recumbency, stupor, flaccid paralysis, coma and death. In a heavily lactating individual, the progression of symptoms may be rapid.
Diagnosis is made through blood chemistry revealing hypocalcemia.
Treatment is the administration of an IV calcium soloution. Calcium gluconate is recommended as this soloution is a bioavaliable form of calcium ion.
Hyperkalemic Periodic Paralysis Hyperkalemic periodic paralysis is often shortened to HYPP and is described as a genetic disorder of the channels of the skeletal muscle cells. HYPP is caused by an autosomal, dominant mutation in the gene that codes for the transport protein associated with the voltage-gaited sodium channels in muscle cells. This mutation can be traced back to the Quarter horse sire . As this mutation is dominant, clinical manifestations of disease are seen in both heterozygous and homozygous individuals, however more frequent and more severe symptoms are generally seen in homozygotes than in hetrozygotes. Horses affected by the HYPP mutation produce faulty voltage-gaited sodium channels. These channels allow sodium to trickle into the muscle cell which slowly makes the intracellular fluid more positive. Eventually the charge of the intracellular fluid will depolarise to threshold causing the involuntary contraction of muscle fibres. High circulating levels of have been shown to increase the leaking of sodium into the muscle cells as an increase in circulating potassium creates a concentration of positively charged ions outside the muscle cells. Quarter horses and Quarter horse-crosses who are descendants of the sire Impressive are predisposed to HYPP. Affected individuals who are under stress or who are feed high potassium diets such as alfalfa hay are more predisposed to experiencing an episode of HYPP than those affected individuals who are kept in a relaxed environment and are feed low potassium diets. Clinically HYPP manifests as muscular and weakness, stiffness in the hindquarters, staggering gait, dog-sitting or recumbency, inability to rise, roaring due to paralysis of the muscles of the upper respiratory tract, prolapse of the third eyelid, systemic paralysis, or death due to cardiac arrest or respiratory failure. There is no pain associated with an episode of HYPP, and there are no side effects or aftereffects seen once the episode has run its course.
Diagnosis can be made through clinical signs and symptoms and is confirmed by genetic testing.
Treatment of HYPP is the administration of IV fluids, using a solution that is potassium-free, as well as the administration of drugs that remove potassium from the body.
130
Made with FlippingBook Publishing Software