What is periodic paralysis?
Periodic paralysis (PP) is a rare genetic disorder. It causes sudden attacks of
short-term muscle weakness, stiffness, or paralysis. These attacks may affect the whole
body or just 1 or 2 limbs.
are several different forms of PP. They all involve defects in ion channels. These are
gateways that let charged minerals (ions) such as sodium and potassium flow into and out
of your cells. This flow of ions is a central part of how your muscles work. In PP, the
ion channels sometimes fail, and the muscle cells don’t work correctly.
PP attacks can start in childhood or adulthood. They may happen after hard exercise or other triggers. Depending on the form of PP that you have, the symptoms may be mild or severe, and they may last for minutes or days. Sometimes, the disease may slowly get worse over time and cause permanent muscle damage.
The main forms of PP are:
(hypo refers to low potassium). Attacks may result from low blood levels of
potassium. Other triggers may include strenuous exercise, foods with a lot of sugars
and starches (carbohydrates), licorice, stress, cold temperatures, and certain
medicines. This is the most common form of PP.
(hyper refers to high potassium). Attacks may result from high blood levels of
potassium. Other triggers may include strenuous exercise, fasting, stress, cold, and
Attacks may result from high levels of thyroid hormone. Thyroid-related problems are
also usually present. Other triggers may include exercise, meals with a lot of
carbohydrates, and stress. This form appears mostly in men, especially in those of
Andersen-Tawil syndrome. Attacks may result from swings in potassium blood levels. Triggers
may also include exercise, stress, and certain medicines. Many people with this form
of PP have a certain set of facial features. These include a broad forehead, widely
spaced eyes, low-set ears, and a small chin.
forms of PP affect the skeletal muscles. These are the muscles you
control to move. Andersen-Tawil syndrome can affect the skeletal muscles and the heart
muscle, making this form of PP more dangerous than most other forms.
What causes periodic paralysis?
different forms of PP all result from genetic problems. These problems result in ion
channel defects. The ion channels normally control the way that charged minerals (ions)
such as potassium, sodium, and calcium enter and leave your muscle cells.
Each muscle cell has a covering, or membrane, that keeps the inside of the cell protected. When your nerve tells your muscle cell to contract, it sends a chemical signal that opens a gate to allow sodium ions to flow into the cell. The rush of charged ions changes the electrical charge inside the cell. This causes a wave of current through the muscle fiber. Calcium ions pour out of sacs in the cells and make the muscle fiber contract. Potassium channels open up, sending potassium ions out of the cell. This causes the muscle to contract.
In PP, the ion channels have flaws that can disrupt the process. The muscle cells then fail to contract or relax in response to the nerve signals.
are dozens of different defects that can cause PP. These affect sodium, calcium, or
potassium ion channels. There are also many unidentified PP defects. In most cases, you
can get PP if just one parent has the condition.
What are the symptoms of periodic paralysis?
Your symptoms may depend somewhat on the form of PP you have. You may first notice symptoms in childhood or in adulthood. You may have attacks often or rarely. In some forms of PP, people tend to have less attacks as they get older. Generally, people with PP may have symptoms such as:
Attacks of muscle weakness that may last for minutes to days
Muscle pain in muscles after exercise
Permanent weakness, more likely later in life
The different forms of PP may cause the following:
Hypokalemic PP often starts in the late childhood or teenage years.
The average is between 5 and 35 years of age. Attacks of skeletal muscle weakness may
last from a couple of hours to a day. These tend to happen at night or in the
morning. You may not be able to move at all during the most severe episodes. After
about age 50, it may cause permanent weakness that slowly gets worse, especially in
the hips and thighs.
often starts by age 10. Attacks of skeletal muscle weakness last an average of 30
minutes to 4 hours. The attacks tend to be frequent but less severe than in other PP
forms. As you get older, you may get fewer attacks, but you also may have permanent
muscle damage that slowly gets worse.
tends to start between 20 and 40 years of age. Attacks happen anywhere from a few
times per year to a few times per week. Attacks can last from hours to days. With
this form of PP, you may also have thyroid-related symptoms such as anxiety,
sweating, weight loss, and anan abnormal sensation of the heartbeat
(palpitations). Some people with thyrotoxic PP don't have symptoms of thyroid
disease, especially early on.
Andersen-Tawil syndrome usually starts before age 18. The attacks last from 1 to 36 hours.
This form can cause irregular heartbeats because it affects heart muscle along with
In general, your symptoms may differ, depending on the form of PP and the particular gene change that you may have.
How is periodic paralysis diagnosed?
doctor will take a health history. He or she will ask about your recent symptoms, past
health problems, and family health history. Your doctor will do a physical exam and
assess your muscles. You may need tests such as:
Blood tests for potassium levels during an attack
Other blood tests to measure levels of other minerals and blood gases
blood tests for known PP defects
conduction studies and electromyography to measure the electrical activity of the
An electrocardiogram (ECG) to check electrical activity of the heart
Blood tests to check levels of thyroid hormones
may first see your primary doctor but then get referred to a neurologist who specializes
in diseases such as PP.
How is periodic paralysis treated?
Treatment aims to reduce the number and severity of attacks. Ways to manage PP may include:
Close control of potassium intake through diet and supplements
(intravenous) potassium treatments, if symptoms are severe from hypokalemic PP
Control of carbohydrates in the diet
of thyroid function. This is very important if you have thyrotoxic PP.
help from a nutritionist. This expert can help you choose a diet that reduces attacks
by decreasing changes in your carbohydrates or minerals.
medicines such as acetazolamide. This medicine can make PP worse in some cases,
other medicines such as carbonic anhydrase inhibitors or potassium-sparing
getting certain types of anesthesia because of possible complications
heart medicine or a pacemaker if you have Andersen-Tawil syndrome
Limiting exposure to triggers and keeping exercise to a moderate level
dichlorphenamide. This medicine can reduce the number of attacks if you have
may need frequent monitoring to measure your blood levels of potassium. A combination of
controlled diet, medicines, and lifestyle changes may help you manage PP.
PP is a rare disorder that causes sudden, temporary attacks of muscle weakness,
stiffness, or paralysis.
PP is a
genetic disorder passed down from a parent. The inheritance is dominant, meaning you
have a chance of getting it if even one parent has the genetic defect for PP.
episodes can start in childhood or adulthood.
attacks may be mild or severe and may last for minutes or days.
Depending on the form of PP you have, attacks may result from low or high potassium
levels in the blood, exercise, stress, cold, carbohydrate-rich meals, fasting,
certain medicines, or high thyroid hormone levels.
Andersen-Tawil syndrome can affect the heart muscle, causing irregular
people get older, they sometimes have permanent muscle damage.
use a combination of diet, medicines, and lifestyle changes to manage PP.
Tips to help you get the most from a visit to your healthcare provider:
Know the reason for your visit and what you want to happen.
Before your visit, write down questions you want answered.
Bring someone with you to help you ask questions and remember what your provider tells you.
At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
Ask if your condition can be treated in other ways.
Know why a test or procedure is recommended and what the results could mean.
Know what to expect if you do not take the medicine or have the test or procedure.
If you have a follow-up appointment, write down the date, time, and purpose for that visit.
Know how you can contact your provider if you have questions.
Online Medical Reviewer:
Anne Fetterman RN BSN
Online Medical Reviewer:
Raymond Kent Turley BSN MSN RN
Date Last Reviewed:
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