Definition of Hypokalemic periodic paralysis:

Hypokalemic periodic paralysis is an inherited disorder that causes occasional episodes of muscle weakness.

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

Causes, incidence, and risk factors:

Hypokalemic periodic paralysis is a condition in which a person has episodes of muscle weakness and sometimes severe paralysis.

The condition is congenital, which means it is present from birth. In most cases, it is passed down through families (inherited) as an autosomal dominant disorder. That means only one parent needs to pass the gene related to this condition on to you in order for you to be affected.

Occasionally, the condition may be the result of a genetic problem that is not inherited.

Unlike other forms of periodic paralysis, persons with congenital hypokalemic periodic paralysis have normal thyroid function and very low blood levels of potassium during episodes of weakness. This results from potassium moving from the blood into muscle cells in an abnormal way.

Risks include having other family members with periodic paralysis. The risk is slightly higher in Asian men who also have thyroid disorders.

Disorders that cause intermittent episodes of paralysis as their primary effect are uncommon. Hypokalemic periodic paralysis occurs in approximately 1 out of 100,000 people.