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Equine veterinary journal2001; 33(5); 452-458; doi: 10.2746/042516401776254790

Laryngeal paralysis: a study of 375 cases in a mixed-breed population of horses.

Abstract: Referred cases (n = 375) of laryngeal paralysis (1985-1998) from a mixed-breed equine population included 351 (94%) cases of recurrent laryngeal neuropathy (RLN) (idiopathic laryngeal hemiplegia) and 24 cases (6%) of laryngeal paralysis from causes other than RLN. Laryngeal movements were classified endoscopically into one of 6 grades, in contrast to the usual 4 grades. The RLN cases had a median grade 4 laryngeal paralysis, of which 96% were left-sided, 2% right-sided and 2% bilaterally affected. RLN cases included 204 (58%) Thoroughbred, 96 (27%) Thoroughbred-cross, 23 (7%) draught, 16 (5%) Warmbloods and 10 (3%) other breeds, including only 4 (1%) ponies. The median age of RLN cases at referral was 6 years (range 2-12) and their median height was 170.2 cm. The work of RLN horses included National Hunt racing (42%), flat racing (1%), hunting (19%), eventing (16%) and miscellaneous work (22%). Reported presenting signs in RLN-affected horses included abnormal exercise-related respiratory sounds in 90% and reduced exercise tolerance in only 64%. However, many horses were referred before their exercise tolerance could be fully assessed. Forty percent of the RLN cases had intercurrent disorders, including 10% with additional upper respiratory and 7% with lower respiratory tract diseases. The 24 nonidiopathic RLN cases included 12 with bilateral laryngeal paralysis, 11 (92%) of which were ponies. Bilateral laryngeal paralysis occurred with hepatic encephalopathy in 7 cases and following general anaesthesia in 2 cases. The 12 cases of acquired unilateral laryngeal paralysis included 7 caused by guttural pouch mycosis.
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Publication Date: 2001-09-18 PubMed ID: 11558739DOI: 10.2746/042516401776254790Google Scholar: Lookup
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  • Journal Article

Summary

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This paper discusses a study of 375 cases of laryngeal paralysis in a mixed-breed horse population, focusing especially on recurrent laryngeal neuropathy (RLN), a common cause of the condition.

Study Overview

  • The research recorded and analyzed 375 instances of laryngeal paralysis in horses from 1985 to 1998. Most of the cases (94%) were of Recurrent Laryngeal Neuropathy (RLN), with the remaining 6% arising from other causes.
  • The study involved horses of various breeds; the predominant being Thoroughbred and Thoroughbred-cross breeds, making up a combined 85% of the RLN cases.
  • Horses’ laryngeal movements were endoscopically classified into six grades, compared to the typical four grades utilized in other studies.

Laryngeal Paralysis in RLN Cases

  • The paper documents that RLN predominantly caused left-sided laryngeal paralysis with 96% of the recorded cases being left-sided, 2% right-sided, and the remaining 2% bilateral.
  • Most of the horses affected by RLN were in the 2-12 year age range, with a median age of 6 years.
  • A wide range of work activities was reported for the RLN-affected horses, with National Hunt racing being the most common (42% of cases), followed by miscellaneous work (22%), hunting (19%), and eventing (16%). Flat racing reported the least number of cases (1%).
  • The primary symptoms in RLN-affected horses were abnormal respiratory sounds (in 90% of cases) and reduced exercise tolerance (in 64% of cases). Many of the horses were referred before a thorough assessment of exercise tolerance could be conducted.

Additional Disorders in RLN Cases

  • About 40% of RLN cases occurred along with other disorders, referred to as intercurrent disorders in the study. These included upper respiratory diseases in 10% of the cases and lower respiratory tract diseases in 7% of the cases.

Non-RLN Cases

  • Apart from the RLN cases, the study also examined 24 non-idiopathic RLN cases. These included 12 cases with bilateral laryngeal paralysis, the majority of which (92%) involved ponies.
  • Bilateral laryngeal paralysis was found to be associated with hepatic encephalopathy in seven instances and following general anaesthesia in two instances.
  • Acquired unilateral laryngeal paralysis was noted in the remaining 12 cases, with guttural pouch mycosis being the cause in seven of these instances.

Cite This Article

APA
Dixon PM, McGorum BC, Railton DI, Hawe C, Tremaine WH, Pickles K, McCann J. (2001). Laryngeal paralysis: a study of 375 cases in a mixed-breed population of horses. Equine Vet J, 33(5), 452-458. https://doi.org/10.2746/042516401776254790

Publication

Equine veterinary journal
ISSN: 0425-1644
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 33
Issue: 5
Pages: 452-458

Researcher Affiliations

Dixon, P M
  • The Wellcome Trust Centre for Studies in Comparative Respiratory Medicine, The University of Edinburgh, Easter Bush Veterinary Centre, Easter Bush, Midlothian, Scotland.
McGorum, B C
    Railton, D I
      Hawe, C
        Tremaine, W H
          Pickles, K
            McCann, J

              MeSH Terms

              • Animals
              • Diagnosis, Differential
              • Female
              • Horse Diseases / diagnosis
              • Horse Diseases / etiology
              • Horse Diseases / physiopathology
              • Horses
              • Laryngoscopy / veterinary
              • Male
              • Physical Conditioning, Animal
              • Prospective Studies
              • Recurrence
              • Recurrent Laryngeal Nerve / physiopathology
              • Respiratory Sounds / etiology
              • Respiratory Sounds / physiopathology
              • Respiratory Sounds / veterinary
              • Retrospective Studies
              • Vocal Cord Paralysis / diagnosis
              • Vocal Cord Paralysis / etiology
              • Vocal Cord Paralysis / physiopathology
              • Vocal Cord Paralysis / veterinary

              Citations

              This article has been cited 12 times.
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