Abstract
An anaphylactic shock is a form of severe allergy that can be fatal. The aim of this essay is to provide in brief the causes, mechanisms, and an outline of management.
Introduction
The earliest report of death because of anaphylactic shock was King Mines (first Pharaoh of ancient Egypt, 2641 B.C) who died because of a wasp sting that resulted in anaphylaxis (Gruchalla, 2004). Anaphylactic shock is defined as a serious acute type of sweeping hypersensitivity involving many organs and body systems. It is characterized by broncho-constriction (spasm), angioneurotic edema (both lead to severe difficulty in breathing), and a decrease in blood pressure (Brown and others, 2006).
Causes and Mechanism
Anaphylactic shock may result from insect stings (wasps and bees), food (peanut, fish, egg…etc), drugs (aspirin, antibiotics, i/v anesthetics…etc), or contacts as contact with latex rubber. Other rare causes include exercise and vaccines. It occurs when an antigen combines with IgE antibody present at a specific receptor on the cell wall of basophils or mast cells (types of white blood corpuscles). As a result, chemically active substances like histamine present in the granules of these cells are released. These chemically active substances (mediators) are responsible for the clinical picture of the shock, thus anaphylactic shock is an immunoglobulin E mediated immune reaction. Another variant of anaphylactic shock with the same clinical picture but not mediated by IgE is an anaphylactoid reaction (Ewan, 1998).
Management of anaphylactic shock
The cornerstone in management is to be ready for rapid progression of the condition manifested by suffocation and mounting to cardiac arrest. Good support for the upper airway (laryngeal edema), proper oxygenation, and ventilation should always be ensured. Drugs like epinephrine (adrenaline) may be injected to support the circulation; Atropine is to be given when significant bradycardia develops. Corticosteroids are administered in high doses as a bolus injection and or i/v drip, however; the effect of corticosteroids maybe 4-6 late. Antihistamine and calcium slow i/v injections to counteract the vasodilator effect of histamine. Observation even after the case improves as the symptoms recur in 20% of the patient after periods up to 8 hours (Lieberman and colleagues, 2005).
Conclusion
An anaphylactic shock is a severe form of IgE-mediated immune response. The course is unpredictable and can be fatal. Characteristic symptoms are angioneurotic edema, dyspnea, and hypotension. Every effort must be done to support the patient’s airway and circulation. Observation is critically important as symptoms may recur after initial improvement.
References
Ewan, P M. (1998). ABC of allergies: Anaphylaxis. BMJ, 316, 1442-1445.
Gruchalla, R S. (2004). Immunotherapy in Allergy to Insect Stings in Children. NEJM, 351(7), 707-709.
Lieberman P, Kemp, S, Oppenheimer, J et al (2005). The Diagnosis and Management of Anaphylaxis: An Update Practice Parameter. The Journal of Allergy and Clinical Immunology, 115 (3), S483-2523.
Simon G A, Mullins R J and Gold M S. (2005). MJA Practice Essentials – Allergy: 2. Anaphylaxis: diagnosis and management. MJA, 185(5), 283-289.