Hyperkalemic periodic paralysis involves disruption of which channel function?

Hyperkalemic periodic paralysis involves disruption of which channel function?

• A. Spinal cord blood vessel occlusion
• B. Deficiency in Vitamin E
• C. Surgical injury of nerves
• D. Disrupts the normal opening and closing of sodium ion channels; signs include fasciculations, weakness, paralysis, or sudden death

Answer: (D)

Voltage-gated sodium channels in skeletal muscle control the initiation and propagation of action potentials. In hyperkalemic periodic paralysis, a mutation disrupts how these channels open and close—improper gating often means faulty inactivation or inappropriate reopening. This altered gating changes muscle fiber excitability, producing episodes that start with fasciculations and progress to weakness or paralysis, with hyperkalemia often triggering or worsening the attacks and, in severe cases, risking life due to respiratory or cardiac involvement. This mechanism is specific to sodium channel function in muscle, unlike vascular injury, vitamin deficiencies, or nerve trauma, which involve different processes.

Voltage-gated sodium channels in skeletal muscle control the initiation and propagation of action potentials. In hyperkalemic periodic paralysis, a mutation disrupts how these channels open and close—improper gating often means faulty inactivation or inappropriate reopening. This altered gating changes muscle fiber excitability, producing episodes that start with fasciculations and progress to weakness or paralysis, with hyperkalemia often triggering or worsening the attacks and, in severe cases, risking life due to respiratory or cardiac involvement. This mechanism is specific to sodium channel function in muscle, unlike vascular injury, vitamin deficiencies, or nerve trauma, which involve different processes.