CASE REPORT / CAS CLINIQUE
PARTICULAR ELECTROPHYSIOLOGICAL FINDING IN A CASE OF FOODBORNE BOTULISM
FADEL H. 1
CHARA B. 1
One observation offoodborne botulism with particular electrophysiological finding is reported. A 16 year-old man, with no medical past. He presented typical neurological features of botulism, including progressive weakness and cranial nerve paralysis, following gastroinlestinal symptoms. The electrophysiological study supported the diagnosis with the classical triad, decrease of the motor amplitudes, decremental response to low frequency and a very high incremental response (1400%), to high frequency repetitive nerve stimulation. The diagnosis was confirmed by the mouse inoculation test for toxin. The authors underline the diagnosis value of the electrophysiology in botulism especially the incremental response to high frequency repetitive nerve stimulation, which could be very high.
Une observation de botulisine alimentaire avec des donnees electrophysiologiques particulieres est rapporte. Un jeune homme de 16 ans, sans passe medical a presenté un tableau neurologique typique de botulisme, incluant une impotence fonctionnelle progressive avec atteinte des nerfs craniens, suivi de symptomes gastro-intestinaux. L’etude electrophysiologique a clarifie le diagnostic, en montrant la trilogie classique: chute des amplitudes motrices, decrement apres stimulation a base frequence et un increment tres eleve (1400%), apres stimulation repetitive a haute frequence. Le diagnostic fut confirme par le test d ‘inoculation de la toxine a la souris. Les auteurs soulignent la valeur diagnostique de electrophysiologie dans le botulisme, surtout 1’increment apres stimulation repetitive a haute frequence, qui pent etre tres elevee.
Mots clés : Botulism, Diagnosis, Increment
Adult-type botulism is a paralyzing disease. It occurs by ingesting food contaminated with botulinum toxin. The toxin produces skeletal muscle paralysis by producing a presynaptic blockade to the release of acetylcholine. Recent studies have pinpointed the site of action of the several types of botulinum neurotoxin at the nerve terminal (Cherington, 1998). The electrodiagnosis allows quick and reliable confirmation of botulism (Sheth et al, 1999). We present a particular observation of foodborne botulism with very high incremental response to high frequency repetitive nerve stimulation.
A 16 years-old man, with no medical past, presented 24 hours after ingesting a sandwich of mortadella, abdominal cramps and vomiting; than four days later, a blurred vision, fever and spittles, than generalized weakeness and hypotonia. His examination five days after the onset showed ab unsteady gait, peripheral paralysis and hypotonia in the four limbs. The tendon reflexes were diffusely abolished. No amyotrophia was noticed and all the sensibilities were normal. Pupils were asymmetrical and dilated; the accommodation, the photo-pupil and the pharyngeal reflexes were abolished; ptosis; extraocular muscle palsies. In addition, weak respiratory effort and urinary retention were also noticed. Botulism was suspected and the electrophysiological study supported the diagnosis with the classical triad: 1-decrease of the motor amplitudes (Figure 1), 2-significant decremental response to 3Hz repetitive median nerve stimulation (Figure 2).
The diagnosis was confirmed by the mouse inoculation test for toxin that found the toxin type C. The patient had been monitored initially in an intensive care unit, to check the vital capacity and to prevent any worsening of the respiratory function. Two weeks later, the recovery started progressively and the patient became clinically free after one month. The electrophysiological control showed a normalization of the motor amplitude, disappearance of the decrement and persistence of a small increment (about 48%).
This case of foodborne botulism is very typical clinically, the electrophysiological study showed the three specific elements of the diagnosis: decrease of motor amplitude, the decremental response and the incremental response, to respectively 3Hz and 20Hz of repetitive median nerve stimulation.