Small/Large Intestine Flashcards
Specific Feature of Duodenum
Brunner’s Glands
Specific Feature of Ileum
Peyer’s Patch
M cells
Intussusception
telescoping of bowel segment into distal segment
compromised blood supply= abdominal pain with currant jelly stools
Children-idiopathic or infection related
Adult-mass or tumor
volvulus
twisting of bowel around its mesentery
-leads to obstruction and infarction
children-midgut
adults-sigmoid
Necrotizing Enterocolitis
acute, necrotizing inflammation of small and or large intestine
- multifactorial
- terminal ileum or ascending colon
- edema to necrosis to gangrenous bowel
- most common acquired GI emergency in PREMATURE or low birth weight neonate
Meckel’s Diverticulum
Persistence of omphalomesenteric duct (vitelline duct)
2% of pop
2:1 M
2’’ length
2 ft of ileocecal valve
2 types of ectopic tissue in 1/2 of cases (gastric and pancreatic)
2 major complications (pain with inflammation; hemorrhage with ulcer)
Hirschsprung Disease
Congenital Aganglionic Megacolon Absence of ganglion cells M:F 4:1 Premature arrest or death of the neural crest cell migration from the cecum to the rectum 1 in 5000 live births -Down syndrome (10%) 5% serious neurologic abnormalities
What are signs of malabsorption? What can it lead to?
Chronic Diarrhea, steatorrhea, weight loss, abdominal pain, flatus
Pyridoxine, folate, VB12, Anemia
Vit K: bleeding
Ca, Mg, and Vit D: osteopenia and tetany
Vit A and Vit D: peripheral neuropathy
What things can cause pancreatic insufficiency? What does this lead to?
Chronic pancreatitis
Cystic Fibrosis
Obstructing cancer
Leads:
Malabsorption of fat and fat soluble vitamins (ADEK)
- increased neutral fat
- normal D-xylose absorption test
Disaccharidase Deficiency
Most common-lactase deficiency
Osmotic diarrhea
Can occur if injury to tips of intestinal villi (where lactase is located)
Abetalipoproteinemia
Decreased synthesis of apolipoprotein B- decreased ability to generate chylomicrons-decreased secretion of cholesterol-fat accumulates in enterocytes
-presents early childhood with failure to thrive
Celiac Disease
Digestive and autoimmune disorder that results in damage to the lining of the small intestine when foods with gluten are eaten
- whites
- .5-1% prevalence
Infants: diarrhea, failure to thrive, abdominal distention, anorexia, weight loss, irritability
Older children: abdominal pain, nausea, vomiting, bloating or constipation
Adults: diarrhea, flatulence, weight loss, and fatigue and anemia
-Dermatitis herpetiformis
How do you make the diagnosis of Celiac disease?
Serologic studies:
IgA or IgG antibodies to tissue transglutaminase (TTG)
IgA or IgG antibodies to deaminated gliadin
IgA endomysial antibodies
(sepcific but less sensitive)
(may have IgA def)
Absence of HLA-DQ2 or HLA-DQ8 has high negative predictive value
What does celiac look like on histology and endoscopy?
Endoscopy:
- atrophic mucosa
- flattened folds
Histology:
Loss of villi
Increased numbers of intraepithelial CD8+ T cell lymphocytes
Tropical Sprue
Similar findings to celiac sprue but responds to antibiotics
Cause unknown
seen in residents/recent visitors to tropics
Damage: jejunum (folic acid) and ilium( B12)
In infectious enterocolitis=acute colitis where are the neutrophils?
neutrophils in the epithelium and lamina propria
Nematode-Ascaris
largest intestinal roundworm and is the most common helminth infection of human worldwide
- eggs are deposited in feces and soil
- infestation can cause morbidity by compromising nutritional status, affecting cognitive process, inducing tissue reactions such as granuloma to larval stages, and by causing intestinal obstruction, which can be fatal
Flatworms
Tapeworm: taenia and diphyllobothrium
-ingestion of raw or undercooked fish, meat or pork that contains the encysted larvae
Giardia
Most common parasite infection in humans
-spread by fecally contaminated food and water
Entamoeba Histolytica
cyts survive outside the host in water, in soil and on foods
- release the trophozoite stage in the digestive tract
- can be asymptomatic or lead to amoebic dysentery or amoebic liver abscess
- fulminating dysentery, bloody diarrhea, weight loss, fatigue, abdominal pain
- flask shaped ulcer
Pseudomembrane colitis
- most often after antibiotics
- yellow green false membrane (mixture of mucous and neutrophils)
- toxin produced by clostridium difficile
- intractable diarrhea, cramps, dehydration, shock, death
Histology
-mushroom shaped
Collagenous colitis
Clinical:
- chronic watery diarrhea
- 3-20 non-bloody stools per day
- middle age and older women
- radiographic studies unremarkable
- normal endoscopic findings
Histology:
subepithelial collagen
Lymphocytic colitis
Clinical:
- chronic watery diarrhea
- 3-20 non-bloody stools per day
- affects males and females equally
- radiographic studies unremarkable
- endoscopic findings normal
- strong association with autoimmune disease
Histology:
intraepithelial lymphocytes
NO epidermal collagen-Trichrome negative!
Whipple Disease
Rare
Gram positive rod shaped actinomycete: tropheryma whipplei
-engulfed by macrophages(PAS positive diastase resistant)
More common in men
Malabsorption, lymphadenopathy, and arthritis
Histology:
Lamina propria distended with foamy macrophages
PAS positive organisms
Inflammatory Bowel Disease
Increasing in incidence-hygiene hypothesis
Genetics-increased risk in family
Mucosal immune response-immune suppression is treatment
Epithelial defects-defects in tight junctions maybe paneth cell issues
Microbiota-change in the bacterial flora especially in the mucous
Crohn’s Disease Clinical
Teen/twenties and fifties/sixties
Caucasians> non Caucasian
Jewish>non Jewish
Disordered response to bacteria
Diarrhea, crampy abdominal pain: RLQ, low grade fever
-increased incidence of cancer in SI and colon
Symptoms:
Usually begins with intermittent attacks of mild diarrhea, fever, abdominal pain
Asymptomatic periods
Recurrent attacks or flare ups of diarrhea
-can present abruptly with RLQ pain
Complications: fibrosing strictures, fistulas, gallstones, malabsorption, CRC
Extraintestinal:
-migrating polyarthritis, kidney stones
What is the gross anatomy in Crohn’s disease
- May occur at any point along the GI tract
- Usually affects terminal ileum, ileocecal valve, cecum
- mucosa show linear ulceration and fissure formation
- segmental involvment sparing other areas
- serosal creeping fat
- cobblestoning
- fistula with bladder
Crohn’s disease histology
- Transmural inflammation
- cryptitis-crypt abscesses
- ulceration
- non caseating granulomas
Ulcerative Colitis Clinical
Autoimmune
Symptoms:
-relapsing attacks of BLOODY mucoid diarrhea with pain
-recurs after asymptomatic interval
-may have an explosive initial attack with serious bleeding to constitute a medical emergency
Complications: primary sclerosing cholangitis, CRC, toxic megacolon, malnutrition
Extraintinal: primary sclerosing cholangitis
What is the gross anatomy of ulcerative colitis?
Inflammation primarily involving the mucosa of the colon
- diffuse continuous inflammation that begins in the rectum and progresses proximally
- pseudopolyps
- loss haustra
Ulcerative colitis histology
Early Phase: neutrophils and crypt abscesses
Later phase: mucosal ulcerates and pseudopolyps form
Late Phase: atrophy and possible dysplasia
-increased risk of colon carcinoma
- NO granulomas
- ONLY in mucosa/submucosa not transmural
