Hyperkalemic periodic paralysis
Periodic paralysis - hyperkalemic; Familial hyperkalemic periodic paralysis; HyperKPP; HyperPP; Gamstorp disease; Potassium-sensitive periodic paralysisHyperkalemic periodic paralysis (hyperPP) is a disorder that causes occasional episodes of muscle weakness and sometimes a higher than normal level of potassium in the blood. The medical name for high potassium level is hyperkalemia.
Muscle weakness
Weakness is reduced strength in one or more muscles.
Hyperkalemia
High potassium level is a problem in which the amount of potassium in the blood is higher than normal. The medical name of this condition is hyperka...
HyperPP is one of a group of genetic disorders that includes hypokalemic periodic paralysis and thyrotoxic periodic paralysis.
Hypokalemic periodic paralysis
Hypokalemic periodic paralysis (hypoPP) is a disorder that causes occasional episodes of muscle weakness and sometimes a lower than normal level of p...
Thyrotoxic periodic paralysis
Thyrotoxic periodic paralysis (TPP) is a condition with episodes of severe muscle weakness. It occurs in people who have high levels of thyroid horm...
Causes
HyperPP is congenital. This means it is present at birth. In most cases, it is passed down through families (inherited) as an autosomal dominant disorder. In other words, only one parent needs to pass the gene related to this condition on to their child in order for the child to be affected.
Autosomal dominant
Autosomal dominant is one of many ways that a genetic trait or disorder can be passed down through families. In an autosomal dominant disease, if you...
Occasionally, the condition may be the result of a genetic problem that is not inherited.
It is believed that the disorder is related to problems with the way the body controls sodium and potassium levels in cells.
Risk factors include having other family members with periodic paralysis. It affects men and women equally.
Symptoms
Symptoms include attacks of muscle weakness or loss of muscle movement (paralysis) that come and go. There is normal muscle strength between attacks.
Paralysis
Muscle function loss is when a muscle does not work or move normally. The medical term for complete loss of muscle function is paralysis.
Attacks usually begin in childhood. How often the attacks occur varies. Some people have several attacks a day. They are usually not severe enough to need therapy. Some people have associated myotonia, in which they cannot immediately relax their muscles after use.
Myotonia
Myotonia congenita is an inherited condition that affects muscle relaxation. It is congenital, meaning that it is present from birth. It occurs mor...
The weakness or paralysis:
- Most commonly occurs at the shoulders, back, and hips
- May also involve the arms and legs, but does not affect muscles of the eyes and muscles that help with breathing and swallowing
- Most commonly occurs while resting after activity or exercise
- May occur on awakening
- Occurs on and off
- Usually lasts 15 minutes to 1 hour, but may last up to an entire day
Triggers may include:
- Eating a high carbohydrate meal
- Rest after exercise
- Exposure to cold
- Skipping meals
- Eating potassium-rich foods or taking medicines that contain potassium
- Stress
Exams and Tests
The health care provider may suspect hyperPP based on a family history of the disorder. Other clues to the disorder are muscle weakness symptoms that come and go with normal or high results of a blood potassium test.
Potassium test
This test measures the amount of potassium in the fluid portion (serum) of the blood. Potassium (K+) helps nerves and muscles communicate. It also ...
Between attacks, a physical examination shows nothing abnormal. During and between attacks, the potassium blood level can be normal or high.
During an attack, muscle reflexes are decreased or absent. And muscles go limp rather than staying stiff. Muscle groups near the body, such as the shoulders and hips, are involved more often than the arms and legs.
Tests that may done include:
- Electrocardiogram (ECG), which may be abnormal during attacks
ECG
An electrocardiogram (ECG) is a test that records the electrical activity of the heart.
ImageRead Article Now Book Mark Article - Electromyography (EMG), which is usually normal between attacks and abnormal during attacks
EMG
Electromyography (EMG) is a test that checks the health of the muscles and the nerves that control the muscles.
ImageRead Article Now Book Mark Article -
Muscle biopsy, which may show abnormalities
Muscle biopsy
A muscle biopsy is the removal of a small piece of muscle tissue for examination.
ImageRead Article Now Book Mark Article
Other tests may be ordered to rule out other causes.
Treatment
The goal of treatment is to relieve symptoms and prevent further attacks.
Attacks are seldom severe enough to require emergency treatment. But irregular heartbeats (heart arrhythmias) may also occur during attacks, for which emergency treatment is needed. Muscle weakness can become worse with repeated attacks, so treatment to prevent the attacks should occur as soon as possible.
Heart arrhythmias
An arrhythmia is a disorder of the heart rate (pulse) or heart rhythm. The heart can beat too fast (tachycardia), too slow (bradycardia), or irregul...
Glucose or other carbohydrates (sugars) given during an attack may reduce the severity of the symptoms. Calcium or diuretics may need to be given through a vein to stop sudden attacks.
Outlook (Prognosis)
Sometimes, attacks disappear later in life on their own. But repeated attacks may lead to permanent muscle weakness.
HyperPP responds well to treatment. Treatment may prevent, and may even reverse, progressive muscle weakness.
Possible Complications
Health problems that may be due to hyperPP include:
-
Kidney stones (a side effect of medicine used to treat the condition)
Kidney stones
A kidney stone is a solid mass made up of tiny crystals. One or more stones can be in the kidney or ureter at the same time.
ImageRead Article Now Book Mark Article - Irregular heart beat
- Muscle weakness that slowly continues to get worse
When to Contact a Medical Professional
Contact your provider if you or your child has muscle weakness that comes and goes, especially if you have family members who have periodic paralysis.
Go to the emergency room or call the local emergency number (such as 911) if you faint or have difficulty breathing, speaking, or swallowing.
Prevention
The medicines acetazolamide and thiazides prevent attacks in many cases. A low potassium, high carbohydrate diet, and light exercise may help prevent attacks. Avoiding fasting, strenuous activity, or cold temperatures also may help.
References
Boegle AK, Narayanaswami P. Treatment and management of disorders of neuromuscular hyperexcitability and periodic paralysis. In: Bertorini TE, ed. Neuromuscular Disorders: Treatment and Management. 2nd ed. St Louis, MO: Elsevier; 2022:chap 18.
Doughty CT, Amato AA. Disorders of skeletal muscle. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff’s Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 109.
Kang MK, Kerchner GA, Ptacek LJ. Channelopathies: episodic and electrical disorders of the nervous system. In: Jankovic J, Mazziotta JC, Pomeroy SK, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 98.
Weimer M, Reese JJ, Tilton AH. Acute neuromuscular diseases and disorders. In: Zimmerman JJ, Clark RSB, Fuhrman BP, et al. Fuhrman and Zimmerman's Pediatric Critical Care. 6th ed. Philadelphia, PA: Elsevier; 2022:chap 68.
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Muscular atrophy - illustration
Muscular atrophy is the decrease in size and wasting of muscle tissue. Muscles that lose their nerve supply can atrophy and simply waste away.
Muscular atrophy
illustration
Review Date: 12/31/2023
Reviewed By: Walead Latif, MD, Nephrologist and Clinical Associate Professor, Rutgers Medical School, Newark, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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