GI - Ex 4 Flashcards
Three fecal screening tests
Examination for parasites - fecal float or Baermann technique
Fecal blood: occult (upper GI) and grossly visible (lower)
Fecal cytology
Fecal Occult Blood
20-50x more sensitive than gross examination
*Measure pseudoperoxidase activity of Hgb
- Can get false positive: meat diet, vegetables that contain pseudoperoxidase
- Dietary restriction for 3 days prior!
*Can get false negative: high fluid content can dilute blood, blood not uniformly distributed in sample, or reader error
Fecal Cytology
Inflammation - indicates colonic inflammation (neutrophils normally not present)
Neoplasia - rarely found; if found indicates colonic origin
Microflora - heterogenous normally; if homogeneity –> suggests over growth
Clostridial spores in feces
Gram +, spore forming anaerobe; “Safety Pin”
Release enterotoxins –> cause diarrhea
- **No correlation between number of spores noted and C. perfringens entertain levels
- “normal” dogs have spores
The Pancreas Functions
Exocrine: synthesis/secretion of digestive enzymes (6)
- trypsinogen, chymotrypsinogen, proelastase, procarboxypeptidases, lipase, and amylase
Endocrine: insulin & glucagon secretion –> glucose regulation
Digestion/Absorption
- EPI
- results in inadequate food DIGESTION
- Need to differentiate from malabsorption
- intestinal dz prevents absorption
- EPI usually normal protein; malabsorption usually hypoproteinemia
*Clinical signs of maldigestion and malabsorption are similar
EPI - Maldigestion
- EPI
- Pancreatic Acinar Atrophy
- Chronic pancreatitis
- Generally voluminous, poorly formed stool
- Weight loss
- BW may not be helpful
*BEST TEST = TLI
Malabsorption
- Intestinal dz
- generally diffuse, severe
- can be inflammatory, neoplastic, congenital
- Generally voluminous, poorly formed stool
- Weight loss
- *Can see severe HYPOPROTEINEMIA - GI loss
- depends on duration, severity
Fecal Fat
*Generally used to screen for undigested fats
Positive = undigested fats present –> maldigestion –> EPI suggested
*Very insensitive! Many EPI animals will not have detectable fat in their feces
TLI
Most sensitive and specific test for EPI
TLI - Dogs
< 2.5 = EPI
> 5.0 = malabsorption (intestinal dz)
- 5-5.0 = gray zone –> repeat assay in a few weeks
- sample exposed to extreme heat in transit, recovering from pancreatitis, food not withheld properly, or early EPI
TLI in Cats
Levels <8.0 = EPI
Absorption of B12 and Folate
Folate = proximal SI
B12 = distal SI
B12 and Folate both decreased
Generalized malabsorption
EPI in cats may mimic malabsorption
Decreased folate, normal B12
Proximal SI defect
Decreased B12, normal folate
Distal SI defect
Cats, EPI, and Folate/B12
EPI –> dec Intrinsic Factor release (IF necessary for B12 absorption) –> dec B12 absorption
Intestinal dz may accompany EPI –> dec folate
If above happens together you have dec B12 AND dec folate! This will appear as malabsorption
Increased Folate and decreased B12
Bacterial overgrowth
- intestinal bacteria can synthesize folate and bind B12 and prevent its absorption
**Dogs with confirmed bacterial overgrowth can have normal folate, B12 levels
