Title: Digoxin Toxicity With Normal Digoxin Levels?
题目：地高辛浓度正常的地高辛中毒
Author作者: Feng Xiao ?
Digoxin toxicity can occur in patients with normal digoxin levels. In patients taking digoxin in recommended doses, digoxin toxicity can occur in the setting of hypokalemia or hypomagnesemia, even though the serum digoxin level is within normal limits.
地高辛中毒可发生在地高辛水平正常的患者。服用推荐剂量的地高辛患者，即使血清地高辛浓度在正常范围内，地高辛中毒也可在低钾血症或低镁血症情况下发生。
Digoxin directly inhibits the sodium-potassium ATPase pump in the membrane of the cardiac myocyte, causing an increase in intracellular sodium and calcium which increases myocardial contractility.
地高辛直接抑制心肌细胞膜的钠 - 钾ATP酶泵，导致细胞内的钠和钙的增加,进而增加心肌收缩力。
Hypokalemia increases digoxin cardiac sensitivity because potassium and digoxin compete for the same ATPase-binding site. Magnesium is a cofactor of the sodium-potassium ATPase pump. Hypomagnesemia increases myocardial digoxin uptake, further inhibiting sodium-potassium ATPase pump activity.
由于钾和地高辛竞争同样的ATP酶结合位点，低钾血症会增加心脏对地高辛的敏感度。镁是钠 - 钾ATP酶泵的辅助因子。因此低镁血症会增加心肌地高辛的吸收，进一步抑制钠 - 钾ATP酶泵活性。
It is known that long-term digoxin users often have hypokalemia or hypomagnesemia, presumably due to diuretic usage in patients with congestive heart failure.
众所周知，长期使用地高辛的患者往往有低钾或低镁血症，因为充血性心脏衰竭患者多需要利尿剂。
In a suggestive clinical setting, do not exclude the possibility of digoxin toxicity simply because the digoxin level is in the therapeutic range, and be sure to check serum potassium and magnesium levels.
在临床怀疑地高辛中毒情况下，不要仅仅是因为地高辛浓度在治疗范围内就排除这种可能性，一定要检查血清钾和镁的水平。
References参考文献:?
(1) Raja Rao MP, et al. J Emerg Med 2013; epub, May 20, 2013.?
(2) Dec GW. Med Clin North Am 2003;87:317-337.?
(3) Chan KE, et al. J Am SocNephrol 2010;21:1550-1559.