Equis ISSN 2398-2977
CNS: myeloencephalopathy - degenerative
Synonym(s): EDM
Contributor(s): Frank Andrews, Caroline Hahn, Robert J MacKay, Michael Porter, Vetstream Ltd
Introduction
- Progressive degenerative disorder of the central nervous system (CNS).
- Cause: etiology unknown; vitamin E deficiency has been implicated, along with a familial tendency.
- Signs: symmetric tetraparesis and ataxia in foals and young horses.
- Diagnosis: clinical signs and elimination of other neurogenic and neuromuscular syndromes.
- Treatment: none available. Supplementation of vitamin E may reduce clinical signs but is not curative.
- Prognosis: progressive condition which may stabilize as animal matures.
Pathogenesis
Etiology
- Available evidence strongly supports the hypothesis that equine degenerative myeloencephalopathy (EDM) is caused by a vitamin E deficiency that has a familial predisposing component.
- Other risk factors elucidated include prior use of insecticides and exposure to wood preservatives.
- Pathophysiology therefore may include exposure to environmental oxidants and lack of antioxidants, including vitamin E.
Specific
- Access to dirt lots, use of heated pelleted feed and sun-baked forages with low vitamin E contents.
- Familial tendency.
Pathophysiology
- Progressive diffuse spinal cord disease → tetraparesis and ataxia.
- Diffuse degenerative disease of the brainstem and spinal cord that affects proprioceptive relay nuclei as well as dorsal and ventral spinocerebellar tracts.
Timecourse
- Once signs of EDM appear the disease is usually slowly progressive, although some cases may stabilize with maturity.
- No significant improvement/remission is seen with age.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Nayler R J (2010) Equine degenerative myeloencephalopathy in a horse in the UK. Vet Rec 167 (10), 380-382 PubMed.
- Hahn C (2006) The wobbly horse: differential diagnoses. In Pract 28 (1), 8-13 VetMedResource.
- Gandini Get al (2004) Equine degenerative myeloencephalopathy in five Quarter Horses: clinical and neuropathological findings. Equine Vet J 36 (1), 83-85 PubMed.
- Goehring L S et al (2001) The mystery of equine herpes myeloencephalopathy. Equine Vet Educ 13 (1), 53-59 VetMedResource.
- Miller M M & Collatos C (1997) Equine degenerative myeloencephalopathy. Vet Clin North Am Equine Pract 13 (1), 43-52 PubMed.
- Mayhew I G, Brown C M et al (1987) Equine degenerative myeloencephalopathy; A vitamin E deficiency which may be familial. J Vet Intern Med 1 (1), 45-50 PubMed.
- Beech J (1987) Equine degenerative myeloencephalopathy. Vet Clin North Am Equine Pract 3 (2), 379-383 PubMed.