大学院生の岸本先生にまとめてもらった症例報告がJournal of Anesthesiaに通りました。
Ectopic ACTH syndrome revealed as severe hypokalemia and persistent hypertension during the perioperative period: a case report
Both severe hypokalemia and persistent hypertension are clinical symptoms of hyperaldosteronism. Hyperaldosteronism may occur as primary or secondary syndromes. Excess ACTH produced ectopically by tumors may induce hyperaldosteronism through the mineralocorticoid activity of glucocorticoids that are upregulated by ACTH. Licorice, with the active ingredient glycyrrhiza, is also a well known inducer of hyperaldosteronism under specific conditions.
In this report, we describe a case of severe hypokalemia due to ectopic ACTH syndrome (EAS) elicited by an intrathoracic carcinoid tumor, which transformed to produce ACTH during the 6 year clinical course, and was modulated by licorice ingestion. Hypokalemia was not clearly recognized preoperatively, but became obvious within the 3 hours of general anesthesia with epidural blockade. At the end of anethesia, arterial blood gas analysis indicated severe hypokalemia ([K+]=1.7 mEq/L) and metabolic alkalosis (pH=7.56, PaCO2=54.9 mmHg, HCO3-=44.5 mmol/L, BE=21.8mmol/L) without any typical symptoms, such as muscle weakness or ECG abnormalities. The hypokalemia was resistant to potassium supplmentation and persisted for 4 days. Periopetative inbalance between the administration and elimination of potassium and surgical stress might contribute to the rapid exaggeration or induce the clinical manifestation of EAS.