Clinical and endoscopic evidence of progression in 152 cases of equine recurrent laryngeal neuropathy (RLN).
Abstract: Examination of the long-term histories and clinical findings was performed in 351 horses suffering from recurrent laryngeal neuropathy (RLN) to examine for possible evidence of progression of this disorder. Fifty-two out of 351 cases (15%) had evidence of progression of the degree of laryngeal dysfunction over a median period of 12 months (range 1.5-48 months) with the onset of progression occurring at median age 7 years. In 30 cases, there was both endoscopic (median deterioration of 3 endoscopic grades; range 1-5 grades) and clinical evidence, with 29 (97%) of these horses concurrently developing sudden-onset, abnormal exercise-related respiratory 'noises' and 13 (43%) concurrently reporting reduced exercise performance. In the remaining 22 horses there was solely clinical evidence of RLN progression, including the sudden onset of abnormal exercise-related respiratory sounds in 16 (73%) and the worsening of such sounds in 6 (23%), associated with reduced exercise performance in 13 (59%) of these 22 cases. Endoscopically, 13 (59%) of the latter 22 cases had marked (total or almost total) RLN that did not appear compatible with their previous exercise-performance histories. This evidence of progression of RLN may be of particular significance in disputes concerning horses that are apparently normal at pre-purchase examination but are later shown to have RLN and also in the surgical treatment of less severe cases of RLN.
Publication Date: 2002-01-31 PubMed ID: 11817549DOI: 10.2746/042516402776181169Google Scholar: Lookup
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- Journal Article
- Case Reports
- Clinical Examination
- Clinical Findings
- Clinical Pathology
- Clinical Study
- Clinical Symptoms
- Diagnosis
- Disease Diagnosis
- Disease Etiology
- Disease Progression
- Endoscopy
- Equine Diseases
- Equine Health
- Exercise
- Horses
- Laryngeal Dysfunction
- Longitudinal Study
- Respiratory Disease
- Veterinary Medicine
- Veterinary Practice
- Veterinary Research
Summary
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The research article explores the progressive nature of recurrent laryngeal neuropathy (RLN) in horses. It specifically studies the evident progression of RLN in a pool of 351 horses, finding that about 15% of the cases showed progression over time, with worsening symptoms such as abnormal respiratory sounds during exercise, and in some cases, declining exercise performance.
Study Overview and Method
- The study was conducted on 351 horses diagnosed with recurrent laryngeal neuropathy (RLN) with an aim to determine if the disorder progresses over time.
- Key parameters like clinical findings, longitudinal histories, and endoscopic grades were reviewed for all the subjects under study.
- The main points of interest were observing changes (or progression) in the degree of laryngeal dysfunction and how the onset of this progression corresponds to the age of the horses.
Main Findings
- Out of the total studied cases, 15% (52 out of 351 horses) exhibited definite progression in their condition over a median period of 12 months. The median age at the onset of this worsening was 7 years.
- The study further subdivides these 52 cases into two main categories. The first category consists of 30 horses showing both clinical and endoscopic evidences. Ninety seven percent of these developed abnormal exercise-related respiratory sounds and 43% reported reduced exercise performance.
- The remaining 22 out of 52 cases showed only clinical evidence of the deterioration, with abnormal respiratory noises being seen in 73% of the horses and worsening of such noises in 23%. Fifty nine percent of these reported a decline in their exercise performance.
- Upon endoscopic examination, 59% of the latter category had severe RLN, a revelation inconsistent with their previous exercise-performance history.
Implications of the Findings
- The investigation of the progression of RLN has significant implications, particularly in cases where horses appear normal during a pre-purchase examination but are later found to have RLN.
- It also plays a vital role in planning the surgical treatment approach for less severe cases of RLN, as understanding the progression can help decide the need and urgency for surgical intervention.
Cite This Article
APA
Dixon PM, McGorum BC, Railton DI, Hawe C, Tremaine WH, Pickles K, McCann J.
(2002).
Clinical and endoscopic evidence of progression in 152 cases of equine recurrent laryngeal neuropathy (RLN).
Equine Vet J, 34(1), 29-34.
https://doi.org/10.2746/042516402776181169 Publication
Researcher Affiliations
- The Wellcome Trust Centre for Studies in Comparative Respiratory Medicine, The University of Edinburgh, Easter Bush Veterinary Centre, Midlothian, Scotland.
MeSH Terms
- Animals
- Disease Progression
- Female
- Follow-Up Studies
- Horse Diseases / physiopathology
- Horses
- Laryngoscopy / veterinary
- Male
- Physical Conditioning, Animal
- Recurrent Laryngeal Nerve / physiopathology
- Respiratory Sounds / physiopathology
- Respiratory Sounds / veterinary
- Vocal Cord Paralysis / physiopathology
- Vocal Cord Paralysis / veterinary
Citations
This article has been cited 8 times.- Draper ACE, Piercy RJ. Pathological classification of equine recurrent laryngeal neuropathy. J Vet Intern Med 2018 Jul;32(4):1397-1409.
- Boyko AR, Brooks SA, Behan-Braman A, Castelhano M, Corey E, Oliveira KC, Swinburne JE, Todhunter RJ, Zhang Z, Ainsworth DM, Robinson NE. Genomic analysis establishes correlation between growth and laryngeal neuropathy in Thoroughbreds. BMC Genomics 2014 Apr 3;15:259.
- Dupuis MC, Zhang Z, Druet T, Denoix JM, Charlier C, Lekeux P, Georges M. Results of a haplotype-based GWAS for recurrent laryngeal neuropathy in the horse. Mamm Genome 2011 Oct;22(9-10):613-20.
- Rhee HS, Steel CM, Derksen FJ, Robinson NE, Hoh JF. Immunohistochemical analysis of laryngeal muscles in normal horses and horses with subclinical recurrent laryngeal neuropathy. J Histochem Cytochem 2009 Aug;57(8):787-800.
- Hardwick JL, Ahern BJ, Crawford KL, Allen KJ, Anderson BH, Rose KJ, Franklin SH. Yearling laryngeal function grades II.2 and below are not associated with reduced performance. Equine Vet J 2025 Jul;57(4):953-966.
- McGivney CL, McGivney BA, Farries G, Gough KF, Han H, Holtby AR, MacHugh DE, Katz LM, Hill EW. A genome-wide association study for recurrent laryngeal neuropathy in the Thoroughbred horse identifies a candidate gene that regulates myelin structure. Equine Vet J 2025 Jul;57(4):943-952.
- Hardwick JL, Ahern BJ, Crawford KL, Allen KJ, Franklin SH. Yearling laryngeal function in Thoroughbreds that underwent a laryngoplasty differs from controls. Equine Vet J 2025 Mar;57(2):431-440.
- Lean NE, Franklin SH, Steel C, Woolford L, White J, Ahern BJ. Evaluation of recurrent laryngeal neuropathy in domestic and feral horse populations in Australia using histologic and immunohistochemical analysis: A pilot study. Vet Med Sci 2023 Jul;9(4):1610-1617.
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