What is acute periodic paralysis?

Updated: Dec 28, 2017
  • Author: Courtney A Bethel, MD, MPH; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Acute periodic paralysis may be classified as hypokalemic, hyperkalemic, or normokalemic. Note the following:

  • Normokalemic paralysis causes the most severe and prolonged attacks
  • Patients usually feel well between attacks, but some have myotonia (ie, muscle stiffness) or residual weakness after repeated episodes
  • A genetic defect has been linked to these diseases, but in some instances, hypokalemia may cause acute weakness in healthy individuals
  • Acute hypokalemic periodic paralysis may be primary (ie, familial) or secondary to excessive renal or GI losses or endocrinopathy; in these cases, intracellular shift of potassium depolarizes the cell membrane, rendering it inexcitable and ensuring that no muscle contraction can occur, with the result that the patient experiences paralysis; this may occur independent of the sodium-potassium pump
  • Familial periodic paralysis usually occurs in Caucasian males, is autosomal dominant, and may last as long as 36 hours
  • Attacks usually occur at night or in early morning upon awakening and can be precipitated by a diet high in carbohydrates, rest following exercise, or glucose and insulin given intravenously

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