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Forgash JT, Chang YM, Mittelman NS, Petesch S, Benedicenti L, Galban E, Hammond JJ, Glass EN, Barker JR, Shelton GD, Luo J, Garden OA. Clinical features and outcome of acquired myasthenia gravis in 94 dogs. J Vet Intern Med 2021; 35:2315-2326. [PMID: 34331481 PMCID: PMC8478050 DOI: 10.1111/jvim.16223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 06/25/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Background Factors known to be associated with outcome of acquired myasthenia gravis (MG) in dogs are limited. Hypothesis/Objectives Of dogs with MG, advancing age and comorbid neoplasia are associated with poor long‐term prognosis and low rates of remission. Animals Ninety‐four client‐owned dogs with MG diagnosed by acetylcholine receptor antibody (AChR Ab) assay between 2001 and 2019 from a university clinic and 3 private clinics in the United States. Methods Cases were retrospectively evaluated and data were collected to determine clinical signs, treatment, and response to therapy defined by means of a clinical scoring rubric. Immunological remission was defined as a return of the AChR Ab concentration to <0.6 nmol/L. Multivariable binary logistic regression analysis was used to identify clinical criteria predicting remission. Results An anticholinesterase drug was used to treat 90/94 (96%) dogs, which in 63/94 (67%) was the sole treatment; other drugs included immune modulators. Clinical remission (lack of clinical signs ≥4 weeks after treatment cessation) was observed in 29 (31% [95% confidence interval (CI): 22.4‐40.8%]) dogs, clinical response (lack of clinical signs on treatment) in 14 (15% [95% CI: 9.0‐23.6%]) dogs, clinical improvement (on treatment) in 24 (26% [95% CI: 17.8‐35.2%]) dogs, and no clinical improvement in 27 (29% [95% CI: 20.5‐38.6%]) dogs. Immunological remission was observed in 27/46 (59%) dogs, with clinical remission in all 27. Younger age (P = .04) and comorbid endocrine disease (P = .04) were associated with clinical remission. Initial AChR Ab concentration (P = .02) and regurgitation (P = .04) were negatively associated with clinical remission. Conclusions and Clinical Importance Clinical remission in MG is less likely in older dogs and dogs presenting with regurgitation or high initial AChR Ab concentration, but more likely in younger dogs and dogs with comorbid endocrine disease.
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Affiliation(s)
- Jennifer T Forgash
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu-Mei Chang
- Research Support Office, Royal Veterinary College, University of London, London, United Kingdom
| | - Neil S Mittelman
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Scott Petesch
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Leontine Benedicenti
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Evelyn Galban
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James J Hammond
- Department of Neurology and Neurosurgery, Pieper Memorial Veterinary Center, Middletown, Connecticut, USA
| | - Eric N Glass
- Section of Neurology and Neurosurgery, Red Bank Veterinary Hospital, Tinton Falls, New Jersey, USA
| | - Jessica R Barker
- Department of Neurology and Neurosurgery, Bush Veterinary Neurology Service, Springfield, Virginia, USA
| | - G Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jie Luo
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Oliver A Garden
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Mignan T, Targett M, Lowrie M. Classification of myasthenia gravis and congenital myasthenic syndromes in dogs and cats. J Vet Intern Med 2020; 34:1707-1717. [PMID: 32668077 PMCID: PMC7517852 DOI: 10.1111/jvim.15855] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 06/22/2020] [Accepted: 06/26/2020] [Indexed: 12/19/2022] Open
Abstract
Myasthenia, a syndrome of impaired neuromuscular transmission, occurs as either an acquired or congenital condition. Myasthenia gravis (MG) is an acquired autoimmune disorder with autoantibodies against the neuromuscular junction (NMJ) of skeletal muscle whereas congenital myasthenic syndromes (CMSs) are a clinically heterogeneous group of genetic disorders affecting the NMJ with a young age of onset. Both conditions are diseases for which recognition is important with regard to treatment and outcome. We review the published literature on MG and CMSs in dogs and cats, and by comparison with published classification used in humans, propose a classification system for MG and CMSs in dogs and cats. Myasthenia gravis is first classified based on focal, generalized, or acute fulminating presentation. It then is subclassified according to the autoimmune disease mechanism or seronegativity. Autoimmune disease mechanism relates to the presence or absence of a thymoma, or administration of thiourylene medication in cats. Congenital myasthenic syndromes are classified according to the affected NMJ component, the mechanism of the defect of neuromuscular transmission, the affected protein, and ultimately the mutated gene responsible. In proposing this categorization of MG and CMSs, we hope to aid recognition of the disease groups for both conditions, as well as guide treatment, refine prognosis, and provide a framework for additional studies of these conditions.
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Affiliation(s)
| | - Mike Targett
- School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, UK
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