NMS Q&A Family Medicine

Medical Problems of the Gastrointestinal Tract 93respectively. Hookworm causes pruritus on occasion and,after attainment of a large worm load in the intestines,may cause microcytic, hypochromic anemia throughconsumption of host blood. E . histolytica is the etiologyof amebiasis and acutely causes diarrhea, dysentery, andsevere abdominal pain and may ultimately result inchronic systemic disease. Each of the parasites discussedhere that are passed through the fecal–oral route aremore incident and prevalent in groups that practice oral–anal sex.6. The answer is C. Pseudomembranous colitis is themost likely diagnosis in view of the woman’s recent andcontinuing treatment with antibiotics and the waterydiarrhea. The leading bacterial causation is C. difficile . Ahospital stay of 4 weeks or longer results in a 50% rate ofC . difficile acquisition, compared with a 3% prevalenceof GI colonization in the general population; a 2-weekstay appears to present a risk of 13% for acquisition.Although pneumonia may be recurrent or persistent andantibiotics continue to be indicated, the diarrhea andmarked leukocytosis require a working diagnosis ofpseudomembranous colitis. Neither IBS nor carcinomaof the colon causes watery diarrhea or leukocytosis.Ulcerative colitis is unlikely in view of the clinicalsetting.7. The answer is D. Metronidazole is effective againstC . difficile and is inexpensive; the most important sideeffects are neurologic. The second choice of antibiotics isvancomycin, the chief caveat being nephrotoxicity. Eachof the other antibiotics mentioned is a risk factor for thedisease, being broad spectrum and not specifically effectiveagainst C . difficile . Among the antibiotics, clindamycinis fraught with the greatest risk of C . difficile disease.Only 20% of antibiotic-related diarrhea is caused byC . difficile , but virtually all cases of pseudomembranouscolitis result from C . difficile . Pseudomembranous colitiscarries a 1% to 2.5% case mortality.MATCHING QUESTIONS 8 THROUGH 128. The answer for carcinoma of the colon is D, age 50years.9. The answer for vascular ectasia (angiodysplasia) is A,chronic renal failure.10. The answer for blue rubber bleb nevus syndrome isB, cutaneous hemangiomas.11. The answer for celiac sprue is C, chronic diarrhea,abdominal pain.12. The answer for Kaposi sarcoma, cytomegaloviruscolitis is E, acquired immunodeficiency disease.MATCHING QUESTIONS 13 THROUGH 1713. The answer for migraine headache is A, DAs, SAs.14. The answer for vestibular nausea is D, histamine1 blocker, anticholinergics.15. The answer for pregnancy-induced nausea is E, ginger,vitamin B 6 , promethazine.16. The answer for gastroenteritis is A, DAs, SAs.17. The answer for postoperative nausea, vomiting is B,DAs, SAs, dexamethasone.DISCUSSION OF QUESTIONS 13 THROUGH 17These recommendations are based on the theories of themechanisms involved in production of nausea associatedwith the five conditions. The nausea of migraine is associatedwith the neurotransmitter dopamine, antagonists ofwhich are used for headache with nausea, such as metoclopramide(Reglan) or prochlorperazine (Compazine).For nausea alone in migraine are recommended the foregoingclasses of drugs as well as serotonin antagonists,such as ondansetron (Zofran). Vestibular nausea is mediatedby histamine and by acetylcholine, and hence, it istreated by histamine 1 blocking agents (“antihistamines”)and by anticholinergic agents. The mechanism of nauseaassociated with pregnancy is poorly understood, but therecommendations made, that is, ginger and vitamin B 6 ,are based on empiric response and safety for use duringthe first trimester of pregnancy. Hyperemesis gravidarumis treated by either promethazine (Phenergan) or an SAand, as a second-line approach, glucocorticoids. Neurotransmittersassociated with gastroenteritis are dopamineand serotonin; therefore, DAs are used, as justexemplified. The same applies to postoperative nauseaand vomiting.18. The answer is D. Angiodysplasia may occur throughoutthe GI tract but is found most frequently in olderpatients and those with chronic renal failure, particularlyin the upper tract. This may be a result of increased plateletdysfunction associated with uremia. All other choicesmay be sources of small intestinal bleeding but relativelyinfrequently as compared with angiodysplasia.19. The answer is B. Risk of intestinal infarction withembolization. Angiography functions as a diagnostic toolfor brisk GI bleeding by the show of dye that appears inthe lumen when the arterial blood supply to the bleedingsegment of bowel has been cannulated. It is also a therapeutictool that works by embolization of the vessel thatsupplies the bleeding area. The chief danger is that ofinfarction of the segment, that is, hemorrhaging. Small