Central neuropathology of equine grass sickness

Hahn, Caroline; Mayhew, I. G.; Lahunta, Alexander de

doi:10.1007/s004010000289

Cited by 49 publications

(43 citation statements)

References 19 publications

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“…The muscle fasciculations, typically, but not exclusively, affecting the quadriceps and triceps muscle groups, is one particular clinical sign which is difficult to attribute to dysfunction of the autonomic nervous system. Although the precise underlying mechanisms in EGS remain unconfirmed, such tremors may partly reflect a degree of lower motor neuron paresis, consistent with the reported somatic lower motor neuron degeneration in the ventral horn of the spinal cord (Hahn 2000;Wijnberg et al 2006). Indeed, the presence of myasthenia in EGS is supported by the frequent adoption of a base-narrow stance and low head carriage and frequent weight shifting observed in most cases (Lyle and Pirie 2009); although, none of these signs were reported in the donkey described.…”

supporting

confidence: 68%

Equine grass sickness in a donkey

Pirie

2013

Equine Veterinary Education

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supporting

confidence: 68%

Equine grass sickness in a donkey

Pirie

2013

Equine Veterinary Education

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“…Central histopathological changes are also found in EGS (Hahn et al 2001). The loss of SP and CGRP from the nasal mucosa may be relevant in this respect, as the nerve cell bodies are present in the trigeminal ganglion (Grunditz et al 1994).…”

Section: Discussionmentioning

confidence: 92%

“…The loss of SP and CGRP from the nasal mucosa may be relevant in this respect, as the nerve cell bodies are present in the trigeminal ganglion (Grunditz et al 1994). Although the central changes are anatomically specific (Hahn et al 2001), the severity of the lesions does not correlate with the severity of clinical signs (Wright and Hodson 1988;Hahn et al 2001). However, there is a strong suggestion that CNS lesions are more extensive and severe in acute and subacute than in chronic cases (Gilmour 1973;Hahn et al 2001).…”

Section: Discussionmentioning

confidence: 99%

“…While the aetiology of EGS is unknown, the overall pathology is felt to be compatible with neurotoxicosis and retrograde axonal transport of a neurotoxin is the probable cause of lesions in ganglionic structures (Griffiths et al 1994), but a circulating factor probably explains the central neuropathological changes (Hahn et al 2001). To date, there is no published information on the state of the autonomic innervation in the nasal mucosa of EGS horses, despite rhinitis sicca being a common component of the clinical presentation.…”

Section: Discussionmentioning

confidence: 99%

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Changes in nasal mucosal innervation in horses with grass sickness

Prince

Corcoran

Mayhew

2003

Equine Veterinary Journal

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Summary Reasons for performing study: Equine grass sickness is a dysautonomia characterised by widespread destruction of autonomic ganglia, resulting in the clinical signs of dysphagia, constipation, profuse sweating, tachycardia, rhinitis sicca and high mortality rate. Rhinitis sicca is a common finding in horses with the chronic form and we have postulated that alterations in autonomic innervation of the nasal mucosa might underlie this clinical presentation. Objectives: In this study, the expression and distribution of nerve fibres immunoreactive for calcitonin gene‐related peptide (CGRP), substance P (SP), the general neuronal marker protein gene‐product 9.5 (PGP 9.5; ubiquitin) and the intermediate neurofilaments (PAN‐N; neurofilaments L, M and H) in the nasal mucosa of normal horses (n = 10) and horses with EGS (n = 18; acute n = 8, subacute n = 3, chronic n = 7) was assessed. Methods: Innervation density and distribution was investigated in the different groups using standard immunohistochemical techniques. Results: Significant differences were noted when comparing the density and distribution of nerve fibres immunoreactive for PGP 9.5 and PAN‐N, with PGP 9.5 consistently giving better staining in all groups and at all sites in the nasal mucosa. An apparent increase in the density of innervation was noted for acute vs. normal cases. A significant reduction in the density of innervation was noted only with PAN‐N when comparing normal horses and acute cases with the chronic group (P<0.05). CGRP and SP immunoreactive nerve fibres were typically most abundant in the epithelial and subepithelial layers, but the quality of staining and nerve fibre density was greater for SP, achieving significant difference in several comparisons. The density of innervation for SP was significantly reduced in the chronic group compared to the normal and acute groups (P<0.01). A significant decrease was noted for CGRP only for the acute and chronic groups (P<0.05). Conclusions: These results demonstrate a reduction in the expression of the sensory neuropeptides in nasal mucosal innervation as a consequence of equine dysautonomia, and may underlie the clinical presentation of rhinitis sicca noted with this disease. Potential relevance: Nasal biopsy may be of use in antemortem diagnosis of grass sickness and identification of mucosal denervation; and might also be useful in the treatment of rhinitis in EGS cases.

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“…EGS is highly fatal although several reports of recovery exist (Doxey et al 1995(Doxey et al , 2000. Histopathology of submucosal and myenteric nerve plexus in living animals or peripheral autonomic ganglia and certain brainstem nuclei post mortem is required to confirm the diagnosis (Scholes et al 1993;Hahn et al 2001;McCarthy et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Concurrent atypical myopathy and equine dysautonomia in two horses

Vercauteren

Heyden

Lefère

et al. 2007

Equine Veterinary Journal

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This report concerns 2 horses that suffered typical clinical signs of atypical myopathy (AM) and equine grass sickness (EGS) concurrently. Clinical details and pathological lesions of the cases are described. EGS and AM are relatively rare diseases and the concurrency of the diseases in the same animals is therefore considered unlikely to be a coincidence. However, it is not suggested that the evidence shows a common aetiology but rather the existence of common predisposing causes.

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Central neuropathology of equine grass sickness

Cited by 49 publications

References 19 publications

Equine grass sickness in a donkey

Equine grass sickness in a donkey

Changes in nasal mucosal innervation in horses with grass sickness

Concurrent atypical myopathy and equine dysautonomia in two horses

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