Denervation of Muscle in Myasthenia Gravis

Brody, Irwin A.

doi:10.1001/archneur.1964.00460220012002

Cited by 30 publications

(5 citation statements)

References 9 publications

(2 reference statements)

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“…This could be due to block or to loss of muscle fibres. Histological evidence of 'neurogenic atrophy' in myasthenic muscle has been reported by Fenichel and Shy (1963), Brody and Engel (1964), Fenichel (1966), Brownell et al (1972, and Oosterhuis and Bethlem (1973) and was seen in one patient in the brachial biceps muscle in this study. Others have attributed a shortened duration of voluntarily (Oosterhuis et al, 1972) or electrically evoked (Ballantyne and Hansen, 1974 a,b) motor unit potentials to degeneration of distal nerve branches or to block of end plates.…”

Section: Discussionsupporting

confidence: 82%

Electrical and mechanical responses in the platysma and in the adductor pollicis muscle: in patients with myasthenia gravis.

Krarup¹

1977

Journal of Neurology, Neurosurgery & Psychiatry

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SUMMARY Electrical and mechanical muscular responses to single and repetitive stimuli were recorded in 24 patients with myasthenia gravis. Findings in the platysma were compared with those in m. adductor pollicis (ADP). In the platysma, but not in the ADP, electrical and mechanical responses to single stimuli were often lower than normal, and could be normalised after tetanus and by edrophonium. The decrement of electrical and mechanical responses to repetitive stimuli was two to three times greater in the platysma than in the ADP; post-tetanic facilitation of the action potential was four times greater. The staircase phenomenon was abnormal in the platysma in patients with moderate and severe myasthenia, and also in the ADP in some patients without decrement in the action potential. Edrophonium was more effective in alleviating decrement in the platysma than in the ADP. In the platysma, block of neuromuscular transmission could account for most abnormalities. The finding in some patients of an abnormal staircase after correction for block of fibres indicates a lesion in excitation-contraction coupling. In six patients only the platysma showed abnormalities, in 10 patients abnormalities were more pronounced in the platysma than in the ADP, and in three patients more pronounced in the ADP than in the platysma; in five patients the platysma and the ADP were equally affected.The purpose of this study of patients with myasthenia gravis was to compare the diagnostic yield obtained from recording of the electrical and mechanical responses in a proximal (platysma) and in a distal (m. adductor pollicis) muscle. MethodThe recording of electrical and mechanical responses in the platysma has been described (Krarup, 1977). Electrical and mechanical responses were also recorded in m. adductor pollicis (ADP), using the method of Slomic et al. (1968 The temperature on the skin over the platysma (36°C) was slightly higher than on the skin over the ADP (33°C), but could not be the reason for the two to three times greater decrement in the platysma than in the ADP Desmedt, 1974, 1975).The programme of stimulation has been described (Krarup, 1977). In addition, the effect of edrophonium chloride (Tensilon) was examined on trains of stimuli at 3s-1. Edrophonium, 10 mg, was given intravenously, at first 2 mg and 45 seconds later 8 mg. Trains of stimuli were delivered at half minute intervals for up to two minutes, at one minute intervals for up to 10 minutes, and often for up to 25 minutes after the injection. PATIENTS WITH MYASTHENIA GRAVISTwenty-four patients with clinical evidence of myasthenia gravis were examined. Thirteen were females and 11 were males; 11 were 22-38 years old and 13 were 43-73 years old. Fifteen had moderate or severe (type IIa-IV, Osserman and Genkins, 1971), 241Protected by copyright. on 12 May 2018 by guest.

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Section: Discussionsupporting

confidence: 82%

Electrical and mechanical responses in the platysma and in the adductor pollicis muscle: in patients with myasthenia gravis.

Krarup¹

1977

Journal of Neurology, Neurosurgery & Psychiatry

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“…In previous reports of neurogenic atrophy in myasthenic muscle (Steidl, Oswald, and Kottke, 1962;Fenichel and Shy, 1963;Brody and Engel, 1964;Fenichel, 1966;Hughes and Brownell, 1968) the affected muscle fibres have shown either a diffusely scattered or a 'grouped' pattern of distribution. Both patterns were seen in our case 2.…”

mentioning

confidence: 90%

“…Coers and Desmedt (1958), Bickerstaff and Woolf (1960), and MacDermot (1960) described abnormalities in the terminations of motor nerve fibres as shown by methylene blue techniques, and their findings have been confirmed by subsequent workers. Substantial neurogenic muscular atrophy is not a generally recognized feature of the disease, although minor degrees of neurogenic atrophy have occasionally been reported (Fenichel and Shy, 1963;Brody and Engel, 1964;Hughes and Brownell, 1968). There are no known abnormalities in the central nervous system or in the cell bodies and axons of the motor neurones.…”

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confidence: 99%

Neurogenic muscle atrophy in myasthenia gravis

Brownell

Oppenheimer

Spalding

1972

Journal of Neurology, Neurosurgery & Psychiatry

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SUMMARY Two cases of severe myasthenia gravis are described, with histological findings. Both cases showed severe neurogenic atrophy of the muscles of the tongue, with fatty pseudohypertrophy and a remarkable proliferation of terminal nerve fibres. Similar, but less severe, changes were present in other bulbar muscles. The findings are in keeping with the view that functional interruption at the neuromuscular junctions results first in failure to transmit the contractile impulse, and at a later stage in denervation atrophy. Terminal proliferation of axons is regarded as an attempt, on the part of motor fibres, to compensate for the breakdown of normal neuromuscular interaction.

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“…The second variety was called "type I1 fiber atrophy," because it appeared a s reduced diameter of only the fibers whose histochemical activities were in the normal range and characteristic of normal type I1 fibers (viz., high myosin ATPase, high phosphorylase, high menadione a-glycerophosphate dehydrogenase, low lactate dehydrogenase, low T P N H dehydrogenzse and low DPNH dehydrogenase activities). The cross-sectional contour of these fibers was less rounded than normal but more rounded than the "denervated" fibers (FIGURES 6 ,7 ,8 ) . T h e significance of type I1 fiber atrophy is not known.…”

mentioning

confidence: 95%

Discussion

1966

Annals of the New York Academy of Sciences

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Denervation of Muscle in Myasthenia Gravis

Cited by 30 publications

References 9 publications

Electrical and mechanical responses in the platysma and in the adductor pollicis muscle: in patients with myasthenia gravis.

Electrical and mechanical responses in the platysma and in the adductor pollicis muscle: in patients with myasthenia gravis.

Neurogenic muscle atrophy in myasthenia gravis

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