What causes HypoKPP?
All of the periodic paralyses are caused by abnormalities in the ion channels (especially the sodium and calcium channels) of the muscle membrane. The ion channels control the movement of sodium, chloride, potassium and calcium across the cell membrane and from one cell compartment to another. This movement of ions produces the electrical ‘spark’ which allows our muscles to move. Hypokalemic Periodic Paralysis is caused by a flaw in an ion channel in the muscle membrane. This flaw makes the person with HypoKPP extremely sensitive to decreases in serum potassium that wouldn’t bother the average person. Anyone can be made weak by a drastic lowering of serum potassium, but the person with HypoKPP gets weak with even a slight fall in potassium level, and patients with HypoKPP may become profoundly paralyzed while their potassium levels remain within normal limits.
