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Veterinary Pathology May 2024A 1.5-year-old American quarter horse gelding (case 1) and an 11-month-old American quarter horse filly (case 2) were presented for acute onset pelvic lameness and...
A 1.5-year-old American quarter horse gelding (case 1) and an 11-month-old American quarter horse filly (case 2) were presented for acute onset pelvic lameness and lethargy. Case 1 had nasal discharge, while case 2 developed rapid muscle atrophy. Both horses had elevated serum creatine kinase activity. The horses showed similar polyphasic histiocytic and lymphoplasmacytic myositis with necrosis, mineralization, and regeneration. Additionally, case 1 had subsp. e-induced suppurative retropharyngeal lymphadenitis with renal purpura hemorrhagica and myoglobinuric nephropathy. A focal pulmonary abscess caused by was found in case 2. Genetic testing revealed case 1 as heterozygous and case 2 as homozygous for the E321G variant, supporting the diagnosis of myosin heavy-chain myopathy, with concomitant bacterial disease as potential triggers.
Topics: Animals; Horses; Horse Diseases; Myosin Heavy Chains; Male; Muscular Diseases; Female; Streptococcal Infections; Streptococcus equi; Muscle, Skeletal
PubMed: 37818977
DOI: 10.1177/03009858231204253