A 62-year-old man presented with seven years of progressive dysphagia, dysphonia and difficulty in closing both eyes. His examination showed weakness and atrophy of facial and bulbar muscles without ocular involvement (Figure A, B and C). Single-fiber electromyography revealed increased jitter (Figure D). To evaluate for concurrent myopathy, a muscle biopsy was performed and showed angulated atrophic type II fibers, a particular finding described in patients with myasthenia gravis11. Oosterhuis H, Bethlem J. Neurogenic muscle involvement in myasthenia gravis. A clinical and histopathological study. J Neurol Neurosurg Psychiatry. 1973;36(2):244-54. https://doi.org/10.1136/jnnp.36.2.244
https://doi.org/10.1136/jnnp.36.2.244...
,22. Werneck LC. The muscle lesion in myasthenia gravis: a study of 17 cases with muscle histochemistry. Arq Neuropsiquiatr. 1982;40(1):67-76. https://doi.org/10.1590/S0004-282X1982000100007
https://doi.org/10.1590/S0004-282X198200...
(Figure E). Acetylcholine receptor antibody was positive (2.2 nmol/L). Pronounced facial and tongue atrophy is uncommon in myasthenia gravis and usually associated with the muscle-specific receptor tyrosine kinase antibody, which was negative in this patient33. Farrugia ME, Robson MD, Clover L, Anslow P, Newsom-Davis J, Kennett R et al. MRI and clinical studies of facial and bulbar muscle involvement in MuSK antibody-associated myasthenia gravis. Brain. 2006;129:1481-92. https://doi.org/10.1093/brain/awl095
https://doi.org/10.1093/brain/awl095...
,44. Nikolić AV, Bačić GG, Daković MŽ, Lavrnić SĐ, Rakočević Stojanović VM, Basta IZ et al. Myopathy, muscle atrophy and tongue lipid composition in MuSK myasthenia gravis. Acta Neurol Belg. 2015;115(3):361-5. https://doi.org/10.1007/s13760-014-0364-1
https://doi.org/10.1007/s13760-014-0364-...
.
Clinical, electrophysiological and left biceps brachii muscle biopsy findings. Bilateral facial weakness, Bell’s sign (A) and atrophy of the tongue (B), temporal and masseter muscles (arrows) (C). Repetitive stimulation was unremarkable (upper image) and the single-fiber electromyography demonstrated increased jitter (bottom image) (D). Muscle ATPase (pH 9.4) stain revealed angulated fiber II atrophy (arrowhead) (E). Bar = 100µm.
References
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1Oosterhuis H, Bethlem J. Neurogenic muscle involvement in myasthenia gravis. A clinical and histopathological study. J Neurol Neurosurg Psychiatry. 1973;36(2):244-54. https://doi.org/10.1136/jnnp.36.2.244
» https://doi.org/10.1136/jnnp.36.2.244 -
2Werneck LC. The muscle lesion in myasthenia gravis: a study of 17 cases with muscle histochemistry. Arq Neuropsiquiatr. 1982;40(1):67-76. https://doi.org/10.1590/S0004-282X1982000100007
» https://doi.org/10.1590/S0004-282X1982000100007 -
3Farrugia ME, Robson MD, Clover L, Anslow P, Newsom-Davis J, Kennett R et al. MRI and clinical studies of facial and bulbar muscle involvement in MuSK antibody-associated myasthenia gravis. Brain. 2006;129:1481-92. https://doi.org/10.1093/brain/awl095
» https://doi.org/10.1093/brain/awl095 -
4Nikolić AV, Bačić GG, Daković MŽ, Lavrnić SĐ, Rakočević Stojanović VM, Basta IZ et al. Myopathy, muscle atrophy and tongue lipid composition in MuSK myasthenia gravis. Acta Neurol Belg. 2015;115(3):361-5. https://doi.org/10.1007/s13760-014-0364-1
» https://doi.org/10.1007/s13760-014-0364-1
Publication Dates
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Publication in this collection
Mar 2017
History
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Received
26 July 2016 -
Accepted
31 Oct 2016