17.5
过敏反应：过敏反应性休克
过敏反应是一种严重且危及生命的超敏反应，由免疫球蛋白E抗体介导。当IgE与过敏原结合时，可促使肥大细胞和嗜碱性粒细胞释放组胺、白三烯和前列腺素等介质。这些介质可导致血管扩张、水肿和炎症，从而引发多种症状。
引起过敏反应的主要过敏原包括食物（例如花生、贝类）、药物（例如青霉素、天冬酰胺酶、促肾上腺皮质…
过敏反应是由IgE抗体介导的速发型超敏反应。这些抗体与过敏原结合，形成过敏原-IgE抗体复合物。常见的过敏原包括花粉、尘螨、药物和某些食物成分。
这些复合物与肥大细胞和嗜碱性粒细胞上的受体结合，导致细胞迅速脱颗粒，释放组胺、白三烯和前列腺素。
这些介质可引起血管扩张、支气管收缩、水肿和中性粒细胞活化，从而引发炎症反应。
这些反应可能严重影响血管系统、胃肠道、皮肤和呼吸系统。它们还可能表现为食物过敏、荨麻疹、鼻炎和哮喘等疾病。
多种药物可引起过敏性休克，包括青霉素、门冬酰胺酶、单克隆抗体、促肾上腺皮质激素、肝素、疫苗、局部麻醉药以及氯己定等消毒剂。
过敏性休克的诊断方法是临床性的，基于症状进行判断。皮肤试验，例如皮内注射青霉噻唑-多聚赖氨酸，可用于后续确定青霉素过敏。
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Q1: What is anaphylaxis and how does it develop?
Anaphylaxis is a severe, immediate hypersensitivity reaction mediated by IgE antibodies. When IgE binds to allergens, it forms complexes that attach to mast cells and basophils, triggering rapid degranulation. This releases mediators like histamine, leukotrienes, and prostaglandins, causing vasodilation, bronchoconstriction, edema, and inflammation throughout the body.
Q2: Which drugs commonly trigger anaphylactic reactions?
Penicillin is responsible for approximately 75% of anaphylactic deaths due to widespread use. Other drugs causing anaphylaxis include asparaginase, monoclonal antibodies, corticotropin, heparin, vaccines, local anesthetics, and antiseptics like chlorhexidine. These reactions occur through IgE-mediated mechanisms similar to food and environmental allergens.
Q3: What body systems are affected during anaphylaxis?
Anaphylaxis primarily affects the cardiovascular, respiratory, gastrointestinal, and integumentary systems. Symptoms include urticarial rash, hives, angioedema, bronchoconstriction, wheezing, shortness of breath, and hypotension. Severe cases progress to anaphylactic shock, characterized by sudden blood pressure drops, respiratory distress, and potential cardiovascular collapse.
Q4: How is anaphylaxis diagnosed in clinical practice?
Anaphylaxis diagnosis is primarily clinical, based on symptom presentation. Skin tests, such as intradermal injection of penicilloylpolylysine, can later identify penicillin allergy. Detecting particular IgE in plasma confirms allergic reactions, though these tests are reserved for cases where the allergen cause remains unclear.
Q5: What are common allergens that cause anaphylaxis?
Common allergens include food items like peanuts and shellfish, environmental substances such as grass pollen and dust mites, insect stings, and pharmaceutical agents. Radiological contrast agents, vaccines, and latex also trigger anaphylaxis. These allergens bind to IgE antibodies, initiating the cascade of mast cell and basophil degranulation.
Q6: What mediators are released during anaphylaxis and what effects do they produce?
Mast cells and basophils release histamine, leukotrienes, and prostaglandins upon degranulation. These mediators cause vasodilation, bronchoconstriction, edema, and neutrophil activation, generating an inflammatory response. The resulting cascade produces symptoms ranging from mild urticaria to life-threatening cardiovascular collapse and respiratory distress.
Q7: How does anaphylaxis differ from other hypersensitivity reactions?
Anaphylaxis is an immediate, IgE-mediated hypersensitivity reaction occurring within minutes of allergen exposure. Unlike delayed hypersensitivity reactions, which develop over hours or days, anaphylaxis causes rapid degranulation of mast cells and basophils. This distinguishes it from other hypersensitivity types in onset speed and severity.