Infant Botulism.

AUDIENCE: This oral board case is appropriate for emergency medicine residents and medical students (with senior resident assistance) on emergency medicine rotation.

INTRODUCTION: Although a somewhat rare disease, infant botulism is a true pediatric emergency that carried a 90% rate of mortality prior to the development of an antitoxin.1 While botulism infections can be iatrogenic, foodborne, or involve infected wounds, infant botulism remains the most common presentation of this disease and accounts for approximately 70% of new cases annually.2 Caused by Clostridium botulinum , the inactive spores are ingested by the infant and germinate in the large intestine.3,4 The resulting neurotoxin prevents the release of acetylcholine at the presynaptic membrane which results in flaccid paralysis. Classically, the bulbar musculature is affected before somatic muscular, which results in the typical presentation of "descending paralysis."2,5 While confirmatory testing is important, it is often delayed by more than 24 hours, making both clinical recognition and implementation of treatment before confirmatory testing of vital importance.6,7 Treatment consists of providing airway, nutritional, and hydration support in addition to administering botulinum-specific antitoxin.8,9 While patients over the age of 12 months are treated with equine botulinum antitoxin, the Food and Drug Administration (FDA) has approved a human-derived immunoglobulin treatment, Botulism Immune Globulin Intravenous (BIG-IV, ie, "Baby BIG") for pediatric patients less than 12 months of age.1,2,6 Ordering BIG-IV is a complex and multidisciplinary process, requiring the treating physician to discuss any suspicious case with the Infant Botulism Treatment and Prevention Program (IBTPP) which is a branch of the California Department of Public Health.6 With early recognition and implementation of treatment, most infants will make a full recovery.

EDUCATIONAL OBJECTIVES: At the end of this oral board session, examinees will: 1) demonstrate an ability to obtain a complete pediatric medical history, 2) perform an appropriate physical exam on a pediatric patient, 3) investigate a broad differential diagnosis for neuromuscular weakness in a pediatric patient, 4) recognize the classic presentation of infant botulism and implement treatment with botulinum specific antitoxin before confirmatory testing, 5) recognize impending airway failure and intubate the pediatric patient with appropriately dosed medications and ET tube size, and 6) demonstrate effective communication with healthcare team members and parents.

EDUCATIONAL METHODS: This oral board case followed the standard American Board of Emergency Medicine-style case in a tertiary care hospital with access to all specialists and resources needed. This case was tested using 12 resident volunteers ranging from PGY 1-2 in an ACGME (Accreditation Council for Graduate Medical Education) accredited emergency medicine residency program. Learners were debriefed immediately after the case and were given the opportunity to provide feedback.

RESEARCH METHODS: The learners participating in the oral board case provided immediate feedback both by verbal discussion and via a written survey requiring them to rate the efficacy of the exercise. The efficacy of the educational content was assessed by comparing scoring measures of the ACGME core competencies across all learners based on post graduate year (PGY). Scoring measures were determined using a scale from 1-8, with 1-4 being unacceptable performance and 5-8 being acceptable. Efficacy required full completion of the oral board case by the residents as well as a debriefing session during which key educational concepts were discussed.

RESULTS: The practice oral board candidates consisted of 7 PGY1 and 5 PGY2 level residents. The average score of participating residents for each training level was PGY1: 4.5 and PGY2: 5.7. All except for 2 PGY2 residents missed at least one critical action with the majority of PGY1 residents missing more than one critical action for the case. All participating residents rated the educational value of the case as 4.75 (1-5 Likert scale, with 5 being excellent).

DISCUSSION: The educational content of this oral board case and debriefing session were effective for teaching the presentation, evaluation, and appropriate management of infant botulism. Infant botulism is a true pediatric emergency and prompt recognition and treatment is imperative in order to decrease mortality. While mortality was approximately 90% one hundred years ago, today infant botulism carries a much better prognosis due to the advent of antitoxin treatment with a mortality closer to 15%.1 This case highlights several classic physical exam findings including bulbar findings in addition to somatic weakness. Additionally, this case requires definitive airway management with endotracheal intubation, which is true for approximately 50% of infants with botulism.1 While a stool culture or direct toxin assay of the gastric contents, serum, or stool should be performed to confirm the diagnosis, these tests are often performed by the state health department or the Centers for Disease Control (CDC) and often take up to five days to result, during which time the patient will continue to deteriorate. Therefore, the treating physician should seek emergent consultation with the IBTPP to help facilitate the multidisciplinary decision to initiate treatment with human-derived anti-botulinum toxin antibodies.6 If the IBTPP deems that infant botulism is highly suspected based on the history and physical exam, then appropriate treatment should not be delayed and BIG-IV should be administered.6, 7 With early recognition and implementation of treatment, most infants will make a full recovery within several months to a year. Upon discharge, patients will likely require outpatient neurology follow-up in addition to physical therapy to aid in recovery. Because infant botulism is a true pediatric emergency with potentially high mortality, reaching the appropriate diagnosis expeditiously will allow the emergency physician to communicate effectively with worried parents regarding the disease progression and facilitate correct treatment early in order to prevent significant sequela.

TOPICS: Pediatric weakness, pediatric neurotoxin, infant botulism, neuromuscular weakness.