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Anaphylaxis
Pharm (Test 3)
| Question | Answer |
|---|---|
| What are the 4 roles and functions of histamine? | 1)mediator of allergic reactions and inflammatory processes, 2)affects gastric secretion, 3)neurotransmitter, 4)neuromodulator |
| Where is bound histamine found? | in vesicles in mast cells or basophils |
| Histamine is (active or inactive?) in bound form. | inactive |
| Where are mast cells found? | tissues -- nose, mouth, feet, internal body surfaces, blood vessels |
| Where is non-mast cells histamine found? | in the brain as an endogenous NT |
| What type of cells store and release histamine from the fundus of the stomach? | enterochromaffin-like cells (activates acid-production from parietal cells) |
| The major pathophysiologic mechanism of mast cells and basophil histamine release is _________________. | immunologic |
| Negative feedback from ________ receptors found in skin and basophils limits reaction in the skin and blood. | H2 |
| What type of drugs (2 examples?) compete w/ histamine for sites within cells and displace histamine. | amine drugs -- morphine and tubocurarine |
| H1 receptors are similar to _____________ receptors. | muscarinic receptors |
| Where are H1 receptors located? | presynaptic in the brain; endothelium, smooth muscle cells, nerve endings (brain) |
| H1 receptor activation causes: | bronchoconstriction, slowed conduction through the AV node, coronary artery vasoconstriction |
| H2 receptors are similar to ______________ receptors. | 5-HT1 receptors |
| Where are H2 receptors located? | postsynaptic in the brain; gastric mucosa, cardiac muscle cells, and some immune cells |
| H2 receptor activation causes: | CNS stimulation, increased myocardial contractility, increased HR, bronchodilation, increased secretion of H+ ions by gastric parietal cells (dec. pH) |
| H3 receptors are similar to _______________ receptors. | H4 |
| Where are H3 receptors located? | heart presynaptic postganglionic SNS |
| Activation of H3 receptors causes: | dec. NE release, dec. synthesis and release of histamine (negative feedback) |
| H4 receptors are similar to _______________ receptors. | H3 |
| Where are H4 receptors located? | blood cells, bone marrow (eosinophils, neutrophils) |
| What are some cardiac effects caused by histamine on H1 and H2 receptors? | dec. in SBP and DBP (vasodilation), inc. HR, vasodilation (nitric oxide), coronary vasoconstriction, edema, inc. capillary permeability |
| What are the direct effects of histamine on the myocardium? This is caused by stim. of which receptor? | inc. contractility, inc. HR (result of H2 receptor stimulation) |
| How do H1 and H2 receptors differ in their vasodilatory effects? | H1=rapid onset, transient; H2=slower onset, sustained |
| What effect does H1 receptor stim. have on pulmonary system? | bronchoconstriction |
| What effect does H2 receptor stim. have on pulmonary system? | bronchodilation |
| Asthma patients have ______-______X greater sensitivity when it comes to histamine-induced bronchoconstriction. | 100-1000X |
| What effect does histamine have on the GI system? | excessive secretion of gastric fluid with a low pH |
| What effect does histamine have on the CNS? Due to which receptor? | CNS stimulation (agitation); H2 receptor |
| True or False: Histamine receptor blockers inhibit the release of histamine. | False; it affects ability of histamine to get to receptors |
| What are some examples of H1 receptor blockers? | diphenhydramine/Benadryl, dimenhydrinate/Dramamine, meclizine/bonine, promethazine/phenergan |
| How do H1 receptor blockers work? | prevent activation of H1 receptors by histamine -- competitive antagonist; may activate muscarinic, 5HT3, alpha receptors |
| What are some examples of H2 receptor blockers? | cimetidine/tagament, famotidine/Pepcid, ranitidine/zantac |
| How do H2 receptor blockers work? | prevent inc. in intracellular cAMP which would activate the protein pump of the gastric parietal cell to secrete H+ ions |
| What is the drug of choice for anaphylaxis treatment? | epinephrine |
| How does epi work to treat anaphylaxis? | physiologic antagonist; has opposite effect on smooth muscle, but acts on different receptors |
| What drugs can be used to prevent the release of histamine? How do they work? | cromolyn and beta2 agonists; dec. the degranulation of mast cells that occurs when immunologic triggering |
| Define anaphylaxis | severe immediate hypersensitive reaction mediated by IgE antibodies formed in response to a foreign antigen |
| Define anaphylactic shock. | the cardiovascular collapse that results from anaphylaxis |
| Define anaphylactoid reaction. | non IgE mediated reaction that clinically resembles anaphylaxis |
| Drug reactions are frequent in anesthesia. Only _____% are true allergic reactions. | 10% |
| How does re-exposure to an antigen trigger an anaphylactic reaction? | re-exposure to the antigen causes the bridging of cell-surface IgE receptor molec. which activates enzymes which starts a cascade which leads to an introduction of extracellular Ca+ and mobilization of intracellular Ca+ and thus release of mediators |
| What are some examples of mast cell mediators? | histamine, kinins, heparin, leukoagglutinis, leukotrienes, platelet-activating factor, prostaglandins, serotonin |
| What are some physiologic manifestations of anaphylaxis? | bronchospasm, tachycardia, hypotension, edema, urticaria, excessive resp/GI secretions, inflammation, abdominal pain, N/V/D |
| What are some cutaneous signs of anaphylaxis? | urticaria, angioedema, erythema, periorbital and facial edema |
| What are some resp signs of anaphylaxis? | coughing, sneezing, hoarseness, intraoral edema, laryngeal edema, stridor, cyanosis, tachypnea, WHEEZING, dec. pulmonary compliance, pulm. edema, acute resp distress |
| define urticaria. | skin wheals, pruritic |
| Define angioedema. | deep nonpitting cutaneous edema from vasodilation and increased permeability of subq vessels. can involve the airway with compromise |
| What are some cardiovascular signs of anaphylaxis? | diaphoresis, hypotension, tachycardia, arrhythmias, dec. SVR, cardiac arrest, pulm. HTN |
| Define Grade 1 anaphylaxis. Give epi? | erythema, urticaria w/ or w/o angioedema; epi NOT given |
| Define Grade 2 anaphylaxis. | moderate severity, cutaneous signs, hypotension and tachycardia, cough, diff. to ventilate |
| Define Grade 3 anaphylaxis. | life-threatening severity, CV collapse, tachycardia or bradycardia, dysrhythmias, bronchospam |
| Define Grade 4 anaphylaxis. | cardiac and/or resp arrest |
| What are some risk factors for anaphylaxis. | receiving parenteral drugs, history of allergic rxn or atopy, asthma, women (2.5x-- cosmetics w/ quaternary ammonium), history of previous anesthetic |
| What are some examples of drugs associated w/ reactions? | muscle relaxants (most frequent! usually non IgE), morphine, Demerol, codeine, induction agents (pentothal, ketamine, benzos, propofol), locals, ABX, blood, protamine, latex |
| True or False: Sugammadex is approved by the FDA for treatment of Roc-induced anaphylaxis. | False-- not approved d/t hypersensitivity concerns |
| What is the treatment regimen for anaphylaxis? | remove agent, airway mgmt., fluids, epi, vaso, d/c anesthetic agents, antihistamines (Benadryl/Pepcid), glucocorticoids (hydrocortisone) |
| How much fluid should you give to treat anaphylaxis? | 25-50mL/kg (2-4L) |
| How much epi should you give for moderate hypotension during anaphylaxis? | 10-100mcg |
| How much epi should you give for circulatory collapse/pulselessness during anaphylaxis? | 1-3mg |
| What is an appropriate infusion dose of epi during anaphylaxis? | 4-10mcg/min |
| How much vaso should you give for moderate hypotension during anaphylaxis? | 0.5-2units |
| How much vaso should you give for circulatory collapse/pulselessness during anaphylaxis? | 40 units |
| What dose of diphenhydramine should you give for anaphylaxis? | 1mg/kg (max=50mg) |
| What dose of famotidine should you give for anaphylaxis? | 20mg |
| What dose of hydrocortisone should you give for anaphylaxis? | 5mg/kg (50-100mg) |
| What are some adjunct drugs used to treat anaphylaxis? | aminophylline, albuterol inhaler, dopamine, norepi, NaBicarb |
| What can be done to prevent anaphylaxis? | avoid risky practice, careful history taking, intradermal skin test, RAST test, leukocyte histamine release test, pharm. prophylaxis |
| What drugs should be given for anaphylaxis prophylaxis? | Benadryl (H1), decadron, ranitidine (H2) |
Created by:
lindseymontgomery
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