Non-epileptic myoclonus and mitochondrial encephalomyopathy

Cukiert, A.; Naylor, F. G. M.; Scapolan, H. B.; Vilela, M. M.; Aloe, F. S.; Siffert, J. O.; Tsanaglis, Ana M.; Haddad, Monica; Machado, Teresa C.; Carvalho-Alegro, Mary; Levy, J. A.; Marques-Assis, L.

doi:10.1590/S0004-282X1989000300016

Abstracts

Two brothers presented to us with a progressive myoclonic syndrome with slight cerebellar symptoms. Neurological examination disclosed moderate cerebellar signs and pale optic discs; asymmetric, asynchronous and arhythmic myoclonus, an arthresthesic deficit and no muscular weakness. EEG background activity was moderately slow with no irritative discharges. CT was normal in both cases, Intermitent photic stimulation increased the frequency of the myoclonic jerks, which became bilateral and synchronous, progressing to a generalized tonic-clonic seizure. EPs and MRI in one case were normal. Anticonvulsant drugs were ineffective. The diagnosis of mitochondrial encephalomyopathy was based on the finding, in muscle specimens, of thickened basement membranes with myofibrillary degeneration and increased number of mitochondria peripherally distributed and with a dense granular matrix and some vacuoles. The clinical and EEG data suggest a. subcortical origin for this type of myoclonic syndrome.

Foram examinados dois irmãos portadores de uma síndrome mioclônica progressiva com discretos sintomas cerebelares. O exame neurológico mostrava sinais cerebelares moderados e papilas pálidas; mioclonias assíncronas, arrítmicas e assimétricas, um déficit artrestésico e ausência de fraqueza muscular. A atividade de base do EEG era moderadamente lenta e sem atividade irritativa. A TC era normal em ambos os casos. A estimulação fótica intermitente aumentava a freqüência dos abalos mioclônicos que se tornavam bilaterais e sincronos, progredindo para uma crise tônico-clônica generalizada. Potenciais evocados e RMN em um caso foram normais. Drogas anticonvulsivantes foram ineficazes no controle das mioclonias. O diagnóstico de encefalomiopatia mitocondrial foi realizado através do achado em espécimes musculares de membranas basais espessadas, com degeneração miofibrilar e um número elevado de mitocondrias distribuídas perifericamente e com uma matriz densa, granular e com alguns vacúolos. Os achados clínicos e eletrográficos sugerem uma origem subcortical para esta síndrome mioclônica.

Non-epileptic myoclonus and mitochondrial encephalomyopathy

Mioclonias não epilépticas e encefalomiopatia mitocondrial

A. Cukiert^I; F. G. M. Naylor^II; H. B. Scapolan^I; M. M. Vilela^I; F. S. Aloe^I; J. O. Siffert^I; Ana M. Tsanaglis^III; Monica Haddad^I; Teresa C. Machado^I; Mary Carvalho-Alegro^III; J. A. Levy^III; L. Marques-Assis^I

^IFaculty of Medicine, University of São Paulo (FMUSP) and Hospital das Clínicas, FMUSP: Division of Neurology

^IIFaculty of Medicine, University of São Paulo (FMUSP) and Hospital das Clínicas, FMUSP: Division of Functional Neurosurgery

^IIIFaculty of Medicine, University of São Paulo (FMUSP) and Hospital das Clínicas, FMUSP: Neurology Investigation Center

SUMMARY

Two brothers presented to us with a progressive myoclonic syndrome with slight cerebellar symptoms. Neurological examination disclosed moderate cerebellar signs and pale optic discs; asymmetric, asynchronous and arhythmic myoclonus, an arthresthesic deficit and no muscular weakness. EEG background activity was moderately slow with no irritative discharges. CT was normal in both cases, Intermitent photic stimulation increased the frequency of the myoclonic jerks, which became bilateral and synchronous, progressing to a generalized tonic-clonic seizure. EPs and MRI in one case were normal. Anticonvulsant drugs were ineffective. The diagnosis of mitochondrial encephalomyopathy was based on the finding, in muscle specimens, of thickened basement membranes with myofibrillary degeneration and increased number of mitochondria peripherally distributed and with a dense granular matrix and some vacuoles. The clinical and EEG data suggest a. subcortical origin for this type of myoclonic syndrome.

RESUMO

Foram examinados dois irmãos portadores de uma síndrome mioclônica progressiva com discretos sintomas cerebelares. O exame neurológico mostrava sinais cerebelares moderados e papilas pálidas; mioclonias assíncronas, arrítmicas e assimétricas, um déficit artrestésico e ausência de fraqueza muscular. A atividade de base do EEG era moderadamente lenta e sem atividade irritativa. A TC era normal em ambos os casos. A estimulação fótica intermitente aumentava a freqüência dos abalos mioclônicos que se tornavam bilaterais e sincronos, progredindo para uma crise tônico-clônica generalizada. Potenciais evocados e RMN em um caso foram normais. Drogas anticonvulsivantes foram ineficazes no controle das mioclonias. O diagnóstico de encefalomiopatia mitocondrial foi realizado através do achado em espécimes musculares de membranas basais espessadas, com degeneração miofibrilar e um número elevado de mitocondrias distribuídas perifericamente e com uma matriz densa, granular e com alguns vacúolos. Os achados clínicos e eletrográficos sugerem uma origem subcortical para esta síndrome mioclônica.

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Dr. A. Cukiert - R. Baltazar da Veiga 361 apto 151 - 04510 São Paulo SP - Brasil.

1. Berkovic SF, Andermann F, Carpenter S, Wolfe S - Progressive myoclonus epilepsies: specific causes and diagnosis. N Engl J Med 315: 296, 1986.
2. Bird TD, Shaw CM - Progressive myoclonus epilepsy with dentatorubral degeneration: a clinicopathological study of the Ramsay-Hunt syndrome. J Neurol Neurosurg Psychiat 41: 140, 1978.
3. Byrne E, Trounce I - Oxigen electrode studies with human skeletal muscle mitochondria in vitro: a reappraisal. J Neurol Sci 69: 319, 1982.
4. Crosby TW, Chou SM - 'Ragged-red' fibers in Leigh disease. Neurology 24: 49, 1974.
5. DiMauro S, Bonilla E, Zeviani M, Nagakawa M, DeVivo D - Mitochondrial myopathies. Ann Neurol 17: 521, 1985.
6. Ekbom K - Hereditary ataxia, photomyoclonus, skeletal deformities and lipoma. Acta Neurol Scand 51: 393, 1975.
7. Fukuhara N, Tokiguchi S, Shirakawa K, Tsubaki T - Myoclonus epilepsy associated with ragged red fibers (mitochondrial abnormalities): disease entity or a syndrome? J Neurol Sci 47: 117, 1980.
8. Hunt JR - Dyssinergia cerebellaris myoclonica: primary atrophy of the dentate system. A contribution to the pathology and symptomatology of the cerebellum. Brain 44: 490, 1921.
9. Karpati G, Carpenter S, Larbrisseau A, Lafontaine R - The Kearns-Shy syndrome: a multisystem disease with mitochondrial abnormality demonstrated in skeletal muscle and akin. J Neurol Sci 19: 133, 1973.
10. May DL, White HH - Familial myoclonus, cerebellar ataxia and deafness. Arch Neurol 19: 331, 1968.
11. Morgan-Hughes J A - Mitochondrial diseases. Trends in Neuroscience 9: 15, 1986.
12. Nakano T, Sakai H, Amaro N, Yagishita S, Ito Y - An autopsy case of degenerative type of myoclonus epilepsy associated with Friedreich's ataxia and mitochondrial myopathy. Brain and Nerve 34:321, 1982.
13. Pavlakis SG, Phillips PC, DiMauro, S, DeVivo DC, Rowland LP - Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes: a distinctive clinical syndrome. Ann Neurol 16: 481, 1984.
14. Petty RKH, Harding AE, Morgan-Hughes JA - The clinical features of mitochondrial myopathy Brain 109: 915, 1986.
15. Riggs JE, Schochet SS, Fakadej AV, Papadimitriou A, DiMauro S, Crosby TW, Gutmann L, Moxley RT - Mitochondrial encephalomyopathy with decreased succinate-cytochrome C reductase activity. Neurology 34: 48, 1984.
16. Sazaki H, Kuzuhara S, Kanazawa I, Nakinishi T, Ogata T - Myoclonus, cerebellar disorder, neuropathy, mitochondrial myopathy and ACTH deficiency. Neurology 33: 1288, 1983.
17. Smith NJ, Espir MLE, Mattrews WB - Familial myoclonic epilepsy with ataxia and neuropathy with additional features of Friedreich ataxia and peroneal muscular atrophy. Brain 101: 461, 1978.
18. Walter GF, Brucher JM, Martin JJ, Centerick C, Pilz P, Freund M. - Leigh's disease-several nosological entities with identical histopathological complex? Neuropathol Appl Neurobiol 12: 95, 1986.
19. Ziegler DK, Van Speybroech NW, Seitz EF - Myoclonic epilepsia partialis continua and Friedreich ataxia. Arch Neurol 31: 308, 1974.

Publication Dates

Publication in this collection
06 June 2011
Date of issue
Sept 1989

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] 1. Berkovic SF, Andermann F, Carpenter S, Wolfe S - Progressive myoclonus epilepsies: specific causes and diagnosis. N Engl J Med 315: 296, 1986.

[2] 2. Bird TD, Shaw CM - Progressive myoclonus epilepsy with dentatorubral degeneration: a clinicopathological study of the Ramsay-Hunt syndrome. J Neurol Neurosurg Psychiat 41: 140, 1978.

[3] 3. Byrne E, Trounce I - Oxigen electrode studies with human skeletal muscle mitochondria in vitro: a reappraisal. J Neurol Sci 69: 319, 1982.

[4] 4. Crosby TW, Chou SM - 'Ragged-red' fibers in Leigh disease. Neurology 24: 49, 1974.

[5] 5. DiMauro S, Bonilla E, Zeviani M, Nagakawa M, DeVivo D - Mitochondrial myopathies. Ann Neurol 17: 521, 1985.

[6] 6. Ekbom K - Hereditary ataxia, photomyoclonus, skeletal deformities and lipoma. Acta Neurol Scand 51: 393, 1975.

[7] 7. Fukuhara N, Tokiguchi S, Shirakawa K, Tsubaki T - Myoclonus epilepsy associated with ragged red fibers (mitochondrial abnormalities): disease entity or a syndrome? J Neurol Sci 47: 117, 1980.

[8] 8. Hunt JR - Dyssinergia cerebellaris myoclonica: primary atrophy of the dentate system. A contribution to the pathology and symptomatology of the cerebellum. Brain 44: 490, 1921.

[9] 9. Karpati G, Carpenter S, Larbrisseau A, Lafontaine R - The Kearns-Shy syndrome: a multisystem disease with mitochondrial abnormality demonstrated in skeletal muscle and akin. J Neurol Sci 19: 133, 1973.

[10] 10. May DL, White HH - Familial myoclonus, cerebellar ataxia and deafness. Arch Neurol 19: 331, 1968.

[11] 11. Morgan-Hughes J A - Mitochondrial diseases. Trends in Neuroscience 9: 15, 1986.

[12] 12. Nakano T, Sakai H, Amaro N, Yagishita S, Ito Y - An autopsy case of degenerative type of myoclonus epilepsy associated with Friedreich's ataxia and mitochondrial myopathy. Brain and Nerve 34:321, 1982.

[13] 13. Pavlakis SG, Phillips PC, DiMauro, S, DeVivo DC, Rowland LP - Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes: a distinctive clinical syndrome. Ann Neurol 16: 481, 1984.

[14] 14. Petty RKH, Harding AE, Morgan-Hughes JA - The clinical features of mitochondrial myopathy Brain 109: 915, 1986.

[15] 15. Riggs JE, Schochet SS, Fakadej AV, Papadimitriou A, DiMauro S, Crosby TW, Gutmann L, Moxley RT - Mitochondrial encephalomyopathy with decreased succinate-cytochrome C reductase activity. Neurology 34: 48, 1984.

[16] 16. Sazaki H, Kuzuhara S, Kanazawa I, Nakinishi T, Ogata T - Myoclonus, cerebellar disorder, neuropathy, mitochondrial myopathy and ACTH deficiency. Neurology 33: 1288, 1983.

[17] 17. Smith NJ, Espir MLE, Mattrews WB - Familial myoclonic epilepsy with ataxia and neuropathy with additional features of Friedreich ataxia and peroneal muscular atrophy. Brain 101: 461, 1978.

[18] 18. Walter GF, Brucher JM, Martin JJ, Centerick C, Pilz P, Freund M. - Leigh's disease-several nosological entities with identical histopathological complex? Neuropathol Appl Neurobiol 12: 95, 1986.

[19] 19. Ziegler DK, Van Speybroech NW, Seitz EF - Myoclonic epilepsia partialis continua and Friedreich ataxia. Arch Neurol 31: 308, 1974.