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64 Cards in this Set
- Front
- Back
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What are the 4 major congenital abnormalities seen in the colon?
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-Duplication
-Malrotation -Omphalocele -Gastroschisis |
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What is Omphalocele?
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Herniated gut within a sac with the umbilical cord at its apex
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Why does the gut herniate in Omphalocele?
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Because of a defect in the abdominal wall closure
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How is Gastroschis different from Omphalocele?
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-It occurs lateral to the umbilical cord
-There is NO sac covering the herniated gut |
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Which of the congenital anomalies tends to be silent? Catastrophic?
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Silent = malrotation
Catastrophic = gastroschisis |
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What is Heterotopia?
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A congenital anomaly where gastric or pancreatic tissue forms a nodule in the mucosa or intestinal wall
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Where is the most common site for congenital atresia of the bowel to form?
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Duodenal
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What results when there is failure of involution of the vitelline duct during utero?
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Meckel diverticulum
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Where are Meckel diverticula most commonly seen? What is the incidence? Are they significant?
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-Antimesenteric side of the small intestine
-2% -Not usually symptomatic |
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Is a Meckel diverticulum true or not true?
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True - it has all 3 layers of the normal bowel wall
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What is Hirschprung disease?
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Aganglionic megacolon
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What causes Hirschprung disease?
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Failure of neural crest to migrate to the colon
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What is the incidence of Hirschprung disease, and in what sex?
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1:5000 births
M:F = 4:1 |
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What is ALWAYS affected in Hirschprung disease?
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The rectum
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What do you see on gross exam of the bowel in Hirschsprung disease?
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-Dilation of the bowel proximal to the aganglionic section
-Obstruction of the affectd segment |
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What are the 2 most common clinical manifestations of Hirschprung disease?
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-Failure to pass meconium
-Obstructive constipation |
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What are 4 things that can cause ACQUIRED megacolon?
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1. Functional psychosomatic disorder
2. Chagas disease 3. Organic obstruction 4. Toxic megacolon FCOT not to be confused with Epcot :) |
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How does Chagas disease cause acquired megacolon?
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The organism invades the bowel wall and destroys the enteric plexuses
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What are organic obstructions of the bowel?
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-Neoplasms
-Strictures |
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What are 2 diseases in which Toxic megacolon develops as a complication?
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-Ulcerative colitis
-Crohn's disease |
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What are the 5 major mechanisms of diarrhea?
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1. Secretory
2. Osmotic 3. Exudative 4. Malabsorptive 5. Deranged motility |
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What is seen in Secretory diarrhea?
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-Large volumes
-Isotonic with plasma -Persists with fasting |
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What is seen in Osmotic diarrhea?
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-Large volumes
-Osmotic gap to plasma -Abates with fasting (was caused by too much junk in colon) |
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What is seen in Exudative diarrhea?
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-Mucosal destruction
-Bloody diarrhea -Persists with fasting |
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What is seen in Malabsorptive diarrhea?
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-Bulky stools
-Fatty stools -Abates with fasting |
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What is Deranged motility diarrhea?
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A diagnosis of exclusion caused by improper neuromuscular function.
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What are 4 causes of Secretory diarrhea?
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-Viruses
-Enterotoxic bacteria -Neoplasms -Laxative use |
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What are 3 causes of Osmotic diarrhea?
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-Lactase deficiency
-Antacids -Bile acid malabsorption |
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What are 3 causes of Exudative diarrhea?
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-Bacteria
-IBD -Typhlitis |
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What are 3 causes of malabsorptive diarrhea?
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-Pancreatic insufficiency
-Bacterial overgrowth -Sprue |
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What are 3 things that can cause deranged motility leading to diarrhea?
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-Short bowel syndrome
-IBS -Hyperthyroidism |
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What are the 4 major categories of Enterocolitis?
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1. Bacterial
2. Viral 3. Parasitic 4. Collagenous/Lymphocytic |
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What are 3 ways that Bacterial enterocolitis can be categorized?
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-Pathogenic mechanism
-Virulence factors -Specific organism |
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What are 3 types of pathogenic mechanisms seen in Bacterial enterocolitis?
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1. Bug has preformed toxin
2. Bug is toxigenic 3. Bug is enteroinvasive |
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What are 2 bugs that produce preformed toxin?
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-Staph aureus
-Clostridium |
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What are 4 bacteria that proliferate and make toxins?
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-ETEC
-Campylobacter -Vibrio -C. difficile |
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What are 4 enteroinvasive organisms?
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-EIEC
-Salmonella -Shigella -Yersinia |
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What type of pathology is seen grossly in Shigella enterocolitis?
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Patches of coagulated EXUDATE
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What is the pathology always seen in hemorrhagic diarrhea?
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Exudative
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What bacteria causes typhoid fever?
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Salmonella
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What is the most common stool isolate in the US?
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Campylobacter
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What are 2 sequelae associated with campylobacter?
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-Guillain barre
-Reactive arthritis |
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What is the microscopic picture seen in Acute self-limited colitis?
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Intact Crypt architecture with neutrophilic infiltrates
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What are 5 main causes of acute self-limited colitis?
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-Campylobacter
-Salmonella -Shigella -Viruses -Parasites |
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What is Pseudomembranous colitis?
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Antibiotic-associated colitis
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What is the 'Pseudomembrane" in antibiotic colitis?
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A plaque-like adhesion of fibrinopurulent necrotic debris overlying sites of mucosal injury
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What causes pseudomembranous colitis?
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C. diff toxins when a dcrease in gut normal flora allows this bug to increase to the point that it becomes toxic.
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How is c. diff colitis diagnosed?
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By detection of toxin in the stools
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What is the major parasite that causes enterocolitis?
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Entamoeba histolytica
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What develops in 40% of E. histolytica cases of amebic dysentery?
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Amebic liver abscesses
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What do the ulcers look like in Amebic dysentery?
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Flask shaped
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What are 2 types of noninfectious colitis?
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-Collagenous
-Lymphocytic |
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What is collagenous colitis and in what patients is it seen?
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Thickening of the sub-epithelial collagenous plate; seen in middle-aged women
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What does thickening of the subepithelial collagenous plate result in in these poor middle aged women?
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Chronic Watery diarrhea
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What is lymphocytic colitis?
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Chronic water diarrhea due to an autoimmune disease
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How are collagenous and lymphocytic colitis diagnosed? Why?
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By doing a biopsy and looking at the microscopic appearance; bc there is no abnormality on endoscopy
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What is seen on microscopy in lymphocytic colitis?
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Intraepithelial lymphocytic infiltrates
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How is collagenous colitis diagnosed on microscopy?
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By doing a stain for collagen (red)
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What is a miscellaneous inflammatory cause of severe watery diarrhea?
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GVHD
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What would you see on microscopy of an intestinal biopsy in GVHD?
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Apoptotic cells
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What drug commonly induces intestinal injury?
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NSAIDs
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What is Typhlitis?
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Neutropenic colitis
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Where is the colon affected mostly in Typhlitis, and how is it confirmed?
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-Cecum
-See hemorrhagic necrosis but WITHOUT inflammation -Automated neut count <1500 |
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Why does diarrhea develop from diversion colitis?
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Due to a lack of short chain fatty acids
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