Gastrointestinal Tract PDF

CHAPTER Gastrointestinal Tract 17 PBD9 Chapter 17 and PBD8 Chapter 17: The Gastrointestinal Tract BP9 Chapter 14 and BP8 Chapter 15: Oral Cavity and Gastrointestinal Tract 1 A 23-year-old primigravida gives birth at term to a boy 3 A 23-year-old woman, G2, P1, gave birth at term to a infant. Ultrasound examination before delivery showed poly- boy of normal weight and length following an uncomplicated hydramnios. A single umbilical artery is seen at the time of pregnancy. The infant initially did well, but at 6 weeks, he birth. The infant vomits all feedings, and then develops a fever began feeding poorly for 1 week, and his mother noticed that and difficulty with respirations within 2 days. A radiograph much of the milk he ingested was forcefully vomited within shows both lungs and the heart are of normal size, but there 1 hour. Now, on physical examination, the infant is afebrile, are pulmonary infiltrates and no stomach bubble. What is the and there are no external anomalies. A midabdominal mass is most likely diagnosis? palpable. Bowel sounds are active. The medical history indi- A Achalasia cates that both the mother and her first child had the same ill- B Diaphragmatic hernia ness during infancy. Which of the following conditions is most C Esophageal atresia likely to explain these findings? D Hiatal hernia A Annular pancreas E Pyloric stenosis B Diaphragmatic hernia F Zenker diverticulum C Duodenal atresia D Pyloric stenosis 2 A 24-year-old man has developed abdominal pain and E Tracheoesophageal fistula increasing fatigue over the past 6 months. On physical exami- nation, he is afebrile and appears pale. On palpation, there is 4 A 24-year-old woman gives birth to term infant after an mild pain in the right lower quadrant of the abdomen. There uncomplicated pregnancy. Apgar scores are 9 and 10 at 1 and are no masses, and bowel sounds are active. Laboratory stud- 5 minutes after birth. The infant’s length and weight are at the ies show hemoglobin, 8.9 g/dL; hematocrit, 26.7%; MCV, 55th percentile. There is no significant passage of meconium. 74 μm3; platelet count, 255,000/mm3; and WBC count, 7780/ Three days after birth, the infant vomits all oral feedings. On mm3. His stool is positive for occult blood. Upper gastroin- physical examination, the infant is afebrile, but the abdomen testinal endoscopy and colonoscopy showed no lesions. One is distended and tender, and bowel sounds are reduced. An month later, he continues to experience the same abdomi- abdominal ultrasound scan shows marked colonic dilation nal pain. Which of the following is most likely to cause this above a narrow segment in the distal sigmoid region. A biopsy patient’s illness? specimen from the narrowed region shows an absence of gan- A Acute appendicitis glion cells in the muscle wall and submucosa. Which of the B Angiodysplasia following is most likely to produce these findings? C Celiac disease A Colonic atresia D Diverticulosis B Hirschsprung disease E Giardia lamblia infection C Intussusception F Meckel diverticulum D Necrotizing enterocolitis E Trisomy 21 F Volvulus 263 264 UNIT II Diseases of Organ Systems 5 A 3-year-old child has attained enough mobility, curios- 9 A 30-year-old man has sudden onset of hemateme- ity, and dexterity to explore places in the home that should sis after a weekend in which he consumed large amounts of not be accessed. The child finds a bottle with a liquid under alcohol. The bleeding stops, but he has another episode under the kitchen sink, and he drinks it. Within minutes he has chest similar circumstances 1 month later. Upper gastroesophageal pain. His mother takes him to the emergency department, and endoscopy shows longitudinal tears at the gastroesophageal brings the bottle. Analysis of the residual contents reveals a junction. What is the most likely mechanism to cause his pH of 12. Which of the following complications is most likely hematemesis? to occur following this injury? A Absent myenteric ganglia A Pharyngeal diverticulum B Autoimmune inflammation B Esophageal stenosis C Herpes simplex virus infection C Gastric lymphoma D Portal hypertension D Duodenal ulceration E Vomiting E Megacolon F Widened diaphragmatic crura 6 A 22-year-old woman has had multiple episodes of aspi- 10 A 16-year-old boy who is receiving chemotherapy for ration of food associated with difficulty swallowing during the acute lymphoblastic leukemia has had pain for 1 week when past year. On auscultation of her chest, crackles are heard at the he swallows food. Physical examination shows no abnormal base of the right lung. A barium swallow shows marked esoph- findings. Upper gastrointestinal endoscopy shows 0.5- to ageal dilation above the level of the lower esophageal sphincter. 0.8-cm mucosal ulcers in the region of the mid to lower esoph- A biopsy specimen from the lower esophagus shows an absence agus. The shallow ulcers are round and sharply demarcated, of the myenteric ganglia. What is the most likely diagnosis? and have an erythematous base. Which of the following is A Achalasia most likely to produce these findings? B Barrett esophagus A Aphthous ulcerations C Plummer-Vinson syndrome B Reflux esophagitis D Sliding hiatal hernia C Herpes simplex esophagitis E Systemic sclerosis D Gastroesophageal reflux disease E Mallory-Weiss syndrome 7 A 24-year-old woman living in eastern Bolivia has had increasing difficulty with swallowing both liquids and solids 11 A 44-year-old woman has had increasing difficulty for the past year. She has substernal discomfort from a feeling swallowing liquids and solids for the past 6 months. On phys- that foods “get stuck” going down. On examination her BMI ical examination, her fingers have reduced mobility because is 18. A barium swallow radiologically shows marked esopha- of taut, nondeforming skin. A barium swallow shows marked geal dilation. An endoscopic biopsy is obtained and micro- dilation of the esophagus with “beaking” in the distal portion, scopically shows reduced ganglion cells in myenteric plexus where there is marked luminal narrowing. A biopsy s pecimen along with lymphocytic infiltration. Which of the following from the lower esophagus shows prominent submucosal organisms is most likely infecting this woman? fibrosis with little inflammation. Which of the following is A Bordetella pertussis most likely to produce these findings? B Candida albicans A Barrett esophagus C Corynebacterium diphtheriae B Hiatal hernia D Herpes simplex virus C Iron deficiency E Trypanosoma cruzi D Portal hypertension E Systemic sclerosis 8 A 53-year-old man consumes a very large meal, washed down with considerable alcohol. The ensuing discomfort 12 A 57-year-old woman has had burning epigastric prompts him to take an emetic, but soon afterward he devel- pain after meals for more than 1 year. Physical examination ops lower chest pain. Physical examination reveals crepitus shows no abnormal findings. Upper gastrointestinal endos- in subcutaneous tissue over his chest along with tachycardia copy shows an erythematous patch in the lower esophageal and tachypnea. Which of the following abnormalities of the mucosa. A biopsy specimen shows basal zone squamous epi- esophagus is most likely present in this man? thelial hyperplasia, elongation of lamina propria papillae, and A Stricture scattered intraepithelial neutrophils with some eosinophils. B Achalasia Which of the following is the most likely diagnosis? C Ectopia A Barrett esophagus D Rupture B Esophageal varices E Varices C Iron deficiency D Reflux esophagitis E Systemic sclerosis CHAPTER 17 Gastrointestinal Tract 265 13 A 51-year-old man has sudden onset of massive emesis of bright red blood. On physical examination, his tempera- ture is 36.9° C, pulse is 103/min, respirations are 23/min, and blood pressure is 85/50 mm Hg. His spleen tip is palpable. Laboratory studies show a hematocrit of 21%. The serologic test result for HBsAg is positive. He has had no prior episodes of hematemesis. The hematemesis is most likely to be a conse- quence of which of the following? A Barrett esophagus B Candida albicans infection C Esophageal varices D Reflux esophagitis E Squamous cell carcinoma F Zenker diverticulum 16 A 73-year-old man with a history of chronic alcoholism has had increasing difficulty swallowing and has noticed a 3-kg weight loss over the past 2 months. On physical examina- tion, there are no remarkable findings. Upper gastrointestinal endoscopy shows a 3-cm ulcerative mass in the midesophagus that partially occludes the esophageal lumen. Esophagectomy is performed; the gross appearance of the lesion is shown in the figure. Which of the following is most likely to be seen on 14 A 55-year-old man has had increasing difficulty swal- microscopic section of this mass? lowing during the past 6 months. There are no significant A Adenocarcinoma findings on physical examination. Upper gastrointestinal B Dense collagenous scar endoscopy shows areas of erythematous mucosa 3 cm above C Dilated vascular channels the Z-line. A biopsy specimen from the lower esophagus has D Multinucleated cells with intranuclear inclusions changes in the mucosal epithelium illustrated in the figure. E Squamous cell carcinoma Which of the following complications is most likely to occur as a consequence of this patient’s condition? 17 A 66-year-old man living in Tehran, Iran, has been A Achalasia bothered by difficulty swallowing for the past year. He is B Adenocarcinoma now consuming liquid food. Yesterday he regurgitated food C Diverticular formation stained with blood. On esophagoscopy, there is an ulcerated D Lacerations (Mallory-Weiss syndrome) obstructing lesion 20 cm from the lips. Biopsies are taken and E Squamous cell carcinoma on microscopy show infiltrating nests of keratinized cells with distinct cell borders and hyperchromatic, angulated nuclei. 15 A 68-year-old man from Birmingham, England, has had Which of the following is the most likely risk factor for his “heartburn” and substernal pain after meals for 25 years. For disease? the past year, he has had increased pain with difficulty swal- A Genetic susceptibility lowing both liquids and solids. On physical examination, there B Autoimmunity are no remarkable findings. Upper gastrointestinal endoscopy C Diet shows an ulcerated lower esophageal mass that nearly occludes D Infection the lumen of the esophagus. A biopsy specimen of this mass is E Reflux most likely to show which of the following neoplasms? A Adenocarcinoma B Carcinoid tumor C Leiomyosarcoma D Non-Hodgkin lymphoma E Squamous cell carcinoma 266 UNIT II Diseases of Organ Systems 18 A 38-year-old woman has had nausea for 6 months. She reports no vomiting or diarrhea. On physical examina- tion, there are no remarkable findings. Upper gastrointestinal endoscopy shows diffuse gastric mucosal erythema with focal mucosal erosions, but no ulcerations. The esophageal and duodenal mucosal surfaces appear normal. Gastric biopsies are obtained and microscopic examination shows focal muco- sal hemorrhage, loss of the surface epithelium, and increased numbers of neutrophils, lymphocytes, and plasma cells in an edematous mucosa. No Helicobacter pylori organisms are seen. Laboratory studies show a normal serum gastrin level. Which of the following pharmacologic agents is most likely to pro- duce these findings? A Aspirin B Chlorpromazine C Cimetidine D Clindamycin 22 A 59-year-old man has had nausea and vomiting for E Omeprazole 5 months. He has experienced no hematemesis. On physical examination, there is no abdominal tenderness, and bowel 19 A 72-year-old man takes large quantities of nonsteroidal sounds are present. Upper gastrointestinal endoscopy shows anti-inflammatory drugs (NSAIDs) because of chronic degen- erythematous areas of mucosa with thickening of the rugal erative arthritis of the hips and knees. Over the past 2 weeks, folds in the gastric antrum. The microscopic appearance of a he has had epigastric pain with nausea and vomiting and an gastric biopsy specimen with a Steiner silver stain is shown episode of hematemesis. On physical examination, there are in the figure. Which of the following factors is most likely no remarkable findings. A gastric biopsy specimen is most responsible for this gastric mucosal pathology? likely to show which of the following lesions? A Cysteine proteinase A Acute gastritis B Cytotoxin-associated gene A B Adenocarcinoma C Heat-stable enterotoxin C Epithelial dysplasia D Shiga toxin D Helicobacter pylori infection E Verocytotoxin E Hyperplastic polyp 23 A 47-year-old woman with a lengthy history of heart- 20 A 54-year-old, previously healthy man sustained an burn and dyspepsia experiences sudden onset of abdominal extensive thermal burn injury involving 70% of the total body pain. On physical examination, she has severe mid epigastric surface area of his skin. He was hospitalized in stable condi- pain with guarding. Bowel sounds are reduced. An abdomi- tion. Three weeks after the initial burn injury, he developed nal plain film radiograph shows free air under the left leaf of melanotic stools. His blood pressure dropped to 80/40 mm the diaphragm. She is immediately taken to surgery, and a Hg, and his hematocrit declined to 18%. Where are gastroin- perforated duodenal ulcer is repaired. Which of the following testinal ulcerations most likely to be found in this man? organisms is most likely to have produced these findings? A Colon A Campylobacter jejuni B Duodenum B Cryptosporidium parvum C Esophagus C Giardia lamblia D Ileum D Helicobacter pylori E Stomach E Salmonella typhi F Shigella flexneri 21 A 51-year-old woman has been feeling increasingly G Yersinia enterocolitica tired for the past 7 months. There are no remarkable findings on physical examination. Laboratory studies include hemo- 24 A 35-year-old man has had epigastric pain for more than globin, 9.5 g/dL; hematocrit, 29.1%; MCV, 124 μm3; platelet 1 year. The pain tends to occur 2 to 3 hours after a meal and is count, 268,000/mm3; and WBC count, 8350/mm3. The retic- relieved if he takes antacids or eats more food. He has noticed ulocyte index is low. Hypersegmented polymorphonuclear a 4-kg weight gain in the past year. He does not smoke and leukocytes are found on a peripheral blood smear. The serum drinks 1 glass of Johannisberg Riesling daily. The result of a gastrin is markedly increased. Antibodies to which of the fol- urea breath test is positive, and a gastric biopsy specimen con- lowing are most likely to be found in this patient? tains urease. He begins a 2-week course of antibiotics, but on A Gastric H+,K+-ATPase day 4, he feels better and discontinues treatment. Three weeks B Gliadin later, the epigastric pain recurs. If he does not seek further C Helicobacter pylori treatment, which of the following complications is he most D Intrinsic factor receptor likely to develop? E Tropheryma whippelli A Carcinoid syndrome B Fat malabsorption C Hematemesis D Migratory thrombophlebitis E Vitamin B12 deficiency CHAPTER 17 Gastrointestinal Tract 267 25 A 52-year-old man notes nausea with abdominal dis- specimen shows a monomorphous infiltrate of lymphoid cells comfort after meals. On physical examination, there are no microscopically. Helicobacter pylori organisms are identified abnormal findings. Upper endoscopy is performed, and there in mucus overlying adjacent mucosa. Cytogenetic analysis are three ovoid nodules in the fundus and antrum ranging shows t(11;18)(q21;q21). He receives antibiotic therapy for from 0.3 to 1.2 cm in size. They have rounded, smooth sur- H. pylori, and the repeat biopsy specimen shows a resolution faces. Biopsies are taken and on microscopic examination of the infiltrate. What is the most likely diagnosis? there are irregular, cystically dilated and elongated foveolar A Autoimmune gastritis glands. Which of the following treatment strategies is most B Chronic gastritis appropriate for his gastric lesions? C Crohn disease A Antibiotics D Diffuse large B-cell lymphoma B Chemotherapy E Gastrointestinal stromal tumor C Corticosteroids F Mucosa-associated lymphoid tissue tumor D Multivitamins E Total gastrectomy F Vagotomy 26 A 49-year-old woman has a history of peptic ulcer disease for which she has been treated with proton pump inhibitors. She has had nausea with vomiting for the past 2 months. Upper GI endoscopy reveals three circumscribed, round, smooth lesions in the gastric body from 1 to 2 cm in diameter. Biopsies are taken and microscopically show the lesions to consist of irregular glands that are cystically dilated and lined by flattened parietal and chief cells. No inflammation, Helicobacter pylori, metaplasia, or dysplasia is present. What is the most likely diagnosis? A Fundic gland polyps B Gastric adenomas C Hyperplastic polyps D Hypertrophic gastropathy 30 A 26-year-old man is brought to the emergency depart- 27 A 53-year-old woman has had nausea, vomiting, and ment after sustaining abdominal gunshot injuries. At laparotomy, midepigastric pain for 5 months. On physical examination, there while repairing the small intestine, the surgeon notices a 1-cm are no significant findings. An abdominal CT scan shows gastric mass at the tip of the appendix. The yellow-tan submucosal mass outlet obstruction. Upper gastrointestinal endoscopy shows an is removed, and the microscopic appearance of the mass is shown ulcerated 2 × 4 cm bulky mass in the antrum at the pylorus. A in the figure. Immunohistochemical staining is positive for chro- urease test is positive. Which of the following neoplasms is most mogranin and synaptophysin but negative for Ki-67. Which of likely to be seen in a biopsy specimen of this mass? the following is the most likely cell of origin of this lesion? A Adenocarcinoma A Lipoblast B Leiomyosarcoma B Ganglion cell C Neuroendocrine carcinoma C Goblet cell D Non-Hodgkin lymphoma D Neuroendocrine cell E Squamous cell carcinoma E Smooth muscle cell 28 A 67-year-old woman has experienced severe nausea, 31 A 55-year-old man experiences episodes of diaphoresis, vomiting, early satiety, and a 9-kg weight loss over the past dyspnea, and diarrhea for 10 months. On physical examina- 4 months. On physical examination, she has muscle wasting. tion he has midabdominal discomfort with deep palpation, Upper gastrointestinal endoscopy shows that the entire gas- and bowel sounds are reduced. There are no abnormal find- tric mucosa is eroded and has an erythematous, cobblestone ings with upper endoscopy. Abdominal CT scan shows three appearance. An abdominal CT scan shows that the stomach is nodules in the liver, from 1 to 3 cm in size. Laboratory stud- small and shrunken. Which of the following is most likely to be ies show a high level of serum 5-hydroxyindoleacetic acid found on histologic examination of a gastric biopsy specimen? (5-HIAA). Camera endoscopy is performed, and on review of A Chronic atrophic gastritis the images, there is a midjejunal mass that partially obstructs B Primary gastric lymphoma the lumen. At laparotomy a 5-cm submucosal jejunal mass is C Gastrointestinal stromal tumor resected, and on microscopy it is composed of nests and tra- D Granulomatous inflammation beculae of round cells with pink, granular cytoplasm. The cells E Signet ring cell adenocarcinoma of this mass are most likely related to which of the following embryologic derivatives? 29 A 52-year-old man has had a 4-kg weight loss and nau- A Endoderm sea for the past 6 months. He has no vomiting or diarrhea. B Ectoderm On physical examination, there are no remarkable findings. C Neural crest Upper gastrointestinal endoscopy shows a 6-cm area of irreg- D Notochord ular, pale fundic mucosa and loss of the rugal folds. A biopsy E Splanchnic mesoderm 268 UNIT II Diseases of Organ Systems 32 A 61-year-old man with increasing fatigue, early satiety, 35 A 61-year-old man has had severe abdominal pain and and nausea for 5 months vomited dark granular material yes- bloody diarrhea for the past day. On physical examination, his terday. Endoscopy reveals a large ulcerated mass in the gas- abdomen is diffusely tender, and bowel sounds are absent. tric fundus. Biopsies are taken and microscopically the mass Abdominal plain films show no free air. Laboratory studies is composed of spindle cells that are positive for c-Kit with show a normal CBC and normal levels of serum amylase, immunohistochemical staining. Mitoses are frequent. Gastrec- lipase, and bilirubin. His Hgb A1c is 10%. He develops shock. tomy is performed, and the 10-cm circumscribed mass arises A year ago he had an acute myocardial infarction. Which of from the gastric wall. Which of the following therapies is most the following lesions is most likely to be found in this man? likely to be a useful adjunct in treatment of his disease? A Appendicitis A Amoxicillin B Cholecystitis B Azathioprine C Pancreatitis C Cyclophosphamide D Intestinal infarction D Imatinib E Pseudomembranous colitis E Prednisone F Radiation 36 A 71-year-old woman with a history of rheumatic heart disease is hospitalized with severe congestive heart failure. 33 A 57-year-old man from Innsbruck, Austria, goes to the Four days after admission, she develops cramping lower emergency department because of increasing abdominal pain abdominal pain. On physical examination, she is afebrile. The with distention that developed over the past 24 hours. On abdomen is distended and tympanitic, without a fluid wave, physical examination, there is diffuse abdominal tenderness. and bowel sounds are absent. A stool sample is positive for The abdomen is tympanitic, without a fluid wave, and bowel occult blood. An abdominal plain film shows no free air. sounds are nearly absent. There is a well-healed, 5-cm trans- Colonoscopy shows patchy areas of mucosal erythema with verse scar in the right lower quadrant of the abdomen. There is some overlying tan exudate in the ascending and descending no caput medusa. A stool sample is negative for occult blood. colon. No polyps or masses are found. What is the most likely An abdominal plain film shows dilated loops of small bowel diagnosis? with air-fluid levels, but there is no free air. At laparotomy, A Ischemic colitis the surgeon notices a 20-cm portion of reddish black ileum B Mesenteric vasculitis that changes abruptly to pink-appearing bowel on distal and C Shigellosis proximal margins. His medical history is significant only for D Ulcerative colitis an appendectomy at age 25 years. Which of the following is E Volvulus most likely to have produced his findings? A Adenocarcinoma of the ileum 37 A 60-year-old man has had increasing fatigue for the B Adhesions past 8 months. On physical examination, he appears pale. On C Crohn disease digital rectal examination, no masses are palpable, but a stool D Indirect inguinal hernia sample is positive for occult blood. Auscultation of the abdo- E Intussusception men shows active bowel sounds, and on palpation there are F Tuberculosis no masses or areas of tenderness. Laboratory studies show G Volvulus hemoglobin, 8.3 g/dL; hematocrit, 24.6%; MCV, 73 μm3; plate- let count, 226,000/mm3; and WBC count, 7640/mm3. Colo- 34 An 11-month-old, previously healthy infant has not pro- noscopy shows no identifiable source of the bleeding. Angi- duced a stool for 1 day. The mother notices that the infant’s ography shows a 1-cm focus of dilated and tortuous vascular abdomen is distended. On physical examination, the infant’s channels in the mucosa and submucosa of the cecum. What is abdomen is very tender, and bowel sounds are nearly absent. the most likely diagnosis? An abdominal plain film radiograph shows no free air, but A Angiodysplasia there are distended loops of small bowel with air-fluid levels. B Collagenous colitis Which of the following is most likely to produce these findings? C Diverticulosis A Duodenal atresia D Internal hemorrhoids B Hirschsprung disease E Mesenteric vein thrombosis C Intussusception D Meckel diverticulum 38 A 21-year-old man has had increasingly voluminous, E Pyloric stenosis bulky, foul-smelling stools and a 7-kg weight loss for the past year. There is no history of hematemesis or melena. He has some bloating, but no abdominal pain. On physical exami- nation, there are no palpable abdominal masses, and bowel sounds are present. Which of the following laboratory find- ings is most likely to be present on examination of his stool? A Entamoeba histolytica trophozoites B Giardia lamblia cysts C Increased stool fat D Occult blood E Vibrio cholerae organisms CHAPTER 17 Gastrointestinal Tract 269 39 A 34-year-old woman is bothered by a low-volume, 43 A potluck lunch party is held at the office at noon. Vari- mostly watery diarrhea associated with flatulence. The symp- ous meats, salads, breads, and desserts that were brought in toms occur episodically, but they have been persistent for the earlier that morning are served. Everyone has a good time, past year. She has experienced a 4-kg weight loss. She has and most of the food is consumed. By midafternoon, the no fever, nausea, vomiting, or abdominal pain. On physical single office restroom is being used by many employees who examination, there are no significant findings. A stool sample have vomiting and acute, explosive diarrhea accompanied by is negative for occult blood, ova, and parasites, and a stool abdominal cramping. Which of the following infectious agents culture yields no pathogens. An upper gastrointestinal endos- is most likely responsible for this turn of events? copy is performed and a biopsy specimen from the upper part A Bacillus cereus of the small bowel shows severe diffuse blunting of villi and B Clostridium difficile a chronic inflammatory infiltrate in the lamina propria. Which C Escherichia coli of the following serologic tests is most likely to be positive in D Salmonella enterica this patient? E Staphylococcus aureus A Anticentromere antibody F Vibrio parahaemolyticus B Anti–DNA topoisomerase I antibody C Antimitochondrial antibody 44 A healthy 21-year-old woman develops a profuse, watery D Antinuclear antibody diarrhea 1 day after a meal of raw oysters. On physical exami- E Antitransglutaminase antibody nation, her temperature is 37.5° C. A stool sample is negative for occult blood. There is no abdominal distention or tender- 40 A 41-year-old woman has had diarrhea and fatigue with ness, and bowel sounds are present. The diarrhea subsides a 3-kg weight loss over the past 6 months. On physical exami- over the next 3 days. Which of the following organisms is most nation, she is afebrile and has mild muscle wasting, but her likely to produce these findings? motor strength is normal. Laboratory studies show no occult A Cryptosporidium parvum blood, ova, or parasites in the stool. A biopsy specimen from B Entamoeba histolytica the upper jejunum is obtained, and microscopic findings are C Staphylococcus aureus reviewed. The patient begins following a special diet with no D Vibrio parahaemolyticus wheat or rye grain products. The change in diet produces dra- E Yersinia enterocolitica matic improvement. Which of the following microscopic fea- tures is most likely to be seen in the biopsy specimen? 45 A 26-year-old man traveling to Ching Mai, Thailand, A Crypt abscesses and mucosal ulceration had fever, headache, and muscle pains for a day followed by B Foamy macrophages within the lamina propria watery diarrhea of 5 to 10 stools per day for 4 days. In the C Lymphatic obstruction past day, the diarrhea has been bloody and accompanied by D Noncaseating granulomas tenesmus. On physical examination there is diffuse abdominal E Villous blunting and flattening pain. Microscopic examination of the stool shows numerous leukocytes and gram-negative curved rods. The diarrhea sub- 41 An epidemiologic study of children with failure to sides, but 2 weeks later he has increasing weakness in his legs. thrive is undertaken in Guatemala. Some of these children Which of the following organisms is most likely to produce his with ages 1 to 3 years have repeated bouts of diarrhea, but disease? do not improve with dietary supplements. Jejunal biopsies A Bacillus cereus show blunted, atrophic villi with crypt elongation and chronic B Campylobacter jejuni inflammatory infiltrates. What is the most likely factor contrib- C Clostridium perfringens uting to recurrent diarrhea in these children? D Giardia lamblia A Abetalipoproteinemia E Rotavirus B Bacterial infection C Chloride ion channel dysfunction 46 A 36-year-old man experiences cramping abdomi- D Disaccharidase deficiency nal pain with fever and watery diarrhea 2 days after eating E NOD2 gene mutations a chicken salad sandwich. Physical examination shows mild diffuse abdominal pain on palpation, but there are no masses. 42 A 40-year-old man has episodic abdominal bloating, Bowel sounds are present. A stool sample is negative for flatulence, and explosive diarrhea. These symptoms appear occult blood. He recovers completely within 5 days without to be related to the milk shakes that he loves to consume. treatment. Which of the following infectious organisms is On physical examination, there are no remarkable findings. most likely to produce these findings? Laboratory studies show no increase in stool fat and no occult A Bacillus cereus blood, ova, or parasites in the stool. A routine stool culture B Entamoeba histolytica yields no pathogens. When he does not consume milk shakes C Escherichia coli or ice cream sodas, he is not symptomatic. Which of the fol- D Rotavirus lowing conditions best accounts for these findings? E Salmonella enterica A Autoimmune gastritis F Staphylococcus aureus B Celiac disease G Yersinia enterocolitica C Cholelithiasis D Cystic fibrosis E Disaccharidase deficiency 270 UNIT II Diseases of Organ Systems 47 In an epidemiologic study of infections of the gastro- 49 Over a holiday weekend, more than 100 adults at a intestinal tract, cases of patients living in Haiti from whom resort hotel develop a diarrheal illness marked by volumi- definitive cultures were obtained are analyzed for clinical nous, watery stools more than 10 times per day. They also and pathologic findings that may be useful for diagnosis. A report headache, abdominal cramping pain, and myalgias. On group of patients is identified who initially had abdominal physical examination they have manifestations of dehydration pain and diarrhea during week 1 of their illness. By week 2, and mild fever. Laboratory studies of stool samples show no these patients had splenomegaly and elevations in serum AST increase in leukocytes or fat, and no RBCs. Their illness lasts and ALT levels. By week 3, they were septic and had leuko- just 1 to 3 days and resolves with no sequelae. Which of the penia. At autopsy, the patients who died were found to have following infectious agents is the most likely cause for their ulceration of Peyer patches. Which of the following infectious illness? agents is most likely to produce these findings? A Cytomegalovirus A Campylobacter jejuni B Clostridium botulinum B Clostridium perfringens C Norovirus C Mycobacterium bovis D Staphylococcus aureus D Salmonella typhi E Strongyloides stercoralis E Shigella sonnei F Vibrio cholerae F Yersinia enterocolitica 50 A 5-month-old, previously healthy infant girl in Ban- gladesh develops a watery diarrhea that lasts for 1 week. The infant has a mild fever during the illness, but has no abdomi- nal pain or swelling. On physical examination, her tempera- ture is 37.7° C. A stool sample is negative for occult blood, ova, or parasites. Her parents are told to give her plenty of fluids, and she recovers fully. Which of the following organisms is most likely to produce these findings? A Campylobacter jejuni B Cryptosporidium parvum C Escherichia coli D Listeria monocytogenes E Norwalk virus F Rotavirus G Shigella flexneri 51 A study of children living in rural Malawi in Africa reveals a high prevalence of iron deficiency anemia. Stool samples are positive for occult blood. Pruritus of the skin of 48 A 65-year-old woman is being treated in the hospital their feet as well as cough are additional findings in many of for pneumonia complicated by septicemia. She has required these children. Which of the following parasitic infestations is multiple antibiotics and was intubated and mechanically ven- the most likely cause for these findings? tilated earlier in the course. On day 20 of hospitalization, she A Ancylostoma duodenale has abdominal distention. Bowel sounds are absent, and an B Ascaris lumbricoides abdominal radiograph shows dilated loops of small bowel C Cryptosporidium parvum suggestive of ileus. She has a low volume of bloody stool that is D Enterobius vermicularis positive for Clostridium difficile toxin. Laboratory studies show E Schistosoma mansoni leukocytosis and hypoalbuminemia. At laparotomy, a portion of distal ileum and cecum is resected. The gross a ppearance of 52 A 31-year-old woman had increasingly severe diarrhea the mucosal surface is shown in the figure. What is the most 1 week after returning from a trip to Central America. Gross likely diagnosis? examination of the stools showed mucus and streaks of blood. A Gas gangrene with myonecrosis The diarrheal illness subsided within 4 weeks, but now she B Inflammatory bowel disease has become febrile and has pain in the right upper quadrant of C Ischemic bowel disease the abdomen. An abdominal ultrasound scan shows a 10-cm, D Pseudomembranous enterocolitis irregular, partly cystic mass in the right hepatic lobe. Which of E Toxic megacolon the following infectious organisms is most likely to produce these findings? A Clostridium difficile B Cryptosporidium parvum C Giardia lamblia D Entamoeba histolytica E Strongyloides stercoralis CHAPTER 17 Gastrointestinal Tract 271 A Cystic fibrosis B Diverticular disease C Inflammatory bowel disease D Irritable bowel syndrome E Viral gastroenteritis 55 A 49-year-old woman has had abdominal cramps and diarrhea with six stools per day for the past month. She has a history of similar episodes of self-limited pain and diarrhea, which have occurred multiple times during the past 20 years. Each episode lasts about 2 weeks and resolves without treat- ment. Findings on physical examination are unremarkable, but a stool sample is positive for occult blood. Laboratory studies show no ova or parasites in the stool. Colonoscopy shows dif- 53 A 27-year-old man has sudden onset of marked abdomi- fuse and uninterrupted mucosal inflammation and superficial nal pain. On physical examination, his abdomen is diffusely ulceration extending from the rectum to the ascending colon. tender and distended, and bowel sounds are absent. He Colonic biopsy specimens from the area show the findings in undergoes surgery, and a 27-cm segment of terminal ileum the figure. She is at greatest risk for developing which of the with a firm, erythematous serosal surface is removed. The following complications? microscopic appearance of a section through the excised ileum A Adenocarcinoma is shown in the figure. Which of the following additional com- B Diverticulitis plications is the patient most likely to develop as a result of C Fat malabsorption this disease process? D Perirectal fistula formation A Adenocarcinoma E Primary biliary cirrhosis B Enterocutaneous fistula F Pseudomembranous colitis C Intussusception D Liver abscess E Mesenteric artery thrombosis 54 A 30-year-old woman has a 5-year history of recurrent episodes marked by days of abdominal bloating with alternat- ing constipation and diarrhea. She notes hard stools of nar- row caliber, low volume mucous diarrhea, and pain in the left lower quadrant. Her symptoms are relieved by defecation, which occurs more frequently now. On physical examination there are no abnormal findings. Laboratory studies including stool for ova and parasites, bacterial pathogens, and fat show no abnormalities. An abdominal CT scan is unremarkable. What is the most likely diagnosis? 272 UNIT II Diseases of Organ Systems 58 A 26-year-old man has had intermittent cramping abdominal pain and low-volume diarrhea for 3 weeks. On physical examination, he is afebrile; there is mild lower abdominal tenderness but no masses, and bowel sounds are present. A stool sample is positive for occult blood. The symp- toms subside within 1 week. Six months later, the abdominal pain recurs with perianal pain. On physical examination, there is now a perirectal fistula. Colonoscopy shows many areas of mucosal edema and ulceration and some areas that appear normal. Microscopic examination of a biopsy specimen from an ulcerated area shows a patchy acute and chronic inflam- matory infiltrate, crypt abscesses, and noncaseating granulo- mas. Which of the following underlying disease processes best explains these findings? A Amebiasis B Crohn disease C Sarcoidosis D Shigellosis E Ulcerative colitis 59 A clinical study of adult patients with chronic bloody diarrhea is performed. One group of these patients is found to have a statistically increased likelihood for the following: antibodies to Saccharomyces cerevisiae but not anti–neutrophil cytoplasmic autoantibodies, NOD2 gene polymorphisms, TH1 and TH17 immune cell activation, vitamin K deficiency, mega- 56 A 35-year-old woman has had increasing lower back loblastic anemia, and gallstones. Which of the following dis- pain for 5 years. During the past year she also has had arthritic eases is this group of patients most likely to have? pain involving the knees, hips, and wrists. A stool sample is A Angiodysplasia positive for occult blood. A pelvic radiograph shows changes B Crohn disease consistent with sacroiliitis. A colonoscopy is performed, and C Diverticulitis she undergoes a total colectomy. The figure shows the gross D Ischemic enteritis appearance of the colectomy specimen. What is the most likely E Ulcerative colitis underlying mechanism of the illustrated condition? A Development of autoantibodies directed against 60 A 65-year-old woman has a routine health maintenance tropomyosin examination. A stool sample is positive for occult blood. B Development of antimicrobial antibodies that cross CT scan of the abdomen shows numerous air-filled, 1-cm out- react with colonic mucosa pouchings of the sigmoid and descending colon. Which of C Development of TH17 immune responses the following complications is most likely to develop in this D Germline inheritance of the APC gene mutation patient? E Mutations in the NOD2 gene A Adenocarcinoma B Bowel obstruction 57 A 30-year-old woman has suffered intermittent bouts of C Pericolic abscess lower abdominal pain and low-volume diarrhea for the past D Malabsorption 2 years. On colonoscopy there is friable mucosa from the rec- E Toxic megacolon tum to the ascending colon, and a perianal fistula is noted. Biop- sies are taken and on microscopic examination show acute and 61 The mother of a 4-year-old child notes blood when laun- chronic mucosal inflammation with focal erosion. Her stool is dering his underwear. Physical examination reveals a rectal negative for ova, parasites, and bacterial pathogens. Which of mass. On proctoscopy, there is a smooth-surfaced, peduncu- the following ongoing testing procedures is most useful for lated, 1.5-cm polyp. It is excised and microscopically shows long-term follow-up of this woman? cystically dilated crypts filled with mucin and inflammatory A Abdominal CT scanning debris, but no dysplasia. What is the most likely diagnosis? B Biopsy screening for dysplasia A Familial adenomatous polyposis C Genetic mutational analysis for NOD2 B Gardner syndrome D Serologic titers for Saccharomyces C Juvenile polyp E Stool cultures for microbiota D Lynch syndrome E Peutz-Jeghers syndrome CHAPTER 17 Gastrointestinal Tract 273 A 63 A 70-year-old man has a routine health maintenance examination. On physical examination, there are no remark- able findings, but a stool sample is positive for occult blood. A colonoscopy is performed and shows a 5-cm sessile mass in the upper portion of the descending colon at 50 cm from the anal verge. The histologic appearance at low power of a biopsy specimen of the lesion is shown in the figure. The patient refused further workup and treatment. Five years later, he has B constipation, microcytic anemia, and a 5-kg weight loss over 6 months. On surgical exploration, there is a 7-cm mass encir- 62 A 53-year-old woman undergoes a routine checkup. cling the descending colon. Which of the following neoplasms The only abnormal finding is a stool specimen that contains is he now most likely to have? occult blood. Colonoscopy shows a 1.5-cm, solitary, rounded, A Adenocarcinoma erythematous polyp on a 0.5-cm stalk at the splenic flexure. B Non-Hodgkin lymphoma The polyp is removed; its histologic appearance is shown in C Carcinoid tumor the figure at low (A) and high (B) magnifications. Her colonic D Leiomyosarcoma lesion is most likely associated with which of the following? E Mucinous cystadenoma A Low risk for development of carcinoma F Villous adenoma B Inheritance of an abnormal tumor suppressor gene C Presence of similar lesions in the small intestine D History of iron deficiency anemia E Risk for development of endometrial carcinoma 274 UNIT II Diseases of Organ Systems 66 A 33-year-old man has a routine health maintenance e xamination. A stool sample is positive for occult blood. On 64 A 19-year-old man is advised to see his physician because colonoscopy, a 6-cm ulcerative lesion is seen projecting into genetic screening has detected a disease in other family mem- the cecum. There are three smaller sessile lesions from 1 to bers. On physical examination, a stool sample is positive for 3 cm in size. The microscopic appearance of a section of the occult blood. A colonoscopy is performed, followed by a col- ulcerated lesion is shown in the figure. The smaller lesions are ectomy. The figure shows the gross appearance of the mucosal reported as sessile serrated adenomas. Which of the following surface of the colectomy specimen. Microscopic examination molecular biological events is thought to be most c ritical in the shows these lesions are tubular adenomas. Molecular analy- development of such lesions? sis of this patient’s normal fibroblasts is most likely to show a A Amplification of ERBB2 gene mutation in which of the following genes? B Defective DNA mismatch repair gene A APC C Germline transmission of a defective RB1 gene B MLH1 D Overexpression of E-cadherin gene C KRAS E Translocation of retinoic acid receptor alpha gene D NOD2 E p53 65 A 44-year-old woman has had increasing abdominal dis- tention for the past 6 weeks. On physical examination, there is an abdominal fluid wave, and bowel sounds are present. Para- centesis yields 1000 mL of slightly cloudy serous fluid. Cyto- logic examination of the fluid shows malignant cells consistent with adenocarcinoma. Molecular analysis of these cells shows an MSH2 gene mutation with microsatellite instability. Her medical history indicates that she has had no major medical illnesses and no surgical procedures. Her sister was diagnosed with endometrial cancer and her brother had carcinoma of the stomach. Which of the following conditions is the most likely cause of this patient’s symptoms? A Angiodysplasia B Crohn disease 67 A 73-year-old man has noted a change in bowel habits C Diverticulosis for the past year. Defecation is more difficult and the caliber D Lynch syndrome of stools has decreased. On physical exam, there are no abnor- E Peptic ulcer disease mal findings except for stool positive for occult blood. Colo- noscopy is performed for the first time in this man, followed by colonic resection with the gross appearance shown in the figure. Which of the following molecular abnormalities has most likely led to these findings? A Acquired APC gene mutation B Homozygous loss of PTEN gene C Inactivation of the RB1 protein by HPV-16 D Mutation in a DNA mismatch repair gene E Tyrosine kinase activation with KIT mutation CHAPTER 17 Gastrointestinal Tract 275 68 A 20-year-old woman in her ninth month of pregnancy 70 A 53-year-old woman has increasing abdominal girth has increasing pain on defecation and notices bright red blood for the past 2 years. On physical examination she has abdomi- on the toilet paper. She has had no previous gastrointestinal nal distension. An abdominal CT scan shows multiple nodules problems. After she gives birth, the rectal pain subsides, and on peritoneal surfaces along with low attenuation mucinous there is no more bleeding. Which of the following is the most ascites. Paracentesis is performed and cytologic examination likely cause of these findings? of the fluid obtained shows well-differentiated columnar cells A Angiodysplasia with minimal nuclear atypia. Where did this proliferative B Hemorrhoids process most likely arise in this woman? C Intussusception A Appendix D Ischemic colitis B Jejunum E Volvulus C Ileum D Pancreas 69 A 20-year-old woman has had nausea and vague lower E Stomach abdominal pain for the past 24 hours, but now the pain has become more severe. On physical examination, the pain is 71 A 59-year-old man with a lengthy history of chronic worse in the right lower quadrant, and there is rebound tender- alcoholism has noticed increasing abdominal girth for the past ness. A stool sample is negative for occult blood. Abdominal 6 months. He has had increasing abdominal pain for the past plain film radiographs show no free air. The result of a serum 2 days. On physical examination, his temperature is 38.2° C. pregnancy test is negative. Which of the following laboratory Examination of the abdomen shows a fluid wave and promi- findings is most useful to aid in the diagnosis of this patient? nent caput medusae over the skin of the abdomen. There is A Entamoeba histolytica cysts in the stool diffuse abdominal tenderness. An abdominal plain film radio- B Hyperamylasemia graph shows no free air. Paracentesis yields 500 mL of cloudy C Hypernatremia yellow fluid. Gram stain of the fluid shows gram-negative D Increased serum alkaline phosphatase rods. Which of the following is the most likely diagnosis? E Increased serum carcinoembryonic antigen A Appendicitis F Neutrophilia with left shift B Collagenous colitis C Diverticulitis D Ischemic colitis E Pseudomembranous colitis F Spontaneous bacterial peritonitis ANSWERS 1 C An esophageal atresia is often combined with a fistula may be difficult to detect, and it is almost always seen in between the esophagus and trachea. Gastrointestinal obstruc- patients older than 70 years, but can cause significant blood tion in utero can lead to polyhydramnios. The presence of a loss. Celiac disease can occur in young individuals, but it single umbilical artery suggests additional anomalies are pres- does not produce significant hemorrhage. Diverticulosis can ent. Vomiting in an infant risks aspiration with development be associated with hemorrhage, but the diverticula are almost of pneumonia. Achalasia is incomplete relaxation of the lower always in the colon of older persons. Giardiasis produces a esophageal sphincter and is usually not manifested at birth. self-limited, watery diarrhea without hemorrhage. Absence of a diaphragmatic leaf, usually on the left, results in PBD9 751 PBD8 765–766 BP8 600 herniation of abdominal contents into the chest and functional gastrointestinal obstruction, but in this case normal-sized lungs suggest no herniated contents were present. A hiatal hernia 3 D The infant’s condition occurred several weeks after from widened diaphragmatic muscular crura predisposes to birth because of hypertrophy of pyloric smooth muscle. gastroesophageal reflux, and obstruction is not a typical com- Pyloric stenosis has features of multifactorial inheritance plication. Pyloric stenosis is a cause for gastric outlet obstruction with a “threshold of liability,” above which the disease is in an infant, but the onset is usually in the second or third week manifested when more genetic risks are present, such as of life. A pharyngoesophageal (Zenker) diverticulum above the family history and twin gestation. The incidence in males is upper esophageal sphincter is usually a disease of adults. 1 in 200 and in females is 1 in 1000, reflecting the fact that PBD9 750 BP9 558 PBD8 765 BP8 600 more risks must be present in females for the disease to occur. Annular pancreas is a rare anomaly that can also cause obstruction of the duodenum, and has variable age of onset, 2 F About 2% of individuals have a Meckel diverticulum, an but a palpable mass would not be expected. Tracheoesopha- embryologic remnant of the omphalomesenteric duct, but only geal fistula, diaphragmatic hernia, and duodenal atresia are a small subset of these individuals have ectopic gastric mucosa serious conditions that are manifested at birth and are often within it, which causes intestinal ulceration. The symptoms associated with multiple anomalies. Pyloric stenosis is an iso- may mimic acute appendicitis, but appendicitis should not last lated condition that typically occurs without other anomalies. for 1 month or cause significant blood loss. Angiodysplasia PBD9 751 PBD8 766 PBD8 766 BP8 592 276 UNIT II Diseases of Organ Systems 4 B In Hirschsprung disease, seen in 1 in 5000 live births, produce surface plaques with minimal erosion in immuno- the aganglionic segment (either a short or long segment) of compromised persons. Diphtheria is most often a childhood the bowel wall produces a functional obstruction with proxi- disease of upper airways, and there can be toxin-mediated sys- mal distention. Most familial cases and some sporadic cases temic disease, including myocarditis, but there is no chronic have RET gene mutations affecting neural crest cell migra- infection. Herpetic ulcers are sharply demarcated, and infec- tion. Atresias are congenitally narrowed segments of bowel tion is most often found in immunocompromised persons. (usually the small intestine) that occur with other anoma- PBD9 395, 754 BP9 558 lies. Patients with trisomy 21 may have intestinal (usually duodenal) atresias. Complete absence of the colonic lumen at a point of atresia is a rare congenital anomaly and is not 8 D Grand Admiral Baron Jan Gerrit van Wassenaer associated with loss of ganglion cells. Intussusception also is was attended by Dr. Herman Boerhaave in 1724, who then a cause of bowel obstruction in infants, but it is not caused described esophageal rupture. Boerhaave syndrome may by an aganglionic segment of bowel. Necrotizing enteroco- follow forceful vomiting, or may occur as a complication of litis is a complication of prematurity. Volvulus is a form of instrumentation. Dissection of air from the rupture extends mechanical obstruction that occurs from twisting of the small into soft tissue, producing the subcutaneous emphysema. bowel on the mesentery or twisting of a segment of the colon There is no serosal barrier above the diaphragm, so esopha- (sigmoid or cecal regions). geal contents spill into the chest cavity, producing marked PBD9 751–752 BP9 573–574 PBD8 766–767 BP8 600–601 mediastinitis that is hard to treat. A stricture is likely to occur with long-standing inflammation or from the fibrosis asso- ciated with systemic sclerosis (scleroderma). Achalasia is a 5 B Caustic alkaline solutions tend to damage the esoph- functional obstruction from failure of inhibitory neurons that agus, and may not even get as far as the stomach. If the relax the lower esophageal sphincter. Ectopia refers to tissue esophagus is perforated, a severe mediastinitis may occur. that is out of place, most often gastric mucosa that is in the The inflammation can resolve with scarring and stenosis, and esophagus, which can lead to esophagitis. Varices present a that tends to affect swallowing of solids more than liquids, risk for marked bleeding. typical for mechanical obstruction. A pharyngeal Z enker PBD9 754 BP9 559 PBD8 768 diverticulum occurs at a point of weakness in the hypophar- ynx, most often between the inferior constrictor muscle and cricopharyngeus muscle; it is a pulsion diverticulum from 9 E Mallory-Weiss syndrome with esophageal tears results motility problems. Gastric lymphomas may be related to from severe vomiting. Most cases occur in the context of Helicobacter pylori infection (MALTomas) and to immune alcohol abuse. The bleeding is usually not as life-threatening dysregulation. Duodenal ulcerations are predominantly as varices. Absent myenteric ganglia occur with achalasia. related to H. pylori infection. Megacolon results from marked Autoimmunity underlies scleroderma with fibrosis and colonic inflammation or motor disturbances, and swallowed esophageal obstruction, but there is typically no bleeding. substances are not likely to reach the colon unaltered. Herpes simplex virus infection causes ulcerations that are PBD9 754 BP9 558 PBD8 767 BP8 588 usually superficial and cause pain, but do not bleed signifi- cantly. Portal hypertension leads to dilation of esophageal submucosal veins, which can bleed profusely; in this case, 6 A In achalasia, there is incomplete relaxation of the lower the patient’s age argues against the presence of cirrhosis esophageal sphincter with lack of peristalsis. Most cases are from alcohol abuse. Widened diaphragmatic crura are pres- “primary” or of unknown origin. They may be caused by ent with hiatal hernia that predisposes to gastroesophageal degenerative changes in neural innervation; the myenteric reflux, and this is not associated with alcohol abuse. ganglia are usually absent from the body of the esophagus. PBD9 754 BP9 559 PBD8 768 BP8 586–587 There is a long-term risk of development of squamous cell carcinoma. In Barrett esophagus, there is columnar epithelial metaplasia, but the myenteric plexuses remain intact. Reflux 10 C The “punched-out” ulcers described result from rup- esophagitis may be associated with hiatal hernia, but myen- ture of the herpetic vesicles. Herpesvirus and Candida infec- teric ganglia remain intact. Plummer-Vinson syndrome is a tions typically occur in immunocompromised patients, and rare condition caused by iron deficiency anemia; it is accom- both can involve the esophagus. Aphthous ulcers (canker panied by an upper esophageal web. Systemic sclerosis sores) also can be found in immunocompromised patients, (scleroderma) is marked by fibrosis with stricture. but these shallow ulcers occur most frequently in the oral PBD9 753–754 BP9 558 PBD8 768 BP8 585–586 cavity. Candidiasis has the gross appearance of tan-to- yellow plaques. Gastroesophageal reflux disease (GERD) can produce acute and chronic inflammation with some 7 E Chronic Chagas disease can lead to damage to not only erosion, although typically not in a sharply demarcated myocardium but also tubular structures of the GI tract, espe- pattern; GERD has no relationship with immune status. cially the esophagus with secondary achalasia. The organisms Mallory-Weiss syndrome results from mucosal tears of the are hard to find microscopically, but they elicit the inflamma- esophagus, and laceration of the esophagus can occur with tory response that damages neurons to produce the motility severe vomiting and retching. problems. Pertussis is whooping cough, typically a childhood PBD9 754–755 BP9 560 PBD8 768–769 BP8 580–581 disease affecting the upper airways. Candidiasis tends to CHAPTER 17 Gastrointestinal Tract 277 11 E Esophageal dysmotility is the E in CREST, a mnemonic focal dysplasia, typical of Barrett esophagus. Patients with that details the key findings with the limited form of systemic a focus of Barrett esophagus have a higher risk of develop- sclerosis (scleroderma): C = calcinosis; R = Raynaud phenom- ing adenocarcinoma than the general population, particularly enon; E = esophageal dysmotility; S = sclerodactyly; T = telan- when high-grade dysplasia is present. Achalasia refers to the giectasias. Although scleroderma is an autoimmune disorder failure of the lower esophageal sphincter to relax, which gives that often includes formation of anticentromere antibodies, rise to dilation of the proximal portion of the esophagus. An little inflammation is seen by the time the patient seeks clinical epiphrenic diverticulum in the lower esophagus is not associ- attention. There is increased collagen deposition in gastrointes- ated with Barrett mucosa, but arises from increased intralumi- tinal submucosa and muscularis. Fibrosis may affect any part nal pressure against lower esophageal sphincter obstruction. of the gastrointestinal tract, but the esophagus is the site most Mallory-Weiss syndrome is associated with vertical lacerations often involved. For a diagnosis of Barrett esophagus, colum- in the esophagus that may occur with severe vomiting and nar metaplasia must be seen histologically, and there is often retching. Squamous cell carcinomas occur in the midesopha- a history of gastroesophageal reflux disease. Hiatal hernia is gus, but they do not arise in association with Barrett esophagus. frequently diagnosed in individuals with reflux esophagitis Instead, they are linked to smoking and alcohol consumption. and can lead to inflammation, ulceration, and bleeding, but PBD9 757–758 BP9 561–562 PBD8 770–771 BP8 588–589 formation of a stricture is uncommon. An upper esophageal web associated with iron deficiency anemia might produce dif- ficulty in swallowing, but this condition is rare. Portal hyper- 15 A Adenocarcinomas of the esophagus are typically tension gives rise to esophageal varices, not fibrosis. located in the lower esophagus, where Barrett esophagus PBD9 750, 753 BP9 560–561 PBD8 223–225 BP8 150 develops at the site of long-standing gastroesophageal reflux disease. Barrett esophagus is associated with an increased risk of developing adenocarcinoma, particularly when high-grade 12 D Her ongoing inflammatory process results from dysplasia is present. Columnar metaplasia may progress to r eflux of acid gastric contents into the lower esophagus. Gas- dysplasia, then adenocarcinoma. Carcinoid tumors occur in troesophageal reflux disease (GERD) is a common problem different parts of the gut, including the appendix, ileum, rec- that stems from a variety of causes, including sliding hiatal tum, stomach, and colon. Leiomyosarcoma of the esophagus hernia, decreased tone of the lower esophageal sphincter, is rare and is unrelated to a history of heartburn. Malignant and delayed gastric emptying. Patients may have a history of lymphomas of the gastrointestinal tract do not commonly heartburn after eating. Barrett esophagus is a complication occur in the esophagus and are not related to reflux esophagi- of long-standing GERD and is characterized by columnar tis. Squamous cell carcinomas of the esophagus are most often metaplasia of the squamous epithelium that normally lines associated with a history of chronic alcoholism and smoking. the esophagus. There may be inflammation and mucosal PBD9 758–759 BP9 562 PBD8 772–773 BP8 589–591 ulceration overlying varices, but this condition usually does not have heartburn as the major feature. Esophageal varices from portal hypertension can lead to marked hematemesis. 16 E This large, ulcerated lesion with heaped-up margins A rare complication of iron deficiency is the appearance of is a malignant tumor of the esophageal mucosa. There are two an upper esophageal web (Plummer-Vinson syndrome). main histologic types of esophageal carcinomas—squamous Progressive fibrosis with stenosis is found in scleroderma. cell carcinoma and adenocarcinoma—with distinct risk fac- PBD9 755–756 BP9 560–561 PBD8 769–770 BP8 588 tors. Smoking and alcoholism are the primary risk factors for esophageal squamous cell carcinoma in the Western world. Adenocarcinoma is most likely to arise in the lower third 13 C Variceal bleeding is a common complication of of the esophagus and to be associated with Barrett esopha- epatic cirrhosis, which can be an outcome of chronic hepa- h gus. Chronic inflammation may lead to stricture and not to a titis B infection. Portal hypertension leads to dilated submu- localized mass. Dilated veins occur in esophageal varices; they cosal esophageal veins that can erode and bleed profusely. do not produce an ulcerated mass. A dense, collagenous scar Barrett esophagus is a columnar metaplasia that results from of the mid esophagus is uncommon, but it may occur after gastroesophageal reflux disease (GERD). Bleeding is not a injury from ingestion of a caustic liquid. Intranuclear inclu- key feature of this disease. Esophageal candidiasis may be sions suggest infection with herpes simplex virus or cytomeg- seen in immunocompromised patients, but it most often pro- alovirus, both of which are more likely to produce ulceration duces raised mucosal plaques and is rarely invasive. GERD without a mass; both occur in immunocompromised patients. may produce acute and chronic inflammation and, rarely, PBD9 758–759 BP9 562–563 PBD8 773–774 BP8 589–591 massive hemorrhage. Esophageal carcinomas may bleed, but not enough to cause massive hematemesis. A Zenker diverticulum is located in the upper esophagus and results 17 C The Turkmen population around the Caspian Sea from cricopharyngeal motor dysfunction; it presents a risk has the highest rate of esophageal cancer on earth, and most for aspiration, but not for hematemesis. of these are squamous cell carcinomas arising in the mid- PBD9 756–757 BP9 559 PBD8 771–772 BP8 587–588 esophagus. Consuming hot tea, contamination with silicates in consumed food, micronutrient deficiencies, and family his- tory have been implicated, as well as human papillomavirus 14 B The biopsy specimen shows residual ulcerated infection. There are no specific gene mutations known to be squamous epithelium along with columnar metaplasia and associated with esophageal carcinoma in this population. In 278 UNIT II Diseases of Organ Systems contrast, tobacco use and alcohol consumption are linked to 21 A The high MCV is indicative of a megaloblastic ane- esophageal cancers in Europe and North America. The main mia, most likely pernicious anemia, resulting from autoim- autoimmune disease affecting the esophagus, systemic scle- mune atrophic gastritis. Delayed maturation of the myeloid rosis (scleroderma), is not a major risk for cancer. Infectious cells leads to hypersegmentation of polymorphonuclear agents such as Candida and herpes simplex virus do not carry leukocytes. Loss of gastric parietal cells from autoimmune a risk for cancer; the role for human papillomavirus in this injury causes a deficiency of both intrinsic factor and acid. In process is not well established. Reflux esophagitis is a risk for the absence of this factor, vitamin B12 cannot be absorbed in adenocarcinomas arising in the lower third of the esophagus. the distal ileum. Among the various anti–parietal cell anti- PBD9 759–760 BP9 563 PBD8 772–774 BP8 589–590 bodies are those directed against the acid-producing pro- ton pump enzyme H+,K+-ATPase. Antigliadin antibodies are found with celiac disease that does not affect the gastric 18 A These findings are consistent with an acute gastritis. mucosa. H. pylori causes chronic gastritis and peptic ulcer If significant inflammation is not present, then the term disease, but does not injure parietal cells. In pernicious ane- gastropathy is used. Heavy consumption of ethanol is probably mia, no antibodies are directed against intrinsic factor recep- the most common cause, but aspirin and nonsteroidal anti- tor on ileal mucosal cells. Infection with Tropheryma whippelli inflammatory drugs (NSAIDs), smoking, and chemotherapy causes Whipple disease, which may involve any organ, but agents can produce the same findings. NSAIDs can be cofac- most often affects intestines, central nervous system, and tors in peptic ulcer disease. Chlorpromazine (used to treat joints; malabsorption is common. nausea) does not have the same association. Cimetidine and PBD9 764–765 BP9 567 PBD8 778–779 BP8 438–439, 592 omeprazole are used to treat peptic ulcer disease by reducing gastric acid production, increasing the serum gastrin. Cimeti- dine is an H2 receptor blocker, and omeprazole is a proton 22 B Helicobacter pylori organisms shown in the figure pump inhibitor. Clindamycin is a broad-spectrum antibiotic r eside in the mucus layer above the gastric mucus and are that may alter flora in the lower gastrointestinal tract. associated with various gastric disorders, ranging from PBD9 760–762 BP9 564–565 PBD8 774–775 BP8 593 chronic gastritis with erythema and thickened rugal folds, as in this case, to peptic ulcers and to adenocarcinoma. H. pylori organisms elaborate several toxic substances that injure the 19 A Prolonged use of nonsteroidal anti-inflammatory epithelium. The H. pylori gene from a pathogenicity island drugs (NSAIDs) is an important cause of acute gastritis. encodes cytotoxin-associated antigen (CagA) and is present NSAIDs inhibit cyclooxygenase-dependent synthesis of in many patients with chronic gastritis and peptic ulcers; prostaglandins E2 and I2, which stimulate nearly all defense it increases the risk for gastric cancer. Cysteine proteinases mechanisms. Excessive alcohol consumption and smoking produced by Entamoeba histolytica aid in tissue invasion. also are possible causes. Acute gastritis tends to be diffuse Heat-stable enterotoxin is produced by strains of Escherichia and, when severe, can lead to significant mucosal hemor- coli that cause traveler’s diarrhea. Shiga toxin is elaborated rhage that is difficult to control. Epithelial dysplasia may by Shigella flexneri organisms, which cause a form of bacillary occur at the site of chronic gastritis. It is a forerunner of gas- dysentery. Verocytotoxin produced by some E. coli strains tric cancer. Infection with Helicobacter pylori is not associated is associated with hemolytic uremic syndrome mediated by with acute gastritis. Hyperplastic polyps of the stomach do endothelial injury. not result from acute gastritis, but may arise in association PBD9 763–764 BP9 566–567 PBD8 776–778 BP8 592–594 with chronic gastritis. Acute gastritis does not increase the risk of gastric adenocarcinoma. PBD9 760–762 BP9 564–565 PBD8 774–775 BP8 593 23 D Although they are not found in the duodenum, elicobacter pylori organisms alter the microenvironment of H the stomach, causing the stomach and duodenum to be sus- 20 E So-called stress ulcers, also known as Curling ulcers, ceptible to peptic ulcer disease. Virtually all duodenal pep- can occur in patients with burn injuries. The ulcers are often tic ulcers are associated with H. pylori infection. Ulceration small (

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