文档介绍：Toxicity, Carbon Monoxide
中山医院急诊科姚晨玲
Background
Carbon monoxide (CO) is a colorless, odorless gas produced by bustion of carbonaceous material
CO is formed as a by-product of pounds
Pathophysiology
CO toxicity causes impaired oxygen delivery and utilization
CO reversibly binds hemoglobin, resulting in relative anemia.
CO binds hemoglobin 230-260 times more avidly than oxygen.
dissociation of CO from HbCO is slow than that of O2 from HbO2 (1/3600)
Pathophysiology
Resulting a leftward shift in the oxyhemoglobin dissociation curve
binds to cardiac myoglobin , resulting myocardial depression and hypotension
CO binds to cytochromes c and P450, impaired oxygen utilization at the cellular level.
Clinical
Acute carbon monoxide poisoning
Mild poisoning
COHb level :10%-20%.
Headache, nausea, vomiting, fatigue.
Moderate poisoning
COHb level :30%-40%.
Confusion, Agitation, Hallucination, Visual disturbance, syncope, seizure
Skin: Classic cherry red skin is rare (ie, “When you're cherry red, you're dead”); pallor is present more often.
Severe poisoning
COHb level :40%-60%.
Noncardiogenic pulmonary edema, arrhythmia, Papilledema
delayed neuropsychiatric symptoms
Long-term exposures or severe acute exposures frequently result in long-term neuropsychiatric sequelae. Additionally, some individuals develop delayed neuropsychiatric symptoms, often after severe intoxications associated a (about 3%-10% of all patients)
After 2-60days “normal period”, chronic headaches, memory problems, and parkinsonian-type tremor, re-occur .
Clinical
delayed neuropsychiatric symptoms
[病例介绍] 年近半百的李某,湖南常宁市人,在新疆打工。2002年11月27日晚,李某和另外2人睡在生火炉的房内,次日被人发现因煤气中毒昏迷,生命垂危。患者立即被送入医院进行高压氧治疗1次后,均神志清楚。李某于11月29日自行乘火车返回湖南常宁,回家后生活尚能自理就未再进行其他治疗。约20天后,李某开始出现少气懒言、情感淡漠、反应迟钝等症状,而且外出后不知道回家。家人以为他中了“邪”,先后请巫婆念咒“安神”、“驱鬼”,患者不仅不见好转,反而四肢瘫软,卧床不起,大小便失禁,完全失语……本月上旬,患者被送入湘雅医院,诊断为急性一氧化碳中毒迟发性脑病。给予高压氧及细胞活化剂治疗目前患者病情已有好转。
Lab Studies
HbCO analysis
Elevated levels are significant; however, low levels do not rule out exposure,