CLINMIC LEC SWEAT AND STOOL

Cystic fibrosis

Sweat is usually performed for the diagnosis of:

Sodium

Chloride

Sweat of cystic fibrosis patients are rich in:

Pilocarpine

Alkaloid that promotes sweating which possesses strong sialogigic and diaphoretic properties

Sweat glands are stimulated to sweat profusely

Sample is either collected on preweighed cause or filter paper as above and analyzed for chloride or it can be measured directly on skin using chloride specific electrode

10-40 mEq/L

Normal levels of sweat chloride in children

60 mEq/L

Indicative of cystic fibrosis

Chloride

Pilocarpine iontophoresis measures what analyte of sweat?

Increased

Cystic fibrosis affects exocrine glands that causes to have sticky sweat.

In this case, chloride is (increased/decreased)

P. aeruginosa

Most common cause of RI in px with cystic fibrosis

P. aeruginosa

Burkholderia cepacia

Staph aureus

Haemophilus influenzae

Px with cystic fibrosis are prone to infections with the following organisms: (PBSH)

¾ water

Feces is composed of ______ water

Gram negative anaerobic bacteria

Common bacteria in GIT

Small intestine

Where the final breakdown and reabsorption of ingested proteins, carbohydrates and fats take place under the influence of digestive enzymes and bile salts

Pancreas

Digestive enzymes are produced by what organ?

Trypsin

Amylase

Lipase

3 enzymes that are responsible for digesting most of the food from the diet

Bile salts

Produced by the liver, sent into the duodenum via bile duct

Needed by Lipase

Emulsifier to promote digestion of fat

Large intestine

capable of reabsorption up to 3000mL or 3L of water

Diarrhea

Occurs when less water is reabsorbed by large intestine

Constipation

occurs when fecal material stays a long time in the large intestine providing time for additional water to be reabsorbed

3-day stool collection or timed collection

Spx collection for quantitative testing

Cammidge method

Diaper scraping method

Jallife method

Insertion of thick walled glass in rectum

used for px that have difficulties to defecate (mga na budlayan mag poopy)

Large intestines

What part of the GIT is no longer capable of digesting?

Water and cellulose

These 2 forms the bulk of the stool

Stool would be acidic, urine would be alkaline

In a protein rich diet, the stool would be (acidic/alkaline) and the urine would be (acidic/alkaline)

Stercobilin

Urobilin

Gives stool its normal color (2)

Pale

VARIATIONS IN STOOL COLOR

• Signify blockage of bile duct

• Use of barium sulfate

Black and tarry

VARIATIONS IN STOOL COLOR

• Upper GI tract bleeding

• Takes 3 days to appear in stool (Hgb degradation)

• Ingestion of iron, charcoal, and bismuth

• Most clinically significant color

Acholic stool

Associated with bile duct obstruction

Bright red

VARIATIONS IN STOOL COLOR

• Lower GI tract bleeding (colon or rectum)

• Rifampin (anti-TB drug)

• Beets (genetically predisposed)

Green

VARIATIONS IN STOOL COLOR

• Seen in patients taking oral antibiotics

• Biliverdin increased

• Green veg and food coloring

Yellow

VARIATIONS IN STOOL COLOR

• Milk dirt

• Corn meal

• Rhubarb

• Fats

Bristol’s chart

drawing ka buli search sa net

3 and 4

What number on the Bristol’s chart is considered normal?

Pea soup stool

Typhoid fever stool

Rice water stool

Cholera stool

Noodle-like stools

Stool consistency associated with cancer

Soft to well-formed

Normal consistency of stool

Constipation

STOOL APPEARANCES

• Small and hard/Goat droppings

Slender and flattened/Ribbon-like

STOOL APPEARANCES

• Intestinal constriction, malignancy

Bulky, frothy, greasy and may float

STOOL APPEARANCES

• Steatorrhea and biliary obstruction

Mucus-coated stools

STOOL APPEARANCES

• Intestinal inflammation or irritation, pathologic colitis (excessive straining during defecation)

Blood-streaked mucus

STOOL APPEARANCES

• Damage to intestinal walls

• Dysentery

• Malignancies

Small caliber

STOOL APPEARANCES

• Cancer tumor

• Ulcer

Hirschsprung’s disease

A stool of a large caliber is associated with what disease?

Invasive bacteria

ex. Shigella, Enteroinvasive E. coli (EIEC), Campylobacter, Salmonella, Yersinia (SECSY)

Neutrophils present is a sign of:

Toxin producing bacteria, viruses, parasites

ex. S. aureus, Vibrio spp.

Neutrophils absent is a sign of:

Fresh specimen

Slide preparation for leukocyte counting must be performed on:

Methylene blue

WET PREP

• Faster

• Difficult to interpret

Gram stain

DRY PREP

• Permanent slide

• Gram differentiation = initial treatment

• Better in differentiating the organism that causes diarrhea

Lactoferrin latex agglutination test

• Detects fecal leukocytes which remains sensitive in refrigerated and frozen specimens

• Lactoferrin is a component of the secondary granules of leukocytes

• Positive result is indicative of bacterial pathogen

Muscle fibers

• examined within 24 hours of collection

• Can be helpful in diagnosis and monitoring of patients with pancreatic insufficiency

• Patients should be instructed to include red meat in their diet to produce a representative sample

10% alcoholic eosin

What is used to stain the striations or identification of muscle fibers?

Creatorrhea

It is defined as an increase in undigested muscle fibers.

>10/hpf

For muscle fibers, presence of _________ undigested fibers is reported as increased.

Undigested fibers

both horizontal and vertical striations are still present

Qualitative fecal fat

• Microscopic screening for presence of excess fecal fat from patients suspected of having steatorrhea

• Monitor patients undergoing treatment for malabsorption disorders

Oil Red O

Sudan IV

Sudan III - most common

In qualitative fecal fat, lipids are stained using: (3)

Among the 3, which is the most common?

Neutral fat stain

A step in qualitative fecal fat that stains TAG (readily stained by Sudan III)

Split fat stain

A step in qualitative fecal fat that do not stain directly; mixed with acetic acid and heated before staining of Sudan III

Neutral fats (TAG)

LIPIDS OBSERVED IN FECES

• Readily stained by Sudan III

• Large orange-red droplets located near the edge of the coverslip

• Steatorrhea: >60 droplet/hpf

Fatty acids salts/Fatty acids (Soap)

LIPIDS OBSERVED IN FECES

• Don’t stain directly with Sudan III

• Observed after the specimen has been mixed with acetic acid and heated

• Size and number of stained fat droplets are counted

100 small; <4 um in size/HPF

Normal fatty acid salts size and number

100, 1-8 um/HPF

Slightly increased fatty acid salts size and number

100 droplets; 6-75 um/HPF

Increased fatty acid salts size and number

Cholesterol

LIPIDS OBSERVED IN FECES

• Stained by Sudan III after heating

• As specimen cools forms crystal that can be identified microscopically

Fatty acid salts

Cholesterol

These 2 are considered as SPLIT FATS

Fecal occult blood testing

• Most frequently performed chemical screening test for stool

• Performed because any bleeding in excess of 2.5 ml/150 g of stool is pathologically significant and no visible signs of bleeding may be present with this amount of blood

150g

How much stool is usually produced in a day?

Colorectal cancer

FOBT is used as a mass screening test for what cancer?

Melena

Large amounts of fecal blood (50-100 ml/day) that turned the stool black and tarry

Pseudoperoxidase activity of hemoglobin

What is the principle of FOBT?

Benzidine

INDICATORS FOR FOBT

• not used; overly sensitive; can detect <2.5 ml/150g of blood

Gum Guaiac

INDICATORS FOR FOBT

• MOST COMMON but LEAST SENSITIVE

• Dietary restrictions

• Cannot detect upper GIT

• Commonly used because it is cheap

Horseradish

Aspirin

Red meat

Raw broccoli, cauliflower, radish, turnips, melons - should not be eaten at least 3 days prior to treatment

Menstrual and hemorrhoid contamination

False-positive interferences for FOBT (HARRM)

Aspirin

Blocks cyclooxygenase pathway

Red meat

Has myoglobin which is a false-positive interference for FOBT

Vitamin C

False-negative interference for FOBT

Causes false negative if the value is >250 mg/dl

Iron supplement with vitamin C

If Vit C is not in the choices for false-negatives for FOBT, the next best answer is:

Hemoquant

• Fluorometric test for hemoglobin based on the conversion of heme to fluorescent porphyrins

• Detects blood from upper GIT bleeding

• Required dietary restrictions esp to red meat

• SENSITIVE AND SPECIFIC

Hemoccult immunochemical test (ICT)

• Immunochemical test

• Uses a polyclonal anti-human hemoglobin antibody that is specific for the globin portion of human hemoglobin

• Does not require dietary or drug restriction

• Not good for upper GIT bleeding

  • immunochemically nonreactive

Blood

Which of the ff is not normally found in stool? Water, Bacteria, Electrolyte or Blood?

Bleeding → Hemoglobin → Normal flora converts hemoglobin → Porphyrins

Porphyrins do not have psuedoperoxidase activity

What is the problem with pseudoperoxidase test?

Quantitative fecal fat

Used as confirmatory test for steatorrhea

At least 3-day specimen in paint cans

What is the specimen needed for quantitative fecal fat?

100g/dL for 3 days

Patient must maintain a regulated intake of fat prior and during the collection period for quantitative fecal fat. How much?

Carmine and activated charcoal

Markers taken on the first and last day of collection for quantitative fecal fat

Van de Kamer titration method

• Gold Standard for fecal fat measurement; used routinely

• Fecal lipids are converted to fatty acids and content is reported as grams of fat coefficient of fat retention for 24 hours

• NORMAL VALUES: 1 to 6 g/dal ot 95% coefficient of retention

Weighing → extraction → titration

What is the general procedure for Van de Kamer method?

Acid steatocrit

A rapid test to estimate the amount of fat excretion; reliable tool to monitor patient's response to therapy and screen for steatorrhea in pediatric population

5N perchloric acid

What is the reagent used in acid steatocrit?

13,000 rpm for 15 minutes in microhematocrit centrifuge

For acid steatocrit, give the rpm, time, and centrifuge used.

<10%

Acid steatocrit result indicative of steatorrhea in children

Near-infrared reflectance spectroscopy (NIRS)

Technique that quantitates water, fat, and nitrogen in grams per 24 hours

• Requires a 48 to 72-hour stool collection to exclude day-to-day variation

• The result is based on the measurement and computed processing of signal data from reflectance of fecal surface, which is scanned between 1400m to 2600m.

Pros: less stool handling, excluded day to day variability

APT test

Used to distinguish between the presence of fetal blood or maternal blood in infant's stool or vomitus

Distinguishes not only between fetal hemoglobin and hemoglobin A but also between maternal hemoglobin AS, CS and SS, and fetal hemoglobin

1% sodium hydroxide

Reagent used in apt test, added to pink, hemoglobin-containing supernatant

Fetal hemoglobin

APT TEST

• Solution remains pink. Interpretation?

Maternal hemoglobin

APT TEST

• Yellow-brown supernatant after 2 minute of standing. Interpretation?

Cord blood and adult blood

2 controls used in APT test

Fetal hemoglobin resistance to alkali denaturation

What is the principle of APT test?

>200 g/day

Diarrhea leads to increased daily stool weight of about: