A Report of Ten Cases of Acute Lithium Intoxication

Abstract

We report the cases of 10 patients with acute lithium intoxication who were treated over the past 6 years. The range of lithium overdose was 600 mg to 9,600 mg and the lithium concentration of all cases was greater than the toxic concentration. Three of the 10 cases were treated with fluid therapy. Another 3 cases were treated with continuous hemodiafiltration (CHDF). The rest were treated with hemodialysis (HD). The serum lithium concentration of the 3 patients with fluid therapy gradually decreased. However, it took 24 hours after the treatment to reach the therapeutic level in Case 2 since the slope was comparatively loose. In the meantime, the high lithium concentration of patients with CHDF (Cases 4, 8, 10) and HD rapidly decreased and it finally reached the therapeutic level. But a post-dialysis rebound effect in the lithium concentration was detected in Case 9. This report shows that CHDF and HD is an effective and sufficient treatment for lowering the serum concentration of lithium in a short period in acute lithium toxicity. As the serum lithium concentration of a patient with HD often rebounds and repeated or prolonged treatment may be required, we reaffirmed the patient＇s condition. Thus, completion of HD should be judged based on not only serum lithium concentration but also sufficient observation of the clinical course. 緒 言 炭酸リチウムは躁病および双極性障害の躁状態 に対して広く使用されている薬剤の 1 つである． しかし，血清リチウム濃度の治療域（ 0.6～1.2 mmol/L ） ，中毒域（ 1.5～2.5 mmol/L 以上）と致 死 域（ 3.0～4.0 mmol/L 以上）が近接しており， 過量服薬だけでなく，脱水や利尿剤の投与，感染 によっても中毒域や致死域に到達する． 1） また， ループ利尿剤，チアジド系利尿降圧剤，アンジオ テンシン変換酵素阻害薬，非ステロイド性消炎鎮 痛剤等の多くの薬剤との併用により相互作用を引 き起こし，血清リチウム濃度が上昇し，中毒症状 を引き起こすことがある． 2） リチウム中毒の症状 は軽症時では意識障害や振戦，構音障害などの中 枢神経症状，悪心，嘔吐，下痢などの消化器症状 が認められる．しかし，重症時には昏睡，痙攣だ けでなく心電図異常（洞不全症候群，QT 延長症 候群） ，致死的不整脈（心室細動，心室頻拍）な どの循環器症状が認められている． 3） そのため， 早急な中毒域からの離脱の可否が予後に大きく影 響する．