Milla is a 4 month old girl, brought into ED by her parents. She’s been quieter than normal for the last couple of days and today seems really weak and not sucking on the breast any more. On examination she has poor head control and marked hypotonia. They also mention a history of constipation for the last few days. Has she been eating honey?
- Infants (under 1 year old) can get botulism from ingesting spores in honey or dust. Older children would have to actually ingest the toxin
- Symptoms are constipation and weakness
- Prognosis is excellent
- BabyBIG can shorten the length of hospital stay
- Recommend against giving honey to under 1 year olds (breastfeeding mothers eating honey is fine)
What is it?
Botulism is caused by C botulinum – it is a gram positive, spore-forming anaerobe. It produces botulinum toxin which is extremely potent and harmful. There are 4 types which cause the disease in humans: A, B, E and F.
It can come from foods e.g. honey or poorly prepared meat (50% are type A); or from wounds (80% are type A). Often babies with infantile botulism have had honey ingestion. Many cases have no known cause, though, and are thought to be due to inhalation of spores from dust.
Exclusive breastfeeding is in fact a risk factor (possibly due to the nature of the flora which allows more spore germination).
Why is it ‘infantile’?
In people over 1 year old, ingestion of C botulinum spores doesn’t cause problems, because the spores cannot germinate in the gut (i.e. you would actually have to ingest the toxin).
In those under 1 year old, however, the spores can germinate in the gut and consequently produce the actual toxin. This is because of infants’ relative lack of gastric acid, immature immunity and reduction in normal flora.
It usually occurs in 2-4 months of age but some patients are older.
How does it present?
Constipation is often the first sign, along with a dry mouth. Then facial palsy can occur.
Following this there is a worsening weakness with a poor suck, poor head control, hypotonia, hyporeflexia and a weak cry.
How is it diagnosed?
Stool culture needs to be obtained and cultured for the toxin. In view of constipation, patients may need a saline washout to get a stool sample.
Specific assays can be used to test for the toxin. This is done in California – they inject the toxin into mice and if the mice die of respiratory arrest within 24 hours then the patient is toxin positive. This has also been used to specify the type of C botulinum.
Patients usually do also undergo nerve conduction studies, EMG and brain MRI to exclude other causes.
What’s the management?
Ventilatory support is needed due to respiratory weakness and loss of gag reflex.
Antitoxin (botulism immunoglobulin – BabyBIG) can shorten the course of the disease, if given in the early stages.
N.B. Avoid giving aminoglycosides as this can worsen neuromuscular function. Antibiotics are also thought to worsen the disease by increasing the release of toxin.
Is the toxin effective?
Well, the toxin is certainly not cheap at around $50,000 for treatment of a 5kg baby.
The largest infantile botulism study was by Los Angeles Children’s Hospital ICU (2012) looked at all their infantile botulism patients over a 30 year period
- 52 patients with botulism who received no toxin; and 15 who received BIG-IV
- Outcomes were length of stay, length of ICU stay and length of mechanical ventilation
The use of BIG-IV significantly reduces the length of ICU stay, length of mechanical ventilation and length of hospital stay. It should be given within 10 days of onset of symptoms.
What’s the prognosis?
The prognosis is excellent. In the study mentioned above, all patients (both groups) survived to discharge and none had any serious sequelae.
Complications are essentially secondary to being in hospital.