Botulism: Electrophysiological Studies Shin Joong O h , M D
In a patient with botulisni type B, electrophysiological studies showed: (1) a pattern in the repetitive nerve stimulation test resembling that found in the Eaton-Lambert syndrome but without any significant increment at high rates of stimulation orposttetanic exhaustion phenomenon; (2) a prominent response to guanidine hydrochloride; (3) a short mean duration of motor unit potentials that reversed with recovery; ( 4 ) a mild, prolonged latency and low amplitude of the H-reflex; (5) mild peripheral nerve dysfunction; and (6) a long-lasting persistence of abnormalities beyond the time of clinical recovery. The literature reports two types of responses in the repetitive nerve stimulation test in botulism: in the severe form one obtains a low-amplitude muscle potential, a decremental response at low rates of stimulation, and an insignificant incremental response at high rates of stimulation; in the mild form a normal amplitude of muscle potential occurs together with a normal response to low rates of stimulation and a significant incremental response at high rates of stimulation. O h SJ: Botulism: electrophysiological studies. Ann Neurol 1:481-485, 1777
W e report here the results of comprehensive elecrrophysiological studies in a 54-year-old man with botulism type B. Material a n d Method T h e patient developed bulbar symptoms, ophthalmoplegia, respiratory distress, and proximal muscle weakness one day after eating home-preserved tomatoes. T h e diagnosis of botulism type B was established in pretreatment serums and stools using the mouse-toxin neutralizing test. The patient was treated with trivalent botulism antitoxin and paniciine and recovered in a month [ l ] . To study neuromuscular transmission, we used the Harvey-Masland method with surface recording electrodes placed o n the abductor muscle of the fifth finger and stimulating elecrrodes on the transsulcal segment of rhe d n a r nerve [21. The change of response at low rates of stimulation was expressed as the percent difference i n the peak-to-peak amplitude between the first muscle potential (MP)and the smallest or greatest among the ensuing five. At high rates of stirnulation the change of response was expressed as the percent difference in the amplitude between the first MP and the smallest or greatest subsequent potential within the first second. Postcetanic facilicacion and exhaustion phenomena were tested by observing the response to stimulation at 5 per second immediately and 4 minutes after tetanic stimulation, respectively. Results that differed from normal means by more than 2 standard deviations were considered abnormal. T o measure the duration and amplitude o f motor unit potentials (MUP) we used Buchthal's method employing a coaxial needle and compared rhe results with his normal values [31. The H-reflex was studied according to Braddom and Johnson's method, using their normal values 14 1. To study the nerve conduction velocity (NCV), we used
From the Lkpartment of Neurology, University of Alabama School of Medicine, and t h e Veterans Administration Hospital, Birming-
ham, AL.
Mayer's method [ 5 ] , taking 2 standard deviations from normal as abnormal. The skin temperature of the patient's extremities ranged from 32" to 32.5%.
Results REPETITIVE NERVE STIMULATION. The first test was done on the second hospital day (Figure). The peakto-peak amplitude of M P o n the abductor muscle of the fifth finger with supramaximal stimulation of the ulnar nerve was 1,950pv(normal, above 3,784). Decremental responses at 2 and 5 per second stimulation were 227( (normal, 7.2) and 2156 (normal, 10.0), respectively. At 50 cps stimulation the amplitude of M P was increased to 2,450 p v , only a 2596 increment (normal, 50.3 1. Immediately after retanic stimulation the amplitude of M P was 3,040 pv, and the decrement at 5 cps was only 9% (normal, 8.8).Four minutes after tetanic stimulation the amplitude of M P was 2,24Opv, and the decrement at 5 cps was 11%' (normal, 9.4). Edrophonium chloride, 10 mg intravenously, and neostigmine bromide, 1.5 gm intramuscularly, produced no change. Intravenous administration of 15 mI of 10% calcium gluconate over a 5-minute period produced a 205+ increase in the amplitude of MP. Guanidine hydrochloride, u p to 30 mg per kilogram of body weight per day, was tried on two occasions, with an electrophysiological improvement [ 13. During the first trial, from the fifth to the seventh hospital day, the amplitude of MP was increased from 2,350 to 5,500 p v . During the second trial, from the thirteenth t o the nineteenth hospital day, rhe amplitude of MP was increased again from 4,570 to 7,500 pv. By the thirty-seventh hospital day, when the patient
Address reprint requests to Dr Oh, Department of Neurology, University of Alabama School of Medicine, University Station, Birmingham, AL 35294.
Accepted for publication Nov 22, 1976.
48 1
MUPs. T h e r e was a significant ( p < 0.001) increase in the mean duration of MUPs in the deltoid.
I A
10 msec
In a patient with botulisni type B, electrophysiological studies showed: (1) a pattern in the repetitive nerve stimulation test resembling that found in the Eaton-Lambert syndrome but without any significant increment at high rates of stimulation orposttetanic exhaustion phenomenon; (2) a prominent response to guanidine hydrochloride; (3) a short mean duration of motor unit potentials that reversed with recovery; ( 4 ) a mild, prolonged latency and low amplitude of the H-reflex; (5) mild peripheral nerve dysfunction; and (6) a long-lasting persistence of abnormalities beyond the time of clinical recovery. The literature reports two types of responses in the repetitive nerve stimulation test in botulism: in the severe form one obtains a low-amplitude muscle potential, a decremental response at low rates of stimulation, and an insignificant incremental response at high rates of stimulation; in the mild form a normal amplitude of muscle potential occurs together with a normal response to low rates of stimulation and a significant incremental response at high rates of stimulation. O h SJ: Botulism: electrophysiological studies. Ann Neurol 1:481-485, 1777
W e report here the results of comprehensive elecrrophysiological studies in a 54-year-old man with botulism type B. Material a n d Method T h e patient developed bulbar symptoms, ophthalmoplegia, respiratory distress, and proximal muscle weakness one day after eating home-preserved tomatoes. T h e diagnosis of botulism type B was established in pretreatment serums and stools using the mouse-toxin neutralizing test. The patient was treated with trivalent botulism antitoxin and paniciine and recovered in a month [ l ] . To study neuromuscular transmission, we used the Harvey-Masland method with surface recording electrodes placed o n the abductor muscle of the fifth finger and stimulating elecrrodes on the transsulcal segment of rhe d n a r nerve [21. The change of response at low rates of stimulation was expressed as the percent difference i n the peak-to-peak amplitude between the first muscle potential (MP)and the smallest or greatest among the ensuing five. At high rates of stirnulation the change of response was expressed as the percent difference in the amplitude between the first MP and the smallest or greatest subsequent potential within the first second. Postcetanic facilicacion and exhaustion phenomena were tested by observing the response to stimulation at 5 per second immediately and 4 minutes after tetanic stimulation, respectively. Results that differed from normal means by more than 2 standard deviations were considered abnormal. T o measure the duration and amplitude o f motor unit potentials (MUP) we used Buchthal's method employing a coaxial needle and compared rhe results with his normal values [31. The H-reflex was studied according to Braddom and Johnson's method, using their normal values 14 1. To study the nerve conduction velocity (NCV), we used
From the Lkpartment of Neurology, University of Alabama School of Medicine, and t h e Veterans Administration Hospital, Birming-
ham, AL.
Mayer's method [ 5 ] , taking 2 standard deviations from normal as abnormal. The skin temperature of the patient's extremities ranged from 32" to 32.5%.
Results REPETITIVE NERVE STIMULATION. The first test was done on the second hospital day (Figure). The peakto-peak amplitude of M P o n the abductor muscle of the fifth finger with supramaximal stimulation of the ulnar nerve was 1,950pv(normal, above 3,784). Decremental responses at 2 and 5 per second stimulation were 227( (normal, 7.2) and 2156 (normal, 10.0), respectively. At 50 cps stimulation the amplitude of M P was increased to 2,450 p v , only a 2596 increment (normal, 50.3 1. Immediately after retanic stimulation the amplitude of M P was 3,040 pv, and the decrement at 5 cps was only 9% (normal, 8.8).Four minutes after tetanic stimulation the amplitude of M P was 2,24Opv, and the decrement at 5 cps was 11%' (normal, 9.4). Edrophonium chloride, 10 mg intravenously, and neostigmine bromide, 1.5 gm intramuscularly, produced no change. Intravenous administration of 15 mI of 10% calcium gluconate over a 5-minute period produced a 205+ increase in the amplitude of MP. Guanidine hydrochloride, u p to 30 mg per kilogram of body weight per day, was tried on two occasions, with an electrophysiological improvement [ 13. During the first trial, from the fifth to the seventh hospital day, the amplitude of MP was increased from 2,350 to 5,500 p v . During the second trial, from the thirteenth t o the nineteenth hospital day, rhe amplitude of MP was increased again from 4,570 to 7,500 pv. By the thirty-seventh hospital day, when the patient
Address reprint requests to Dr Oh, Department of Neurology, University of Alabama School of Medicine, University Station, Birmingham, AL 35294.
Accepted for publication Nov 22, 1976.
48 1
MUPs. T h e r e was a significant ( p < 0.001) increase in the mean duration of MUPs in the deltoid.
I A
10 msec
