Hypokalaemic periodic paralysis thyrotoxic

Ptacek Again, those are pretty rare. The patients are thyrotoxic and they have paralysis just like the hypokalaemics, except that when you ablate their thyroid, the thyrotoxic periodic paralysis resolves. There was one small family reported. I believe that this is a hereditary disorder, but we don t see it as a hereditary disorder much because it is a predisposing mutation and you also have to be thyrotoxic for the paralysis to manifest. We ve looked for Ca channel mutations in those patients but haven t found any. 

Ptacek The one thing that is different is that their K levels tend to be much lower. The familial hypokalaemic patients would typically have a K+level of2.1—3.2 during an attack. If I see a patient that has a l< level of 1.7—1.9 (which is alarmingly low), the first thing I think of is thyrotoxic periodic paralysis, because they tend to be really low. I don t know precisely why this is the case. 

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