Infant Botulism in the Outpatient Setting

Source: Khouri JM, Habritz HA, Payne JR, et al. Outpatient infant botulism in the United States, 1976–2021. J Pediatr. 2025:276:114365; doi: 10.1016/j.jpeds.2024.114365.Investigators from the California Department of Public Health (CDPH), Richmond, CA, conducted a study to characterize cases of outpatient infant botulism (IB). Study participants were children whose health care providers contacted CHPD for possible use of human botulism immune globulin intravenous (BIG-IV) between 1976 and 2021, as this agency is the sole distributor of BIG-IV in the United States. A confirmed diagnosis of IB was based on a typical clinical presentation with detection of botulism neurotoxin in the serum or stool or isolation of C. botulinum from the stool. Data on study children were collected by review of medical records and reports from healthcare providers or family members and included demographics, onset of symptoms, type of feedings, date of diagnosis, and clinical findings. Although cases of IB from throughout the US were included, the majority of patients were from California, and more information was available on these children. The characteristics of infants with IB who were treated as outpatients were compared to those requiring hospitalization.A total of 4,372 cases of IB were reported to CDPH during the period 1976–2021, including 17 (0.4%) infants who were treated as outpatients. Among those with outpatient IB, 11 (65%) were in California, with 1 case each in 6 other states. During the last decade, only 4 outpatient cases of IB were reported to CDPH. The median age of children with outpatient IB was 20 weeks, with a range of 6 to 55 weeks. At the time of disease onset, 15 (88%) patients with outpatient IB were primarily breastfed, and 11 were exclusively receiving breast milk. There were 8 (47%) children who had received some solid food. One child had ingested a small amount of honey, but this was not thought to be the source of exposure. The most common symptom in patients with outpatient IB was constipation, occurring in 16 (94%); decreased head control was reported in 13 (81%), weakness in 12 (75%), and ptosis in 11 (69%). Patients with outpatient IB were significantly older than those who required hospitalization (median, 20 weeks vs 14.6 weeks; P = 0.01). Among those in California, the median time from symptom onset to diagnostic stool collection for the 11 children with outpatient IB was 9.5 days, compared to 3.0 days for the 1,294 patients hospitalized for IB (P <0.001).The authors conclude that the diagnosis of outpatient IB should be considered in a previously healthy infant presenting with constipation, mild hypotonia, and/or ptosis.Dr Bechtel has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.IB is a rare condition with considerable morbidity. Severely ill infants requiring hospitalization present with descending paralysis, ptosis, and respiratory failure, in addition to constipation.1 Making a timely diagnosis is crucial, as BIG-IV can significantly reduce costs and improve outcomes. (See AAP Grand Rounds. 2008;19[3]:30-31.)2 However, infants with less severe symptoms can be missed, as the authors of the current study show. These infants in the outpatient setting most often presented with constipation; decreased head control and ptosis were less frequently seen and likely not recognized by practitioners. Additionally, the source for ingesting botulism spores in these cases rarely was identified.The current study has several limitations that should be considered. First, the study identified only 17 outpatient cases of IB over a 45-year period, which limits the generalizability of the findings. Second, there is likely underreporting, as outpatient IB cases likely are underrecognized and underreported due to the mildness of symptoms and the lack of necessity for hospitalization. Third, there was geographical bias, as most cases were from California, which may not represent the entire US population. Fourth, there are diagnostic challenges, as the reliance on astute clinicians and capable diagnostic laboratories means that some cases may go undiagnosed, especially in areas with limited resources. Finally, the study’s retrospective nature relies on historical data and medical records, which may be incomplete or subject to recall bias.Practitioners ought to consider the diagnosis of IB in the outpatient setting when young, breastfed infants present with constipation, especially if there is hypotonia or ptosis.Inpatient care of infants with IB includes prompt administration of BIG-IV as well as meticulous respiratory and nutritional support. As the focus of the current study was diagnosis of outpatient IB, therapeutic recommendations, unfortunately, were either not recorded or reported by the authors.