Polioencephalomalacia
Polioencephalomalacia (PEM), also referred to as cerebrocortical necrosis (CCN), is a neurological disease seen in
Causes
Thiamine deficiency
Thiamine availability is controlled by the direct dietary consumption of thiamine. Thiamine availability is also regulated by
Overconsumption of glucose
Since glucose metabolism is regulated by thiamine, the overconsumption of glucose can also result in thiamine inadequacy.[7] When there is a sudden increase of glucose in the body, thiamine will be depleted so that thiamine is not available when the next round of glucose needs to be metabolized.
High sulfur intake
In light of recent research, high concentrations of sulfur intake have also been deemed responsible for PEM.[8][9] Sulfur is necessary for the synthesis of important sulfur-containing amino acids and their contribution to the synthesis of different hormones, enzymes, and structural proteins. The ruminant diet, especially that of cattle, can be overly concentrated with sulfur. In ruminants, the same rumen microbes that generate thiamine molecules reduce sulfur into toxic sulfides. Among the sulfide toxins is hydrogen sulfide, a gas compound that will compete with oxygen to bind with red blood cells and eventually enter the brain to disrupt neural activity.[10]
Clinical symptoms
Clinical signs of PEM are variable depending on the area of the cerebral cortex affected and may include head pressing, dullness, opisthotonos, central blindness, anorexia, muscle tremors, teeth grinding, trismus, salivation, drooling, convulsions, nystagmus, clonic convulsions, and recumbency.[11] Early administration of thiamine may be curative, but if the lesion is more advanced, then surviving animals may remain partially blind and mentally dull.
See also
- Cortical laminar necrosis[12]
References
- ^ a b "Overview of Polioencephalomalacia - Nervous System". Merck Veterinary Manual. Retrieved 2019-12-02.
- ^ "Thiamine deficiency induced polioencephomalacia (PEM) of sheep and cattle". 2017-05-27.
- ^ Harper, Harold (1942). "Carbohydrate Metabolism in Thiamine Deficiency" (PDF). The Journal of Biological Chemistry. 142: 239–248 – via JBC.
- ^ "Overview of Polioencephalomalacia - Nervous System - Merck Veterinary Manual". Merck Veterinary Manual. Retrieved 2017-05-27.
- ^ Edmondson, Paul. "What is Thiaminase Poisoning - Insectivore". www.insectivore.co.uk. Retrieved 2017-05-27.
- ISBN 9780824750367.
- ISBN 9781455748570.
- ^ "Sulfur Toxicity | College of Veterinary Medicine". vetmed.iastate.edu.
- ISBN 9789400914537.
- ^ "Dietary Sulfur in Ruminant Diets" (PDF). Westway Feed Products.
- ^ "Merck Veterinary Manual". Retrieved 2017-06-17.
- ^ Clinical Management of Polioencephalomalacia in goats S.Sivaraman,G.Vijayakumar,E.venkatesakumar, and K.K.Ponnuswamy Indian Veterinary Journal ,May, 2016, 93,(05) : 70-72"
External links
- Polioencephalomalacia: Disease Caused by a Deficiency of Thiamine at tvsp.org
- http://ag.ansc.purdue.edu/sheep/ansc442/Semprojs/2002/neurological/polio.htm
- http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/102000.htm