Seasonal pasture myopathy in horses in the midwestern United States: 14 Cases (1998-2005)

Carrie J Finno, Stephanie J. Valberg, Arno Wünschmann, Michael J. Murphy

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

Objective - To determine clinical signs, diagnostic findings, tissue tremetone concentrations, and clinical outcome or postmortem findings in horses evaluated for acute severe nonexertional rhabdomyolysis initially attributed to white snakeroot toxicosis. Design - Retrospective case series. Animals - 14 horses. Procedures - Records of the University of Minnesota Veterinary Medical Center or Diagnostic Laboratory were searched from 1998 to 2005. Inclusion criteria included serum creatine kinase (CK) activity > 45,000 U/L, severe nonexertional myonecrosis of proximal postural muscles at necropsy, or signs of weakness without palpably firm muscles on physical examination. Vitamin E and selenium concentrations were measured in 6 horses; tremetone concentration was measured in 7. Results - Clinical signs occurred during unfavorable weather conditions. Clinical signs of generalized weakness (n = 11 horses), muscle fasciculations (10), lethargy (6), and prolonged recumbency (4) were common. Serum CK activity ranged from 46,487 to 959,499 U/L (reference range, 82 to 449 U/L), and aspartate transaminase activity was > 1,500 U/L (reference range, 162 to 316 U/L). Two horses survived with aggressive antioxidant and fluid treatment. Postmortem examination revealed acute severe myonecrosis with lipid accumulation primarily in neck, proximal forelimb and hind limb, intercostal, and diaphragm muscles. Histopathologic signs of myocardial necrosis were detected in 7 horses. Vitamin E and selenium concentrations were within reference limits. Tremetone was not detected in liver or urine samples. Conclusions and Clinical Relevance - Cases of rhabdomyolysis have been attributed to white snakeroot toxicosis; however, tremetone was not detected in any horses. Similarities exist between cases of seasonal pasture myopathy and cases of atypical myopathy in Europe.

Original languageEnglish (US)
Pages (from-to)1134-1141
Number of pages8
JournalJournal of the American Veterinary Medical Association
Volume229
Issue number7
DOIs
StatePublished - Oct 1 2006

Fingerprint

Midwestern United States
muscular diseases
Muscular Diseases
Horses
pastures
horses
rhabdomyolysis
muscles
Rhabdomyolysis
creatine kinase
Creatine Kinase
Selenium
Vitamin E
Muscles
selenium
vitamin E
poisoning
necropsy
Reference Values
Intercostal Muscles

ASJC Scopus subject areas

  • veterinary(all)

Cite this

Seasonal pasture myopathy in horses in the midwestern United States : 14 Cases (1998-2005). / Finno, Carrie J; Valberg, Stephanie J.; Wünschmann, Arno; Murphy, Michael J.

In: Journal of the American Veterinary Medical Association, Vol. 229, No. 7, 01.10.2006, p. 1134-1141.

Research output: Contribution to journalArticle

Finno, Carrie J ; Valberg, Stephanie J. ; Wünschmann, Arno ; Murphy, Michael J. / Seasonal pasture myopathy in horses in the midwestern United States : 14 Cases (1998-2005). In: Journal of the American Veterinary Medical Association. 2006 ; Vol. 229, No. 7. pp. 1134-1141.
@article{fd0ed09796e24173b04351bdf6e640be,
title = "Seasonal pasture myopathy in horses in the midwestern United States: 14 Cases (1998-2005)",
abstract = "Objective - To determine clinical signs, diagnostic findings, tissue tremetone concentrations, and clinical outcome or postmortem findings in horses evaluated for acute severe nonexertional rhabdomyolysis initially attributed to white snakeroot toxicosis. Design - Retrospective case series. Animals - 14 horses. Procedures - Records of the University of Minnesota Veterinary Medical Center or Diagnostic Laboratory were searched from 1998 to 2005. Inclusion criteria included serum creatine kinase (CK) activity > 45,000 U/L, severe nonexertional myonecrosis of proximal postural muscles at necropsy, or signs of weakness without palpably firm muscles on physical examination. Vitamin E and selenium concentrations were measured in 6 horses; tremetone concentration was measured in 7. Results - Clinical signs occurred during unfavorable weather conditions. Clinical signs of generalized weakness (n = 11 horses), muscle fasciculations (10), lethargy (6), and prolonged recumbency (4) were common. Serum CK activity ranged from 46,487 to 959,499 U/L (reference range, 82 to 449 U/L), and aspartate transaminase activity was > 1,500 U/L (reference range, 162 to 316 U/L). Two horses survived with aggressive antioxidant and fluid treatment. Postmortem examination revealed acute severe myonecrosis with lipid accumulation primarily in neck, proximal forelimb and hind limb, intercostal, and diaphragm muscles. Histopathologic signs of myocardial necrosis were detected in 7 horses. Vitamin E and selenium concentrations were within reference limits. Tremetone was not detected in liver or urine samples. Conclusions and Clinical Relevance - Cases of rhabdomyolysis have been attributed to white snakeroot toxicosis; however, tremetone was not detected in any horses. Similarities exist between cases of seasonal pasture myopathy and cases of atypical myopathy in Europe.",
author = "Finno, {Carrie J} and Valberg, {Stephanie J.} and Arno W{\"u}nschmann and Murphy, {Michael J.}",
year = "2006",
month = "10",
day = "1",
doi = "10.2460/javma.229.7.1134",
language = "English (US)",
volume = "229",
pages = "1134--1141",
journal = "Journal of the American Veterinary Medical Association",
issn = "0003-1488",
publisher = "American Veterinary Medical Association",
number = "7",

}

TY - JOUR

T1 - Seasonal pasture myopathy in horses in the midwestern United States

T2 - 14 Cases (1998-2005)

AU - Finno, Carrie J

AU - Valberg, Stephanie J.

AU - Wünschmann, Arno

AU - Murphy, Michael J.

PY - 2006/10/1

Y1 - 2006/10/1

N2 - Objective - To determine clinical signs, diagnostic findings, tissue tremetone concentrations, and clinical outcome or postmortem findings in horses evaluated for acute severe nonexertional rhabdomyolysis initially attributed to white snakeroot toxicosis. Design - Retrospective case series. Animals - 14 horses. Procedures - Records of the University of Minnesota Veterinary Medical Center or Diagnostic Laboratory were searched from 1998 to 2005. Inclusion criteria included serum creatine kinase (CK) activity > 45,000 U/L, severe nonexertional myonecrosis of proximal postural muscles at necropsy, or signs of weakness without palpably firm muscles on physical examination. Vitamin E and selenium concentrations were measured in 6 horses; tremetone concentration was measured in 7. Results - Clinical signs occurred during unfavorable weather conditions. Clinical signs of generalized weakness (n = 11 horses), muscle fasciculations (10), lethargy (6), and prolonged recumbency (4) were common. Serum CK activity ranged from 46,487 to 959,499 U/L (reference range, 82 to 449 U/L), and aspartate transaminase activity was > 1,500 U/L (reference range, 162 to 316 U/L). Two horses survived with aggressive antioxidant and fluid treatment. Postmortem examination revealed acute severe myonecrosis with lipid accumulation primarily in neck, proximal forelimb and hind limb, intercostal, and diaphragm muscles. Histopathologic signs of myocardial necrosis were detected in 7 horses. Vitamin E and selenium concentrations were within reference limits. Tremetone was not detected in liver or urine samples. Conclusions and Clinical Relevance - Cases of rhabdomyolysis have been attributed to white snakeroot toxicosis; however, tremetone was not detected in any horses. Similarities exist between cases of seasonal pasture myopathy and cases of atypical myopathy in Europe.

AB - Objective - To determine clinical signs, diagnostic findings, tissue tremetone concentrations, and clinical outcome or postmortem findings in horses evaluated for acute severe nonexertional rhabdomyolysis initially attributed to white snakeroot toxicosis. Design - Retrospective case series. Animals - 14 horses. Procedures - Records of the University of Minnesota Veterinary Medical Center or Diagnostic Laboratory were searched from 1998 to 2005. Inclusion criteria included serum creatine kinase (CK) activity > 45,000 U/L, severe nonexertional myonecrosis of proximal postural muscles at necropsy, or signs of weakness without palpably firm muscles on physical examination. Vitamin E and selenium concentrations were measured in 6 horses; tremetone concentration was measured in 7. Results - Clinical signs occurred during unfavorable weather conditions. Clinical signs of generalized weakness (n = 11 horses), muscle fasciculations (10), lethargy (6), and prolonged recumbency (4) were common. Serum CK activity ranged from 46,487 to 959,499 U/L (reference range, 82 to 449 U/L), and aspartate transaminase activity was > 1,500 U/L (reference range, 162 to 316 U/L). Two horses survived with aggressive antioxidant and fluid treatment. Postmortem examination revealed acute severe myonecrosis with lipid accumulation primarily in neck, proximal forelimb and hind limb, intercostal, and diaphragm muscles. Histopathologic signs of myocardial necrosis were detected in 7 horses. Vitamin E and selenium concentrations were within reference limits. Tremetone was not detected in liver or urine samples. Conclusions and Clinical Relevance - Cases of rhabdomyolysis have been attributed to white snakeroot toxicosis; however, tremetone was not detected in any horses. Similarities exist between cases of seasonal pasture myopathy and cases of atypical myopathy in Europe.

UR - http://www.scopus.com/inward/record.url?scp=33749267999&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749267999&partnerID=8YFLogxK

U2 - 10.2460/javma.229.7.1134

DO - 10.2460/javma.229.7.1134

M3 - Article

C2 - 17014363

AN - SCOPUS:33749267999

VL - 229

SP - 1134

EP - 1141

JO - Journal of the American Veterinary Medical Association

JF - Journal of the American Veterinary Medical Association

SN - 0003-1488

IS - 7

ER -