EMS World

AUG 2011

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Page 51 of 71

CE ARTICLE administration in the deltoid (arm) of asymptomatic patients and may be a preferred route.4 Ideally, the patient with known hypersensitivity to an allergen will have been prescribed an EpiPen and will have self-administered epinephrine prior to EMS’ arrival. In patients with laryn- geal swelling, racemic epinephrine via small-volume nebulizer can be used to reduce swelling, but it should never take the place of more definitive airway control, such as endotracheal intuba- tion, if airway compromise is imminent. Epinephrine should be used with caution in elderly patients and in patients with known heart disease or hypertension. Adjunctive treatment for anaphylaxis should also include antihistamines and can include corticosteroids if protocol allows. IV administration of diphenhydr- amine will assure that hemodynamic compromise and hypoperfusion do not interfere with rapid absorption, as could occur with IM or PO administra- tion. Treatment with antihistamines in the emergency department is usually accomplished by using both a H1 hydramine) blocker and a H2 (diphen- blocker like ranitidine, and should be considered in the prehospital environment if available. While corticosteroids such as methylpred- nisolone will have no immediate hemody- namic effects on the patient with anaphy- laxis,5 it can help prevent the potential late-phase reaction that can occur with biphasic anaphylaxis. For bronchospasm unrelieved with epinephrine administration, administra- tion of an inhaled bronchodilator via small- volume nebulizer should be considered. Maintaining an adequate blood pressure is important in the treatment of anaphylaxis. Hypotension in anaphylaxis occurs secondary to increased capillary permeability and the third-spacing of fl uids. As such, fl uid volume should be replaced after administration of epineph- rine, which increases peripheral vascular resistance and slows the third-spacing of fl uids. The exact volume of isotonic crys- talloid administered should be titrated to the return of an adequately perfusing blood pressure and could be signifi cant, as much as 5 L, in severe anaphylaxis. For hypotension refractory to fl uid volume 48 AUGUST 2011 | EMSWORLD.com Table 2: Coombs and Gell Hypersensitivity Classifi cation COMMON DISORDERS TYPE ALSO KNOWN AS... I II Allergy (IgE- mediated allergic responses) Cytotoxic, antibody- dependent (tissue-specifi c reactions) III IV Immune complex disease Cell-mediated immune response Atopy (allergic reaction) Anaphylaxis Asthma Autoimmune hemolytic anemia Erythroblastosis fetalis Thrombocytopenia Goodpasture’s syndrome Myasthenia gravis Graves’ disease Systemic lupus erythematosus (SLE) Serum sickness Contact dermatitis Chronic transplant rejection Multiple sclerosis administration, a vasopressor such as IV epinephrine or dopamine can be admin- istered as a controlled drip. Patients who are taking beta-blockers can have an anaphylactic reaction that is refractory to adrenergic agents. While data is limited, it appears that glucagon may be effective in such situations.6 Glucagon has positive inotropic and chronotropic effects on the myocardium and can also reverse bronchospasm. Systemic Lupus Erythematosus Systemic lupus erythematosus (SLE, or lupus), a Type III hypersensitivity reaction, is a multisystem autoimmune connective tissue disorder in which the body’s immune system produces antibodies that target its own tissues and organs, resulting in wide- spread tissue destruction and infl amma- tion. There is no one specifi c cause of SLE, though the abnormal humoral and cellular immune system reactions that result in the formation of these antibodies are thought to be controlled by genetic, environmental and hormonal factors.7 It results in a broad range of clinical presentations that can include the kidneys, liver, cardiovascular system, respiratory system, skin and joints. It is known as “the great imitator” because it often mimics or can be confused with other diseases. There are four types of lupus: SLE, discoid lupus erythematosus, drug-induced lupus erythematosus and neonatal lupus. Of these, SLE is the most common and MEDIATORS IgE IgG IgM IgG Complement T cells serious form. Patients with SLE are at risk for many complications, and their medica- tion regimen often includes corticosteroids and immunosuppressive agents that may cause further complications. SLE is much more prevalent in women than men. It may occur at any age, but appears most often in people between the ages of 10 and 50. African-Americans and Asians are affected more often than other races.8 The triad of joint pain, rash and fever in a woman of childbearing age should raise the suspicion for SLE, as they are the most commonly found symptoms in patients with the disease. Fever is a common and challenging problem in patients with the disease, as it can represent a manifestation of active SLE, an active infection, malignancy, or a reaction to medications such as immu- nosuppressive agents. Dermatologic manifestations include the malar or butterfl y rash that is the hall- mark of SLE and occurs in about 50% of patients with the disease.9 It can be exacerbated by exposure to ultraviolet light. Lesions and ulcerations of the mucous membranes can also occur. The vast majority of patients with SLE will experience arthritis and myalgias at some point in the course of the disease. In addition, many patients will have episodes of nephritis; however, many will have no symptoms from lupus nephritis until it progresses to renal failure.

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