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What is Primary Periodic Paralysis?

Learn about this neuromuscular condition and the path to diagnosis. 

PPP overview

Primary Periodic Paralysis (PPP) is a rare condition that impacts your muscles.1,2 It can cause episodes of muscle weakness or temporary paralysis, often brought on by triggers.

These episodes usually begin in childhood, typically before age 20.3 Some attacks can begin as early as age 2.

Because PPP is often inherited genetically, people with PPP may have family members who also have PPP symptoms.4

Because PPP is so rare and can be mistaken for other health conditions, it may sometimes take 20+ years to get a diagnosis.3

Over time, uncontrolled PPP may lead to Permanent Muscle Weakness, which does not go away and is independent of PPP episodes.1,3

What causes PPP?

PPP is usually passed down from a parent to a child.4 However, you can still have PPP without a genetic connection if you have the signs and symptoms.2

Understanding the signs and symptoms of PPP

PPP causes recurrent, progressive and debilitating episodes of muscle weakness and temporary paralysis, negatively impacting your daily life.1,2

PPP episodes can vary in number, severity and duration:1

Number of episodes

In some people, episodes happen every day. For others, episodes occur weekly or monthly.

Severity of episodes

PPP episodes may involve weakness that limits some daily activities. More severe episodes can mean complete, but temporary, paralysis.

Length of episodes

Most episodes last a few hours. In some cases, they can last for days.


Before an episode begins, many people report feeling:1

PPP often affects the following muscles:1,2

You could feel anything from muscle weakness to full paralysis during a PPP attack. The length of an attack can vary from hours to days.


You may experience lingering symptoms following an episode of PPP:1




Extreme fatigue


“I usually became paralyzed in the middle of the night, so I would have to holler for my mom or sisters to help turn me because I would be in so much pain. I would have total feeling from head to toe, but couldn’t move a thing.”

Recognizing PPP’s impact

The burden of PPP episodes is not only physical. Weakness, loss of energy and stiff muscles can limit your ability to engage in activities with friends and family, resulting in a serious impact on your emotional state.1

The different types of PPP

There are several subtypes of PPP. What makes them different is the level of potassium in your blood during the episode, what happens during the episode, what triggers it, and which genes are involved.1,2,5

All types of PPP cause muscle weakness that can impact several parts of the body.1,2,6,7,8

Hypokalemic Primary Periodic Paralysis (HypoPPP):

PPP episodes may involve a decrease in potassium levels.2,9

Take potassium supplements as recommended by a healthcare provider.2,9 Eat a low sodium, low carbohydrate diet.

Hyperkalemic Primary Periodic Paralysis (HyperPPP):

PPP episodes may involve an increase in potassium levels.2,9 In some cases, potassium levels are normal during an episode.

Eat frequent carbohydrate-heavy meals. Avoid potassium-rich foods.2,9

Paramyotonia Congenita (PMC):

Attacks of muscle stiffness that occur during activity such as exercise.10

Avoid cold temperatures and strenuous exercise.9

Andersen-Tawil syndrome (ATS):

Characterized by muscle weakness, changes in heartbeat, and distinct skeletal features.2,11 It is associated with low, normal, or high potassium levels during an episode.

Light exercise may help shorten or decrease the severity of an episode.11


What can trigger a PPP episode?

PPP episodes can happen at any time — but they’re usually brought on by a trigger.1,2 Common triggers across the 4 PPP types may include:

  • Certain foods that have a lot of potassium or carbohydrates
  • Stress
  • Exposure to cold or becoming chilled
  • Alcohol
  • Resting after exercise

Triggers can vary depending on your specific PPP diagnosis, as well as other factors.


The path to a PPP diagnosis

Because of how rare PPP is, it can be challenging to receive an accurate diagnosis.1,2 Your symptoms may be confused for those of more common conditions, like cardiovascular or mental health disorders such as depression.

If PPP is suspected, your doctor may review your medical history and your family’s medical history, then perform a physical exam and blood tests.2 Your doctor may also recommend:

  • Genetic testing
  • Electrocardiogram (EKG)
  • Electromyography (EMG)
  • Compound muscle action potential (CMAP)


  1. Charles G, Zheng C, Lehmann-Horn F, Jurkat-Rott K, Levitt J. Characterization of hyperkalemic periodic paralysis: a survey of genetically diagnosed individuals. J Neurol. 2013;260:2606-2613.
  2. Statland JM, Fontaine B, Hanna MG, et al. Review of the diagnosis and treatment of periodic paralysis. Muscle Nerve. 2018;57:522-530.
  3. Cavel-Greant D, Lehmann-Horn F, Jurkat-Rott K. The impact of permanent muscle weakness on quality of life in periodic paralysis: a survey of 66 patients. Acta Myol. 2012;31:126-133.
  4. Fontaine B, Phillips LH 2nd. A newly approved drug for a rare group of diseases: dichlorphenamide for periodic paralysis. Neurology. 2016;86:1366-1367.
  5. Weber F. Hyperkalemic Periodic Paralysis. In: Adam MP, Feldman J, Mirzaa GM, et al., eds. GeneReviews®. Seattle (WA): University of Washington, Seattle; July 18, 2003.
  6. National Institutes of Health. Paramyotonia congenita. Available at: Accessed March 22, 2024
  7. National Institutes of Health. Andersen-Tawil syndrome. Available at: Accessed March 22, 2024
  8. Cannon, SC. Channelopathies of skeletal muscle excitability. Compr Physiol. 2015;5(2):761-790.
  9. Ralph J, Ptacek L. Muscle channelopathies: periodic paralyses and nondystrophic myotonias. In: Rosenberg RN, Pascual JM, eds. Rosenberg’s Molecular and Genetic Basis of Neurological and Psychiatric Disease. 5th ed. Elsevier; 2015:1177- 1189.
  10. Paramyotonia Congenita. MedlinePlus. Updated August 1, 2015. Accessed June 4, 2024.
  11. Veerapandiyan A, Statland JM, Tawil R. Andersen-Tawil Syndrome. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews®. University of Washington, Seattle; 1993-2019. Updated June 7, 2018. Accessed March 22, 2024.

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