AUBF 4TH LE REVIEWER

small intestine

primary site for the final breakdown and reabsorption

pancreas

organ which secretes digestive enzymes such as trypsin, chymotripsin, amino peptidase, and lipase into the small intestine

liver

organ which produces bile salts which aids in the digestion of fats

500-1500ml

amount of fluid that reaches the large intestine

150ml

amount of fluid excreted in feces

3000ml

maximum amount of water the large intestine is capable of absorbing

100-200g

normal daily stool weight

bacterial metabolism

produces the strong odor associated with feces and intestinal gas

-daily stool weight >200g

-increased liquidity in stools

-frequency >3/day

a patient is said to have diarrhea if one of these 3 parameters is present

-duration

-mechanism

-severity

-stool characteristics

diarrhea classification is based on

acute diarrhea duration

>4 weeks

chronic diarrhea duration

fecal electrolytes (Na & K)

differential lab test for secretory diarrhea

fecal osmolality

differential lab test for osmotic diarrhea

fecal pH

differential lab test for intestinal hypermotility

290mOsm/kg

normal fecal osmolality

30mmol/l

normal fecal Na

75mmol/l

normal fecal K

secretory diarrhea

diarrhea characterized by decreased osmolality, increased water secretion, and increased electrolytes

osmotic diarrhea

diarrhea characterized by increased osmolality, increased water secretion, and decreased electrolytes

secretory diarrhea

diarrhea characterized by >90mmol/l fecal Na

secretory diarrhea

diarrhea characterized by >200g daily stool weight

secretory diarrhea

diarrhea characterized by >5.6 stool pH

secretory diarrhea

diarrhea that tests negative for reducing substances

osmotic diarrhea

diarrhea that tests positive for reducing substances

osmotic diarrhea

diarrhea characterized by

osmotic diarrhea

diarrhea characterized by

osmotic diarrhea

diarrhea characterized by >5.6 stool pH

bacterial, viral, and protozoan infections, enterotoxin producing organisms

possible causes for the increased water and electrolyte secretion in secretory diarrhea

campylobacter

clostridium

cryptosporidium

E. coli

protozoa

salmonella

shigella

staphylococcus

vibrio cholerae

enterotoxin producing organisms

collagen vascular disease

drugs

endocrine disorders

hormones

inflammatory bowel disease

neoplasms

stimulant laxatives

other causes of secretory diarrhea

osmotic diarrhea

diarrhea caused by poor absorption that exerts osmotic pressure across the intestinal mucosa

osmotic diarrhea

diarrhea caused by maldigestion/malabsorption

malabsorption of sugars

amebiasis

antibiotic administration

disaccharidase deficiency (lactose intolerance)

laxatives

malabsorption (celiac sprue)

magnesium containing antacids

poorly absorbed sugars

causes of osmotic diarrhea

clinitest

d-xylose tolerance test

fecal electrolytes

fecal osmolality

lactose tolerance test

microscopic fecal fats

muscle fiber detection

qualitative fecal fats

quantitative fecal fats

stool pH

trypsin screening

common fecal tests for osmotic diarrhea

fecal leukocytes

ova and parasite examinations

rotavirus immunoassay

stool cultures

common fecal tests for secretory diarrhea

intestinal hypermotility

the excessive movement of intestinal contents through the GI tract

irritable bowel syndrom

hypermotility and constipation can be seen in what condition

irritable bowel syndrome

a function disorder in which the nerves and muscles of the bowel are extra sensitive

bloating

cramping

flatus

constipation

diarrhea

symptoms of irritable bowel syndrome

chemicals

emotional stress

exercise

food

triggers for irritable bowel syndrome

enteritis

parasympathetic drugs

complications of malabsorption

intestinal hypermotility may be caused by

rapid gastric emptying (dumping syndrome)

describes hypermotility of the stomach and the shortened gastric emptying half-time

rapid gastric emptying (dumping syndrome)

condition which causes the small intestine to fill too quickly with undigested food from the stomach

early dumping syndrome

rapid gastric emptying is a hallmark of what condition

35-100 minutes

normal gastric emptying half-time

gastric emptying half-time of patients with rapid gastric emptying syndrome

pancreatic insufficiency and small-bowel disorders that cause malabsorption

detection of steatorrhea is helpful in the diagnosis of what conditions

>6g/day

amount of stool fat in steatorrheic patients

bile salts

absence of this substance causes the reabsorption of dietary fat leading to steatorrhea

TRUE: it may be caused by cystic fibrosis, chronic pancreatitis, and carcinoma

TRUE/FALSE: steatorrhea may also be caused by pancreatic disorders

FALSE: steatorrhea is present in both malabsorption and maldigestion

TRUE/FALSE: steatorrhea is only present in malabsorption, and not in maldigestion

d-xylose test

steatorrhea caused by malabsorption or maldigestion may be differentiated by what test

low

urine d-xylose result in malabsorption

high

urine d-xylose result in pancreatitis

FALSE

TRUE/FALSE: containers for ova and parasites are multipurpose and may be used for other tests

random specimen

specimen suitable for qualitative testing for blood and microscopic examination for leukocytes, muscle fibers, and fecal fats

plastic or glass containers with screw caps

random specimens are collected in what container

timed specimen

specimen for quantitative testing

3-day collection

most representative sample for quantitative testing

brown stool

stool color associated with intestinal oxidation of stercobilinogen to urobilin

oxidation of stercobilinogen to urobilin

brown color of stool is caused by what

pale yellow, white, grey (alcoholic) stool

stool color associated with bile-duct obstruction

green stool

stool color associated with patients taking oral antibiotics

pale yellow, white, grey (alcoholic) stool

stool color associated with barium sulfate

green stool

stool color associated with the oxidation of bilirubin to biliverdin

green stool

stool color associated with green vegetables/food coloring

3 days

blood from the upper GIT (esophagus, stomach, duodenum) takes how long to appear in stool

black, tarry stool

stool color associated with degradation of hemoglobin

black, tarry stool

stool color associated with upper GIT bleeding

black, tarry stool

stool color associated with iron, charcoal, bismuth ingestion

red stool

stool color associated with lower GIT bleeding

red stool

stool color associated with beets

red stool

stool color associated with rifampin

constipation

small, hard stools is indicative of

intestinal obstruction

slender, ribbon-like stools is indicative of

biliary obstruction and steatorrhea

bulky and frothy (pale stools) with foul odor is indicative of

intestinal wall damage (amebic dysentery or malignancy)

colitis

constipation

stool with mucus or blood streaked mucus is indicative of

intestinal inflammation or irritation

mucus coated stools are indicative of

pathologic colitis

crohn's disease

colon tumors

excessive straining during elimination

mucus coated stools may be caused by

leukocytes

undigested muscle fibers (cross-striated)

fecal fats

what is observed in the microscopic examination of stool

ulcerative colitis and bacterial dysentery

fecal leukocytes ie. neutrophils are associated with what conditions

diarrhea caused by invasive bacterial pathogens

campylobacter

enteroinvasive E.coli

salmonella

shigella

yersinia

conditions in which neutrophils are observed in stool

diarrhea caused by toxin production

staphylococcus aureus

vibrio spp.

viruses

parasites

conditions in which neutrophils are absent in stool

methylene blue

stain used for wet preparations for stool

gram/wright stain

stain used for dry preparations for stool

methylene blue

stain used for stool that is faster but more difficult to interpret

gram/wright stain

stain used for stool that provides permanent slides

TRUE

TRUE/FALSE: all slide preparations for stool must be prepared with fresh specimens

>=3

MICROSCOPIC EXAMINATION OF STOOL: amount of neutrophils/hpf indicaive of invasive condition

lactoferrin latex agglutination test

test for detection of fecal leukocytes

TRUE

TRUE/FALSE: lactoferrin latex agglutination test remains sensitive in refrigerated and frozen specimens

lactoferrin, a component of granulocyte secondary granules

leukocyte component that indicates the presence of an invasive bacterial pathogen in lactoferrin latex agglutination test

pancreatic insufficiency (ie. cystic fibrosis)

microscopic examination for muscle fibers in stool is helpful in diagnosing what condition

biliary obstruction

gastrocolic fistulas

an increase of striated muscle fibers in stool can be seen in what conditions

10% alcoholic eosin

for the examination of muscle fibers, stools are immersed in what solution

enhances the muscle fiber striations

effects of 10% alcoholic eosin on stool

>10

amount of undigested muscle fibers reported as increased

include red meat in diet, 24 hours before examination

patient preparation for examination of muscle fibers in stool