Primary periodic paralysis (PPP) is a group of rare diseases that temporarily make muscles stiff, weak, or unable to move. These episodes can last from a few minutes to a few days, depending on the type of PPP you have.
For many people, symptoms start in childhood or the teen years. Others don't have any signs until they reach their 60s or 70s.
Triggers like exercise, medicine, or certain foods can set off the attacks. Sometimes you can prevent them simply by making a few changes to your diet or activities. Medicine can help, too.
There’s no cure for PPP, but some people who have it can live active lives. Those who have severe symptoms, though, will have a hard time being active.
PPP happens when there’s a problem with your muscle cells, specifically the channels that let key minerals -- sodium, chloride, calcium, and potassium -- flow in and out of them. You need the right balance of these minerals inside and outside of these cells for muscles to move the way they should.
There are several types of PPP. The problem your cells have with their channels for sodium, chloride, calcium, or potassium determines the kind you have:
- Hypokalemic periodic paralysis (hypoKPP): Potassium levels in the blood drop during these episodes.
- Hyperkalemic periodic paralysis (hyperKPP): Potassium levels in the blood rise during these episodes.
- Paramyotonia congenita: The sodium and potassium balance in your muscle cells is off.
- Andersen-Tawil syndrome (ATS): Potassium doesn't properly move into and out of muscle cells. You may have too much, too little, or the right amount in your blood at any time.
Sometimes,periodic paralysis is brought on by another, or secondary, condition. This is the case with thyrotoxic periodic paralysis (TPP). People with this have a thyroid gland that makes too much thyroid hormone. That, combined with low potassium levels in the blood, causes symptoms that are similar to hypoKPP. This condition is more common in men of Asian, Native American, or Latin American descent.
PPP is caused by a flaw in genes that control the sodium, chloride, calcium, and potassium channels in your muscle cells. When the balance of those minerals is off, your muscles won’t work well when nerves signal them to move. They might respond less and less to those signals, which makes your muscles feel weak. If levels are severely out of balance, the muscles can become unable to move, or paralyzed.
Usually, children get the flawed gene from one of their parents. A mom or dad doesn't need to show symptoms of the disease to pass it to their child. It’s rare, but some people can get the disease if they don’t have a parent with the gene.
Certain things can set off attacks of muscle weakness or paralysis in children and adults. You might get symptoms when you:
- Eat too much or too little potassium
- Eat foods that have a lot of carbohydrates
- Go too long without eating
- Rest after exercise, especially after an intense workout
- Sit for a long time
- Wake up in the morning or after a nap
- Are stressed
- Go outside in cold weather
- Drink alcohol
- Take medicines such as muscle relaxers, asthma drugs, painkillers, or some antibiotics
The main symptoms of PPP are the episodes when muscles get weak or can’t move at all. Each attack can be different from the last one. Sometimes, symptoms show up in just one arm or leg. Other times, they affect whole body.
It’s not as common, but some people also will have other symptoms during their attacks, such as:
- Weakness in the face
- Muscle pain and stiffness
- An irregular heartbeat
- Trouble breathing or swallowing
Each type of PPP can have its own pattern of symptoms. For example:
- You may have attacks every day, or you may have them once a year.
- Attacks can last anywhere from an hour to a day or two.
- Some people have weakness that changes from day to day. Later on, your muscles could become permanently weak and your symptoms could get more severe.
- Attacks can be shorter and less severe, but can happen more often.
- Your symptoms can come on quickly, sometimes causing you to fall.
- Between episodes, you may have muscle spasms or trouble relaxing your muscles.
- Symptoms are most pronounced in the face, tongue, and hand muscles. Your legs are usually less affected.
- You may be unable to relax your muscles for seconds or minutes, but muscle weakness may continue for hours and sometimes days.
- You’re likely to have fewer attacks as you get older.
- Attacks can last from an hour to a few days.
- People with this type also have other symptoms, such as:
- Fast heartbeat or other irregular heart rhythm
- Curved spine (scoliosis)
- Webbed fingers and toes
- Small hands and feet
- Changes to the face, including a wide forehead, low ears, round nose, and wide-set eyes
The muscles usually go back to normal in between attacks. In some forms of the disease, muscles get damaged over time and the weakness eventually doesn’t go away.
Getting a Diagnosis
It often takes time to get the right diagnosis for PPP. It’s a rare condition, and its symptoms are similar to those of more common health problems. Plus, many doctors aren’t very familiar with it. You may need to see a specialist with expertise in neuromuscular conditions, like a neurologist or a physical medicine and rehabilitation specialist, to get the right diagnosis.
To figure out if you or your child has PPP and to find out the type of the disease, your doctor might ask questions, like:
- When did the symptoms start?
- Does anyone else in your family have PPP?
- What happens during the episodes?
- Have you noticed specific symptoms, like weak muscles or a fast or irregular heartbeat?
- What seems to bring on the attacks? For example, do they tend to happen along with certain foods or after exercise?
The doctor may do some tests to see if other conditions could be causing your or your child’s symptoms. If she thinks PPP is a possibility, she’ll confirm it with some of these tests:
- Blood tests to check potassium, thyroid, and other levels
- Electromyography (EMG) and nerve conduction studies to see how well your muscles and nerves are working
- Electrocardiogram (EKG) to check your heart
- Muscle biopsy to check for abnormal muscle cells
Questions for Your Doctor
- What changes will I need to make to my or my child’s diet?
- Do I need to change my or my child’s activity level?
- What medicines might help?
- Do these medicines have side effects?
- How will you know if the condition is getting better or worse? Are there new symptoms I should watch for?
- How often should I see you?
The main treatment for PPP is to avoid anything that triggers the attacks. You might have to make some changes to your or your child’s diet or exercise routine. But medicines can also help control the balance of potassium in your body. Specific treatments vary based on the cause of PPP.
The FDA has approved a drug, dichlorphenamide (Keveyis), to treat hypoKPP, hyperKPP, and similar conditions. It’s a pill you take every day that can help you have fewer attacks.
People with hypoKPP can also take the drug acetazolamide (Diamox) to keep potassium levels in balance. The FDA hasn’t approved this medicine for the treatment of PPP, but your doctor may suggest it if she thinks it will help you.
Potassium supplements can also help prevent attacks of hypoKPP. A diuretic, also called a water pill, can help your kidneys hold on to more potassium.
HyperKPP sometimes doesn't need treatment. You can stop an attack by drinking a glass of soda or other sweet drink. Drugs for asthma, called beta agonists, can help with muscle weakness, though people with irregular heartbeats shouldn’t take them. Your doctor may also try dichlorphenamide or diuretics such as acetazolamide.
For ATS, potassium supplements can prevent attacks of paralysis. You may need to take heart medicines such as beta-blockers to control an abnormal heart rhythm.
Since TPP is caused by an overactive thyroid gland, your doctor will usually treat it by treating the thyroid condition. Medicine, radiation, or surgery usually helps the problem. You may also take a potassium supplement, a beta-blocker, dichlorphenamide, or another type of diuretic to control your symptoms.
Taking Care of Yourself or Your Child
A big part of life with PPP is avoiding the things that trigger episodes of muscle weakness or paralysis. So a few changes to your daily routine can prevent your or your child’s symptoms.
You might need to change the amount of potassium and carbohydrates in your diet. People with hyperKPP will need to avoid foods with a lot of potassium, such as cantaloupe, bananas, raisins, broccoli, Brussels sprouts, lentils, beans, peanut butter, and chocolate. Those with hypoKPP and TPP need to avoid foods that are sweet or starchy, such as desserts, candy, sweetened drinks, pasta, bread, potatoes, and rice. It also helps some people to steer clear of salty foods. A dietitian can help you make the right changes.
Going too long without a meal or snack can bring on an attack. So you may need to eat more often during the day to avoid getting hungry. It’s also a good idea to avoid alcohol, since that can be a trigger for some people.
You might also need to change your or your child’s activity level. Intense exercise is a common trigger for PPP symptoms, but sitting for too long can be a problem, too. Talk to your doctor about how to find the right balance and avoid an attack.
What You Can Expect
Each form of PPP is different. Some people have milder symptoms than others. Your doctor can tell you what to expect with your type of the disease. Often, making diet and lifestyle changes and avoiding your triggers can keep you from having attacks. TPP is curable if you treat the thyroid problems that caused it.
As you get older and have more episodes, your muscles may get weaker over time. Some people need a wheelchair or a scooter to help them get around later in life. But most people with PPP can lead normal, active lives when they do their best to avoid triggers and take any medicine their doctors prescribe.
You can find more information and connect with other people who have primary periodic paralysis through the websites of Periodic Paralysis International and the Periodic Paralysis Association.