A light and electron microscopic study of the neuropathy of equine idiopathic laryngeal hemiplegia.
Abstract: A study has been made of the pathological changes in the recurrent laryngeal nerves from horses with clinical and sub-clinical idiopathic laryngeal hemiplegia. Qualitative and quantitative studies showed in clinical cases there was a progressive distal loss of large myelinated fibres in the left recurrent nerve. Regenerating clusters and onion bulbs were frequently seen in affected nerves both at proximal and distal levels. Degenerating axons were characterized by collections of organelles, and denervated bands of Bungner were common. Similar but less severe changes were seen in the left recurrent nerve of sub-clinical cases, and in both the clinical and sub-clinical cases the distal right recurrent nerve was also affected. Teased fibre studies showed evidence of chronic demyelination and remyelination. The aetiology of this chronic neuropathy remains uncertain but the possibility of nerve compression is discussed.
Publication Date: 1978-11-01 PubMed ID: 745676DOI: 10.1111/j.1365-2990.1978.tb01358.xGoogle Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This study investigates the pathological changes observed in the recurrent laryngeal nerves of horses affected by idiopathic laryngeal hemiplegia—a condition of unknown cause that impairs the function of the larynx. The research reveals a pattern of progressive nerve damage, along with signs of nerve regeneration and chronic demyelination. The exact cause of this condition is still unknown but nerve compression is being considered.
Objective of the Research
- The research primarily aims to understand the pathological changes occurring in horses suffering from idiopathic laryngeal hemiplegia, a condition that affects the function of the larynx and potentially causing difficulty in breathing and changes in voice – a condition of clinical and veterinary importance. The causes of this condition remain unclear.
Methodology
- The laryngeal nerves from affected horses were studied both through light and electron microscopy to analyze the structural and morphological alterations.
- Both qualitative and quantitative studies were performed on these nerves. The research focused on progressive distal loss of large myelinated fibres, a distinct feature of degenerative nerve disorders.
- Teased fibre studies, a method that enables researchers to examine individual nerve fibres, were also conducted to assess the extent of chronic demyelination and remyelination.
Findings
- Significant pathological changes were observed in the left recurrent nerves in clinical cases, including progressive loss of large myelinated fibres—this essentially means the protective layering around nerve fibres was eroding over time.
- Regenerating clusters and onion bulbs, which are formations seen during the process of nerve healing after damage, were often noticed not only at proximal but also distal levels. This indicates the nerves’ attempts to repair themselves.
- Degeneration of the nerves was characterized by visible collections of organelles—a sign of neuronal injury or disease.
- Denervated bands of Bungner, which occur once a peripheral nerve has been injured, were common. These structures support axonal regrowth after an injury.
- Similar, yet less severe, changes were seen in the left recurrent nerve in subclinical cases and the distal right recurrent nerve in both clinical and subclinical cases—this suggests the condition isn’t exclusive to one side.
- Teased fibre studies presented strong evidence for chronic demyelination and remyelination, suggesting a prolonged and ongoing damage-repair process in these nerves.
Conclusions
- The cause of this chronic nerve condition remains uncertain. However, the researchers discuss the possibility of nerve compression playing a role, which might provide a direction for further studies.
Cite This Article
APA
Duncan ID, Griffiths IR, Madrid RE.
(1978).
A light and electron microscopic study of the neuropathy of equine idiopathic laryngeal hemiplegia.
Neuropathol Appl Neurobiol, 4(6), 483-501.
https://doi.org/10.1111/j.1365-2990.1978.tb01358.x Publication
Researcher Affiliations
MeSH Terms
- Animals
- Cell Count
- Horse Diseases / pathology
- Horses
- Laryngeal Nerves / pathology
- Microscopy, Electron
- Myelin Sheath / pathology
- Nerve Degeneration
- Nerve Fibers, Myelinated
- Recurrent Laryngeal Nerve / pathology
- Vocal Cord Paralysis / pathology
- Vocal Cord Paralysis / veterinary
Citations
This article has been cited 17 times.- Cahalan SD, Boehm I, Jones RA, Piercy RJ. Recognising the potential of large animals for modelling neuromuscular junction physiology and disease. J Anat 2022 Nov;241(5):1120-1132.
- Cercone M, Hokanson CM, Olsen E, Ducharme NG, Mitchell LM, Piercy RJ, Cheetham J. Asymmetric recurrent laryngeal nerve conduction velocities and dorsal cricoarytenoid muscle electromyographic characteristics in clinically normal horses. Sci Rep 2019 Feb 25;9(1):2713.
- Sandersen C, Ceusters J, Fourez A, Tosi I, Graide H, Lejeune JP, Serteyn D. Nerve Stimulator-guided Injection of Autologous Stem Cells Near the Equine Left Recurrent Laryngeal Nerve. J Vis Exp 2018 Sep 26;(139).
- 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.
- Collins N, Milne E, Hahn C, Dixon P. Correlation of the Havemeyer endoscopic laryngeal grading system with histopathological changes in equine Cricoarytenoideus dorsalis muscles. Ir Vet J 2009 May 1;62(5):334-8.
- 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.
- Alexander MJ, Barkmeier-Kraemer JM, Vande Geest JP. Biomechanical properties of recurrent laryngeal nerve in the piglet. Ann Biomed Eng 2010 Aug;38(8):2553-62.
- 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.
- Duncan ID, Schneider RK, Hammang JP. Subclinical entrapment neuropathy of the equine suprascapular nerve. Acta Neuropathol 1987;74(1):53-61.
- Harrison GD, Duncan ID, Clayton MK. Determination of the early age of onset of equine recurrent laryngeal neuropathy. 1. Muscle pathology. Acta Neuropathol 1992;84(3):307-15.
- Duncan ID. Determination of the early age of onset of equine recurrent laryngeal neuropathy. 2. Nerve pathology. Acta Neuropathol 1992;84(3):316-21.
- Al Shehab G, Naji R, Alali F, Alali A, Allowaim A, Almohammed A, Aljasim D, Alkhalifah A, Alhammad YMA, Marzok M, Mohamad ZA, Almuhanna AH. Laryngoscopic evaluation of arytenoid movements in pure Arabian horses. Open Vet J 2025 Jun;15(6):2875-2881.
- 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.
- 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.
- Anderson RS, Chu AK, Rylander H, Binversie EE, Duncan ID, Baker L, Salamat S, Patterson MM, Gruel J, Kohler NL, Kearney HK, Ale SM, Momen MM, Muir P, Svaren JP, Johnson R, Sample SJ. Pathologic classification of a late-onset peripheral neuropathy in a spontaneous Labrador retriever dog model. J Comp Neurol 2024 Mar;532(3):e25596.
- Kollech HG, Chao MR, Stark AC, German RZ, Paniello RC, Christensen MB, Barkmeier-Kraemer JM, Vande Geest JP. Extracellular matrix deformations of the porcine recurrent laryngeal nerve in response to hydrostatic pressure. Acta Biomater 2022 Nov;153:364-373.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
