Facts you should know about periodic paralysis syndrome

  • Periodic paralysis syndrome is a group of rare muscle diseases that are inherited (genetic) from a biological parent or from a spontaneous mutation in a person's genetic makeup.
  • There are about seven to eight types of periodic paralysis syndromes, for example, hyperkalemic periodic paralysis or hyperPP and normokalemic periodic paralysis.
  • Signs and symptoms of this syndrome involve episodic muscle weakness. Each type of periodic paralysis syndrome has characteristic symptoms and causes, for example, irregular heartbeats, weakness of the respiratory muscles, and muscle weakness from cold temperatures or increased activity.
  • Genetic alteration determines the kind of periodic paralysis syndrome you have.
  • Periodic paralysis syndrome is diagnosed by family history, characteristic symptoms, laboratory tests, muscle biopsies, muscle cooling and/or muscle exercise, and repetitive stimulation of the nerves electrically; and in some people, provocative testing.
  • Your doctor may order preliminary testing to rule out other causes of your muscle weakness, called a differential diagnosis.
  • Treatment depends upon the type of syndrome you have, and may include medications and changes in your diet.
  • If you have a periodic paralysis syndrome, you have a 50% chance of passing the syndrome on to your child.
  • If your biological Mother or Father has any type of periodic paralysis syndrome, and you have undiagnosed episodic muscle weakness, you may want to talk to your primary care doctor about being tested for the condition.

Our doctors are providing you with this information to introduce you to the types and symptoms of periodic paralysis syndrome.

Periodic Paralysis Syndrome Symptoms & Signs

Periodic paralysis syndrome is a rare group of genetic disorders that lead to sudden attacks of short-term muscle weakness, stiffness, or paralysis.

Signs and symptoms of periodic paralysis syndrome include short-term attacks of weakness or paralysis of muscles. These attacks may affect the whole body or just one or two limbs at a time. Other associated symptoms can include

  • tingling in the muscles,
  • muscle pain after exercise,
  • cramping, and
  • permanent weakness later in life.

What is a periodic paralysis syndrome?

Periodic paralysis syndrome is a group of rare muscle diseases that cause temporary episodes of muscle weakness or paralysis. There are seven to eight types of periodic paralysis syndromes in the medical literature. However, not all doctors agree with this number. Some doctors list fewer types because they group them together.

Is periodic paralysis syndrome a genetic disease? How do you get it?

Most types of periodic paralysis syndromes are genetic and inherited (autosomal dominant). However, some are due to a sporadic genetic mutation. The genetic changes (both hereditary and sporadic) result in abnormal muscle responses to various stimulations like cold environments or exercise, and/or elevated electrolyte blood levels, like potassium (hypokalemia).

You develop the disease by inheriting the altered gene(s) from a parent or by a spontaneous or sporadic mutation in your genetic code.


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What are the signs and symptoms of periodic paralysis syndrome?

Periodic paralysis syndromes are all characterized by symptoms of episodic muscle weakness that usually resolves. The person regains normal strength between the periods of episodic muscle weakness. Depending upon the type of periodic paralysis, episodic attacks of muscle weakness may last a few minutes or go on for days. Permanent muscle weakness may develop in some types of the disease. The specific signs, symptoms, and causes of the types of periodic paralysis syndromes are grouped or listed based on the signs and symptoms each type produces.

What are the types of periodic paralysis syndrome?

There are several types of periodic paralysis syndromes.

  • Hyperkalemic periodic paralysis or hyperPP: Signs and symptoms of this type usually begin in children younger than 10 years old. The first symptom may be a lagging upper eyelid (a condition in which the muscles of the eyelid do not follow eye movement). Other symptoms include a stiffness or heaviness to the muscles that begins in the thighs and calves, and spreads to the arms and neck.
  • Hypokalemia periodic paralysis 1 or hypoPP1L: Signs and symptoms of this type usually begin in childhood, and may continue well into the person’s 30s. The symptoms produced are due to calcium channel mutations in the muscles. People with hypoPP1l also experience irregular heartbeats.
  • Hypokalemia periodic paralysis 2 or hypoPP2: This type is the same as hypoPP 1, but it is due to sodium channel mutation in the muscles instead of calcium channel mutations.
  • Normokalemic periodic paralysis: This is a variant form of hyperPP, which the person to become weak when potassium levels increase during normal variations of potassium levels. Some doctors consider this a variant of hyperPP.
  • Thyrotoxic periodic paralysis or TPP: Adults in their 20s, 30s, and 40s (especially Asian males) usually have this form, and symptoms are weakness that may involve the respiratory muscles. Hyperinsulinemia and a carbohydrate intake may trigger a paralytic attack and is associated with an overactive thyroid gland.
  • Paramyotonia congenita or PCM: This type usually occurs in conjunction with hyperPP and produces muscle stiffness or rigidity, weakness response to cold temperatures or increased activity; and is caused by mutation in genes that form the sodium channel of the muscles.
  • Potassium aggravated myotonias or PAMS: In this form, potassium intake triggers an attack of muscle stiffness that can brought on by exercise.
  • Andersen-Tawil syndrome or ATS: People with this type have inconsistent potassium shifts during attacks of paralysis, and may have symptoms of irregular heart rhythms including a prolonged QT interval. Some people with this genetic disease have unusual body, facial, and hand characteristics such a short stature, scoliosis, widely spaced eyes, small jaw, and low-set ears.
  • Familial periodic paralysis: Doctors use this term to describe four types of periodic paralysis: hypokalemic, hypokalemic, and thyrotoxic and Andersen-Tawil syndrome.

As previously mentioned, not all doctors agree on the types and may group one or two together, for example, as in familial periodic paralysis.

What determines which kind of periodic paralysis syndrome a person has?

The genetic alterations in the chromosomes determines which kind of periodic paralysis syndrome develops. For example, hyperPP is due to gene SNC4A while hypoPP1 is due to gene CACNAIS.

How do medical professionals diagnose periodic paralysis syndrome?

A periodic paralysis syndrome is diagnosed preliminarily by the characteristic symptoms that each type of syndrome produce. Further evidence for the diagnosis are:

  • Elevated creatinine phosphokinase blood levels, potassium levels, and ECG tracings
  • Repetitive stimulation of nerves electrically (electrodiagnosis)
  • Cooling the affected muscles to 20C (68F)
  • Exercise testing
  • Needle electrode examination (examination of electrically caused muscle contraction).
  • Muscle biopsies

Some doctors also use proactive testing to diagnose the syndrome. This type of test uses IV solutions to stimulate or reproduce your symptoms. However, this test is considered potentially dangerous, and should only be performed on a patient in the presence of a well-trained doctor (usually a neurologist).

What about ruling out other diseases or syndromes for this condition (differential diagnosis)?

Your doctor or other medical specialist, for example, a neurologist, will likely run some preliminary tests to rule in or rule out (called a differential diagnosis) other causes of muscle weakness such as licorice intoxication, laxative abuse, and/or severe diarrhea.

Is there a diet to manage symptoms?

An appropriate diet may help decrease the frequency of attacks and/or muscle weakness in some of the syndromes. For example, a low carbohydrate and low-sodium diet may reduce the frequency of paralysis attacks, while a diet with glucose containing candy or a carbohydrate diet with low potassium may improve weakness in hyperkalemic periodic paralysis syndrome.

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What is the treatment for periodic paralysis syndrome?

Treatment depends upon the type of periodic paralysis syndrome you have. Treatment therapies include medications such as dichlorphenamide (Keveyis), oral and/or IV potassium, acetazolamide, and diuretics. Some patients require beta blocker medication, amiodarone (Cordarone), and other drugs. Your neurologist and/or geneticist can advise you on the drugs most effective for your individual problem. Dietary considerations also are important.

Can I pass a periodic paralysis syndrome on to my children?

If you have a periodic paralysis syndrome, you have a 50% chance of having a child with the same condition.

Who should get genetic testing for periodic paralysis syndrome?

If either one of your parents has been diagnosed with any type of periodic paralysis syndrome, and/or if you have symptoms that are similar to any of those of periodic paralysis syndrome and have had no definitive diagnosis of your problems, you might ask your doctor if you should be tested for periodic paralysis syndrome.

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Medically Reviewed on 3/31/2021
Rubin, M. "Familial Periodic Paralysis." Merck Manual; Professional Version. Jan. 1, 2017. <http://www.merckmanuals.com/professional/pediatrics/inherited-muscular-disorders/familial-periodic-paralysis>.

Sripathi, N. "Periodic paralyses." Medscape. Apr. 30, 2018. <http://emedicine.medscape.com/article/1171678-overview>.