Hyperkalemic periodic paralysis Health Article

Definition

Hyperkalemic periodic paralysis is a disorder that involves occasional episodes of muscle weakness and, sometimes, higher-than-normal levels of potassium in the blood.

It is one of a group of genetic disorders that includes hypokalemic periodic paralysis and thyrotoxic periodic paralysis.

Alternative Names

Periodic paralysis - hyperkalemic

Causes, incidence, and risk factors

Hyperkalemic periodic paralysis is due to faulty genes. In most cases, it is passed down through families (inherited). Occasionally, it occurs randomly in families. It is believed that the disorder is related to problems with the way the body controls sodium and potassium levels in cells.

Unlike other forms of periodic paralysis, persons with hyperkalemic periodic paralysis do not have low blood potassium levels. In fact, there may be normal or high levels of potassium in the bloodstream during and between attacks.

Risk factors include a family history of periodic paralysis. The condition occurs in approximately 1 in every 100,000 people. It affects men more often then women.

Symptoms

The disorder involves attacks of muscle weakness or loss of muscle movement (paralysis) that come and go. There is normal muscle strength between attacks.

Attacks usually begin in childhood. How often the attacks occur varies. Some people have several attacks a day. Attacks typically last only 1 to 2 hours, but can sometimes last as long as 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.

The weakness or paralysis:

• Most commonly occurs at the shoulders and hips
• May also involve the arms and legs but does not affect muscles of the eyes and those that help you breathe and swallow
• Most commonly occurs while resting after activity
• May occur on awakening
• Comes and goes
• Usually lasts 1 - 2 hours

Triggers may include:

• Resting after exercise
• Not eating (fasting)
• Exposure to cold
• Eating small amounts of potassium-rich foods or taking medicines that contain potassium