Fecal Analysis

Too little water intake causes ______, while too much water intake causes ______.

constipation, diarrhea

Diarrhea can be defined as an increase in ... of bowel movements.

volume, liquidity, frequency

In the Bristol Stool Scale, diarrhea is defined as types ______.

5-7

Watery diarrhea contains no ...

- WBCs

- Lactoferrin

- Calprotectin

- Blood

- Increased fat

Watery diarrhea is associated with what three types of disorders?

- Functional

- Secretory

- Osmotic

Fatty diarrhea can be due to ______ or ______ of nutrients.

malabsorption, maldigestion

Inflammatory diarrhea has the presence of any of the following ...

- WBCs

- Lactoferrin

- Calprotectin

- Blood

Functional disorders causing watery diarrhea will show improvement at ______ and with ______.

night, fasting

Functional disorders have intestinal ______, causing watery diarrhea.

hypermotility

What are the functional disorders causing watery diarrhea?

- Intestinal distention

- IBS

- RGE

- Fiber, castor oil, emotions, nerves, hormones

Stimulation of intestinal motility by intestinal distention causes a shorter ______ time and therefore buildup of water.

reabsorption

IBS S/Sx

- Muscle sensitivity

- Cramping

- Bloating

- Flatus

- Diarrhea

- Constipation

RGE, rapid gastric emptying causes the ______ to fill up too quickly.

small intestine

Secretory disorders can cause watery diarrhea via ...

- Increased solute secretion

- Reduced water absorption

- High stool volumes

Secretory disorders causing watery diarrhea have persistent S/Sx at ______ and during ______.

night, fasting

What are some enterotoxin-producing organisms which stimulate intestinal secretions?

- Staphylococcus

- E. coli

- Norwalk

- Vibrio

- Salmonella

- Shigella

What are some secretory disorders that cause watery diarrhea?

- Neoplasms

- Crohn's disease

- Gastrectomy, cholecystectomy

- Bile acid malabsorption

Osmotic disorders cause there to be increased amounts of ______ in the intestinal lumen, and therefore an increase in water within the colon.

osmotically active solutes

What are some osmotic disorders causing watery diarrhea?

- Increased retention of water and electrolytes

- Carbohydrate malabsorption (lactose, fructose)

- Laxatives

- Antacids

- Excess sugar alcohols

- Celiac disease

Fatty diarrhea due to malabsorption can be caused by ...

- Loss of surface area

- Impaired circulation

- Impaired lymphatic drainage

- Mucosal infiltration

- genetic mutations

- Impaired motility

- Gastric bypass

Fatty diarrhea due to maldigestion can be caused by ...

- Loss of regulated gastric emptying

- Insufficient pancreatic exocrine function

- Liver or biliary tract disease

Steatorrhea is an increase in stool fat over ______ grams/day.

7

What are the S/Sx of malabsorption or maldigestion?

- Weight loss/failure to thrive

- Edema

- Anemia

- Peripheral neuropathy

- Easy bruising

- Rickets, pathological fractures

- Mental changes

- Impaired night vision

Steatorrhea due to maldigestion can be due to a lack of ______ or an increase in ______.

pancreatic enzymes, neutral fats (not broken down)

Steatorrhea due to malabsorption disorder is caused by an increase in ______.

total fat (fatty acids and salts)

Normal fecal fat level

<100 globules

Bacterial Overgrowth Syndrome is increased bacteria or yeast in the ______.

small intestine

Bacterial Overgrowth Syndrome causes ______.

malabsorption

What are some other causes of malabsorption?

- Parasites

- Viral infections

Inflammatory diarrhea looks ______.

bloody/purulent

Causes of inflammatory diarrhea

- Colorectal cancer

- IBS

- Invasive bacterial or parasitic infection

- C. diff

- Radiation colitis

Stool specimens cannot touch the ______ during collection due to contamination.

toilet bowl/water

The hypochlorites in cleaners often found in the toilet bowls cause a false positive ______ result.

occult blood

Normal stool is brown due to the oxidation of ______ to ______.

stercobilinogen, urobilin

Acholic stools appear ...

Pale, gray, clay-colored, pale yellow/white

Acholic stool is caused by ______ or ______.

post hepatic obstruction, barium

Melena is ______ stools, indicative of large amounts of ______ in the feces.

black, blood

What are some other causes of black stool?

- Charcoal tablets

- Iron therapy

- Pepto-Bismol

Green stool can be caused by ...

- Vegetables

- Biliverdin (antibiotic therapy)

- Food dyes

Red stool indicates ...

- Lower GI bleed (hemorrhoids)

- Beets

- Food dyes

Frothy stool indicates ______.

steatorrhea

Ribbon-like stool indicates ______.

intestinal constriction

Greasy or spongy stool can be caused by ...

- Increased gas

- Steatorrhea

- Constipation

Mucus in the stool is caused by ...

- Constipation

- Malignancy

- Colitis, diverticulitis

- Bacterial or parasitic infection

Normally, there are no ______ in the stool.

leukocytes

Increased neutrophils in the stool is caused by ...

- Ulcerative colitis

- Bacillary dysentery

- Infection

- Abscesses, fistulas

Wet preps of stool use ______ stain, while fixed stool is stained with ______ stain.

methylene blue, Gram/Wright

Undigested striated muscle fibers in the stool indicate ______.

pancreatic insufficiency (CF)

Fecal blood indications

- Colorectal cancer

- Esophageal varices

- Ulcers

- Hemorrhoids

- Drugs (aspirin, iron supplements)

Fecal occult blood relies on ______, which is the least sensitive to reduce false positives.

Guaiac

What are some causes of false positives for occult blood testing?

- Improper collection

- Menstruation

- Hemorrhoidal bleeding

- Myoglobin and hemoglobin in meats and fish

- Peroxidases from intestinal bacteria

- Drugs

- Hypochlorite

What are some causes of false negatives for occult blood testing?

- Ascorbic acid (antioxidants, reducers)

- Outdated or bad reagents

For a quantitative fecal fat test, over 7g of fat in 24 hours suggests ______.

malabsorption

______ stain is used to count the number of fat globules in stool.

Sudan III/IV

Normal fat amounts in stool

- <60 neutral fat globules

- <100 fatty acid fat globules

A fat retention coefficient is used for children who cannot ingest ______g/day of fat.

100

APT is used to detect ______ in feces.

fetal hemoglobin

APT is important in differentiating ______ blood vs ______ blood in feces.

fetal, maternal

For the APT test, a ______ color is positive for fetal blood.

pink

Kleihauer Betke quantitatively measures ______ in maternal blood.

HgF

Fecal carbohydrate tests

- pH

- Clinitest

- Oral tolerance tests to specific sugars

Fermentation of carbs causes fecal pH to drop from 7-7.5 (adult) to ______.

5-6

Clinitest detects ______.

reducing sugars

Clinitest values

Normal = <0.25g/dL

Abnormal = 0.25-0.5g/dL

Carbohydrate intolerance = >0.5g/dL

What are some fecal carbohydrate problems?

- Lactase deficiency

- Celiac disease

- Tropical sprue

- Oral neomycin, kanamycin

- Lactose intolerance

- Xylose

What are the fecal enzymes detected to diagnose decreased pancreas function and CF?

- Trypsin and chymotrypsin

- Elastase-1

Trypsin is degraded in the ______, and therefore not a great diagnostic marker.

distal small bowel

Stool chymotrypsin levels of ______U/g suggest advanced chronic pancreatitis.

<3

Elastase-1 levels of ______mcg/g stool indicate severe insufficiency.

<100

Elastase-1 levels of ______mcg/g stool is normal.

>200

Serum trypsin levels for pancreatic function

<20ng/mL = Chronic pancreatitis (advanced)

>150ng/mL = Pancreatic inflammation

Fecal osmotic gap equation

Osmotic gap = 290 - [2(fecal Na + fecal K)]

Osmotic gap levels

Normal = <125 mOsm/kg

Osmotic diarrhea >100 mOsm/kg

Secretory diarrhea <50mOsm/kg

Chronic diarrhea causes

- IBS

- IBD

- Celiac

What are some S/Sx that raise alarms and warrant further stool tests?

- Anemia

- Unintentional weight loss

- Persistent blood in stool

Functional IBS S/Sx

- Abdominal pain

- Constipation or diarrhea

- Occurs at least 1 day/week over the past 3 months

- Watery diarrhea while awake, often after meals

- Defecation relieves pain

- Worsened with stress or eating

Functional diarrhea (not IBS) S/Sx

- Diarrhea for >25% of stools

- No abdominal pain or bloating

IBD S/Sx

- Blood and pus in stool

- Fever

- Weight loss

- Fatigue

- Skin and joint symptoms

- Family history

- Anal fissures

- Rectal ulcerations

______ test is used to screen for fecal leukocyte activity related to IBD.

Fecal calprotectin

A positive fecal calprotectin result causes a follow up ______ to be done.

colonoscopy

Celiac disease S/Sx

- Malabsorption of gluten/wheat in small intestine

- Chronic diarrhea

- Fatigue

- IDA

- Weight loss