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Flashcards in Gastrointestinal Pathology_1 Deck (348):
1

What is dysphagia?

difficulty in swallowing

2

what causes dysphagia?

diseases that narrow or obstruct the lumen

3

what causes pain and hematemesis?

inflammation or ulceration of the esophageal mucosa

4

what is heartburn?

retrosternal burning pain

5

what causes heartburn?

regurgitation of gastric contents

6

what is the most frequent GI complaint?

gas

7

what are esophageal sinuses?

blind tubes

8

what are esophageal fistulas?

tunnels

9

what is an esophageal perforation?

hollow viscous open up into hollow cavity (usually peritoneal cavity)

10

what are the 2 types of esophageal herniations?

internal or external

11

what is the most common anemia of GI bleeding?

IDA

12

what are the disorders of the esophagus?

1. dysphagia • 2. pain and hematemesis • 3. heartburn • 4. gas • 5. inflammation and ulcers • 6. sinuses • 7. fistulas • 8. perforation • 9. herniation • 10. bleeding • 11. tumors

13

what are the important structures in the esophagus?

1. UES= Upper Esophageal Sphincter • 2. LES= Lower Esophageal Sphincter

14

UES is made up of what?

skeletal muscle • - cricopharyngeus muscle

15

which esophageal structure is involved in scleroderma?

UES

16

where does the LES open up?

into the stomach

17

what size is the gastro-esophageal junction?

3 cm

18

what is a gastro-esophageal junction >3 cm called?

Barrett's esophagus

19

what is the cell type of the LES transitional zone?

columnar

20

what do congenital anomalies of the esophagus do?

produce choking on breast feeding

21

what are the congenital anomalies of the esophagus?

atresia • fistulas • webs • Schatzki's rings • Stenosis

22

what is esophageal atresia?

noncanalzed segment

23

what are esophageal fistulas?

connection/opening between esophagus trachea • - several types

24

how do esophageal webs present?

dysphagia to solids

25

what are the clinical features of Plummer-Vinson/Paterson-Kelly syndrome?

post cricoid web • IDA • glossitis • cheilosis in perimenopausal female • risk of postcricoid squamous cell carcinoma

26

What is a type I Tracheoesophageal fistula?

Esophageal agenesis. Very rare

27

What is a type A/2 TEF?

Proximal and distal esophageal bud- a normal esophagus with a missing mid-segment

28

what is a type B/3A TEF?

Proximal esophageal termination on the lower trachea with distal esophageal bud

29

what is a type C/3B TEF?

proximal esophageal atresia (esophagus continuous with the mouth ending in a blind loop superior to the sternal angle) with a distal esophagus arising from the lower trachea or carina

30

what is the most common type of TEF?

Type C/3B

31

what is a type D/3C TEF?

proximal esophageal termination on the lower trachea or carina with distal esophagus arising from the carina

32

what is a type E TEF?

a variant of type D: if the 2 segments of the esophagus communicate, this is sometimes termed an H type fistula due to its resemblance of to the letter H.

33

which fistula is TEF without EA?

Type E/H

34

where do Schatzki's rings present?

LES

35

what do Schatzki's rings cause?

narrowing (stenosis) of esophagus

36

what is the most common cause of esophageal stenosis?

gastro-esophageal reflux

37

is esophageal stenosis more commonly inherited or acquired?

acquired (corrosives, radiation, Scleroderma CREST syndrome)

38

what is the major symptoms associated with esophageal stenosis?

dysphagia

39

what are the esophageal lesions with motor dysfunction?

Achalasia cardia • Hiatal Hernia • True Diverticula • Zenker's (pharyngeal diverticulum) • Epiphrenic diverticulum

40

what age group is affected by achalasia cardia?

adults

41

what is the nature of achalasia cardia?

'failure to relax'

42

what are the clinical features of achalasia cardia?

1. aperistalsis • 2. complete or partial relaxation of LES with swallowing • 3. Increased resting tone of LES

43

what are the complications associated with achalasia cardia?

- aspiration pneumonia • - candidal esophagitis (due to stagnation of food) • - diverticulae • - squamous cell carcinoma (2-5%)

44

achalasia cardia can also be caused by what?

Chaga's disease (Trypanosoma cruzi) • Diabetic autonomic neuropathy

45

what is Hiatal Hernia?

Upward protrusion of part of stomach through the diaphragmatic esophageal foramen

46

what is a true diverticulum?

out-pouching of the esophageal wall (contains all visceral layers)

47

what is a false diverticulum?

out-pouching of mucosa and submucosa only

48

Zenker's (pharyngeal) diverticulum is seen as what?

mass in neck of elderly patient above UES

49

Zenker's diverticulum is due to what?

disordered cricopharyngeal motor dysfunction

50

Zenker's diverticula produce what problems?

food regurgitation and dysphagia

51

what are the features of traction diverticulum?

asymptomatic and located near midpoint of esophagus

52

where is an epiphrenic diverticulum located?

just above the LES

53

epiphrenic diverticulum is caused by what?

dyscoordinated peristalsis and motor dysfuction of LES

54

epiphrenic diverticulum causes what?

regurgitation of food and aspiration pneumonia

55

what is the most common TEF?

C

56

what is the most life threatening TEF?

B: • cough, sputter, suffocate

57

TEF are associated with what?

heart and other GIT anomalies

58

90% of hiatal hernias are which type?

sliding

59

10% of hiatal hernias are which type?

rolling

60

what are the features of sliding hiatal hernia?

shortened esophagus dragging part of the stomach into the thoracic cavity (stomach continuous with the esophagus)

61

what are the features of rolling hiatal hernia?

(para-esophageal hernia) • - part of the stomach (fundus) herniates alongside esophagus into the thorax

62

which hiatal hernia is vulnerable to serious strangulation?

rolling

63

hiatal hernias are prone to what?

ulceration • bleeding • dysphagia

64

what is the site of Mallory-Weiss syndrome?

gastro-esophageal junction (GEJ)

65

what is Mallory-Weiss syndrome caused by?

excessive vomiting in the presence of LES spasm

66

when is Mallory-Weiss syndrome most common?

alcoholics and pregnancy

67

what is the morphology of Mallory-Weiss syndrome?

irregular longitudinal tear in the GEJ involve only the mucosa

68

what is the morphological difference between Boerhaave's syndrome and Mallory-Weiss syndrome?

in Boerhaave's tear penetrates all layers of esophagus

69

what is the clinical presentation of Mallory Weiss tear?

severe hematemesis

70

what is the clinical presentation of Boerhaave's syndrome?

produces mediastinitis or peritonitis

71

what are esophageal varices?

dilated tortuous submucosal veins

72

when are esophageal varices seen?

long-standing cirrhosis with portal HTN

73

how many patients with cirrhosis bleed and die of varices?

50% • MCC of death

74

what are the causes of esophagitis?

1. reflux of gastric contents • 2. Barrett's esophagus

75

what is the most common cause of esophagitis?

reflux esophagitis

76

what part of the esophagus is affected by reflux esophagitis?

distal part

77

what is the clinical presentation of reflux esophagitis?

dysphagia • heartburn • regurgitation • develop Barrett's esophagus in long standing cases

78

Barrett's esophagus is a complication of what?

long-standing gastroesophageal reflux

79

what is Barrett's esophagus?

columnar metaplasia of distal esophagus

80

what is the cancer risk associated with Barrett's?

30 times more risk of adenocarcinoma in the lower esophagus

81

what is the histological presentation of Barrett's esophagus?

gastric type mucosa above the gastroesophageal junction

82

metaplasia in Barrett's results from what?

chronic GERD

83

what is typical barrett's mucosa?

gastric mucosa with intestinalization • - goblet cells in columnar mucosa

84

what is the most common benign tumor of esophagus?

leiomyoma

85

from what does esophageal leiomyoma arise?

smooth muscle cells

86

what is the incidence of squamous cell carcinoma of the esophagus?

common in China • Rare in US (Adenocarcinoma- MC in USA) • M>F • >50yo

87

what are the risk factors for esophageal squamous cell carcinoma?

cigarette smoking • alcohol • nitrosamines in preserved foods • fungus contaminated foods

88

what is the site of squamous cell carcinoma of the esophagus?

50% are in the middle 1/3

89

what is early carcinoma in SCC of esophagus?

up to submucosa

90

what is the prognosis for early carcinoma in SCC of esophagus?

5 yr= 90% even with lymph node involvement

91

to where does esophageal SCC spread?

locally into mediastinal structures and to lymph nodes

92

what are the clinical features of esophageal SCC?

insidious dysphagia • weight loss • hemorrhage • esophago-tracheal fistula

93

what is the overall survival for SCC of esophagus?

5 yr=5%

94

what is the incidence of esophageal adenocarcinoma?

<25% of esophageal cancers world wide • ** up to 50% of esophageal cancer in USA

95

what is the primary risk factor for esophageal adenocarcinoma?

Barrett's esophagus

96

what is site of esophageal adenocarcinoma?

most arise in the distal 1/3rd of the esophagus

97

what is the histology of esophageal adenocarcinoma?

mucin producing tubular (intestinal), or signet cell/ring (gastric/infiltrative) carcinoma, undifferentiated

98

how does esophageal adenocarcinoma present?

dysphagia

99

what is the overall survival of esophageal adenocarcinoma?

15%

100

what is the typical morphology of esophageal SCC?

irregular reddish, ulcerated, exophytic • MC in midesophageal mass seen on mucosal surface

101

what is the typical histological presentation of esophageal SCC?

#NAME?

102

what is the incidence of the malignant esophageal tumors?

squamous= 75% • adenocarcinoma=25%

103

what are the geographic regions most commonly associated with the malignant esophageal tumors?

Squamous= asia • adeno= usa

104

what is the age group MC affected by the malignant esophageal tumors?

squamous >50yo • adeno >40yo

105

what are the sites of the malignant tumors of the esophagus?

squamous= middle 1/3 • adeno= lower 1/3

106

what are the risk factors associated with the malignant tumors of the esophagus?

SCC- smoking, EtOH, foods • adeno- Reflux esophagitis (Barrett's)

107

what is the prognosis for the malignant tumors of the esophagus?

SCC= 5yr= 5% • adeno= 5yr= 15%

108

What are the cells associated with stomach glands and where are they found?

- parietal cells found in the fundus and body • - chief cells are more at fundus and body

109

what do stomach parietal cells secrete?

HCl and IF

110

what do stomach chief cells secrete?

pepsinogen I and II

111

what are the congenital abnormalities of the stomach?

1. diaphragmatic hernia • 2. congenital hypertrophic pyloric stenosis

112

what causes diaphragmatic hernia?

defect in the diaphragm--> away from the hiatal orifice

113

what herniates in a diaphragmatic hernia?

portions of the stomach and small intestines

114

diaphragmatic hernia results in what?

respiratory impairment • pulmonary hypoplasia

115

what is the problem in congenital hypertrophic pyloric stenosis?

hypertrophy of the circular muscle of the pylorus results in regurgitation and vomiting in the neonatal period

116

what is the classic PE finding in congenital hypertrophic pyloric stenosis?

VGP= visible gastric peristalsis • + • palpable mass in the epigastrium

117

what is the inheritance of congenital hypertrophic pyloric stenosis?

males • multifactorial inheritance

118

what is the treatment for congenital hypertrophic pyloric stenosis?

full thickness muscle splitting incision (pyloromyotomy) is curative (Heller's operation)

119

what is acute gastritis?

inflammation of gastric mucosa

120

what cells are associated with acute gastritis?

presence of neutrophils

121

what cells are associated with chronic gastritis?

lymphocytes and plasma cells

122

what is acute gastritis caused by?

ingestion of strong acids or alkalies, • NSAIDs, • cancer chemotherapy, • irradiation, • alcohol, • uremia, • severe stress and shock states

123

what are the proposed mechanisms of acute gastritis?

increased acid production with decreased surface bicarb buffer

124

what is the morphology associated with acute gastritis?

mucosal edema • hyperemia • PML infiltration • erosions (not deeper than muscularis mucosa) • hemorrhages

125

how deep do erosions in acute gastritis penetrate?

not deeper than muscularis mucosa

126

what is the histologic presentation of acute gastritis?

gastric mucosa infiltration by neutrophils

127

what is the gross morphologic presentation of acute gastritis?

diffusely hyperemic gastric mucosa

128

what are the common causes for acute gastritis?

alcoholism • drugs • infections etc

129

what is chronic gastritis?

chronic mucosal inflammation leading to mucosal atrophy, intestinal metaplasia, and dysplasia

130

what is the MCC of chronic gastritis?

chronic infection by H. pylori

131

what is the mechanism of chronic gastritis caused by H. pylori?

elaboration of urease produces ammonia that buffers gastric acid, protecting organism from acid

132

what are the other diseases (besides chronic gastritis) associated with H. pylori infection?

peptic ulcer disease • gastric carcinoma • gastric lymphoma

133

what causes 10% of chronic gastritis?

autoimmunity: • Ab to parietal cells cause parietal cell destruction (HCl +IF)

134

what is the histological presentation of H. pylori that causes chronic gastritis?

#NAME?

135

how is H pylori in chronic gastritis visualized?

stain with methylene blue

136

what is the problem associated with autoimmune gastritis?

pernicious anemia

137

chronic atrophic gastritis is associated with antibodies against what?

IF • parietal cell

138

what is a gastric ulcer?

a breach in mucosa and extends through muscularis mucosae into submucosa or deeper

139

what is acute erosive gastritis?

erosions above the muscularis mucosa

140

acute gastric ulcers are caused by what?

severe stress • shock/extensive burns • severe head injury • patients in ICU

141

what is the name for acute erosive gastritis caused by severe stress?

stress uclers

142

what is the name for acute erosive gastritis caused by shock, extensive burns?

Curling's ulcers

143

what is the name for acute erosive gastritis caused by severe head injuries?

Cushing's ulcers

144

what is the cause of acute erosive gastritis in patients in ICU?

use of NSAIDs

145

what is the morphology of acute gastric ulcers?

multiple, small (<1cm ulcers) normal adjacent mucosa

146

what is the clinical presentation of acute gastric ulcers?

upper GIT hemorrhage

147

what is the Tx for acute gastric ulcers?

treat underlying cause

148

what do stress ulcers look like?

small, shallow gastric ulcerations

149

chronic peptic ulcers are characterized by what?

solitary, chronic ulcers

150

what is the ratio of duodenal to gastric chronic peptic ulcers?

4:01

151

what is the more common chronic peptic ulcer?

duodenal

152

what is the morphology of chronic peptic ulcer?

sharply punched out mucosal defect with sharp borders and clean ulcer base • - surrounding mucosa shows chronic gastritis & radial convergence of rugal folds towards the ulcer niche (unlike malignant ulcer)

153

how do chronic peptic ulcers present clinically?

epigastric pain 1-3h after meals and worse at night; nausea; vomiting; belching; occult blood in the stool

154

what are the complications of chronic peptic ulcers?

perforation • hemorrhage • obstruction • malignant transformation

155

perforation accounts for how many ulcer deaths?

03-Feb

156

hemorrhage accounts for how many ulcer death?

25%

157

what does obstruction caused by peptic ulcer cause?

severe crampy abdominal pain

158

how common is malignant transformation in peptic ulcer?

extremely rare

159

what are the normal damaging forces in the stomach?

gastric acidity • peptic enzymes

160

what are the normal defensive forces in the stomach?

1. surface mucus secretion • 2. bicarbonate secretion into mucus • 3. mucosal blood flow • 4. apical surface membrane transport • 5. epithelial regenerative capacity • 6. elaboration of prostaglandins

161

what are the forces that lead to increased damage in the stomach and can produce ulcer?

H pylori infection • NSAID • ASA • Cigs • EtOH • gastric hyperacidity • too rapid gastric emptying • psych stress

162

what are the impaired defensive forces in the stomach that can lead to peptic ulcer?

1. decreased mucus secretion • 2. decreased PG synth • 3. delayed gastric emptying

163

what are the microscopic features of gastric ulcer?

sharply demarcated • normal gastric mucosa falling away into deep ulcer whose base contrains inflamed necrotic debris

164

hypertrophic gastropathy is characterized by what?

giant enlargement of the gastric rugal folds

165

hypertrophic gastropathy is caused by what?

hyperplasia of epithelial cells (not due to inflammation)

166

what is the malignant risk associated with hypertrophic gastropathy?

increased risk of cancer

167

what are the 3 variants of hypertrophic gastropathy?

- Menetrier's disease • - Hypersecretory Gastropathy • - Zollinger-Ellison syndrome

168

what is another name for Menetrier's disease?

protein losing gastropathy

169

what are the features of Menetier's disease?

- hyperplasia of surface mucus cells • - glandular atrophy • - excessive loss of proteins in gastric secretion

170

what are the features of hypersecretory gastropathy?

- hyperplasia of parietal and chief cells • - secondary to excessive gastrin stimulaton

171

what is the cause of Zollinger-Ellison syndrome?

gastrinoma of the pancreas secreting gastrin--> elevated serum gastrin levels

172

what are the features of Zollinger-Ellison syndrome?

- multiple peptic ulcerations in stomach, duodenum, jejunum • - hypertrophic rugal folds and parietal cell hyperplasia--> excessive gastric acid production

173

what are the benign tumors of the stomach?

gastric polyps • adenomatous polyps

174

how many gastric polyps are neoplastic?

90% non-neoplastic= • hyperplastic or inflammatory

175

do non-neoplastic gastric polyps have malignant potential?

no

176

what is the tx for gastric polyps?

biopsy

177

what are adenomatous polyps in the stomach?

true neoplasms with proliferative dysplastic epithelium

178

do adenomatous polyps of the stomach have malignant potential?

yes, common in old age

179

adenomatous polyps of the stomach are MC associated with what?

chronic gastritis or familial polyposis syndromes

180

what are the malignant tumors of the stomach?

1. Gastric carcinoma • 2. Gastrointestinal Stromal Tumor • 3. carcinoid (neuroendocrine) tumors • 4. gastric lymphoma

181

what is the incidence of gastric carcinoma?

4 fold decline in incidence over the last 70 years for unknown reasons

182

what are the dietary risk factors for gastric carcinoma?

nitrites (from food preservatives), smoked and salted foods, deficiency of fresh fruits and vegetables

183

what are the host factor risk factors for gastric carcinoma?

chronic gastritis (autoimmune & H. pylori), adenomatous polyps, partial gastrectomy pt

184

what are the genetic risk factors for gastric carcinoma?

blood group A • close relatives of stomach cancer patients • certain racial groups (Japanese)

185

what are the classifications of Gastric Carcinoma?

1. early gastric carcinoma • 2. advanced gastric carcinoma

186

what is early gastric carcinoma?

confined to the mucosa & submucosa, despite lymph node spread

187

what is the prognosis for early gastric carcinoma?

associated with very good prognosis >90% 5yr

188

what is advanced gastric carcinoma?

has extended beyond the submucosa & spread is by local invasion, lymphatics, blood (to liver and lungs)

189

what is Krukenberg tumor?

bilateral ovarian metastases (stomach, breast, pancreas, even gallbladder)

190

what is Virchow node?

left supraclavicular node with mets

191

what is the sister Mary Joseph nodule?

metastasize to the periumbilical region (subQ malignant nodule)

192

what are the histologic types of gastric carcinoma?

intestinal type • gastric type

193

what are the features of intestinal type gastric carcinoma?

glandular, expansile growth pattern

194

what are the features of gastric type gastric carcinoma?

diffuse 'signet ring' infiltrating pattern

195

what is the most important prognostic indicator in gastric carcinoma?

pathologic stage

196

from what do GISTs arise?

interstitial cells of Cajal

197

what are the markers of GISTs?

c-KIT (CD117) & CD34 positive

198

what are carcinoid (neuroendocrine) tumors of the stomach made of?

made of ECL cell tumors

199

carcinoid neuroendocrine tumors of the stomach are associated with what diseases?

MEN1 • Zollinger-Ellison Syndrome

200

what is the most common site for extranodal lymphoma?

gastric lymphoma

201

majority of gastric lymphoma are associated with what?

80% associated with H pylori chronic gastritis

202

when are most gastric adenocarcinomas in the US found?

at a late stage when the neoplasm has invaded and/or metastasized

203

what is a cautious approach for early detection of gastric carcinoma?

all gastric ulcers and all gastric masses must be biopsied

204

what is the level of malignancy of duodenal peptic ulcers?

virtually all are benign

205

what is linitis plastica?

diffuse infiltrative gastric adenocarcinoma

206

what are the features of linitis plastica?

- stomach looks like shrunken leather bottle • - markedly thickened gastric wall • - very poor prognosis

207

which type of gastric carcinoma typically produces krukenberg tumor?

gastric type

208

what structures make up the small intestine?

duodenum • jejunum • ileum

209

what is the purpose of the villi and microvilli in the small intestine?

increase surface area of the mucosa

210

what are the crypts of Lieberkuhn

pits between the bases of the villi in small intestine

211

what is the normal villus:crypt height ratio?

4:01

212

where are the digestive enzymes in small intestines located?

in the membranes of microvilli

213

how do bile ducts connect to the small intestine?

common bile duct and pancreatic duct empty into the 2nd part of the duodenum

214

what types of glands are found in the duodenum?

Brunner's glands

215

what are the lymphoid structures in the ileum?

Peyer's patches

216

what are the structures of the large intestine?

1. cecum & its appendix • 2. colon • - ascending • - transverse • - descending • - sigmoid • 3. rectum • 4. anal canal

217

are there villi and microvilli in the large intestine?

large intestine lacks villi and microvilli

218

does the large intestine have goblet cells?

has numerous goblet cells in the mucosa

219

what is the function of the large intestine?

absorption of fluids, electrolytes and secretion of mucus

220

what is the arterial supply of the intestines up to the hepatic flexure of the colon?

SMA

221

what is the arterial supply to the intestine from the hepatic flexure to the rectum?

IMA

222

what are the arterial interconnections in that supply the intestines called?

mesenteric arcades

223

what is the artery that supplies the upper rectum?

superior hemorrhoidal artery from IMA

224

what is the artery that supplies the lower rectum?

hemorrhoidal artery from internal iliac or internal pudendal artery

225

what is the distribution of venous drainage of the intestines?

same as the arterial supply

226

which intestinal vessels connect to form portal and systemic connections?

anastomotic capillary beds between superior and inferior hemorrhoidal veins

227

are the ascending and descending colon intra- or retroperitoneal?

retroperitoneal

228

where does the accessory blood supply and lymphatic drainage of the ascending and descending colon come from?

posterior abdominal wall

229

do lymphatics have arcades?

no • run as parallel vessels without arcades

230

what is the lymphoid tissue in the intestines?

MALT • mucosa associated lymphoid tissue

231

what is the grossly visible lymphoid structure associated with the ileum?

Peyer's patches

232

what is the function of immune M cells in the intestines?

M (membranous cells) transport Ag to APC in SI and LI

233

what is the direction of small intestinal peristalsis?

anterograde and retrograde

234

what is peristalsis in the intestines mediated by?

intrinsic (myenteric plexus) and extrinsic (autonomic innervation) neural control

235

what are the parts of the myenteric plexus?

meissner plexus (in submucosa) • auerbach plexs (muscle wall layers)

236

what differentiates large from small intestine?

large intestine lacks villi and has numerous goblet cells

237

what are the general symptoms associated with intestinal pathology?

1. anorexia • 2. nausea • 3. vomiting • 4. flatulence • 5. bloating • 6. abdominal discomfort • 7. weight loss • 8. malaise

238

what are the esophagus-specific symptoms of GI pathology?

dysphagia • odynophagia • heartburn • regurgitation • retrosternal pain

239

what are the gastric-specific symptoms of GI pathology?

early satiety • hematemesis • upper abdominal pain/discomfort

240

what are the small intestine specific symptoms of GI pathology?

diarrhea • steatorrhea • anemia • abdominal colic

241

what are the large intestine specific symptoms of GI pathology?

diarrhea • constipation • blood and mucus per rectum • tenesmus • proctalgia • anemia

242

what are the congenital anomalies of the intestines?

- atresia and stenosis • - meckel diverticulum • - Hirschsprung disease

243

what is atresia?

complete obstruction

244

what is the most common site of intestinal atresia?

duodenum

245

what is the common cause of neonatal intestinal obstruction?

duodenal atresia

246

what is the frequency of jejunum and ileum atresia?

jejunum and ileum are equally involved, less so than the duodenum, but more so than the colon

247

how often does atresia of the colon happen?

never

248

what is stenosis?

incomplete obstruction

249

what is more common, intestinal atresia or stenosis?

atresia

250

what is imperforate anus?

failure of cloacal diaphragm to rupture--> • neonatal intestinal obstruction

251

what type of diverticulum is Meckel's diverticulum?

true diverticulum

252

what is the 2% rule of Meckel's diverticulum?

2 feet from ileocecal valve, seen i 2% of people, 2" in size

253

what are the symptoms of Meckel's diverticulum?

asymptomatic

254

what is in Meckel's diverticulum?

may contain gastric or pancreatic tissues &(peptic ulcers, diverticulitis, intestinal obstruction, intussusception)

255

what is the cause of Meckel's diverticulum?

persistent segment of the vitelline duct (h connects the yolk sac + gut lumen)

256

what is another name for Hirschsprung's disease?

aganglionic megacolon

257

what causes Hirchsprung's disease?

arrested migration of nerve elemets into distal part of gut

258

what is Hirschsprung's disease?

absence of ganglion cells in the large bowel (Aurbach's and Meissner's plexus)

259

50% of familial and 15% of sporadic cases of Hirschsprung's disease are due to what?

mutations in the RET gene

260

what does the RET gene do?

promote survival and growth of neurite and direction to migrating neural crest cells

261

Hirschsprung's disease is characterized by what?

aganglionic (aperistaltic) segment--> narrow unaffected proximal colon--> dilation and hypertrophy (megacolon)

262

there is an increased risk of Hirschsprung's disease with what condition?

down syndrome

263

what is the incidence of Hirschsprung's disease?

1:8000 live births • M:F=4:1

264

how does Hirschsprung's disease present?

meconium ileus • abdominal distention • constipation • diarrhea (enterocolitis) • perforation (rare)

265

what is involved in the diagnosis of hirschsprung's disease?

histological demonstration of absence of ganglion cells in intestinal submucosa

266

how is a biopsy suspicious for Hirschsprung's treated for lab dx?

stained for acetyl cholinesterase

267

what are the conditions important in the differential diagnosis of Hirschsprung's disease?

any acquired megacolon: • 1. Chagas disease • 2. Obstruction (neoplastic) or inflammatory stricture of the bowel • 3. toxic megacolon- ulcerative colitis or Crohn disease • 4. functional causes

268

what is diarrhea?

frequent passage of loose watery stools

269

what is secretory diarrhea?

passage of >500ml/day of watery stools, isotonic with plasma (intestinal secretion)

270

what is osmotic diarrhea?

>500mL/d stools, the osmolality of which exceeds that of plasma by >50 mOsm

271

what is exudative diarrhea?

frequent passage of loose, purulent, bloody stools

272

what is dysentery?

painful bloody diarrhea (tenesmus)

273

what does malabsorption look like?

bulky stools with excess fat (floats on water) and increased osmolality

274

what is the volvume/day of secretory diarrhea?

>500mL

275

what is the volume/day of osmotic diarrhea?

>500mL

276

what is the volume of stool in malabsorption?

large volume

277

what is the osmolarity of stool with respect to plasma in secretory diarrhea?

isotonic

278

what is the osmolarity of stool with respect to plasma in osmotic diarrhea?

>50mOsm hypertonic

279

what is the osmolarity of stool with respect to plasma in malabsorption?

hypertonic

280

does secretory diarrhea persist on fasting/

yes

281

does osmotic diarrhea persist on fasting?

no

282

does exudative diarrhea persist on fasting?

yes

283

does malabsorption diarrhea persist on fasting?

no

284

is there steatorrhea in secretory diarrhea?

no

285

is there steatorrhea in osmotic diarrhea?

no

286

is there steatorrhea in exudative diarrhea?

no

287

is there steatorrhea in malabsorption diarrhea?

yes

288

is there blood/pus in secretory diarrhea?

no

289

is there blood/pus in osmotic diarrhea?

no

290

is there blood/pus in exudative diarrhea?

yes

291

is there blood/pus in malabsorption diarrhea?

no

292

what are the types of infective enterocolitis?

1. viral • 2. bacterial • 3. bacterial overgrowth syndrome • 4. parasitic EC • 5. necrotizing EC • 6. collagen & lymphocytic EC

293

what is infective enterocolitis?

acute, self limited infectious diarrhea

294

infective enterocolitis is a major cause of morbidity among which population?

children

295

what is the most common cause of infective enterocolitis?

enteric viruses

296

viral enterocolitis is characterized by what?

food and water infections that cause damage of small intestinal epithelium with shortening of villi • - diarrhea for 1-7 days

297

what are the most common causes of viral enterocolitis?

1. Rotavirus (Group A) • 2. Norwalk Virus • 3. Adenovirus

298

who is affected by Rotavirus Group A infections?

outbreaks in children 6-24 months

299

what happens in rotavirus group A EC?

selectively infects and destroys mature enterocytes in the small intestine, without infecting crypt cells

300

what are the features of Norwalk virus EC?

food borne nonbacterial outbreaks in school children and adults

301

adenovirus EC outbreaks affect which populations?

infants

302

what do the morphologic changes in bacterial EC depend on?

the causative agent

303

what are the pathogenic mechanisms underlying bacterial EC?

1. ingestion of preformed toxins • 2. infection by toxigenic orgnisms

304

Bacterial EC can be caused by ingestion of preformed toxins present in contaminated food by what organisms?

Staph. aureus • Clost. perfringens • Virbrios

305

what are the 2 ways that bacterial EC caused by infection by toxigenic organisms proliferate?

1. proliferate within gut lumen and elaborate an enterotoxin • 2. proliferate, invade, and destroy mucosal epithelial cells

306

which organisms that cause bacterial EC proliferate within the gut lumen and elaborate an enterotoxin?

enteroinvasive organisms: • - E coli • - Shigella • - Salmonella

307

what are the 2 types of enterotoxins associated with bacterial EC?

secretagogues (cholera toxin) • cytotoxins (Shiga toxin)

308

what are the clinical features of bacterial EC caused by ingestion of preformed toxins?

- develop within a matter of hours • - explosive diarrhea • - actue abdominal distress • - passes in a day or so

309

what are the clinical features of bacterial EC caused by infection with enteric pathogen?

- incubation period of several hours to days • - followed by diarrhea and dehydration

310

what are the complications associated with bacterial EC?

- massive fluid loss or destruction of intestinal mucosal barrier • - dehydration, sepsis, perforation

311

what are the major sources Salmonella in the USA?

Feces contaminated beef and chicken

312

what is the more common organism that causes bacterial EC from chicken?

Campylobacter jejuni • - more common than Shigella and Salmonella

313

how does cholera toxin cause secretory diarrhea?

1. permanently activate GTP--> persistent activation of adenylate cyclase--> high levels of intracellular cAMP--> stimulates secretion of chloride and bicarb • 2. chloride and sodium reabsorption is inhibited

314

what is another name for pseudomembranous colitis?

antibiotic associated colitis (EC)

315

what type of colitis is pseudo-membranous colitis?

acute colitis

316

what is pseudo-membranous colitis caused by?

enterotoxins of Clostridium dificile

317

what is the role of the enterotoxins of Colstridium dificile in pseudomembranous colitis?

due to toxins A and B--> cytokine production--> cell apoptosis

318

antibiotic associated colitis is characterized by what?

the formation of an adherent necrotic membrane (pseudomembrane) overlying extensive mucosal inflammation

319

what makes up the pseudomembrane associated with pseudomembranous colitis?

mucus, fibrin, and inflammatory debris

320

similarly to pseudomembranous colitis, fibrinopurulent necrotic pseudomembrane forms in what?

enteroinvasive infections • ischemic EC

321

what are the clinical features of pseudomembranous colitis?

- presents as acute diarrhea while on antibiotic therapy • - toxin detectable in stools • - responds to appropriate antibiotics

322

what is the cause of bacterial overgrowth syndrome?

surgical procedures- decreasing the time for exposure of ingested bacteria to gastric acid • - bacterial overgrowth in the small intestine

323

how does bacterial overgrowth syndrome present clinically?

chronic diarrhea • abdominal pain • malabsorption • weight loss

324

what is involved in the diagnosis of bacterial overgrowth syndrome?

- breath tests for volatile bacterial byproducts • - clinical history • - demonstration of bacteria in the proximal small intestine by direct culture

325

what are the nematodes that cause parasitic EC?

1. ascaris lumbricoides • 2. strongyloides • 3. hookworm • - necator duodenale • - ancylostoma duodenale • 4. enterobius vermicularis (pinworm) • 5. trichuris trichiuria (whipworm)

326

what is the most common nematode cause of parasitic EC?

ascaris lumbricoides

327

what are the features of parasitic EC caused by ascaris lumbricoides?

- obstruct the intestine or biliary tree • - pneumonitis • - hepatic abscess

328

how is ascaris lumbricoides diagnosed?

detection of eggs in the feces

329

what are the features of parasitic EC caused by strongyloides?

- pulmonary infiltrates with eosinophilia • - autoinfection in immnosuppressed

330

what are the features of parasitic EC caused by the hookworms necator duodenale or ancylostoma duodenale?

- intestinal mucosa erosions, focal hemorrhage • - long term infection lead to IDA

331

what are the features of parasitic EC caused by pinworm enterobius vermicularis?

perianal pruritus

332

what causes perianal pruritus in parasitic EC caused by enterobius vermicularis?

worms migrate to the anal orifice and deposit eggs

333

how is enterobius vermicularis diagnosed?

perianal skin tape

334

what are the features of parasitic EC caused by trichuris trichiura?

- Heavy infections- cause bloody diarrhea and rectal prolapse • - in young children

335

what are the features of parasitic EC caused by cestodes?

- never invade beyond the intestinal mucosa • - no eosinophilia

336

what are the cestodes that cause parasitic EC?

Diphyllobothrium latum (fish tapeworm) • Taenia solium (pork tapeworm) • Hymenolepsis nana (dwarf tapeworm)

337

what are the protozal infections that cause parasitic EC?

1. Amebiasis (Entamoeba histolytica) • 2. Giardiasis

338

what is the site of infection in parasitic EC caused by Amebiasis vs. Giardiasis?

Amebiasis= LI (cecum and ascending colon) • Giardiasis= SI (duodenum)

339

what is the difference in the stool caused by parasitic EC from amebiasis vs giardiasis?

Amebiasis= dysentery • Giardiasis= diarrhea

340

what type of ulcers are present in parasitic EC caused by amebiasis vs giardiasis?

amebiasis= flask shaped ulcer • giardiasis= no ulcers

341

what is the difference between trophozoites in amebiasis vs giardiasis?

amebiasis= 1 nucleus • giardiasis= 2 nuclei

342

what is the difference between the flagella of the organisms that cause amebiasis vs giardiasis?

amebiasis= no flagella • giardiasis= flagellated

343

what is the difference between the treatment for amebiasis vs giardiasis?

rx is same for both

344

what is the most common acquired gastrointestinal emergency?

necrotizing enterocolitis

345

which babies are at highest risk for necrotizing enterocolitis?

premature • low birth weight

346

what causes necrotizing enterocolitis?

immaturity of the gut immune system

347

necrotizing enterocolitis is characterized by what?

necrotizing inflammation of the small and large intestine

348

what happens in necrotizing enterocolitis?

initiation of oral feeding--> release of cytokines (PAF)--> inflammatory response • --> gut colonization with bacteria • --> mucosal injury