Case Presentation: A three-month-old previously-healthy girl presented with one week of progressively poor breastfeeding due to a weak latch along with decreased activity level and urine output. Her last bowel movement was 4 days prior to admission which had been her baseline for 1-2 months. She had no recent fevers, illnesses, or exposures. Her family history was unremarkable. She had decreased suck and gag reflexes with diminished facial expressions and a weak cry. Extra ocular movements and pupillary responses were normal, including after repetitive light stimulation, with no ptosis. She had diffuse hypotonia, more prominent in the upper extremities. Significant head lag was observed. Tendon reflexes were intact throughout in her upper and lower extremities. She had normal work of breathing. Complete blood count with differential, comprehensive metabolic panel, TSH, CK, urinalysis, and a respiratory viral PCR panel were normal. CSF had a normal cell count, protein, glucose and negative CSF PCR panel. MRI Head, without sedation needed, was also normal.With concern for infant botulism, botulism immune globulin (BabyBIG) was administered with rapid improvement in symptoms. Botulism testing from the stool later returned positive. She required 5 days of nasogastric tube feeds on the general wards without support needed for ventilation and was discharged home on day 8 of admission.

Discussion: Hypotonia in an infant is frequently encountered by pediatric hospitalists. The differential includes botulism, Guillain barre syndrome, spinal muscular atrophy, viral encephalitis, acute flaccid myelitis, and inborn errors of metabolism. In this case, many features supported botulism but several features raised a degree of doubt including the possible chronic instead of acute constipation, the absence of ptosis or a decreased pupillary response, and the presence of tendon reflexes. This case emphasized the importance of making an early-suspected diagnosis of infant botulism even when all of the clinical symptoms and signs are not present. Despite the high costs of treatment, early treatment with BabyBIG prior to a definitive diagnosis is imperative. Early treatment may lead to the avoidance of the intensive care unit, ventilator support and prolonged tube feeding, as occurred with this patient. As in this case, many patients with infant botulism do not have an identified exposure. Most cases are thought to be caused by ingestion of botulism spores in dust particles and less commonly from honey ingestion. Breastfeeding may play a protective role, decreasing the severity of symptoms.

Conclusions: It is important to recognize that all of the signs and symptoms of infant botulism may not be present, even in confirmed cases. Treatment with BabyBIG for infant botulism should begin when botulism is one of the top differential diagnoses, but not necessarily number one. Early treatment can lead to rapid improvement and avoidance of the acute complications. Breastfeeding may provide a degree of protection.