[Anaphylactic shock].

Abstract

IgE-dependent and IgE-independent hypersensitivity reactions, the latter due to physical, chemical or hyperosmolar stimuli, may evolve as anaphylaxis or an anaphylactoid reaction, by an escalating release of mediators from mast cells and basophils. Without immediate treatment, anaphylaxis goes along with substantial morbidity (shock, multiple organ failure) and mortality; within minutes this explosive clinical response can be fatal. The severity of anaphylactic/anaphylactoid reactions is graded from stages 0 to IV in order to guide the management of this disease, stage III corresponding to anaphylactic shock. Severe anaphylactic reactions may take a progressive course despite adequate therapy; even in the case of an initial favourable response to treatment measures life-threatening symptoms may recur; there may be late-phase reactions 6 to 12 hours after the initial reaction. For the initial emergency management a differentiation between IgE-mediated and IgE-independent anaphylactoid reactions is not required. These are the pertinent principles of therapy in hypotensive and hypoxic patients: removal of the likely noxious agent at the site of introduction, provision of a patent airway, 100% oxygen supplementation, intravenous fluid therapy and pharmacological support with catecholamines. After primary care the monitoring and therapy of the patient with anaphylactic shock has to be continued on the intensive care unit. Guidelines for management of acute anaphylaxis referring to both the stage of disease including shock and the main clinical manifestation (cutaneous, pulmonary, cardiovascular) have been established by a German interdisciplinary consensus conference and were published in 1994; consensus guidelines for emergency medical treatment have been communicated by the ILCOR (1997) and the Project Team of the Resuscitation Council (UK) (1999).