FAMILIAL HYPOKALEMIC PERIODIC PARALYSIS - CLINICAL, DIAGNOSTIC AND THERAPEUTIC ASPECTS

Five generations of a family with hypokalemic periodic paralysis (HOPP ) were studied. Of the 120 screened family members, 64 were found to h ave HOPP of which 38 were suffering from attacks. In the other 26 the diagnosis was made on account of vacuolar myopathy, a reduced muscle f iber conduction velocity or the signs of permanent muscle weakness (PM W) in combination with (grand)children with attacks. Applying these cr iteria skipping of generations did not occur in this family. When defi ned properly, PMW was found in all patients at older age, independent of the previous occurrence of paralytic attacks. Dynamometry and muscl e CT-scanning appeared valuable in the diagnosis and the progression o f PMW. In 2 patients autopsy was performed. Characteristic vacuolizati on was found in the striated muscle tissue in various degrees. Heart a nd smooth muscle tissue were not involved. Therapy is limited. Potassi um salts shortening and preventing the paralytic attacks are tolerated well. Acetazolamide is more effective in the prevention of the paraly tic attacks, but is not tolerated very well. HOPP can be considered as a myopathy characterized by PMW at older age in all patients, combine d with paralytic attacks in more than half the patients.