Histological and ultrastructural evidence that recurrent laryngeal neuropathy is a bilateral mononeuropathy limited to recurrent laryngeal nerves.
BACKGROUND
Recurrent laryngeal neuropathy (RLN) is a common and debilitating peripheral nerve disease of horses, but it remains unclear if this disease is a mono- or polyneuropathy. An understanding of the distribution of the neuropathological lesions in RLN affected horses is fundamental to studying the aetiology of this very significant disease of tall horses.


OBJECTIVE
To determine whether RLN should be classified as a mono- or polyneuropathy.


METHODS
Multiple long peripheral nerves and their innervated muscles were examined systematically in 3 clinically affected RLN horses


RESULTS
Severe lesions were evident in the left as well as right recurrent laryngeal nerves in all horses, both distally and, in one case, also proximally. No primary axonal lesions were evident in other nerves nor were changes found in their innervated muscles.


CONCLUSIONS
RLN is not a polyneuropathy but should be classified as a bilateral mononeuropathy.


CONCLUSIONS
Genetic and local factors specifically affecting the recurrent laryngeal nerves in RLN-affected horses should now be investigated further.
Hahn
C N
CN
Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH259RG, UK.
Matiasek
K
K
Dixon
P M
PM
Molony
V
V
Rodenacker
K
K
Mayhew
I G
IG
D000818:Animals; D005260:Female; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D008297:Male; D020422:Mononeuropathies / Q000473:pathology / Q000662:veterinary*; D011115:Polyneuropathies / Q000473:pathology / Q000662:veterinary*; D012008:Recurrence; D012009:Recurrent Laryngeal Nerve / Q000473:pathology* / Q000648:ultrastructure*; D012135:Respiratory Sounds / Q000662:veterinary; D012720:Severity of Illness Index; D014826:Vocal Cord Paralysis / Q000473:pathology / Q000662:veterinary*