Rhabdomyolysis in hypokalaemic periodic paralysis: a clue to the mechanism that terminates the paralytic attack?

The changes in serum levels of myoglobin (Mb) and creatine kinase (CK) during a spontaneous attack of hypokalaemic periodic paralysis were studied. During paralysis, serum Mb and CK were normal. A rise in plasma potassium, resulting in clinical recovery, was associated with a simultaneous rise in serum Mb, and followed by a rise in serum CK. It is postulated that hypokalaemia might cause muscle ischaemia, which would result in an accumulation of free fatty acids (FFA) within the muscle cells. High concentrations of FFA may induce molecular changes and increase the permeability of the sarcolemma. This might be the mechanism by which potassium is released from muscle cells into the circulation and muscle membrane excitability is restored.