We present the first case of abnormal neuroimaging in a case of infant botulism. 
The clinical findings of the patient with constipation, bulbar weakness, and 
descending, symmetric motor weakness are consistent with the classic findings of 
infant botulism. Magnetic resonance imaging (MRI), however, revealed restricted 
diffusion in the brain and enhancement of the cervical nerve roots. 
Traditionally, normal neuroimaging was used to help differentiate infant 
botulism from other causes of weakness in infants. Abnormal neuroimaging is seen 
in other causes of weakness in an infant including metabolic disorders and 
hypoxic-ischemic injury, but these diagnoses did not fit the clinical findings 
in this case. The explanation for the MRI abnormalities in the brain and 
cervical nerve roots is unclear as botulinum toxin acts at presynaptic nerve 
terminals and does not cross the blood-brain barrier. Possible explanations for 
the findings include inflammation from the botulinum toxin at the synapse, 
alterations in sensory signaling and retrograde transport of the botulinum 
toxin. The patient was treated with human botulism immune globulin and had rapid 
recovery in weakness. A stool sample from the patient was positive for Type A 
Clostridium botulinum toxin eventually confirming the diagnosis of infant 
botulism. The findings in this case support use of human botulism immune 
globulin when the clinical findings are consistent with infant botulism despite 
the presence of MRI abnormalities in the brain and cervical nerve roots.