Periodic Paralysis
Background
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Due to hereditary skeletal muscle ion channelopathies
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Hyperkalemic periodic paralysis:
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Episodes of myotonia & muscle weakness that may last for several hours
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Weakness can occur during rest after strenuous exercise, infusion of potassium, metabolic acidosis, or hypothermia
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The hyperkalemia is transient & occurs only at the time of weakness
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Acute attacks can be fatal because of cardiac dysrhythmias or respiratory failure
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A chronic myopathy frequently develops in older patients
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Treatment consists of a low potassium diet & the administration of thiazide diuretics
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Hypokalemic periodic paralysis:
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Paralysis can be produced by a ↓ in serum potassium levels caused by strenuous exercise, infusion of glucose and insulin, or ingestion of carbohydrates & sodium rich food
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Paralysis usually affects the limbs and trunk, but spares the diaphragm. Chronic muscle weakness occurs in most patients as they age
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Considerations
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Risk of periodic paralysis attacks, with potential for respiratory failure & cardiac dysrhythmias
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Avoid triggers of attacks:
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Hyperkalemic Periodic Paralysis (attacks when K >5.5)
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K infusion
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Metabolic acidosis
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Hypothermia
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Hypokalemic Periodic Paralysis (attacks when K <3.0):
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Glucose/insulin infusion & other K lowering shift drugs
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↓ K
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Hypothermia
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Carbohydrate load
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Sensitivity to NDMRs: use ↓ dose, continuous monitoring with twitch monitor
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Avoid succinylcholine (due to ↑ K) in hyperkalemic periodic paralysis (ok with hypokalemic periodic paralysis)
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Frequent electrolyte monitoring esp. K