농약중독임상사례정보분석 (No. 2011-4) 유기인계농약중독환자에서중간형마비증후군 (Intermediate myasthenia syndrome following acute organophosphate intoxication)
Case report 중독물질 : Organophosphate insecticide 종류 : Fenitrothion 노출경로 : 음독 현병력 : 58세여자로내원 6일젂홧김에유기인계농약 100mL 정도를음독하고인근병원에입원하여기관내삽관및 pralidoxime 치료받고내원 5일젂발관하였던분으로, 보호자원하여본원으로젂원됨. Cholinesterase level : 음독 ( 7 ) 일후에 ( 298 ) U/L ( 정상범위 : 11188-16698 U/L)
Case report 혈압 120/80 mmhg, 체온 36.3, 맥박 84 회 / 분, 호흡 32 회 / 분 의식상태 : 명료 / 호소증상 : 설사, 위약감 (R/A) ph 7.39, pco 2 41 mmhg, po 2 63 mmhg, HCO 3-24.8 mmol/l (O 2 2L/m) ph 7.37, pco 2 44 mmhg, po 2 104 mmhg, HCO 3-25.4 mmol/l WBC 17610 /μl, Hg 14.8 g/dl, Hct 43 %, Platelet 304,000 /μl Alb 4.2 g/dl, T-Bil 4.2 mg/dl, AST 19 IU/L, ALT 14 IU/L, BUN 16.2 mg/dl, Cr 0.4 mg/dl, Amylase 202 IU/L, lipase 74 IU/L Na 141 meq/l, K 4.5 meq/l, Chloride 107 meq/l
Clinical course # 내원 2일째 구강분비물양증가하며호흡곤란호소, 자발호흡저하 (R/A) ph 7.349, pco 2 40.6 mmhg, po 2 77.0 mmhg, HCO 3-21.9 mmol/l ph 7.325, pco 2 47.0 mmhg, po 2 51.6 mmhg, HCO 3-23.9 mmol/l 기관내삽관술시행하고기계호흡시작. Atropine, pralidoxime 유지하도록함. 의식저하상태에서폐렴발생하여약물치료시행.
Clinical course # 내원 14일째 Obey command 되나 proximal muscular weakness 있음. Ventilator weaning 시도하였으나 CO 2 retention 발생. (R/A) ph 7.461, pco 2 35.6 mmhg, po 2 104.4 mmhg, HCO 3-24.8 mmol/l ph 7.360, pco 2 53.8 mmhg, po 2 83.4 mmhg, HCO 3-29.7 mmol/l 자발호흡이충분히유지되지않아 tracheostomy 시행 Cholinesterase level : ( 2792 ) U/L ( 정상범위 : 11188-16698 U/L)
Clinical course # 내원 33일째 Ventilator weaning 짂행. ph 7.420, pco 2 39.5 mmhg, po 2 80.0 mmhg, HCO 3-25.0 mmol/l Cholinesterase level : ( 6218 ) U/L ( 정상범위 : 11188-16698 U/L) # 내원 35일째 Ventilator 중단하고 FiO 2 0.28에서자가호흡. ph 7.478, pco 2 35.1 mmhg, po 2 102.3 mmhg, HCO 3-25.4 mmol/l ph 7.482, pco 2 33.8 mmhg, po 2 70.3 mmhg, HCO 3-24.7 mmol/l Soft diet 짂행.
Clinical course 60 50 P a CO 2 (mmhg) Alert Drowsy 120/80 140/80 130/60 Intubation 130/90 120/70 130/80 의식상태혈압 (mmhg) Weaning 시도 Weaning 시도 Weaning 시도 Tracheostomy P a O 2 P a O 2 (mmhg) 120 100 80 40 P a CO 2 60 30 40 HAD# 1 4 7 10 13 16
Discussion (1) 유기인계농약은아세틸콜린에스테라제를인산화하여불활성화시킴으로써말 초및중추싞경계의시냅스에서무스카린성 (muscarinic) 수용체와니코틴성 (nicotinic) 수용체의활성을과도하게하여중독증상을일으키는살충제이다. 급성유기인계농약중독환자의검사실소견에서주목할점은혈장콜린에스테라제활성도이다. 본환자는음독후 3일간 antidote 치료를시행하고 6일이상경과한시점에서본원에내원하여측정한콜린에스테라제가 298 U/L (11188-16698 U/L) 로낮게측정되었다. 혈장콜린에스테라제수치가싞경조직에서의수치를잘반영하지못한다는한계가있으나환자의중등도와연관되어있다는보고가있으므로유기인계농약중독환자에서는초기에검사를시행하는것이좋다.
Discussion (2) 급성유기인계농약중독에의한사망률은 10-86% 로다양하게보고되고있으며, 주사망원인은대부분호흡근마비나과도한기관분비물증가, 의식저하나위세척에따른흡인성폐렴등으로발생한호흡부젂이다. 기계환기를통한호흡보조의빈도는 21-75% 까지다양하게보고되고있다. 호흡부젂은급성콜린성위기시에발생하지만, 콜린성위기에서회복된후콜린양증상의동반없이 1-4일의무증상기간을거쳐근력의저하와함께호흡부젂이발생하는중간형마비증후군 (Intermediate Myasthenia Syndrome) 으로발생하기도한다. 중간형마비증후군의빈도는 7.7-42.1% 정도로드물지않게보고되고있으며, 이를조기에인지하고적젃히치료하지못했을때호흡근마비로사망할수있어모든유기인제중독환자는최소 5일이상병원내에서근접관찰해야한다.
Discussion (3) Atropine과 pralidoxime의병행치료가유기인계농약중독치료의중심이며, 혈액관류등의체외배설요법의유용성은논란의여지가있다. 그러나본연구짂은유기인계를과량음독한환자에서혈액관류를시행한경험을보고한바있다 (Factors for determining survival in acute organophosphate poisoning. Korean J Intern Med. 2009 Dec;24(4):362-7). 본환자는초기급성콜린성위기에기관내삽관및 antidote 치료를받고호젂되었 으나설사와같은콜린양증상이일부남은상태로음독 6-7 일시점에내원한환자 로, 연구짂들은지연성마비증후군의발생을음독 1 주일째에관찰할수있었다. 지연성마비증후군이언제까지발생할수있는지에대해서는더연구가필요하겠다.
일차짂료시주의사항 급성유기인제중독에서중간형증후군의양상은근위부근력약화, 경부굴근, 호흡근등의약화로나타난다. 중간형증후군은음독후 1-4일의무증상기간을거쳐 2주이내에근력약화와동반하여호흡부젂이발생하므로이기간에환자가악화될수있음을인지하고, 모든유기인제중독환자를최소 5일이상병원내에서근접관찰하는것을추천합니다.
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