Diseases of Lower GI (SI/colon) Flashcards
1
Q
Celiac disease aka…
A
Gluten-Sensitive enteropathy
2
Q
Celiac disease pathogenesis
A
gluten digested by luminal/brush border enzymes – exposure to alpha-gliaden peptide leads to autoAb formation –> inflammation(increased T lymphs) –> villous atrophy –> tissue damage –> loss of mucosal/brush border surface area –> malabsorption, diarrhea
3
Q
Clinical features of celiac dz
A
- Classical: bulky fat diarrhea, flatulence, weight loss, anemia, nutritional deficiencies, growth failure in kids
- atypical: minor GI complaints, anemia, dental enamel defects, infertility, arthritis
4
Q
Host factors for celiac dz
A
Class II HLA-DQ2 or HLA-DQ8 allele; northern european
- association w/other autoimmune dz: type I DM, thyroiditis, Sjogren syndrome
5
Q
Celiac dz diagnosis
A
- probs serology first
- Endoscopy–loss of surface villi
- Serology: IgA Ab to tissue transglutaminase; auto-endomysial Ab
**may have false negative if IgA deficiency
6
Q
Celiac dz biopsy findings
A
- *3 characteristic findings
- villous blunting
- increased intraepithelial lymphocytes – percolating in epithelium
- lymphoplasmacytosis of lamina propria (lamina propria expanded)
7
Q
Does histologic severity correlate with symptoms?
A
not always
8
Q
Endoscopy buzz word for celiac disease
A
“scalloped”, cracked mud appearance
9
Q
Pathogenesis of Whipple dz
A
caused by gram + intracellular bacilli (Tryopheryma whippelii) taken up by macrophages in lamina propria that then obstruct lymphatics –> malabsorptive diarrhea
10
Q
Triad of Whipple dz
A
diarrhea, weight loss, malabsorption
11
Q
Typical presentation of whipple dz
A
middle-aged or elderly white male
12
Q
Diagnosis of Whipple dz
A
tissue biopsy shows organisms (see swollen macrophages)
13
Q
Infectious enterocoliitis Giardiasis cause
A
protozoan parasite Giardia
- causes sporadic/epidemic diarrhea
- waterborne (especially in US)/foodborne
14
Q
incubation pd for giardia
A
7-14 days
15
Q
symptoms of Giardiasis
A
chronic watery diarrhea, malabsorption, flatulence, weight loss, may cause intermittent symptoms
16
Q
can chlorine kill giardia
A
cysts resistant – need filter
17
Q
Pseudomembranous colitis cause
A
most often from C difficile after antibiotics (third gen cephalosporins)
18
Q
cause of most self-limited food borne/waterborne illness
A
viral
19
Q
Important Extraintestinal manifestation in ulcerative colitis
A
Primary sclerosing manifestations
20
Q
Celiac extra-intestinal complaints
A
- fatigue, Fe deficiency anemia, short stature, pubertal delay, aphthous stomatitis
- dermatitis herpetiformis (blistering skin dz)
- lymphocytic gastritis/colitis
21
Q
celiac-associated malignancies
A
- enteropathy associated T-cell lymphoma (EAT lymphoma)
- small intestinal adenocarcinoma
22
Q
other common sxs in Whipple dz
A
arthritis, lymphadenopathy, neurologic disease
23
Q
teardrop shaped organism with sucker
A
Giardia
24
Q
“schools of fish”
A
Giardia
25
where in GI is Giardia most often found
duodenum
26
2 main classes of colitis
infectious causes, noninfectious
27
Infectious causes of colitis
bacterial enterocolitis, pseudomembranous colitis, viral gastroenteritis, parasitic enterocolitis
28
causes of noninfectious colitis
microscopic colitis, ischemic colitis
29
Bacterial infectious enterocolitis
mostly related to contaminated water/food, foreign travel
- typically acute, self-limited colitis
- typically present several weeks after sxs onset
30
types of infectious bacterial enterocolitis
Cholera, campylobecter jejuni, shigellosis, salmonellosis, Enteric (typhoid) fever, Yersinia spp., E coli, mycobacterial infection
31
Campylobacter spp
- major cause of worldwide diarrhea
- gram (-)
- leading cause of foodborne illness in US
32
campylobacter species commonly associated with food-borne bastroenteritis
C. jejuni
33
infection more often seen in immunosuppressed pts
Campylobacter fetus
34
sxs of Campylobacter infection
watery diarrhea +/- blood
35
source of Campylobacter spp
contaminated meat (poultry), water, unpasteurized dairy
36
Infectious Salmonella enterocolitis
Gram (-) bacillus, important cause of food poisoning/traveler's diarrhea
37
Salmonella transmission
food water
38
Sxs of non-typhoid salmonella species
mild, self-limiting gastroenteritis
| - endoscopy: mucosal redness, ulceration, exudates
39
E coli Enterocolitis species
```
Enterotoxigenic
Enteropathic
Enteroinvasive
Enterohemorrhagic (0157H7)
Enteroadherent
```
40
Enterohemorrhagic E coli
(O157H7)=most common strain
- non-invasive, toxin-producing, contaminated hamburgers
- deadly outbreaks
41
E coli O157H7 sxs
- according to infectious diarrhea lecture, it can be variable from asymptomatic to extreme
- this lecture: bloody diarrhea, severe cramps, mild or no fever, sometimes renal failure (HUS)
42
E coli O157H7 on endoscopy
edema, erosions, ulcers, hemorrhage (right colon mostly)
43
E coli with nonbloody diarrhea
- Enterotoxigenic, enteropathic, enteroinvasive, enteroadherent
44
Major cause of traveler's diarrhea
Enterotoxigenic E coli
45
infection in infants/neonates
Enteropathogenic E coli
46
Invasive e coli similar to shigella
Enteroinvasive
- non-bloody diarrhea, dysentery-like illness, bacteremia
- cause of traveler's diarrhea
47
Transmitted via contaminated cheese, water, person-person contact
Enteroinvasive e coli
48
Non-invasive, nonbloody diarrhea
enteroadherent e coli
49
forms coating of adherent bacteria on surface epithelium of enterocytes
Enteroadherent e coli
50
chronic diarrhea and wasting in AIDS
enteroadherent e coli
51
similar to enteropathogenic e coli
enteroadherent e coli
52
antibiotic-associated colitis
pseudomembranous colitis; often after antibiotic therapy
53
most common cause of pseudomembranous colitis
C. difficile
54
antibiotics most commonly causing pseudomembranous colitis
third generation cephalosporins (clindamycin)
55
Pseudomembranous colitis commonly found where
in hospitalized pts (up to 30%)
56
sxs of pseudomembranous colitis
fever, leukocytosis, abdominal pain, cramps, watery diarrhea (can have bloody)
57
pathogenesis of pseudomembranous colitis
disrupted bacterial microbiota in intestine by antibiotics allows C diff overgrowth --> toxin release disrupts epithelium cytoskeleton, Tight junction barrier loss, cytokine release, and apoptosis
58
Pseudomembranous colitis histology
pseudomembranes (adherent layer of inflammatory cells and mucinous debris at sites of colonic mucosal injury)
- surface epithelium denuded, mucopurulent exudates
59
What is pseudomembrane
"volcano-like" eruption of neutrophils/mucinous debris attached to surface epithelium
60
Infectious enterocolitis - viral causes
Cytomegalovirus, Herpes, Enteric Viruses (Rotavirus)
61
most common cause of severe diarrhea as child/diarrheal mortality worldwide
rotavirus
62
population most vulnerable to rotvirus
children 6-24 months
63
location of CMV enterocolitis
mouth - anus
64
location of herpesvirus enterocolitis
esophagus, anorectum
65
pathogenesis of rotavirus
infects/destroysmature enterocytes --> villus surface repopulated by immature secretory cells --> lose absorptive function --> net secreiton of water/electrolytes --> osmotic diarrhea -->DEHYDRATION
66
how to avoid rotavirus infection
VACCINATE
67
Parasitic causes of infectious Enterocolitis
protozoa, esp Entamoeba histolyktica
68
diagnosis of protozoal infections
examine stool
69
prevalent pathogens in tropic/subtropic areas
protozoa
70
how common is E. histolytica
10% of world's population infected
71
sxs of E. histolytica
severe dysentery-like fulminant colitis; can disseminate to other sites (liver)
72
If you have E. histolytica infection, where else an it disseminate beyond GI
Liver
73
Area most commonly affected by E. histolytica
cecum
74
what might you see on mucosa of E histolytica infections
"flask-shaped" ulcers in mucosa (thicker bottom part with thinner "neck" )
75
Other parasite causing enterocolitis besides E. histolytica
Helminth infections
76
diagnose helminth infection
examine stool for ova/parasites
77
what types of places have prevalent heliminth infections
places with deficient sanitation, poor SEC and hot, humid climate
78
side effect of helminth infection
nutritional problems can be severe or life-threatening, esp in children
79
common helminth
Ascaris lumbricoides (roundworm)--
80
where are Ascaris most commony ound
tropics
81
one of most common parasites in humans
Ascaris lumbricoides (roundworm)
82
transmission of Ascaris
ingested from soil contaminated with feces
83
complications of ascaris infection
obstruction, perforation, growth retardation
84
Ischemic colitis
lack of blood flow due to low cardiac output or occlusive disease of vascular supply to bowel
85
Who are more likely to have ischemic colitis
older individuals with co-existing cardiac or vascular disease(however I think most don't have preexisting issue?)
- Young patients: long distance runners, women on oral contraceptives
- Mechanical obstruction: hernia, volvulus
86
Clinical presentation of ischemic colitis
- acute transmural infarction: severe abdominal pain, tenderness, N/V, bloody diarrhea, blood instool
- Peristaltic sounds disappear, rigid abdomen shock, sepsis
87
histology of ischemic colitis
varies from focal acute mucosal necrosis to full thickness necrosis
88
watershed areas
splenic flexure and sigmoid colon
89
what might early ischemic colitis look grossly
small red dots scattered on surface
90
what does regeneration in ischemic colitis look like
Yes; fibrosis, withered, atrohpic crypts
91
microscopic colitis
chronic, nonbloody watery diarrhea without weight loss
92
biopsy appearance of microscopic colitis
mucosal inflammation
93
2 types of microscopic colitis
collagenous colitis, lymphocytic colitis
94
microscopic colitis presents mostly in what population
middle aged and older women; NSAID implicated
95
Diagnosis of microscopic colitis
endoscopy will appear normal so have to do biopsy
| - biopsy shows lymphocytic inflammation (intraepithelial lymphocytes) +/- thickened subepithelial collagen layer
96
lymphocytic colitis shows strong association with what disease
celiac disease, lymphocytic gastritis, and other autoimmune diseases
97
IBD
chronic condition from inappropriate mucosal immune activation
98
2 disorders of IBD
Crohn's and Ulccerative colitis
99
Cause of colitis
- host interactions with intestinal microbiota
- intestinal epithelial dysfunciton
- aberrant mucosal immune responses
100
Mucosal immune response in IBD
T-cell mediated
- Crohns = TH1 type
- UC = TH2 type
- have dysregulation of immunoregulation: pro and anti-inflammatory cytokines
101
Epithelial defects in IBD
defects in of tight junction barrier function,
- Crohns: NOD2 polymorphisms
- UC: ECM2 polymorphisms
102
Crohn's Genetics
NOD2 (chr 16), IBD5 (chr 5), IL23R (chr 1)
103
Genetics of UC
HLA-A11, HLA-A7,
| - HLA-DR2 (Japanese), DRB*103, DRB*12 (Western)
104
Bacteria in IBD?
recent studies indicate antibiotics reduce severity of disease, although specific org not identified
105
Characteristics of Crohn's
Skip lesions, Ileal involvement, transmural chronic inflammation, inflammatory strictures, fissuring ulcers, sinus tracts, fistulae
106
Clinical features in Crohn's
intermittent attacks of relatively mild diarrhea, fever, abdominal pain
- diarrhea tends to be non-bloody
- relapsing/remitting disease
107
Extraintestinal Crohn's features
Uveitis, migratory polyarthritis, sacroiliitis, ankylosing spondylitis, erythemia nodosum
108
Crohn's gives increased risk of what
colonic adenocarcinoma
109
Ulcerative Colitis sxs
Bloody diarrhea or loose stools with lower abdominal pain, cramps
- sxs relieved by defecation
110
Ulcerative colitis extraintestinal manifestations
Primary sclerosing cholangitis
111
UC has increased risk of
colonic adenocarcinoma
112
Characteristics of UC
rectal involvement with retrograde continuous diffuse disease, no ileal involvement (except with "backwash ileitis"), disease worse distally, Mucosal inflammation not transmural, no fissures, sinuses, fistula tracts
113
Cancer risk in IBD
adenocarcinoma risk similar in UC/Crohn's
114
cancer risk in IBD related to
duration of dz, extent of disease (pancolitis vs localized), fam hx, extra-intestinal manifestations (i.e. pSC)
115
Endoscopic surveillance for IBD
assess disease activity and dysplasia, that can become adenocarcinoma
116
Wall appearance in Crohn's vs UC
```
Crohn's = thickened
UC= thinned
```
117
Ulcers in Crohn's vs UC
```
Crohn's = deep, knife-like
UC = superficial, broad based
```
118
pseudopolyps in CD vs UC
CD: moderate
UC: marked
119
Granulomas in IBD
Crohn's - 35%
| UC - no
120
fibrosis in UC vs CD
CD: marked
UC: mild to none
121
serositis in CD vs UC
CD: marked
UC: mild to none
122
Diverticulum
outpouching/herniation of mucosa and submucosa
123
pathogenesis of diverticulum
decreased dietary fiber --> decreased stool bulk --> elevated intraluminal pressure --> mucosal herniation through focal defects in the bowel wall
124
most common place fo diverticula
sigmoid colon
125
prevalence of diverticula
approaches 60% in adult populations over 60
126
sxs of diverticula
asymptomatic or intermittent cramping, lower abdominal discomfort
127
diverticulosis
presence of diverticula
128
diverticulitis
inflammation of diverticula, usually secondary to obstruction
129
diverticulosis microscopic findings
diverticular oupouching lined by mucosa, submucosa, and variable amounts of muscularis propria
- compressed/flattened mucosa
130
diverticulitis microscopic findings
diverticulum becomes infiltrated with acute, then chronic inflammatory cells
- as inflammation extends, mucosa ulferates and pericolonic abscesses or sometimes fistula form
131
diverticula complicaitons
obstruction, perforation, abscess, bleeding
132
appendix
small outpouching at end of ileium
| - "true diverticulum of colon"
133
Appendicitis pathogenesis
luminal obstruction by stone-like mass of stool "fecalith" --> ischemic injury and stasis of luminal contents --> inflammatory response
134
Microscopic findings of appendicitis
mucosal ulceration, transmural acute and chronic inflammation, extension of inflammation into mesoappendix (mesentery connecting ileum to appendix)
135
lifetime risk of appendicitis
7%
136
Appendicitis more common in males or females
M>F
137
Population most commonly affected by appendicitis
adolescents nad young adults
138
classic appendicitis findings
McBurney's sign (tenderness 2/3 of distance from umbilicus to right anterior superior iliac spine)
139
appendicitis treatment
appendectomy; often laparoscopic
140
how does appendicitis often present
acute abdomen (distended)
141
acute abdomen
sudden onset of severe abdominal pain -- etiology unknown
