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Electrodiagnosis of botulism

1992; Elsevier BV; Volume: 121; Issue: 5 Linguagem: Inglês

10.1016/s0022-3476(05)81936-5

1097-6833

Ludwig Gutmann, John B. Bodensteiner, Álvaro Gutiérrez,

Neurological disorders and treatments

Graf and colleagues, in their article entitled "Electrodiagnosis Reliability in the Diagnosis of Infant Botulism (J PEDIATR 1992; 120:747-9), suggest that electrodiagnostic techniques are not reliable in the diagnosis of infant botulism.We question that assertion on the basis of our experience with 10 patients with botulism (6 adults, 4 infants).1, 2 The authors do not clearly define the electrophysiologie measurements used in the evaluation of their patients.They state that 30 Hz nerve stimulation failed to show an incremental response of the compound muscle action potential (CMAP).Whether other criteria were used is uncertain.We concur with the authors that an incremental response of the CMAP to rapid nerve stimulation is not a reliable indicator of botulism.This incremental response was also not present in some of the patients we studied. 1 However, posttetanie facilitation of the CMAP has been present in all our patients.With the patient at rest, one expects to have a small or borderline-small CMAP in response to a single supramaximal nerve stimulus.After a 10-second period of rapid, repetitive nerve stimulation, there is enlargement of this initially small CMAP of at least 40%; it may be several times larger than the initial potential.This enlargement of the CMAP after a brief period of tetanus (posttetanic facilitation) persists for many minutes; this does not occur with other disorders of neuromuscular transmission and is a unique feature of botulism, l, 2 At the same time, the posttetanic facilitation alone is a strong indication that botulism is the diagnosis.This posttetanic facilitation occurs early in the course of the illness and gradually disappears with recovery.We have found this diagnostic procedure to be quick, reliable, and easy, even in the intensive care unit environment, and we believe that posttetanic facilitation of the CMAP is a reliable indicator of botulism.