cranial nerves, extremity strength, and respiratory status 6
- Respiratory support as needed, as prognosis is excellent with appropriate airway control and ventilation 6
- Three of four reported cases required endotracheal intubation 2
Laboratory Confirmation
- Diagnosis is primarily clinical; laboratory confirmation is usually delayed and treatment should begin before confirmation 7
- Testing includes detection of C. botulinum organisms or toxin in stool specimens 4
- Ancillary testing (electrodiagnostic studies, neuroimaging, lumbar puncture) helps rule out mimics like Guillain-Barré syndrome or myasthenia gravis 6, 7
Key Clinical Pearls
Do not exclude infant botulism from the differential based solely on young age—cases have been documented in neonates younger than 30 days. 3 The youngest reported case of foodborne botulism in the United States occurred in a 6-month-old infant, with rapidly progressive rather than insidious weakness. 5