Lecture on Fecalysis

1. FECALYSIS,
DIARRHEA AND
MALABSORPTION
SYNDROMES
M A R I A A N G E L I C A B . V A L D E S , M D , D P S P
C H I N E S E G E N E R A L H O S P I T A L C O L L E G E O F M E D I C I N E
S E C T I O N O F C L I N I C A L P A T H O L O G Y

2. OBJECTIVES
• To discuss:
– Proper collection, handling and transport, gross and
microscopic examination of fecal specimen and its
correlation with clinical conditions
– Diarrhea, Constipation and Malabsorption
Syndromes

3. FECALYSIS

4. FECALYSIS
• Analysis of stool contents
–Collection of Feces
–Examination of feces
• Macroscopic examination
• Microscopic examination
• Chemical examination

5. FECALYSIS
• Early detection of:
– GI bleeding
– Liver & biliary duct disorders
– Maldigestion/ malabsorption syndromes
– Inflammation
– Causes of diarrhea
– Causes of steatorrhea
• Detection & identification of pathogenic bacteria & parasites

6. • “Fecal/Stool Specimen”
• Not an easy task
• Detailed instructions and appropriate containers
• For certain tests, dietary restrictions are required before fecal specimen
collection
• Collect in a clean container (bedpan or disposable container) and
transfer the specimen to the laboratory container
• Specimen must not be contaminated
• Patients should understand that the specimen must NOT be
contaminated with urine or toilet water, which may contain chemical
disinfectants or deodorizers that can interfere with chemical testing.
SPECIMEN COLLECTION,
HANDLING, & PRESERVATION

7. • Containers with preservatives for ova and parasites must NOT be used
for other tests
• Plastic or glass containers with screw tops: for qualitative testing (blood
and microscopic examination for leukocytes, muscle fibers, and fecal fats)
• Material collected on a physician’s glove and samples applied to filter
paper in occult blood testing kits are also received
• For quantitative testing, such as for fecal fats, timed specimens are
required → the most representative sample is a 3 day collection
SPECIMEN COLLECTION,
HANDLING, & PRESERVATION

8. COLLECTION OF FECES
• Adult collection
• Pediatric collection

9. SPECIMEN COLLECTION,
HANDLING, & PRESERVATION
• Do NOT collect for 1 week (>1 week) after ingestion of materials
that leave crystalline residue
– Nonabsorbable antidiarrheal compounds
– Antacids
– Bismuth
– Barium
– Antimalarial agnets
• Oily laxatives

10. SPECIMEN COLLECTION,
HANDLING, & PRESERVATION
• Antibiotics/ contrast media
– Decrease number of organisms, especially protozoa
• Urine or toilet water
– Readily destroy protozoal trophozoites
• Soil or water
– Free-living organisms

11. SPECIMEN COLLECTION,
HANDLING, & PRESERVATION
• Fresh specimens
– Examine within 1 hour
– Liquid specimens – 30 minutes

12. SPECIMEN COLLECTION,
HANDLING, & PRESERVATION

13. SPECIMEN COLLECTION,
HANDLING, & PRESERVATION
• 3 specimens collected every other day
– Minimum necessary for adequate O&P evaluation
– Optimum recovery for parasites that shed diagnostic forms
intermittently
• G. lamblia
• S. stercoralis

14. ADULT COLLECTION
• 24-hour stool collection
–Method:
A. Ingestion of Carmine dye (0.3 g) at the
beginning and charcoal (1.0 g) at the end of
collecting period
B. Use of inert, non absorbable stool markers

15. PEDIATRIC COLLECTION
• Method:
–Use of a thick-walled glass tube, which is
lubricated by clipping into water and then
inserted into the rectum of the young child

17. EXAMINATION OF FECES
• Macroscopic examination
• Microscopic examination
• Chemical Examination

18. EXAMINATION OF FECES
• MACROSCOPIC EXAMINATION
–Quantity
–Consistency
–Color
–Odor

19. MACROSCOPIC
EXAMINATION
• NORMALVALUES FOR FECAL ANALYSIS
– QUANTITY: 100-250 g/day
– COLOR: LIGHT TO DARK BROWN
– CONSISTENCY: SOFT TO WELL FORMED
– *ODOR: FOUL TO OFFENSIVE
– *pH: 7.0 to 8.0

20. MACROSCOPIC
EXAMINATION (QUANTITY)
• QUANTITY
• 100 to 200 gms/day

21. MACROSCOPIC EXAMINATION
(CONSISTENCY)
• CONSISTENCY
–Formed
–Semi-formed
–Watery stool
–Mucoidal

22. CONSISTENCY
• Abnormal forms
–WATERY - Diarrheal
–STEATORRHEA - large
amount, foul smelling gray
stool floats on water
–SCYBALA – small firm
spherical mass during
Constipation
MACROSCOPIC EXAMINATION
(CONSISTENCY)

23. PUTRID ulcerated and malignant tumors of the lower bowel
EXTREMELY FOUL putrefaction due to undigested proteins
usually assoc. with alkaline reaction of feces and
bacterial contamination
SOUR/RANCID Gas formation and fermentation of CHOs;
Due to unabsorbed fatty acids
pH
ACIDIC CHO fermentation
ALKALINE CHON fermetnation
MACROSCOPIC
EXAMINATION (ODOR & pH*)
Odor

24. MACROSCOPIC EXAMINATION
(COLOR)
COLOR
– Normal :
• BROWN
• Due to oxidation of stercobilinogen to urobilin

25. MACROSCOPIC STOOL
CHARACTERISTICS (COLOR)
BLACK Upper GI bleeding
Iron therapy (false positive)
Charcoal (false positive)
Bismuth (antacids)
RED/BLOODY Lower GI bleeding
Beets & food coloring
PALEYELLOW,WHITE,
GRAY
CLAY COLORED
Bile duct obstruction
Barium sulfate (false positive)
GREEN Biliverdin/ oral antibiotics
Green vegetables

26. MACROSCOPIC STOOL
CHARACTERISTICS
(APPEARANCE)
Bulky/ frothy Bile duct obstruction
Pancreatic disorders
Mucus/ blood –
streaked mucus
Colitis
Dysentery
Malignancy
Constipation
Ribbon-like Intestinal obstruction

27. MICROSCOPIC EXAMINATION
• to detect the presence of leukocytes associated with microbial
diarrhea and undigested muscle fibers and fats associated with
steatorrhea

28. MICROSCOPIC EXAMINATION
• FECAL LEUKOCYTES
– Preliminary test to determine if diarrhea is caused by
invasive bacterial pathogens → Minimum number of
neutrophils to be indicative of an invasive condition =
AS FEW AS 3 WBCs/HPF)
• Salmonella
• Campylobacter
• Yersinia spp.
• EIEC

29. MICROSCOPIC EXAMINATION
• FECAL LEUKOCYTES
–Negative (-) Findings:
• Bacteria that cause diarrhea by toxin production
–S. aureus
–Vibrio spp.
• Viruses
• Parasites

30. LEUKOCYTES IN STOOL
• LARGE AMOUNT OF LEUKOCYTES:
– Chronic ulcerative colitis, Chronic Bacillary Dysentry, Localised Abscess,
Fistulas
• MONONUCLEAR LEUKOCYTES:
– Typhoid
• POLYMORPHONUCLEAR LEUKOCYTES:
– Shigellosis, salmonellosis, invasive E. coli diarrhea, ulcerative colitis
• ABSENT LEUKOCYTES:
– Cholera, viral diarrhea, non-specific diarrhea, amoebic colitis, giardiasis

31. METHODS:
WET PREPARATION
• Stained with Methylene blue
• Faster but may be more difficult to interpret

32. METHODS:
DRIED PREPARATIONS
• Stained withWright’s or Gram stain
• Provide permanent slides for evaluation
• Observation of gram (+) and gram (-) bacteria

33. MICROSCOPIC EXAMINATION:
(MUSCLE FIBERS)
• MUSCLE FIBERS
– Undigested striated fibers are counted
• Pancreatic insufficiency (eg cystic fibrosis)
• Biliary obstruction
• Gastrocolic fistulas
• Can be helpful in diagnosis and monitoring of patients with PANCREATIC INSUFFICIENCY
• Frequently ordered with microscopic exam for fecal fats
• Diet preparation:
– Include red meat in diet before collection
– Examine within 24 hours of collection
• Increased amounts of muscle fibers are also seen in
– Biliary obstruction
– Gastrocolic fistulas

34. MICROSCOPIC EXAMINATION:
(MUSCLE FIBERS)
• 10% alcoholic eosin
– Enhances muscle fiber striations
– Count the number of red-stained fibers with well preserved striations

35. MICROSCOPIC EXAMINATION:
(MUSCLE FIBERS)
• Undigested fibers
– Visible striations both veritcally and horizonally
– Increased if >10
• Partially digested
– Striations in only one direction
• Digested
– No visible striations

36. MICROSCOPIC
EXAMINATION (FECAL FATS)
FECAL FATS
• Used to screen specimens microscopically for the presence of excess
fecal fat from patient suspected of having steatorrhea
• Done to monitor patients with malabsorption disorders and suspected
cases of steatorrhea
• >60 droplets/hpf can indicate steatorrhea
• Lipids included
– Neutral fats (triglycerides)
– Fatty acid salts (soap)
– Fatty acids
– Cholesterol

37. MICROSCOPIC
EXAMINATION (FECAL FATS)
• Neutral fats (triglycerides) – Sudan III
– > 60 droplets/hpf → steatorrhea
• Fatty acids/ salts (soaps)
– N: 100 small droplets <4 um/hpf
– Slightly increased: 1-8 um
– Increased: 6-75 um
• Cholesterol

38. MICROSCOPIC EXAMINATION
(FECAL FATS)
METHOD
– Sudan III
• most routinely
used
• Stains neutral fats
– Large orange-
red droplets
– Sudan IV
– Oil Red O stains
stained with Sudan III

39. MICROSCOPIC EXAMINATION (MUCUS)
MUCUS
- Recognizable mucus in stool is ABNORMAL
– Transluscent gelatinous mucus
• spastic constipation
• mucous colitis
– Bloody mucus on stool
• rectal neoplasm
• inflammatory process in the rectal canal
– Mucus with pus and blood
• ulcerative colitis
• bacillary dysentery
• ulcerating diverticulitis
• intestinal TB
– Copius mucus (3 to 4 L/24hr)
• villous adenoma of the colon

40. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
OVA & PARASITES
• Wet mounts
– Saline
• Eggs, larvae, protozoan trophozoites, cysts, RBC &WBC
– Iodine
• Stain glycogen & nuclei of cysts
– Buffered methylene blue
• Stains amoebic trophozoites and NOT amoebic cysts &
flagellates

41. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Categories of stool & appropriate techniques
Protozoan
stage
Saline Iodine Buffered
methylene
blue
Formed Cysts + +
Soft Cyst (occ
trophozoite)
+ + +
Loose Trophozoite + +
Watery Trophozoite + +

42. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Direct saline wet mount
– Detection of motile trophozoites & helminth larvae
– 0.85% saline
• Protozoal cysts: refractile
• Examine ≥ 15 s – motility of slow-moving amoebae
– 1:5 Lugol’s iodine
• Enhance visibility of nuclear structures in protozoal cysts & glycogen
inclusions

43. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Concentration techniques:
– Indications:
• Negative wet mount
• Positive symptoms indicating parasitic infection
• Schistosoma
• Taenia

44. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Concentration techniques:
– Fresh or preserved specimens
– Destroys protozoan trophozoites
– More sensitive
• Protozoan cysts
• Helminth eggs & larvae
– Decreased amount of background material

45. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Concentration techniques:
– Zinc sulfate floatation
method
• Unreliable for:
– Nematode larvae
– Infertile Ascaris
eggs
– Trematode/ large
tapeworm eggs

46. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Concentration techniques:
– Sedimentation
• Heavier parasites settle to bottom
– Floatation
• Lighter parasite cysts & eggs rise to
surface of solution of high SG
– Formalin ethyl acetate
concentration
• Biphasic sedimentation technique

47. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Permanent stains
– Useful:
• Protozoal trophozoites & cysts
– Not useful:
• Helminth eggs or larvae
– Wheatley trichrome stain
– Iron hematoxylin stain
– Modified acid-fast dimethyl
sulfoxide
– Auramine-O

48. MICROSCOPIC EXAMINATION
(OVA & PARASITES)
• Permanent stains
– Modified Kinyoun method
• Acid fast organisms:
– Cryptosporidium
– Cyclospora
– Cytosospora

51. HOOKWORM

52. ROUNDWORM

53. TAPEWORM

54. WHIPWORM

55. PINWORM

56. ENTAMOEBA

57. GIARDIASIS

58. MICROSCOPIC
EXAMINATION
FECAL BLOOD
CAUSES
– Hemorrhoids or anal fissures
– Drugs:
• Salicylates
• Steroids
• Rauwolfia derivatives
• Phenylbutazone
• Indomethacin
– Tarry stool for 2-3 days: blood loss of at least 1000 ml and
occult blood may persist for 5 to 12 days

59. FECAL OCCULT BLOOD TEST
(FOBT)
• UGIB = black tarry stool / overtly bloody
• LGIB = overtly bloody
• >2.5 mL / 250 g of stool bleeding is pathologically significant w/o signs of bleeding
• High positive predictive value for detecting colorectal CA in early stages
• METHOD
• Guaiac
• Immunochemical tests
• Fluorometric porphyrin quantification

60. GUAIAC FOBT
• Most frequently used screening test
• Principle:
• Detect the Pseudoperoxidase activity of hemoglobin
• Least sensitive, for routine testing
• affected by diet (meat & fish, vegetable, fruits, intestinal bacteria)
• Sample collected on 3 consecutive days sampling

61. GUAIAC FOBT

62. FECAL IMMUNOCHEMICAL
TEST (FIT) FOBT
Principle:
• Specific for globin portion of human hemoglobin and uses
polyclonal anti-human hemoglobin antibodies
• No patient preparation
• Specific for human blood in feces
• Does not require dietary or drug restrictions
• More sensitive to LGIB
• Does not detect bleeding from other sources
• Can be used for patients taking aspirin and other anti-inflammatory
medications

63. FECAL IMMUNOCHEMICAL
TEST (FIT) FOBT

64. FOBT

65. APT TEST (FETAL HEMOGLOBIN
TEST)
• Should it be necessary to distinguish between the presence of fetal blood or maternal
blood in an infant’s stool or vomitus
• In the presence of alkali-resistant fetal hemoglobin, the solution remains pink (HbF),
whereas denaturation of the maternal hemoglobin (HbA) produces a yellow-brown
supernatant after standing for 2 minutes.
• The APT test distinguishes not only between HbA and HbF but also between maternal
hemoglobins AS, CS, and SS and HbF.
• Maternal thalassemia major produce erroneous results
due to high concentration of HbF.
Stool specimens should be tested when fresh.They may appear bloody but should not be
black and tarry, because this would indicate already denatured hemoglobin.

66. DIARRHEA &
CONSTIPATION

67. DIARRHEA
• If the amount of fluid entering or secreted
into the large intestine exceeds the capacity
for absorption → diarrhea
• Normally:
Ileum → large intestine → stool
(500-1500 ml (150 ml)
of fluid)

68. CLASSIFICATION OF DIARRHEA
• Inflammatory/Exudative
• Secretory
• Osmotic
• Malabsorption
• Altered motility
• Factitious
• Increased filtration
• Iatrogenic

69. CLASSIFICATION OF DIARRHEA
- INFLAMMATORY/EXUDATIVE
DIARRHEA
• Immune-mediated injury of GI mucosa
– Inflammatory bowel disease
• Crohn’s disease
• Ulcerative colitis
– Infectious
• Salmonella spp.
• Shigella spp.
• Campylobacter spp.
• Enteroinvasive E. coli
• Yersinia enterocolitica
• HIV enteropathy

70. CLASSIFICATION OF DIARRHEA
- SECRETORY DIARRHEA
• Increased secretion of water and electrolytes into the GI tract lumen
– Enteric infection
• Salmonella
• Shigella
• Enterotoxigenic E. coli
• V. cholera
• Staphylococci
• Clostridia
• Protozoan
• Rotavirus
– Hormone mediated

71. CLASSIFICATION OF DIARRHEA
- OSMOTIC DIARRHEA
• Non-absorbed substances retain water in the GI tract
lumen
– Maldigestion - Incomplete breakdown of protein,
lipid, and/or carbohydrates
• Pancreatic insufficiency:
– Chronic pancreatitis, cystic fibrosis, obstruction at ampulla of Vater,
pancreatic adenocarcinoma, somatostatinoma
• Carbohydrate intolerance
– deficiency on Lactase, isomaltase-sucrase and trehalase enzymes
• Others:
– Biliary obstruction, resection of ileum, chronic intestinal ischemia

72. – Malabsorption -Incomplete absorption of substances
across the GI mucosa
• Short bowel syndrome, Whipple’s disease, celiac
disease, tropical sprue, bacterial overgrowth,
abetalipoproteinemia, GI lymphoma, glucose-
galactose malabsorption, congenital chloridorrhea,
hypogamaglobulinemia, parasitic infections
• Osmotically active dietary products:
– Psyllium fiber, magnesium citrate, sorbitol
CLASSIFICATION OF DIARRHEA -
OSMOTIC DIARRHEA

73. CLASSIFICATION OF DIARRHEA
- ALTERED MOTILITY
• Increased peristalsis reduces transit time down GI tract
– Irritable bowel syndrome, hyperthyroidism, fecal impaction, neurologic
diseases, diabetes, hypocalcemia, systemic sclerosis, GI bleeding, post-
vagotomy

74. CLASSIFICATION OF DIARRHEA
- INCREASED FILTRATION
• GI capillary hydrostatic/oncotic pressure imbalance
– Portal hypertension, severe hypoalbuminemia, partial small bowel
obstruction

75. CLASSIFICATION OF
DIARRHEA - IATROGENIC
• Medical treatment side effect
– GI surgery,Abdominal radiation therapy, medications (magnesium citrate,
laxatives, antibiotics, cardiac medications, chemotherapeutic drugs,
metoclopramide, cisapride, lactulose, theophyllin, etc.

76. CLASSIFICATION OF DIARRHEA
FACTITIOUS – SELF INDUCED
– Surreptitious laxative abuse associated with psychiatric disorders

77. CONSTIPATION
• Passage of small firm, spherical masses of stool –
sybala
–Irritable colon syndrome 2o anxiety or overuse of
laxatives
–Carcinoma
–Repeated occult blood determination
• Narrow, ribbon-like stool:
–Spastic bowel or rectal narrowing or stricture

78. INTESTINAL DISORDERS
• Chronic diarrhea
• HIV related diarrhea
• Nosocomial diarrhea

79. TESTING FOR MALABSORPTION
AND CYSTIC FIBROSIS
TESTING FOR MALABSORPTION
Tripeptide Hydrolysis Test Decreased para-aminobenzoic acid results suggest pancreatic insufficiency
Fecal Fat Values 5-10g% suggest malabsorptionValues > 10 g% suggest maldigestion
14C-Triolein Breath Decreased 14CO2 in expired air suggsts fat malabsorption
D-Xylose Absorption Values below reference ranges suggest little to no absorption capacity of the proximal
small bowel mucosa
Vitamin B12 Malabsorption Patients who excrete < 7% are suspected to have pernicious anemia
Β-Carotine Decreased levels are seen in patients with malabsorption and/or malnutrition
TESTING FOR CYSTIC FIBROSIS
Sweat Chloride Increased levels are diagnostic of cystic fibrosis

80. MALABSORPTION SYNDROMES
• Definition:
– Result from impaired digestion or assimilation of food by the small bowel
• Common causes: (pancreatic diseases )
➢Chronic pancreatitis
➢Carcinoma of the pancreas
➢Cystic fibrosis of the pancreas
• Manifestations:
➢ Creatorrhea- undigested meat fibers in the
feces
➢Steatorrhea – an increase in fat (triglyceride
level)
> 5 grams of lipids(FA) in feces/24hrs

81. MALABSORPTION
SYNDROMES
• Classification
–Hepatic maldigestion
–Enteric malabsorption

82. HEPATIC MALDIGESTION
• Interference with bile flow
–Loss of bile salts interference
• Fat emulsificaton
• Diminishes surface area available for lipolytic
action
• Lost of bile salt activation by lipase

83. HEPATIC MALDIGESTION
• Cause
–Neoplasm obstructing the ampulla of vater
• Results
–Hepatic steatorrhea
–Pancreatic steatorrhea

84. ENTERIC MALABSORPTION
• Normal digestion but inadequate net
assimilation of food resulting from:
–Competition by bacteria
–Altered bacterial flora

85. ENTERIC MALABSORPTION
• Causes
– Blind loop syndrome
– Diverticulosis
– Obstruction of the lymph flow
• Whipple disease
• Lymphoma
– Diseases affecting the bowel mucosa
• Amyloidosis
• Inflammation following radiation
– Atrophy of small bowel due to wheat protein, gluten or gliadin-sensitivity in celiac
disease
– Vitamin B6 or B12 deficiency

86. MALABSORPTION SYNDROMES
• Deficiencies of fat-soluble vitamins:
A,D,E,& K
• Weight loss due to large caloric loss & nutritional deficiencies :
➢ Hypoprothrombinemia
➢ Glossitis
➢ Anemia
➢ Edema
➢ Ascites
➢ Osteomalacia

87. MALABSORPTION
SYNDROMES
• Single foodstuff or vitamin or small group of substances deficiency:
➢Lactose intolerance- lactase deficiency
➢Pernicious anemia- Vit. B12 deficiency
due to intrinsic
factor deficiency

88. MALABSORPTION
SYNDROMES
• MAJOR SIGN:
– STEATORRHEA
> Excretion or presence of more than 5 grams of lipid

89. MALABSORPTION
SYNDROMES
• Differentiating Causes:
pancreatic vs. enteric malabsorption
➢cystic fibrosis of the pancreas
- sweat electrolyte determination
Result: increase sweat chloride
- trypsin activity
Result: absence of trypsin in stool

90. MALABSORPTION
SYNDROMES
• Enteric malabsorption
➢D-xylose absorption test (25 g pentose sugar
in water taken orally)
Result: < 3g excretion in urine over a 5- hr
period

91. MALABSORPTION
SYNDROMES
• Celiac disease:
➢cellobiose-mannitol
permeability test
➢lactulose-mannitol test
• Patients with celiac disease under absorb small
molecules such as mannitol and absorb larger
molecules such cellulose and lactulose

92. MALABSORPTION
SYNDROMES
• Intestinal Disaccharidase Deficiency
– PRIMARY DISSACHARIDASE DEFICIENCIES
➢sucrase-isomaltase deficiency
➢lactase deficiency
➢primary galactasia
➢primary trehalase deficiency
– SECONDARY DISSACHARIDASE DEFICIENCIES
(transient and involved more than one enzymes)
➢Celiac disease
➢tropical sprue
➢acute viral gastroenteritis
➢drugs(neomycin,kanamycin, methotrexate)

93. MALABSORPTION
SYNDROMES
• Intestinal Disaccharidase Deficiency
In these disorders:
– unhydrolyzed and unabsorbed carbohydates are fermented by intestinal
bacteria producing gas, lactic acid.
– Normally, absorption of digested carbohydrates is rapid and fairly
complete in the proximal small intestine
– unhydrolyzed dissacharides or unabsorbed monosaccharides due to
deficiencies in transport are osmotically active which causes secretion of
water and electrolytes into the small intestines
– protracted diarrhea, bloating and flatulence

94. MALABSORPTION
SYNDROMES
• Screening tests for disaccharidase deficiencies:
oral challenge of suspected disaccharides
stool analysis- watery, acidic (<pH5.5)
Clinitest tablet (reducing substances)
≥0.5 g/dL or more than 250 mg/dl
(abnormal)
Normal: 250 mg/dL of feces
• Definitive Dx: mucosa of small intestinal biopsy
showing low enzymatic activity

95. MALABSORPTION
SYNDROME
• GLUCOSE – GALACTOSE MALABSORPTION
– Hereditary (autosomal recessive traits) disorder of active absorption
of glucose and galactose from the small intestine
• Problem: Diarrhea
• Laboratory tests
– Glucose oxidase
– Galactose oxidase
– Chromatography
– OGTT (flat curve)

96. THANK YOU