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93 Cards in this Set
- Front
- Back
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Intestinal Atresia
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complete occlusion of lumen
could be from: -fibrous diaphragm - complete fibrosis - complete seperation |
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Intestinal Stenosis
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narrowing of lumen
less common |
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heterotopoc gastric mucosa
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disccrete small nodules of gastric mucosa
- may cause obstruction, ulceration, bleeding, perforation, intussuception, pain |
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gastric metaplasia
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involves surface epithelium only
associated with H. pylori infection and is NOT congenital |
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Hirschsprung's Disease
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aganglionosis of a portion of the intestinal tract
The rectum is always affected with involvement of proximal colon (short segment) or entire colon (long segment). Colon undergoes dilation and hypertrophy (Megacolon) |
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Clinical Features of Hirschsprung's disease
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starts in neonatal period by failure to pass meconium and obstructive constipation
can lead to enterocolitis, fluid and electrolyte imbalances, and perforation leading to peritonitis |
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Incidence of Hirschsprung's disease
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1 in 5000 births
increased frequency among siblings predominant in males (short segment) females have long segment more commonly 10% of cases also have Down Syndrome |
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Necrotizing Enterocolitis
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occurs mainly in premature infants
is multifactorial but C. Difficile plays a role intenstinal ischemia is a prerequisite condition PAF increases mucosa permeability - now bacteria can enter gut tissue |
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Clinical course of NEC
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bloody stools
abdominal distension circulatory collapse pneumatosis intestinalis - Xray showing gas in intestinal wall involves cecum, ileum, and right colon may become gangrenous and cause peritonitis may culminate into sepsis and shock usually require removal of necrotic segment - may develop post-NEC strictures |
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Secretory Diarrhea
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more than 500 ml of fluid stool per day
isotonic with plasma commonly caused by viral damage to mucosal epithelium Traveller's diarrhea - ETEC, Vibrio Laxative abuses Pancreatic cholera syndrome - excessive VIP Carcinoma of Thyroid - excessive calcitonin Zollinger-Ellison syndrome Secreting VIllius Adenoma of Rectum - Prostaglandins Small Intestine Obstruction Portal Hypertension w/ Sever Hypoalbuminemia Giardiasis, Strongyloides, Amebiasis |
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Osmotic Diarrhea
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stool has osmotic anion gap and is more than 500 ml
Inability to metabolize lactose overuse of antacids bile malabsorption |
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Exudative Diarrhea
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mucosal destruction leading to bloody, purulent stools, that are continued on fasting
usually bacterial Shigella Salmonella Campylobacter E. Histolytica Idiopathic Inflammation in Gut Typhoid diseases in immuno suppressed |
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Malabsorption Diarrhea
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Voluminous bulky stools, increased osmolarity, excess of fat, that is better on fasting
mucosal cell abnormalities reduced small intestinal surface area lymphatic obstruction Giardiasis infection |
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Impaired Motility
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surgical reduction of gut length
neural dysfunction - IBS hyperthyroidism Diabetic Neuropathy Syndrome from Cancer small intestinal diverticula bacterial overgrowth of SI |
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Clinical Evaluation of Diarrhea
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History and Physical
Stool Exam - stain for pus - stain for fat (chronic - pancreatic insufficiency, acute - giardia/travellers diarrhea) - check for blood - check for eggs or parasites - measure volume |
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Infectious Enterocolitis
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acute - self limiting diarrhea
major cause of morbidity in children usually viral, but also bacterial bacterial infections - damage to surface epithelium, PMN infiltrate Shigella and Salmonella |
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Antibiotic Associated Colitis
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acute condition from inflammatory cells and debris overlying sites of mucosal injury - makes a "pseudomembrane"
- leads to megacolon, sepsis, and shock caused by toxin A: potent enterotoxin, affects cytoskeleton and is chemotactic to PMNs, which release prostaglandins and leukotrienes toxin B: cytotoxin |
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Cause of AAC
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alteration of normal flora
toxigenic C difficile colonizes - associated with broad spectrum AB's including C diff. - long hospital stays and old age are also risk factors |
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Diagnosis of C. difficile
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pressence of inflammatory cells in stool
bloody diarrhea endoscopy shows colitis or psuedomembranous colitis (not 100% reliable) histology: epithelial necrosis with fibrin overlying. PMN's test for toxin A or B |
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Diversion Colitis
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inflammatory mucosal lesion of surgically isolated segments of colon
enterocytes normally use short chain fatty acids for their calorie supply removal of ileum may deprive nutrition from colin can be mild or resemble ulcerative colitis restore fecal flow or supply fat enema |
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Malabsorption
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diarrhea, weight loss, malnutrition, bulky stools, greasy
fecal fat is the cornerstone of diagnosis - do fat test small intestine biopsy can look for inflammatory cells, villus abnormalities, lymphomas and whipples disease, sprue |
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Pathogenesis Celiac Disease
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chronic disease, lesions in SI, impaired absorption, which improves with wheat restriction
celiac sprue, GSE (also names) fundamentally sensitive to gluten which is a water insoluble protein T cell mediated chronic inflammation with autoimmune intolerance to gluten |
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Morphology of Celiac Disease
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flattened mucosa in small intestine
diffuse enteritis ATROPHY of villi vascular degeneration increase lymphocytes increased mitotic activity in crypts |
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Clinical Features of Celiac Disease
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flattened or scalloped appearance of intestine on endoscopy
flatulence and weight loss blistering dermatitis herpetiformis |
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Diagnosis of Celiac Disease
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documentation of malabsorption
visualization of lesions in bowel, and relief of symptoms with wheat removal -IgA TTG and IgA EMA (TTG is also seen in Sjogrens) |
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Tropical Sprue
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Celiac-like disease seen in the far east, Caribbean
overgrowth of toxigenic gram negative bacteria in JEJUNUM Bacteroides is absent B21, folate, and fat are malabsorbed shortening and thickening of villi with increased infiltrate |
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Whipple Disease
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A rare disease caused by Tropheryma Whippeli
can involve any organ, but mainly intestine and brain G+, proliferates in macros, no immune reaction SI with distended macros, PAS positive causes ssteatorrhea with abd pain, arthritis, and neurochanges FATAL |
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Inflammatory Bowel Disease
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CD - can affect any portion of the tract
most often distal SI UC - limited to colon and rectum extraintestinal inflammatory manifestations common in developed countries exaggerated response to commensal microorganisms, and have defects in barrier function |
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T cell responses of IBS
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CD4+ T cells damage tissue
CD - delayed type hypersensitivity by inductions of INF producing Th1 cells - produces granulomas |
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Diagnosis of IBD
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no single test
pANCA - positive often in patients with UC ASCA antibody is high in CD patients |
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Crohns Disease
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females more often, whites more often and JEWS, Smoking is a risk factor
usually distal ileum, sometimes with involvement of colon dull gray serosa, creeping fat, rubber intestinal wall, hypertrophy of muscularis propria, narrow lumen sharp demarcation between diseased and non-diseased segments aphthous ulcers, linear ulcers, narrow fissures between mucosa folds - can lead to fistulas |
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Histological features of Crohn's Disease
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mucosal inflammation, with bottow heavy appearance
chronic damage to mucosa ulceration transmural inflammation affecting all layers non-caseating granulomas mural changes |
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Clinical Manifestations of Crohn's Disease
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fatigue
prolonged diarrhea w/ pain weight loss and fever poor growth in children long standing CD leads to increased cancer incidence |
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Ulcerative Colitis
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only affects mucosa and submucosa
no granulomas more common in blacks, and females peaks between 20 and 25 pancolitis, and in severe cases can cause backwash ileitis friable and bleeds easily, ulcerations starting in distal colon, and extending from there pseudopolyps tunnels through mucosa NO serpentine ulcers flattened mucosal surface |
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Histology of UC
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mononuclear infiltrate in LP
crypt abscesses = aggregates of neutrophils NO granulomas sometimes muscularis propria will be exposed submucosal fibrosis is a sign of regeneration Basal lymphoplasmacytosis - indicator of chronic inflammation |
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Dysplasia and UC
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dysplasia in multiple sites w/ inflammation masking signs of carcinoma
infiltrative carcinoma with masses - important for early diagnosis nuclear atypia and cytoplasmic differentiation - plaque like lesions, edemoas, or invasive carcinomas |
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Clinical Features of UC
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relapsing disorder with attacks of bloody diarrhea containing stringy mucus
lower abd pain relieved by defecation precipitated by emotional or physical stress |
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toxic Megacolon
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Most severe cases of UC
damage to muscularis propria and neural plexus colon swells and becomes gangrenous |
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Collagenous and Lymphocytic Colitis
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"kinder and gentler"
3 - 20 non bloody watery bowel movements per day cramping abdominal pain unremarkable X rays CC - patches of band like collagen under surface of epithelium (middle aged older women) LC - intraepithelial infiltrate of lymphocytes, strong associated with autoimmune diseases (equal males and females) |
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Bowel Ischemia
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Acute occlusion of one of 3 major branches may lead to meters of infarcted intestine
end arteries can become occluded and cause small infarcts |
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severity of Ischemia
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transmural - all layers
mural infarction - mucosa and submucosa mucosal |
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Morphology of Transmural Infarction
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sudden and total occlusion of arterial blood flow
greatest risk at splenic flexure (right between sup. and inf. mesenterics) infarcts appear hemorrhagic because of blood into damaged areas wall becomes thickend and rubbery sharp demarcation in arterial occlusions venous has dusky areas blended into normal tissue edema, hemorrhage, necrosis sloughing into lumen, becomes gangrenous and can perforate |
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Morphology of Mucosal and Mural Infarcts
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dark red luminal hemorrhage
inflammatory cells and exudate absent from serosal surface superficial ulceration may be present |
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Mild Ischemia
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epithelium or villi may be necrotic or slough off
inflammation is absent mild vascular dilation deep crypts are intact may lead to enterotoxic bacterial overgrowth - psuedomembranous colitis |
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Chronic Ischemia
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chronic vascular insufficiency
may mimic enterocolitis or IBD becomes fibrotic -> stricture |
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Clinical Features of Ischemia
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high death rate
older individuals more common in people with premature bowel disease severe abdominal pain and tenderness with nausea, vomiting, bloody diarrhea or melanotic stool decreased bowl sounds, muscular rigidity diagnosed often delayed due to more common causes may lead to sepsis |
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Angiodysplasia
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non-neoplastic lesion of vascular dilation and malformation
tortuous dilations of submucosal and mucosal blood vessels |
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Congenital Diverticula
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all three layers of bowel
Meckel Diverticulum - persistence of vitelline duct - causes outpouching of antimesenteric border of ileum - just proximal to ileocecal valve - may cause bleeding from peptic ulceration |
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Acquired diverticula
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left side of the colon/sigmoid colon
only outpouching of mucosa and submucosa usually are multiple and become infected |
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morphology of Diverticula
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small flask like or spherical outpouchings
disect into the fat (epiploic appendices) and may be missed flattened or atrophic mucosa with absent muscularis mucosa hypertrophy of muscularis propria in bowel segment taeniae coli are prominent |
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Diverticulitis
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Obstruction and perforation of diverticula - inflammatory changes
eventually becomes fibrotic - can resemble colon cancer |
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Causes of Mechanical Obstruction
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Adhesions
Hernias Volvulus Tumors Strictures Gallstones Meconium |
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Causes Pseudo Obstruction
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paralytic ileus
bowel infarction myopathies and neuropathies |
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Hernias
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Weakness or defect in peritoneal wall
anterior at inguinal and femoral canals, umbilicus, and surgery sites viscera can protrude into sac and become trapped - infarct |
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Adhesions
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caused by surgical procedures, infection and endometriosis
can cause peritonitis as peritonitis heals, adhesions may develop |
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Intussusception
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one segment of intestine constricted by peristalsis - telescoped into distal segment of intestine - pulls mesentery in with it
patient is otherwise healthy sometimes associated with rotavirus - inflammation serves as traction poiint |
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Volvulus
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complete twisting of bowel
sigmoid, cecum, stomach |
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Polyps
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tumorous mass, protruding into lumen
Sessile: lacks a definable stalk Pedunculated: has astalk nonneoplastic - result of abnormal mucosal maturation adenomatous - epithelial polyps arise as result of dysplasia - neoplastic precursor |
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Inflammatory Polyps
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non-neoplastic
psuedopolyps islands of inflammed, regenerating mucosa - patients with severe IBD |
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Lymphoid Polyps
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essential normal variant of mucosa
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Hyperplastic polyps
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most common and are small
well formed glands and crypts w/ feathery epithelial profile - may progress to adenocarcinoma |
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Juvenile Polyps
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malformations of mucosal epithelium and lamina propria
large, rounded, smooth lamina propria makes up most of bulksurface is congested or ulcerated single - no malignant potential -- AD disorder juvenile polyposis syndrome -- there are multiple polyps in the GI tract -- does have risk for transformation |
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Peutz-Jeghers polyps
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involve epithelium, lamina propria, muscularis mucosa
rare AD condition melanotic mucosa and cutaneous pigmentation around the lips, genitalia, and palms increased risk for intussesception patients have increased risk of developing other carcinomas (sex cord tumors) mutation of STK11 on Chromosome 19 -- serine/threonine kinase activity |
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Cowden syndrome
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AD syndrome - multiple harmatomas of all three germ layers
predisposes to breast and thyroid cancers PTEN gene on Chromosome 10 |
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Cronkhite-Canada syndrome
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GI hamartomas and ectodermal abnormalities (nail atrophy and skin pigmentation)
eitiology is unknown |
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Adenomas
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intraepithelial neoplasms
tubular adenomas - most common villous adenomas - least common tubulovillous adenomas low - high grade precursor lesions to colorectal adenocarcinomas large villous are the most worrisome small tubulars are the most innocent can be assymptomatic, cause anemia or occult bleedint villous are most likely to bleed - can also secrete mucus - leads to hypoproteinemia or hypokalemia |
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Serrated Adenoma
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resemble benign hyperplastic polyps
have dysmaturational crypts |
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High grade dysplasia (CIS)
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little or no metasstatic potential because of lack of lymphatic channels
when is penetrates muscularis mucosa and the submucosal space - termed adenocarcinoma can remove via endoscope provided the lesions does not have lymphatic or blood supply, is well differentiated, and superficial |
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Colorectal Carcinoma
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occur sporadically
-directly proportional to amount of adenomas - peak incidence pf polyps precedes peak incidence of carcinoma - carcinomas are often surrounded by adenomas - complete recision of adenoma reduces carcinoma prevalence |
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Molecular Carcinoma
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APC/B cadherin - chromosomal instability - increased mutations of oncogenes and tumor supressors
- follows adenoma/carcinoma pathway loss of APC -5q21 - first event in formation of adenomas mutation of KRAS - most frequent oncogene in cancer and adenomas loss of p53 - last step in carcinogenesis Microsatellite instability pathway - damage to mismatch repair genes |
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Morphology of Colorectal carcinoma
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most common in rectum/sigmoid
right sided carcinomas have increase microsatellite instability rarely familial |
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Patterns of Colorectal Carcinoma
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Proximal Colon:
polyploid, exophytic mass rarely cause obstruction Distal Colon: annular, encircling lesions sides are firm, center is ulcerated |
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Histology of Colorectal Carcinoma
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tall columnar - anaplastic
strong desmoplastic stromal response produce mucin - worse prognosis |
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Clinical Features of Colorectal Carcinoma
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assymptomatic for years
insidous onset cecal and right colon lead to fatigue weakness, iron def. anemia left sided lesions lead to crampy lower left quad pain, and occult bleeding (if an elderly man has iron def. anemia is colorectal cancer until proven otherwise) met. to liver, lungs and bones |
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Familial Polyposis Syndrome
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AD disorder
high propensity for malignant transformation Peutz-Jaeghers - hamartomatous polyp, increased risk for cancer juvenile polyposis syndrome Cowden syndrome FAP - many andenomatous polyps - always progresses to ccarcinoma HNPCC - colorectal cancer, endometrial carcinoma, and ureter/pelvis |
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Clinical features of FPS
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unusually young children
multiple tumors in single organ positive family history |
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Familila Adenomatous Polyposis Syndrome
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chromosome 5q21
Classic: 500-2500 adenomas include stomoach and SI Tubular adenomas usually, occasional villous early detectionis important in cancer prevention Attenuated: fewer polyps, mainly in colon still high risk for cancer Gardner's: FAP with ostomas, epidermal cysts, fibromatosis Turcot: polyps and CNS tumors APC gene mutation |
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Hereditary Nonpolyposis Colorectal Cancer Syndrome (HNPCC)
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Lynch Syndrome
increased risk of colorectal and extraintestinal cancer low number of adenomas, but occur and an earlier age -microsatellite repair problems from DNA repair gene mutations |
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Carcinoid Tumors
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from mucosal endocrine cells
predominantly in the GI peak incidence in people over 60 |
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Histology of Carcinoid Tumors
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form islands, sheets, ect.
scant pink cytoplasm round nucleous have membrane bound secretory granules stain positive for chromogranin A, Synaptophysin, and enolase granules |
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Clinical Features of Carcinoid Tumors
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rarely produce local symptoms
bleeding may occur, but most are assymptomatic the secretory products can lead to Zollinger-Ellison, Cushings, ect. |
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Carcinoid Syndrome
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excess elaboration of serotonin
vasculomotor disturbances cutanous flushes cyanosis imtenstinal hypermotility diarrhea cramps/nausea bronchospasms hepatomegaly nodular liver pulmonic and tricuspid stenosis pericardial fibrosis |
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MALT lymphomas
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spordaic Bcell lymphoma
most common in West Hemis. in early stages act like focal tumor - ameanable to surgery relapses may occur t(11:18) is common mutation CD 10 and 5 NEGATIVE arise anywhere in gut |
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immunoproliferative small intestinal disease (IPSID)
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mediterranean lymphoma
B cell lymphoma with diffuse mucosal plasmacytosis - secrete lots of IgAlpha heavy chain malabsorption and weight loss prior |
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Intestinal T cell Lymphoma
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long standing malabsorption syndrome
diagnosed in younger adults with long history of malabsorption mostly in proximal SI |
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Morphology if GI lymphomas
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plaque like expansion of mucosa and submucosa
produce full mural thickening can protrude into lumen, and ulcerate can invade muscular layer and decrease motility |
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Mesenchymal Tumors
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Lipomas - in submucosa
Lipomatous hypertrophy at ileocecal valve Leiomyomas, and leiomyosarcomas - GIST's |
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Gastrointestinal Stromal Tumors (GIST's)
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mostly in stomach but sometimes in SI
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Tumors of the Anal Canal
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basaloid pattern, SCC, ad adenocarcinoma
Basaloid - sporatic and uniform SCC - HPV infection, linked to immunosuppression |
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Acute Appendicitis
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inflammation associated with obstruction - fecalith
-causes collapse of venous drainage - ischemic injury - bacterial proliferation |
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Morphology and Histology of Acute Appenidicitis
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neutrophillic exudate throughout all three layers
subserosal vessels are congested with perivascular neutrophil presence changes appearance of serosa from glistening to dull (early appendicitis) fibrinopurulent exudate and abscesses form on wall - suppurative necrosis green-black gangrenous necrosis through wall which is likely to rupture and cause peritonitis histological diagnosis is PMN's in muscularis propria |
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Carcinoid Tumor of Appendix
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most common
discovered at time of surgery or exam of resected appendix usually in distal tip - solid bolous swelling |
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Mucocele
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globular enlargement of appendix by mucus, usually as a result of fecalith obstruction
mucin secreting cells atrophy may occasionally spill into peritoneal cavity - infection may also be from mucin secreting adenoma or adenocarcinoma - pseudomyxoma peritoneii |
