Shivers
Shivers is a progressive neuromuscular disease.
The cause of shivers is . Proposed theories include viral infection or sensory neuropathy/myopathy. Another theory describes shivers as a type of equine polysaccharide storage myopathy, or EPSM, where genetically predisposed horses experience muscle damage when fed high carbohydrate diets. Due to the unknown cause the pathogenesis can only be speculated on. It is believed there is a lesion within the sensory or motor pathways between the brainstem and the affected muscles/receptors. There is some speculation that it may be related to genetics, as it is most common in breeds. . The affected limb(s) will be flexed & abducted and quiver while in the air. The tail may also be extended. Symptoms tend to be more apparent when the horse is intensively worked or when the horse is asked to or circle. In some cases, there is a lessening of symptoms when the horse is rested. The horse will appear normal after the episode. Clinically shivers is seen as fasciculations of the muscles of the Diagnosis can be quite difficult as there is no clear etiology for shivers. Clinical presentation, muscle biopsy and case history all contribute to the diagnosis of shivers. Patellar and stifle abnormalities must be also ruled out as conditions such as OCD of the stifle joint and upward fixation of the patella may present similar clinical signs as shivers. Joint disease can be ruled out through radiography of the stifle and the patella. Other neurological conditions such as equine protozoal myeloencephalitis (EPM), and wobbler’s disease may also present similarly to mild cases of shivers. . In animals that have been identified as suffering from EPSM some control of symptoms may be achieved through diet modification to reduce the carbohydrate intake and to increase the fat content of feed. There are also reports that selenium and vitamin E supplementation may reduce the clinical signs of shivers. There is no known definitive treatment for shivers, as the disease is thought to be
Prognosis is poor for athletic return as the disease is progressive.
Stringhalt
Stringhalt is an idiopathic hyperflexia neuromuscular disease affecting the digital extensor muscle of the hindquarters. Stringhalt is categorized into 2 groups depending on cause, Classic or sporadic and Australian or plant associated.
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