Title: Anaphylaxis
题目：（严重）过敏性反应
Authors 作者: Mike Winters, MD & Ellen Lemkin, MD

I. Diagnosis involves 3 criteria, only have to meet one:
诊断包括3个标准，至少要符合其中之一：
a. Sudden onset of illness (minutes – hours) w/involvement of skin/mucosa & either the upper/lower respiratory or cardiovascular systems;
突然发病 （几分钟－几个小时），涉及皮肤，粘膜，上下呼吸道，或心血管系统；
b. 2 or more of the following that occur suddenly after exposure to a known or likely antigen: 1. Skin or mucosa involvement, 2. Respiratory symptoms, 3. Cardiovascular symptoms, 4. GI symptoms;
在接触已知或可疑过敏原后突然出现2个或2个以上的如下症状；1. 皮肤或粘膜，2. 呼吸症状，3. 心血管症状，4. 胃肠道症状；
c. Hypotension (SBP <90 or 30% decrease from baseline)
低血压 （收缩压低于90或比基础血压降低30％）

II. Treatment 治疗
a. Epinephrine is the key! ***Cardiac arrest can occur in 5 minutes of envenomation, 15 minutes of drug exposure, 30 minutes of food*** Give IM immediately (mid-anterolateral thigh); 0.1mg/kg (up to 0.3mg); Repeat in 5 minutes if doesn’t work (1:1000 epinephrine); Low-dose continuous infusion if no response to 2 IM injections (1:10,000 at 1-10mcg/min).
肾上腺素是关键！＊＊＊心脏骤停可在毒蛇咬伤5分钟，药物接触15分钟，食物接触30分钟内出现＊＊＊ 立即以0.1mg／kg体重的量立即肌注（1:1,000），可用到0。3mg／kg。如无效可重复一次。如用两次肌注都无反应，可用低剂量（1－10毫微克／min）持续注射（1:10,000）。
b. IVF: 1/3 of patient’s effective circulating volume can be extravasated within 10-15 minutes!!! Give 10ml/kg fluids in first 5-10 minutes .
静脉输液：1／3病人的有效循环容积会在10－15分钟内渗到血管外!!! 因此在前5－10分钟内要给10ml／kg的液体。
c. H1-blockers (diphenhydramine, cetirizine): No high quality studies prove usefulness in anaphylaxis; Take 1-2 hours to work; Decrease itching, urticaria, and nasal symptoms; Older and newer agents work equally well.
H1拮抗剂（扑尔敏，西替利嗪）：没有高质量的研究证实它们在严重过敏反应的效用；要1－2小时后才起效；可减轻痒，寻麻疹，和鼻部症状；新旧药物药效相当。
d. H2-blockers (ranitidine): No high quality studies prove usefulness in anaphylaxis; Enhance the relief of urticaria & tachycardia; Ranitidine 50mg IV or 1mg/kg over 15 minutes
H2拮抗剂（雷尼替丁）；没有高质量的研究证实它们在严重过敏反应的效用；加速寻麻疹和心动过速的缓解；雷尼替丁50mg静脉注射或1mg／kg在15分钟内滴注。
e. Glucocorticoids (methylprednisolone, prednisone): No high quality studies prove usefulness in anaphylaxis; Take hours to work; In theory, may reduce risk of biphasic symptoms .
糖皮质激素（甲基强的松龙，强的松）：没有高质量的研究证实它们在严重过敏反应的效用；要几个小时后才起效；理论上来说，可能会防止症状的二次反复。
f. Glucagon: For patients who have anaphylaxis and are on a beta-blocker, should consider giving glucagon because epinephrine may not work; 5-10mg
高血糖素：对于服用β受体阻滞剂的过敏病人，可考虑用高血糖素（5－10mg），因肾上腺素可能无效。
g. Patients who are discharged MUST receive epinephrine pen (or Rx).
出院的病人一定要带肾上腺素自注笔（或处方）。

III. Disposition 出院处理
a. Remember that biphasic reactions can happen up to 3 days later – and occur in 1 out of 4 patients!
记住1／4病人会出现二次反复，甚至在3天以后发生！
b. Have to look at each individual patient; 6-8 hours has no good evidence
要因人而异，没有证据支持只观察6－8小时就可以了。

VI. BOTTOM LINE 要点
a. Anaphylaxis is a fairly broad diagnosis.
严重过敏反应是一个相当广的诊断。
b. Don’t be afraid of epinephrine! It’s the only drug that will save a life in anaphylaxis.
不要畏惧肾上腺素！它是一个唯一能够在严重过敏反应时拯救生命的。
c. Make sure there’s an algorithm/care set for anaphylaxis for your ED.
保证在你们科里要建立一个治疗严重过敏反应的方案。

Reference 参考文献:
Simmons FER, Ardusso LRF, Bilo MB et al. 2012 update: World Allergy Organization guidelines for the assessment and management of anaphylaxis. Current Opinion in Allergy & Clinical Immunology 2012;12(4):389-399.