NMS Q&A Family Medicine

224 NMS Q&A Family MedicineExamination Answers1. The answer is D. Montelukast is indicated for preventionand maintenance therapy in asthma. The drug is notapplicable to acute attacks of asthma; it should not beused as monotherapy for the treatment of exerciseinducedasthma because it should not be used in acuteattacks (although it is quite conceivable that a personcould be subject to exercise-induced asthma while onMontelukast and should be treated accordingly); not onlyis rescue medication not contraindicated when a patientis on montelukast but should be used if an attack occurswhile the patient is on montelukast. The drug is not indicatedin status asthmaticus – again because status is acuteand montelukast is a maintenance medication.2. The answer is A. Immune hemolytic anemia is notmediated by IgE antibodies. It is a Type II or cytotoxichypersensitivity reaction mediated through IgG antibody.Each of the other conditions is IgE mediated: allergicasthma, atopic dermatitis (and other atopic manifestationssuch as rhinitis and food allergies), allergic gastroenteropathy,and anaphylaxis. The last includes manifestationssuch as hypotension, bronchospasm, gastrointestinal anduterine muscle spasm, urticaria, and angioedema. IgEantibodies are formed immediately after the exposure of asensitive person to the allergen. Each of these allergic reactionsis treatable at the most conservative level by H-1antihistamines and most aggressively by epinephrine.Type III reactions entail immune complex–mediated reactionsincluding serum sickness. Type IV reactions areT-cell mediated and are delayed, such as contact allergies(e.g., rhus), and the autoimmune diseases lupus erythematosusand glomerulonephritis result in chronic inflammationbut not anaphylaxis.3. The answer is D. Mast cell granule release in responseto membrane-bound IgE cross-linking with a specific allergen.This is a classic immediate hypersensitivity (Type I)response. This individual must have had prior exposureto the antigens (but may not recall the first uneventfulsting), which previously led to the production of these IgEantibodies on the mast cell surface. The early phaseresponse is characterized by capillary permeability andfluid leakage. It is invoked in allergy skin testing as anotherexample of its applicability. Late-phase responses (not tobe confused with delayed hypersensitivity, Type IV)include local invasion by basophiles, eosinophils, monocytes,and lymphocytes. Analogous clinical situationsinclude the rapid onset and recovery (15 to 30 minutes) ofbronchospasm in asthmatic exposure to inhaled allergenicantigens. The late response in asthma occurs 3 to8 hours later and can last up to 24 hours. There aremucosal and conjunctival counterparts to these reactions.The late phase resembles the actual clinical picture inasthma, for example, resulting in air trapping.4. The answer is D. Epinephrine, 1:1,000, injected intramuscularly,or on occasion intravenously, is the treatmentfor anaphylaxis. The greatest single error made in themanagement of acute anaphylaxis is timidity; failure toact in a timely and aggressive manner. Epinephrine, 1:100,injected would be a dangerous overdose and has occurredby accident with fatal consequences. Diphenhydramine,50 mg, injected intravenously would be too mild aresponse, given the rapidly developing systemic involvementof the anaphylaxis. Cromolyn–nedocromil by nasalinhalation is a preventive treatment for allergic rhinitisand has no application in anaphylaxis. To combat hypotension,besides the epinephrine, fluid therapy and othervasopressors may be employed, for example, dopamine,norepinephrine and phenylephrine. Specific therapy forpersistent bronchospasm should be treated with beta-agonistssuch as albuterol by inhalation.5. The answer is C. If the patient with anaphylaxis hasbeen taking the nonselective beta-adrenergic blockingagent, propranolol, the effective dosage of epinephrinefor reversing the pathophysiology may well be increased.This occurs, of course, because of the blocking effect onthe beta-adrenergic portion of the action of epinephrine.None of the other choices has any bearing on the treatmentof anaphylaxis.6. The answer is A. Late occurrence of anaphylactoidsymptoms and signs is frequent after anaphylaxis, due tothe late-phase reaction discussed in Question 3, manifestationsof which are possible for up to 24 hours and formthe basis for the continued monitoring of anaphylaxispatients for that period. If these include angioneuroticedema and urticaria, oral diphenhydramine (Benadryl) isappropriate. If late manifestations involve bronchospasm,a frequent part of the acute syndrome, rescue medicationsuch as albuterol is appropriate. Fluid therapy applies onlyin the case of hypotension, a development not to beexpected during the late-phase reaction.7. The answer is C. Peanuts, tree nuts, vertebrate fish,and shellfish account for 90% of all food allergies. Anelimination diet is a practical technique available in primarycare. Additional foods that are often involved infood allergy situations include beer, chocolate, tomatoes,and egg (albumen). In practice, it may be helpful toinclude all eight of the foregoing groups in an elimination