Rapid clinical diagnosis is crucial for early initiation of antitoxin therapy. Treatment should not be delayed if there is a suspicion of infant botulism (IB), as it can be fatal.
Human-derived botulinum antitoxin (botulism intravenous immune globulin) is the FDA-approved therapy of choice, and it is the only specific treatment. Antitoxin treatment should be initiated as early as possible while awaiting the confirmatory test results.
Careful cardiorespiratory monitoring is crucial, especially in the early phase. Serious cases may require intubation.
Breast milk is the food of choice. Parenteral feeding should be avoided to prevent secondary bacterial infections.
Antibacterial therapy should not be used for IB, as C botulinum in the infant's gut could cause a surge of neurotoxin release with antibiotics.
It is recommended to consult with the Infant Botulism Treatment and Prevention Program of the California Department of Public Health for suspected cases of IB from any state in the United States (contact 510-231-7600). The service provides 24-hour consultation and is the only US center that helps distribute antitoxin for the treatment of IB cases. The CDC is also available for 24/7 consultancy service for IB (contact 770-488-7100). However, the CDC only provides antitoxin for cases of adult botulism.
A pediatric infectious disease physician and pediatric neurologist should be consulted.
Diagnosis Overview:
This summary discusses botulism in infants. Botulism in adults and children is addressed separately.
Infant botulism (IB), also called floppy baby syndrome, is a neuroparalytic illness caused by a toxin of Clostridium botulinum. Clostridium botulinum is a gram-positive rod-shaped anaerobic bacterium that produces flaccid muscular paralysis by means of several toxins. It produces 7 known neurotoxins; types A and B are most commonly related to IB. Illness can be gradual or abrupt in onset, with constipation usually being the first symptom. It can then progress to descending symmetrical paralysis. It is the most common form of infectious botulism in the United States; the US Centers for Disease Control and Prevention (CDC) reports an average annual incidence of 110 cases, with a mean age of onset of 13 weeks (range 1-63 weeks).
Infection occurs from ingestion of C botulinum spores through contaminated milk or food or ingestion of contaminated dust particles. The minimal infective dose may be as low as 10-100 spores, which colonize in the gastrointestinal tract and produce a toxin that is then absorbed in the intestines. The botulinum toxin is the most potent bacterial toxin; its required minimal dose is a million times less than that of sodium cyanide. The toxin is transported by the bloodstream to the nervous tissue, where it irreversibly binds to the presynaptic cholinergic receptors. Once the toxin is internalized, it acts as a protease in the cytoplasm and blocks the release of acetylcholine. The lack of available acetylcholine at the neuromuscular junction for muscle excitation causes the vast array of symptoms of IB. Respiratory failure is the most severe complication, with about 50% of infants requiring mechanical ventilation.
Raw honey consumption is the classic associating factor in the literature (up to 25% of honey products have been found to contain spores of C botulinum); however, most cases have no known honey exposure. Other risk factors are home-canned foods, ingestion of environmental dust, and living close to sites of construction or cultivation. Infants seem more prone to develop IB at weaning. Formula-fed infants are typically younger at the onset of IB, with a more severe and rapidly progressive course. Meckel diverticulum is a known risk factor as well.
Classic signs and symptoms include:
- Cranial nerve palsies (ptosis, sluggish pupillary reflexes, difficulty in suckling and swallowing, and diminished gag reflex).
- Poor feeding and constipation.
- Weakness, lethargy, and hypotonia.
- Flattened facial expression.
- Weak cry, often hoarse.
- Pooled oral secretions, drooling, poor suck.
- Signs of autonomic dysfunction (no tearing or salivation, blood pressure instability, and hot skin).
- Descending weakness progressing to flaccid paralysis.
- Respiratory distress (later symptom).
Symptoms are typically most severe 1-2 weeks after they initially begin. Recovery is slow but usually complete. Case fatality rate is less than 2%. Diaphragmatic function recovers before peripheral muscles, allowing the patient to come off mechanical ventilation early in the recovery period.
IB may be underestimated due to:
- Insufficient physician awareness.
- Inaccessibility to appropriate laboratory tests.
- Mild infections that do not require medical attention.
- An association between the fulminant type of IB and sudden infant death syndrome (SIDS) has been noted; one study found C botulinum toxin in 10 of 211 (4.9%) SIDS cases.
- Honey has been associated with IB in a number of case reports.
