GI goljan small bowel disorders Flashcards
1
Q
Signs and Sx of small bowel disease
A
colicky pain;
diarrhea;
anemia
2
Q
Signs and Sx of large bowel disease
A
diarrhea; dysentery; pain; Tenesmus; Fe deficiency; Hematochezia
3
Q
Define colicky pain associated w/ small bowel disease
A
pain then pain free interval accompanied by constipation & inability to pass gas;
Sx of bowel obstruction from adhesions from previous surgery
4
Q
What is diarrhea a sign of in the small intestine?
A
infection;
malabsorption;
osmotic diarrhea
5
Q
If bloody diarrhea occurs, what is this a sign of in the small intestine
A
infarction;
volvulus;
dysentery
6
Q
Anemia from small intestine may be due to malabsorption of what?
A
iron
folate
vit B12
7
Q
Diarrhea is a sign of what in the large bowel?
A
infection;
laxative abuse;
inflammatory bowel disease
8
Q
If diarrhea is bloody, what is it a sign of in the large bowel?
A
infarction;
dysentery
9
Q
Define dysentery and what is associated
A
bloody diarrhea w/ mucus => infection
10
Q
What are the 5 causes of pain in large bowel disease?
A
inflammatory bowel disease; ischemic colitis; diverticulitis; appendicitis; peritonitis
11
Q
define tenesmus as a sign in large bowel pain
A
painful, ineffective straining at stool => commonly in ulcerative colitis
12
Q
If a patient is iron deficient, what should be considered?
A
polyps;
colorectal cancer
13
Q
Define hematochezia and its causes
A
massive loss of whole blood per rectum
causes: sigmoid diverticulosis (most common); angiodysplasia
14
Q
define diarrhea
A
more than 250g of stool/day;
acute diarrhea=> less than 3wks
chronic diarrhea=> over 4wks
15
Q
What are the 3 types of diarrhea?
A
invasive (inflammatory);
secretory;
osmotic
16
Q
What are important screening tests for diarrhea?
A
fecal smear for leukocytes;
stool osmotic gap
17
Q
How do you calculate stool osmotic gap?
A
300mOsm/kg - 2x(random stool Na+ + random stool K+)
18
Q
what is the stool osmotic gap for secretory diarrhea? what does it indicate?
A
Gap < 50mOsm/kg from POsm => indicates diarrheal fluid approximates POsm
19
Q
What is the stool osmotic gap for osmotic diarrhea?
A
Gap > 100mOsm/kg from POsm => indicates hypotonic loss of stool due to presence of osmotically active substances
20
Q
What is the pathogenesis of lactase deficiency?
A
colon anaerobes degrade undigested lactose into lactic acid and H2 gas leading to abdominal distention w/ explosive diarrhea
21
Q
What diseases are associated w/ malabsorption?
A
Pancreatic insufficiency; Bile salt/acid deficiency; small bowel disease; Celiac disease; Whipple disease
22
Q
Define malabsorption
A
increased fecal excretion of fat w/ concurrent deficiencies of fat-soluble vitamins, minerals, carbs, proteins
23
Q
What is the pathogenesis of malabsorption?
A
pancreatic insufficiency;
bile salt/acid deficiency;
small bowel disease
24
Q
What is pancreatic insufficiency most common cause?
A
chronic pancreatitis due to alcohol in adults and CF in children
25
In pancreatic insufficiency, what leads to maldigestion of fats? how does it present?
diminished lipase activity => presents w/ neutral fats and fat droplets in the stool
26
in pancreatic insufficiency, what leads to maldigestion of proteins? how will it present
due to diminished trypsin => presents w/ undigested meat fibers in stool
27
in pancreatic insufficiency, what alters carb digestion?
carb digestion is NOT affected => amylase is present in salivary glands and disaccharidases present in brush border of intestinal epithelium
28
what are bile salt/acid needed for?
required to micellarize monoglycerides and fatty acids
29
What are the 5 pathogenesis for bile salt/acid deficiency?
inadequate synthesis of bile salts/acids from cholesterol;
intrahepatic/extrahepatic blockage of bile;
bacterial overgrowth in small bowel w/ destruction of bile salts/acids;
excess binding of bile salts;
terminal ileal disease
30
What are examples of intrahepatic/extrahepatic blockage of bile that may lead to bile salt/acid deficiency?
primary biliary cirrhosis;
| stone in common bile duct
31
What are examples of bacterial overgrowth in small bowel that may cause destruction of bile salts/acids?
small bowel diverticula;
| autonomic neuropathy
32
examples of bile salt/acid deficiency due to excess binding of bile salts?
cholestyramine
33
How does terminal ileal disease lead to bile salt/acid deficiency? give examples
prevents recycling of bile salts/acids =>
| ex: Crohn's disease; resection of ileum
34
How does small bowel disease lead to malabsorption?
loss of villi will lead to decreased reabsorption of micelles into enterocytes
35
What is pathogenesis of small bowel disease leading to malabsorption?
inability to reabsorb micelles due to loss of villous surface;
lymphatic obstruction
36
What are examples of diseases associated w/ inability to resorb micelles?
celiac disease;
| Whipple's disease
37
What are examples of lymphatic obstruction assoc w/ malabsorption?
Whipple's disease;
| abetalipoproteinemia
38
What is the best screening for fat malabsorption? how is it done? what is a positive test?
quantitative stool for fat which is a 72hr stool collection;
| positive test > 7g of fat/24hr
39
What is a screening test that indicates small bowel disease? how does it work?
Xylose does NOT require pancreatic enzymes for absorption => lack of reabsorption of orally administered xylose
40
What is a test to evaluate pancreatic insufficiency specifically?
serum immunoreactive trypsin => trypsin specific for pancreas
41
What will decreased trypsin indicate? increased trypsin indicate?
decreased=> chronic pancreatitis
| increased => early CF
42
What will a CT scan showing dystrophic calcification indicate?
chronic pancreatitis
43
What are tests for bacterial overgrowth? best test
C-xylose (best and measures CO2 in breath)
lactulose-H2;
Bile breath test (oral radioactive)
44
Clinical findings in malabsorption?
steatorrhea;
fat-soluble vitamin deficiencies (ADEK)
water-soluble vitamin deficiencies (folate, B12);
folate and iron deficiency anemias
ascites and pitting edema (hypoproteinemia)
45
Define celiac disease
inappropriate immune response to gluten in wheat products => may be related to proteins in rye and barley
46
epidemiology of celiac disease
1% in N. america;
whites >>> blacks, asians;
any age but infancy and 3rd decade assoc w/ pregnancy
47
What is celiac disease associated with?
```
Dermatitis herpetiformis;
AI disease => hashimoto's, primary biliary cirrhosis;
Type I DM;
IgA deficiency;
down syndrome, Turner's syndrome
```
48
Pathogenesis of celiac disease
```
multiorgan autoimmune disease;
inappropriate T cell and IgA mediated response;
timing and dose when gluten introduced in diet;
tissue transglutaminase (tTG) in lamina propria has pivotal role
```
49
How does tTG in lamina propria lead to Celiac disease?
1) deaminates mucosally absorbed gluten to produce deaminated and neg charged gluten peptides
2) enhances immmunostim effect of deaminated gluten peptides
3) peptides phagocytosed by antigen processing cells in lamina propria
4) complex w/ HLA-DQ2 or DQ8 to gluten specific CD4 Th cells
5) CD4 Tcells produce cytokines that release matrix proteases casuing cell death, degradation in epithelial cells in villi
50
What are important diagnostic antibodies for celiac disease?
1) anti-tTG IgA
2) anti-endomysial IgA
3) anti-gliadin IgA
51
clinical findings in celiac disease
```
steatorrhea;
weight loss;
failure to thrive in infants and children;
pallor due to anemia;
dermatitis herpetiformis
```
52
What systemic findings are associated w/ celiac disease?
Bone=> osteoporosis, arthritis
CNS=> seizures, depression
Reproductive=> delayed puberty, miscarriages, infertility
53
What is the relationship of dermatitis herpetiformis in celiac disease?
considered as form of celiac disease w/ villous atrophy in 75% of cases w/ or w/o diarrhea
54
How is celiac disease diagnosed?
anti-tTG; anti-endomysial Ab diagnosed Ab;
| endoscopic biopsy
55
How will an endoscopic biopsy of celiac disease look on histo?
```
flattened villi (especially in duodenum and jejunum;
hyperplastic glands w/ intense lymphocytic inflam
```
56
Tx for celiac disease
gluten free diet;
correct nutritional deficiencies (fat sol vits; folate; vitamin B12; Ca+;
corticosteroid in refractory cases
57
What is epidemiology of Whipple's disease?
men > women;
| middle age;
58
What causes Whipple's disease? how is it ID?
Tropheryma whippelii => PCR
59
how does Whipple's disease view on micro?
blunting of villi;
foamy PAS positive macs in lamina propria;
macs obstruct lymphatics and reabsorption of chylomicrons => malabsorb of fat
60
clinical findings of Whipple's disease
```
steatorrhea;
fever;
recurrent polyarthritis;
generalized LAD;
increased skin pigmentation
```
61
Tx for Whipple's disease
Antibiotics
62
What are diseases of small bowel diverticula?
meckel diverticulum;
| small bowel pulsion diverticula
63
What does Meckel diverticulum arise from?
vitelline (omphalomesenteric) duct remnant;
true diverticulum;
2in long; 2ft from ileocecal valve; 2% pop; 2% Sx
64
What is found in Meckel diverticulum? risks associated?
contains pancreatic rests and heterotopic gastric mucosa => increases risk for bleeding
65
clinical findings in meckel diverticulum
newborn;
bleeding (most common);
diverticulitis
66
What is found in the newborn w/ meckel diverticulum?
fecal material in umbilical area due to persistence of vitelline duct
67
Bleeding in meckel diverticulum is a commonly from what?
iron deficiency in newborns and young children
68
How is meckel diverticulum distinguished from appendicitis?
clinically impossible => Tc99 nuclear scan to identify parietal cells in ectopic gastric mucosa
69
Where is the most common site of small bowel pulsion diverticula? systemic associations?
duodenum;
| wide mouthed diverticula => systemic sclerosis
70
Complications of small bowel pulsion diverticula?
diverticulitis (perforation danger)
| bacterial overgrowth => may produce bile salt and vitB12 deficiencies
71
what are primary malignancies associated w/ small bowel?
primary adenocarcinoma;
carcinoid tumor;
malignant lymphoma
72
Where does primary malignant lymphoma of the small bowel occur? what is its origin?
Peyer's pathches of terminal ileum => usually B cell origin (Burkitt's lymphoma)
73
Where is the common site for primary adenocarcinoma in the small bowel?
duodenum
74
What is the most common small bowel malignancy?
carcinoid tumor
75
What type of tumor is the carcinoid tumor of small bowel?
neuroendocrine tumor
76
What does a carcinoid tumor contain on EM?
neurosecretory granules visible on EM
77
What is the malignancy associated w/ carcinoid tumors?
mets potential correlates w/ size (>2cm) and depth (50% of bowel thickness)
78
Does location alter any mets or invasion threat of carcinoid tumors?
foregut (stomach) and hindgut (rectum) invade but RARELY mets;
midgut (terminal ileum) invade and mets
79
Where are carcinoid tumors of the small bowel located?
```
Vermiform appendix (40%)
small bowel (20%)
```
80
carcinoid tumor of the vermiform appendix mets potential?
usually <2cm that is too small to mets to liver
81
in the small bowel, where do carcinoid tumors present and what is mets potential?
majority in terminal ileum;
| commonly mets to liver
82
What do carcinoid tumors of the small bowel produce?
bioactive compounds (serotonin) to deliver to liver via portal vein
83
What must occur for carcinoid tumors to cause systemic effects of carcinoid syndrome?
liver mets MUST occur to produce syndrome;
serotonin must enter hepatic vein to access systemic circulation;
may occur w/o mets if in bronchus (RARE)
84
How does carcinoid tumor present grossly?
bright yellow tumor
85
clinical findings of carcinoid syndrome
flushing of skin (due to serotonin, histamine);
diarrhea;
intermittent wheezing & dyspnea (bronchospasm);
facial telangectasia;
tricuspid regurgitation and pulmonary stenosis
86
Why is flushing of skin associated w/ carcinoid syndrome?
vasodilation triggered by emotion, alcohol, other foods
87
Why is tricuspid regurgitation and pulm stenosis assoc w/ carcinoid syndrome?
serotonin increases collagen production in valves
88
How is carcinoid syndrome diagnosed?
increased urine 5-HIAA;
CT scan of liver detects mets;
scanning techniques to detect primary location and mets
89
Tx of carcinoid syndrome
avoid alcohol;
surgical resection of primary tumor;
CTX;
somatostatin analogue
90
What does Tx w/ somatostatin analogue do in carcinoid syndrome?
effective in controlling diarrhea and flushing
