How do high or low potassium levels contribute to familial periodic paralysis?

In familial periodic paralysis, muscle weakness occurs because the muscle fibers lose their electrical potential—a process known as depolarization—rendering them incapable of excitation. This condition is fundamentally linked to abnormal ion channels or pumps in the skeletal muscle membrane, which disrupt the movement of ions, including potassium.1

The role of potassium varies by the specific type of the disorder:

• Hypokalemic periodic paralysis: During an attack, blood potassium levels fall below normal. The condition can be triggered by factors that lower potassium levels, and it is often associated with mutations in calcium channels.12
• Hyperkalemic periodic paralysis: This form is associated with an increase in blood potassium levels. Attacks can be precipitated by oral potassium therapy and are linked to mutations in sodium channels.12

In both cases, the resulting ionic imbalance prevents proper muscle function. Treatment typically involves medications that help regulate potassium levels, such as acetazolamide, or the administration of potassium, glucose, or diuretics depending on the specific diagnosis.123