Infantile botulism is caused by Clostridium botulinum, which is an anaerobic spore-forming, gram-positive bacillus. It can be found in the soil, water, and air with a lethal toxin dosage as low as 1mcg/kg. Botulism infection can occur in five different ways:
Even though there are multiple ways to contact botulism, only three main serotypes are responsible for all of these infections:
Infantile botulism, ithe most common form of botulism infection, predominates 70% of all new cases of botulism annually. Infants will ingest contaminated milk or food, and the neurotoxin will colonize and replicate in the large intestine. Infantile botulism is caused equally by Type A and Type B serotypes. Foodborne botulism is rarely a childhood illness and is often seen in clusters.
Infantile botulism infection is responsible for approximately 70% of all new botulism cases a year. In the United States (US) alone, 1.9/100,000 live births yield approximately 77 new cases annually. There is an equal distribution of males and females. Risk factors for infantile botulism include higher birth weights, infants of mothers of advanced maternal age, and breastfed infants. Over 50% of the new cases of infantile botulism in the past 30 years have occurred in California.
The C. botulism toxin is the been most implicated in infected food and dust particles. There is a strong association with foods that have been canned and preserved at home or with incorrect sterilization technique or poor refrigeration. Approximately 20% of cases involve honey or corn syrup. How the spores are transported in these foods is still unclear. Also, living near construction sites with excessive dust particles and vacuum cleaner debris has also been implicated in infections.
The active form of the C. botulinum spore produces a neurotoxin that causes descending paralysis. This active form is made of polypeptide chains connected with disulfide bonds. The toxin will enter the presynaptic nerve terminals where it prevents the release of acetylcholine by blocking calcium channels. The resulting action causes an overall decrease of acetylcholine at the neuromuscular junction and leads to flaccid paralysis. Traditionally, the toxin will first affect bulbar musculature than somatic musculature.
Clostridium botulinum is a gram-positive anaerobic bacillus that is spore forming. The inactive state is also heat-resistant.
Parents often describe their infant as having poor feeding, lethargy, a weak cry, and constipation. Babies can present with ptosis in the face and eyes, excessive drooling due to weak suck reflex, and shallow breathing due to respiratory suppression. The classic presentation is characterized by a “floppy baby.”
Progression of the infection shows advanced symptoms of toxin infestation including descending bilateral, symmetric paralysis and bulbar palsies (diplopia, dysarthria, dysphonia, and dysphagia). Many breastfed mothers notice breast engorgement due to their infant’s poor feeding and poor suck. These symptoms can be subtle, especially since constipation, poor feeding, and drooling are all symptoms commonly brought up. Anal sphincter tone will be relaxed and decreased. Deep tenor reflexes can be either diminished or normal. Sensation will be intact but can be hard to distinguish due to weakened muscular tone. Usually, the mental status will be preserved.
Some symptoms may not be obvious until neuromuscular fatigue sets in. Muscular fatigue tests include the following:
The diagnosis should always be suspected with a clinically floppy infant or a history and physical with consistent findings. The reasoning is that routine lab tests are often normal. There may be secondary lab findings due to associated sequela from the botulism infection.
To confirm the diagnosis, both a stool culture and direct toxin assay are required. Toxin assay can be obtained from the stool, serum, or gastric contents. A stool culture can be obtained with an enema but not glycerin suppositories. Stool samples can be put into a sterile urine container. Do not put stool samples in containers with preservatives. They can be stored in a refrigerator prior to being sent but should not be frozen. Results for the direct toxin specimen are often available the morning after the specimen has been received. Stool culture results can vary from one week to one month.
No imaging is required to make the diagnosis. Testing of the infected food can be done, however, results are often inconclusive and or delayed.
Until the diagnosis is confirmed, continue supportive care for the patient. With any patient, first assess and stabilize airway, breathing, and circulation. Approximately 50% of infantile botulism cases will require intubation and an advanced airway regardless of whether they are treated with Botulism Immune Globulin Intravenous (Human); however, those who are not treated may require mechanical ventilation longer. As a result, a clinician should have a very low threshold to intubate a patient. This will require careful monitoring and admission to the intensive care unit.
If trying to decide if the patient requires an advanced airway, the best way to measure respiratory depression at the bedside is with the use of a continuous end-tidal carbon dioxide monitor. To help combat the respiratory distress, patients should be placed in Trendelenburg position at a 20-degree angle with a neck roll to stabilize the neck, cervical spine, and prevent sliding. If the patient has a decreased gag reflex, he or she is at increased risk for aspiration.
Human botulinum neurotoxin a/b immune globulin has shown to decrease the length of hospital stay and length of mechanical ventilation. It is a single dose treatment that is infused intravenously over 30 minutes.
There is no indication for the use of antibiotics in infantile botulism. Further supportive care involving ventilation, nutrition, and position are also essential in the patient’s care.
Prognosis is good with recognition and administration of Human Botulism Immune Globulin Intravenous. After hospitalization, patients need to follow up with neurology and physical therapy. Most cases of infantile botulism result in complete recovery within several months to a year.