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Normokalemic periodic paralysis

Other Names for this Disease
  • Normokalemic PP
  • NormoKPP
  • Periodic paralysis type 3
  • Potassium-sensitive normokalemic periodic paralysis
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What are the signs and symptoms of normokalemic periodic paralysis?

Normokalemic periodic paralysis (normoKPP) is thought to be a variant of hyperkalemic periodic paralysis. Some people with hyperkalemic periodic paralysis have increased levels of potassium in their blood (hyperkalemia) during attacks, while in other cases, attacks are associated with normal blood potassium levels (normokalemia). Ingesting potassium can trigger attacks in affected individuals, even if blood potassium levels do not go up.[1] It has been reported that the potassium-sensitivity in normoKPP resembles hyperkalemic periodic paralysis, whereas other features resemble hypokalemic period paralysis.[2]

The condition causes episodes of extreme muscle weakness that usually begin in infancy or early childhood. These episodes often involve a temporary inability to move muscles in the arms and legs. Factors that may trigger attacks may include rest after exercise; ingesting potassium-rich foods or drinks; stress; fatigue; fasting; and/or exposure to cold temperatures.[1][3][4] Muscle strength generally improves between attacks, although many affected people continue to have mild stiffness (myotonia) in some muscles.[1]
Last updated: 9/12/2012

  1. Hyperkalemic periodic paralysis. Genetics Home Reference. April 2007; Accessed 9/11/2012.
  2. Karin Jurkat-Rott and Frank Lehmann-Horn. Hyperkalemic Periodic Paralysis Type 1. GeneReviews. May 31, 2011; Accessed 9/12/2012.
  3. Michael Rubin. Periodic paralysis. Merck Manuals. January 2008; Accessed 9/12/2012.
  4. Patrick F. Chinnery, Timothy J. Walls, Michael G. Hanna, David Bates, Peter R. W. Fawcett. Normokalemic periodic paralysis revisited: Does it exist?. Annals of Neurology. August 2002;