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Pathology > Small and Large Intestine > Flashcards

Small and Large Intestine Flashcards

1
Q

Disrupted migration of neural crest cell from cecum to rectum
Distal intestinal segment lacks both Meissner’s submucosal and Auerbach’s myenteric plexus (aganglionosis)

A

Hirschprung’s

Congenital aganglionic megacolon

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2
Q

Gene alteration in Hirschprung’s

Heterozygous loss of function mutations in receptor tyrosine kinase

A

RET accounting for majority of familial cases 15% sporadic

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3
Q

Hirschprung involves the

Dx

A

Rectum
Sigmoid

Absence of ganglion in affected segment

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4
Q

Weakess or defect in wall of peritoneal cavity permiting protrusion of serosa lined pouch of peritoneum

A

Hernia sac

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5
Q

Hernia complications

A

Incarceration entraped

Strangulation infarcted

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6
Q

Mucosal infarct

Hypoperfusion

A

No deeper than muscularis mucosa

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7
Q

Mural infarct

Hypoperfusion

A

Mucosa to submucosa

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8
Q

Transmural infarct is caused by

A

acute vascular obstruction

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9
Q

Atherosclerosis is frequent in origin of

A

mesenteric vessel

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10
Q

Intestinal ischemia pathogenesis (2)

A

1 initial hypoxic - resistant

2 reperfusion - greatest damage (free radical, neutrophil infiltration, inflamm mediator protein and cytokine)

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11
Q

Variables that determine severity of ischemia

A

Severity of vascular compromise
Time frame which it develops
Vessels affected

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12
Q

Watershed zones susceptible to ischemia

A

Splenic flexure (SM And IM termination)
Sigmoid
Rectum (IM, pudendal, iliac)

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13
Q

epithelial atrophy and necrosis is a signature of ischemic intestinal disease bec of the anatomy:

A

intestinal capillary run alongside gland from crypt to surface before making hairpin turn at surface to empty into postcap venule
Allows oxygenated blood to supply
crypts but leaves the epithelium vulnerable to ischemic injury

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14
Q

Transmural ischemia complication

A

coagulative necrosis of muscularis prop 1-4d with purulent serositis and perforation

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15
Q

Involves splanchnic bed
Impaired venous movement impairs entry of oxygenated arterial blood
Less abrupt transition

A

Mesenteric venous thrombosis

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16
Q

Atrophy or sloughing of surface epithelium
Neutrophilic inf if acute
Fibrous scarring of lamina propria if chronic
Stricture
Partially detached villous if acute
Hyperchromatic nuclei of crypt cell

A

Ischemia of intestinal vessel

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17
Q

Ischemic bowel disease occurs in

Sudden severe abd pain, tenderness
nausea vomiting grossly melanotic stool

A

older with coexisting cardiac or vascular disease

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18
Q

May masquerade as inflammatory bowel disease

Episodes of bloody diarrhea with periods of healing

A

Chronic ischemia

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19
Q

Ischemic GI as consequence of viral tropism and infection of endothelial cell
Complication of immunosuppresive therapy

A

CMV infection

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20
Q

GI irradiation
Vascular injury with radiation fibroblast within the stroma
Anorexia, cramps, malabsorptive diarrhea (acute)
Indolent often inflammatory (chronic)

A

Radiation enterocolitis

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21
Q

Transmural necrosis

Most common acquired gastrointestinal emergency of neonates esp premature after initiation of oral feeding

A

NEC

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22
Q

Malformed submucosal and mucosal blood vessel
Most often in the cecum or right colon after 6th decade
20% of major episodes of lower intestinal bleeding
hemorrhage may be chronic and intermittent or acute and massive

A

Angiodysplasia

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23
Q

Vessels within inferior hemorrhoidal plexus below anorectal line

A

External hemorrhoids

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24
Q

Dilation of superior hemorrhoidal plexus within distal rectum

A

internal hemorrhoids

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25
Q

Chronic malabsorptive disorders (3) most common

A

Pancreatic insufficiency
Celiac
Crohn

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26
Q

Important cause of malab and diarrhea following allogeneic hematopoietic stem cell transplantation
Small bowel and colon
secondary to targeting antigen on recipient’s epithelial cells by donor T cell
Epithelial apoptosis of crypt
Watery diarrhea

A

graft-versus-host disease

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27
Q

Inc in stool mass freq fluidity volumes greater than 200ml

A

Diarrhea

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28
Q

Painful bloody small volume diarrhea

A

dysentery

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29
Q

Isotonic stool and persists during fasting

A

Secretory diarrhea

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30
Q

Lactase deficiency due to osmotic forces by unabsorbed luminal solute
Fluid more than 50mOsm more concentrated than plasma
Condition ABATES with fasting

A

Osmotic diarrhea

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31
Q

Inadequate nutrient absorption with steatorrhea and RELIEVED by fasting

A

Malabsorption

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32
Q

Inflammatory disease

Purulent bloody stool CONTINUES during fasting

A

Exudative diarrhea

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33
Q

Four phases of nutrient absorption

A

intraluminal digestion
terminal digestion
transepithelial transport
lymphatic transport

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34
Q

proteins carbohydrates fats broken down into absorbable forms

A

Intraluminal digestion

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35
Q

Hydrolysis of carbohydrates and peptides by disaccharides and peptidase in brush border of small intestinal mucosa

A

terminal digestion

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36
Q

nutrient fluid and electrolytes are transported across and processed within small intestine

A

Transepithelial transport

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37
Q

Absence of CFTRc leading to defect in intestinal and pancreatic Cl ion secretion

A

Cystic fibrosis

Defective luminal hydration
Meconium ileus
Intraductal concretion in pancreas 
Exocrine pancreatic insufficiency 80%
Failure in intraluminal phase

Tx oral enzyme supplement

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38
Q

Immune mediated (innate and immune) enteropathy triggered by ingestion of gluten-containing cereal

A

Celiac sprue

Gluten sensitive enteropathy

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39
Q

Gluten is digested into AA by brushborder enzymes and into a degradation resistant peptide called

A

gliadin

presented to CD4 T cell and CD8 by alleles on APC

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40
Q

Celiac disease is assoc with allelles

A

HLA DQ2
HLA DQ8

Also assoc with type 1 DM, thyroiditis, Sjogren’s

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41
Q

Celiac dse dx

A

Second portion of duodenum and proximal jejunum biopsy with inc no of CD8 T

42
Q

Intraepithelial lymphocytosis CD8 T
crypt hyperplasia
villous atrophy

A

Celiac disease

43
Q

Sensitive nonivasive test for celiac disease

A

IgA antibodies to tissue transglutaminase
IgA or IgG deaminated gliadin

Highly specific: antiendomysial antibody

44
Q

Most common celiac disease assoc cancer

A

Enteropathy assoc T cell lymphoma
aggressive tumor
Small intestinal adenocarcinoma

45
Q

AR, mutation in gene encoding lactase
Rare, explosive diarrhea watery frothy stool and abdominal distention after milk
Abate when milk terminated

A

Congenital lactase deficiency

46
Q

Downregulation of lactase gene expression

Assoc with viral or bacterial infection

A

Acquired lactase

47
Q

AR, inability to secrete TAG rich lipoproteins
Transepithelial transport defect
Lipid defect in plasma resulting in acanthocytic red cell (spur)

A

Abetalipoproteinemia

48
Q

Abetalipoproteinemia results from mutation in

A

microsomal triglyceride transfer protein

49
Q

Chronic nonbloody watery diarrhea without weight loss
Middle aged older women
Dense subepithelial collagen layer
Inc intraepithelium lymph with mixed inflamm infiltrate in lamina propria

A

Collagenous microscopic colitis

50
Q

Chronic nonbloody watery diarrhea without weight loss
Subepithelial collagen is of normal thickness, inc in epithelial lympho greater
Assoc with celiac and autoimmune thyroiditis, arthritis, gastritis

A

Lymphocytic microscopic colitis

51
Q

Loss of brushborder surface area and deficient enterocyte maruration as result of immune mediated epithelial damage

A

Celiac disease

52
Q

Celiac disease and tropical sprue defect in malabsorption

A

Terminal digestion
Terminal transport
Autoimmune enteropathy

53
Q

Chronic pancreatitis
Cystic fibrosis
Primary bile acid malabsorption

A

Intraluminal digestion

Primary bile also transepithelial transport

54
Q

Dissacharide def malabsorption

A

Terminal digestion

55
Q

Whipple disease malabsorption

A

Lymphatic transport

56
Q

Abetalipoproteinemia malabsorption

A

Transepithelial transport

57
Q

Viral gastro
Bacterial gastro
Parasitic gastro

A

Terminal digestion

Transepithelial transport

58
Q

Inflammatory bowel disease

A

Intraluminal digestion
Terminal digestion
Transepithelial transport

59
Q

Cholera toxin enterotoxin delivered via retrograde transport causea secretory diarrhea by

A 
stimulating adenylate cyclase 
inc cAMP
opens CFTR 
releases Cl ions dec Na and bicarb absorption
osmosis of water out to lumen
60
Q

C jejuni virulence

A 
motility - flagella 
adherence - colonization, invasion
toxin production - cholera like enterotoxin 
invasion - dysentery 
Enteric fever - LN prolif
61
Q

C jejuni can result with

A

reactive arthritis in HLA B27

Erythema nodosum
GBS

62
Q

Acute self-limited colitis
Prominent lamina propria intraepithelial neutrophil infiltrate
Cryptitis, crypt abscess

Not distinguised by biopsy

Dx

A 
C jejuni
Shigella 
Salmonella
E coli
Yersinia

Stool culture

63
Q

Less resistant to acidic environment, infective at less than 100,
Shigella is taken up by
Modulating epithelial junctions to expose basolateral bacterial receptor
Injected into host cytoplasm by type III secretion

A

M microfold cell

64
Q

Inhibits eukaryotic protein synthesis and causes host cell death

A

Shiga toxin stx

65
Q

Shigella infection is prominent in the

Pseudomembrane, hemorrhagic ulcerated mucosa

A

left colon
ileum (M cell in Peyer’s)

Initially watery becoming dysenteric
Antidiarrheal meds contraindicated

66
Q

Shigella complication

A

Reactive arthritis
Reiter’s (urethritis and conjunctivitis) HLAB27 +
Also HUS

67
Q

Principal cause of traveller’sc

Express heat labile toxin similar to cholera and heat stable toxin inc cGMP similar to increased cAMP

A

Enterotoxigenic E coli

68
Q

Consumption of inadequately cooked ground beef, milk and vegetable
Produce shiga like toxin causes dysentery
HUS

A

Enterohemorrhagic E coli

69
Q

Do not produce toxin but shigella like
Invade gut epithelium
Dysentery

A

Enteroinvasive E coli

70
Q

Attach by fimbriae

Produce LT and shiga like toxin but min damage

A

Enteroaggregative E coli

71
Q

Salmonella possess virulence genes that encode
capable of transfering bacteria protein to M cell activating Rho GTPases
Also releases eicosanoid drawing neutrophil

A

type III secretion system

72
Q

Enteric fever course

A

Febrile phase
2 week sustained fever with abdominal tenderness mimicking AA, rose spots
Extraintestinal complication: enceph meningitis pneumoniae carditis chole
Sickle cell patients susceptible to osteomyelitis

73
Q

Toxins of this organism cause ribosylation of small GTPases such as Rho leading to disruption of epithelial cytoskeleton and tight junction barrier loss
Formation of pseudomembranous colitis

A

Clostridium difficile

Rf: antibiotic

Neutrophil emanating from crypt - volcanic eruption

74
Q

C difficile dx

A

detection of C difficile toxin and histopath

75
Q

Most common cause of severe childhood diarrhea and death

Minimal effective inoculuM

A

Rotavirus

10 viral

76
Q

Rotavirus selectively infects and destroys mature (absorptive) enterocyte in small intestine and villus surface is repopulated by

A

immature secretory cell

77
Q

Eggs hatch in intestine larvae penetrate mucosa
Migrate via splanchnic circ to liver creating hepatic abscess
Then to lung as pneumonitis
Larva also migrates to trachea and swallowed

A

Ascaris lumbricoides

78
Q

Penetrate unbroken skin
Migrate through lungs to trachea
Autoinfection

A

Strongyloides

79
Q

Hookworm
Larval penetration into skin
Lung development swallowed into duodenum suck blood and cause IDA

A

Necator

Ancylostoma

80
Q

Most common pathogenic parasite in human

A

Giardia

Ingestion of cyst

81
Q

Diverticulosis pathogenesis

A

Elevated intraluminal pressure in sigmoid
Nerves and vasa recta of penetrate muscularis propria creating discontinuities bec of taenia coli
Spasmodic seq of bowel segments

82
Q

Small flask like out pouching in between taenia coli of sigmoid
Surrounded by fat containing epiploic appendices
May infect into diverticulitis and perforate
Low fiber, colonic spasm

A

Diverticulosis

83
Q

Reduced freq of enteric infection due to improved hygiene resulted in inadequate dev of regulatory process limiting mucosal immune responses in early life in IBD

A

hygiene hypothesis

84
Q

IBD results from combination of errant

A

host interaction with intestinal microbiota
intestinal epithelial dysfunction
aberrant mucosal immune response

85
Q

Susceptibility gene in Crohn’s encoding protein that binds to intracellular bacterial peptidoglycan activating NF kappa B
Rendering them less effective to recognize and combat bacteria and trigger inflammation

A

NOD2 nucleotide oligomerization binding domain 2

ATG16L1

IRGM

Monozygotic concordance rate: 50%

86
Q

Inflammatory bowel disease pathogenesis

A

1 genetics
2 mucosal immune response (THI, TH17, IL23, IL13)
3 epithelial defect
4 microbiota

87
Q

Smoking inc risk of

and dec that of

A

Crohn’s disease

Ulcerative colitis

88
Q

Most common sites of Crohn’s

A

terminal ileum
ileocecal valve
cecum

89
Q

Multiple separate sharp delineated areas of skip lesions
Earliest lesion: apthous ulcer becoming serpentine
Sparing of interspersed mucosa become cobblestone
Fissures between folds
Transmural; Fat extending around serosal surface: creeping fat
Distortion of mucosal architecture (ulceration) with crypt abscess (neutrophil)

A

Crohn’s

Intermittent attacks of relatively mild diarrhea, fever, and abdominal pain
RLQ pain 20% mimicking AA
IDA in colonic disease

90
Q

Pseudopyloric metaplasia (gastric antral appearing gland)
Paneth cell metaplasia in left colon (normally absent)
Hallmark: Noncaseating granuloma
Granuloma in mesenteric LN
Cutaneous granuloma nodules misleading: metastatic Crohn disease
Absence of granuloma does not preclude a diagnosis of
IDA may develop

A

Crohn’s disease

Fibrosis of ileum tx with surgery
Recurrence at site of anastomosis
Fistulas, perforation, abscess
Extraintestinal manif: arthritis, sacroilitis, ankylosing spondylitis 
Risk of malignancy
91
Q

Ulcerative colitis involves

A

rectum and extends proximally to involve part of the colon

Skip lesions

92
Q

Mild mucosal inflammation of distal ileum referred as

A

backwash ileitis

93
Q

Slightly red, granular with broad based ulcers
Regenerating islands bulging into lumen termed pseudopolyp
Mucosal atrophy and flat smooth mucosal surface
Absent mural thickening, serosal surface is normal and strictures do not occur

A

Ulcerative colitis

94
Q

Toxic megacolon with risk of perforation
Skip lesions absent and inflammation limited to mucosa and superficial submucosa
Sparing of muscularis propria
Granuloma not present

A

Ulcerative colitis

95
Q

Bloody diarrhea with stringy mucoid material and lower abdominal pain and cramps relieved by defecation
Tx: colectomy

Infectious enteritis precedes onset

A

Ulcerative colitis

96
Q

Clinical overlap of 2 IBD

Small intestine not involved

A

Ideterminate colitis

97
Q

Feared long term complication of IBD

Related to factors

A

Dysplasia

8-10 inc after initiation
Pancolitis greater risk than with left sided disease
Greater freq severity of active inflamm (neutrophil)

Surveillance program 8 years after diagnosis of IBD

98
Q

At time of dx px with this disease is subjected to surveillance bec of significant risk of neoplasia

A

Primary sclerosing cholangitis

Regular extensive mucosal biopsy
Dysplasia in flat areas

99
Q 
Ileum and colon with occasional rectal involvement
Skip lesion
Stricture
Thick bowel wall
Transmural inflamm
Moderate pseudopolyp
Deep knifelike ulcer
Marked lymphoid rx
Marked fibrosis
Marked serositis
Granuloma, fistula and sinus
Perianal fistula in colonic dse
Fat and vitamin malabsorption
Malignant potential only with colonic involvement
Recurrence after surgery
No megacolon
A

Crohn’s disease

100
Q 
Colon only always with rectal involvement
Diffuse distribution
Rare strictures
Thin bowel wall appearance
Limited mucosa and submuc inflamm
Marked pseudopolyp
Superficial, broad based ulcer
Moderate lymphoid
Mild to no fibrosis
No serositis, granuloma, fistula and sinus
No perianal fistula
No fat/vitamin malab
With malignant potential
No recurrence after surgery
With toxic megacolon
A

Ulcerative colitis

Pathology (24 decks)

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