Skeletal muscle changes associated with equine myotonic dystrophy.
Abstract: A progressive neuromuscular disorder in young horses, clinically apparent as early as 1 month of age, is characterized by generalized myotonia, muscle stiffness, muscle weakness and atrophy. Myotonia is identified by percussion dimpling and myotonic EMG discharges. Changes in one case included testicular hypoplasia, cataract formation, and glucose intolerance, indicating a systemic involvement. Pathologic changes in skeletal muscles from three affected foals were examined. Sarcoplasmic masses, ringed fibers, internal positioning of sarcolemmal nuclei, and nuclear rowing were among the primary histologic changes noted. Variation in fiber diameter size, especially atrophy, and type I predominance were also prominent changes. A neurogenic involvement was indicated by type grouping changes in several muscles.
Publication Date: 1990-01-01 PubMed ID: 2239155DOI: 10.1007/BF00307698Google Scholar: Lookup
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- Case Reports
- Journal Article
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- U.S. Gov't
- P.H.S.
- Clinical Findings
- Clinical Pathology
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Disease Etiology
- Equine Diseases
- Equine Health
- Equine Science
- Genetics
- Histology
- Horses
- Metabolism
- Muscle
- Muscle Fiber Types
- Musculoskeletal System
- Neurological Diseases
- Veterinary Care
- Veterinary Medicine
- Veterinary Research
- Young Horses
Summary
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The research paper focuses on a progressive neuromuscular disorder in young horses, exploring its symptoms, systemic implications and the pathological changes it causes in the animals’ skeletal muscles.
Overview of the Condition
- The disorder, apparent as early as when the horses are one month old, is marked by generalized myotonia (a condition causing muscles to contract and relax slowly), muscle stiffness, muscle weakness, and muscle loss (atrophy).
- Myotonia is identified through signs such as percussion dimpling (skin dimples remaining after being tapped) and myotonic electrical discharges in the muscles, recorded by an electromyogram (EMG).
Systemic Implications
- Case studies reveal systemic involvement of the disorder, with symptoms like testicular shrinkage (testicular hypoplasia), cataract formation in the eyes, and glucose intolerance in the bloodstream, which are all away from the muscular system.
Pathological Changes in Skeletal Muscles
- Skeletal muscles from three affected foals were examined to identify the characteristic changes the disorder causes. The primary histologic changes observed included the presence of sarcoplasmic masses (accumulations within the cell’s cytoplasm), ringed fibers (muscle fibers with distinct concentric rings), internal positioning of sarcolemmal nuclei (nuclei located internally in the cell membrane), and nuclear rowing (clusters of nuclei arranged in rows).
- There were also variations in muscle fiber diameter size with a special focus on muscle atrophy (shrinkage or wasting away of muscle), and a predominance of Type I muscle fibers (slow-twitch fibers primarily used in long-duration, aerobic activities).
Neurogenic Involvement
- The study suggests a neurogenic (originating in the nervous system) involvement in the disorder. This is indicated by changes in type grouping (the clustering of similar types of muscle fibers) in several muscles affected by the disorder. This could hint toward a nervous system dysfunction in controlling muscle activity.
Cite This Article
APA
Hegreberg GA, Reed SM.
(1990).
Skeletal muscle changes associated with equine myotonic dystrophy.
Acta Neuropathol, 80(4), 426-431.
https://doi.org/10.1007/BF00307698 Publication
Researcher Affiliations
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040.
MeSH Terms
- Animals
- Female
- Horse Diseases / pathology
- Horses
- Male
- Muscles / pathology
- Myotonic Dystrophy / pathology
- Myotonic Dystrophy / veterinary
Grant Funding
- RR00515 / NCRR NIH HHS
References
This article includes 19 references
- J Neurol Neurosurg Psychiatry. 1971 Apr;34(2):132-9
- J Neurol Sci. 1974 Mar;21(3):273-88
- J Neuropathol Exp Neurol. 1951 Apr;10(2):109-24
- Arch Neurol. 1978 Nov;35(11):741-5
- Science. 1962 Sep 21;137(3534):979-80
- Neurology. 1969 Mar;19(3):221-33
- J Small Anim Pract. 1981 Jul;22(7):451-65
- Exp Neurol. 1974 Dec;45(3):462-73
- Acta Neuropathol. 1975;31(4):297-303
- J Neurol Sci. 1985 Aug;70(1):55-65
- J Neurol Neurosurg Psychiatry. 1974 Nov;37(11):1195-201
- J Neurol Sci. 1976 Jan;27(1):1-16
- Br Med J. 1960 Oct 29;2(5208):1284-8
- Acta Neuropathol. 1979 Mar 15;45(3):231-40
- J Neurosci. 1982 Jul;2(7):924-33
- Adv Neurol. 1977;17:143-59
- Electromyogr Clin Neurophysiol. 1981 Feb-Mar;21(2-3):97-105
- J Am Vet Med Assoc. 1983 Jul 15;183(2):229-32
- J Neurol Sci. 1972 Jul;16(3):253-69
Citations
This article has been cited 4 times.- Valberg SJ, Williams ZJ, Ames EG, Mickelson JR, Nout-Lomas YS, Landolt G, Sanz M, Gardner K. Aberrant skeletal muscle morphogenesis and myofiber differentiation characterize equine myotonic dystrophy. PLoS One 2026;21(1):e0341655.
- Zakia LS, Palumbo MIP, Teixeira RBC, Resende LAL, Soares MP, de Oliveira-Filho JP, Amorim RM, Borges AS. Neuromyotonia in a horse. J Vet Intern Med 2019 Jan;33(1):287-291.
- Shiga T, Okuno S, Uchida K, Chambers JK, Nakayama H. Electrophysiological and histopathological findings of muscular disease suspected as myotonic dystrophy in a Shiba dog. J Vet Med Sci 2018 Mar 24;80(3):480-484.
- Orizio C, Esposito F, Paganotti I, Marino L, Rossi B, Veicsteinas A. Electrically-elicited surface mechanomyogram in myotonic dystrophy. Ital J Neurol Sci 1997 Aug;18(4):185-90.
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