However, vision recovery does occur in some cases, and reports have varied on the long-term prognosis. History
Purtschers retinopathy was first characterized in 1910 and 1912 as a syndrome of sudden blindness after head trauma, with patches of hemorrhage and whitening of the retina in both eyes. Later, it was discovered to occur after other types of trauma, such as chest trauma, and is associated with several non-traumatic systemic diseases. Purtschers retinopathy may also be associated with acute pancreatitis, vasculitis, embolization of such materials as fat and amniotic fluid, systemic lupus erythematosus, thrombotic thrombocytopenic purpura, and chronic kidney failure. Purtschers retinopathy may be caused by extensive fractures of the long bones. References


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The subacute form causes weakness, fasciculations, cramping, and stiffness of muscles, which can lead to recumbency, as well as a stilted gait, dysphagia, ptyalism, and a weak suckle. It may be treated with selenium supplementation, but there is a 30–45% mortality rate. Other sequelae include aspiration pneumonia, failure of passive transfer, and stunting of growth. Clinical laboratory changes include evidence of rhabdomyolysis (elevated CK and AST, myoglobinuria) and low blood selenium levels. On necropsy, muscles are pale with areas of necrosis and edema evidenced as white streaks.Horses may also develop a more chronic delayed form of the disease called Neuroaxonal Dystrophy (NAD) or Equine Degenerative Myeloencephalopathy (EDM). EDM is a more severe form of NAD. The diseases are characterized by the damage and degeneration of the central nervous system. This disease process is heritable in certain breed bloodlines, such as Quarter Horse, Appaloosa, Morgan, Lusitano, and Arabian. It is hypothesized that horses develop this disease continuum because they have a defect in the uptake or utilization of Vitamin E and therefore have a higher baseline requirement. Sheep (Stiff Lamb Disease)
In lambs, the disease typically occurs between 3 and 8 weeks of age, but may occur in older lambs as well. Progressive paralysis occurs, which is evident through the following symptoms: arched back, difficulty moving and an open shouldered stance.