Term
| How do Abx adversely affect the GI system? |
|
Definition
modify normal flora
change bacterial CHO metabolism-> diarrhea
favor overgrowth of pathogenic bacteria
-not active against clostridium
(toxins-> enteritis) |
|
|
Term
T/F:
antibiotic-associated diarrhea carries a worse prognosis than diarrhea from other causes |
|
Definition
|
|
Term
| Which Antibiotics cause problems? |
|
Definition
tetracyclines
Trimethoprim sulfa
erythromycin
lincomycin
ceftiofur
fluoroquinolones |
|
|
Term
| Which antibiotic leads to clostridial overgrowth and liberation of clostridial toxins? |
|
Definition
|
|
Term
| which antibiotic is reported to cause problems in practice but not demonstrated experimentally (diarrhea from this drug resolves quickly)? |
|
Definition
|
|
Term
| Why is erythromycin probelmatic? |
|
Definition
variable degree of absorption
- high conc. of active drug in feces
of horses trx orally
some mares exposed to foals trx with erythromycin have developed severe colitis |
|
|
Term
| Which drugs rarely cause diarrhea due to their lack of activity on anaerobic bacteria of the intestine? |
|
Definition
|
|
Term
| When are antibiotics used for diarrhea? |
|
Definition
Potomac horse fever: oxytet
Clostridium: metronidazole
neutrophil count<1500; immuno-compromised horses:
- enrofloxacin (not foals),
- Kpen or Ampicillin w/ gentamycin |
|
|
Term
| list the clinical signs of liver disease |
|
Definition
icterus
anorexia
depression
weight loss
abdominal pain
Photosensitization
alopecia and thickened scaly skin |
|
|
Term
| What causes photosensitization? |
|
Definition
phyloerythrin from chlorophyll deposits in skin
occurs in both acute and chronic liver disease
in white areas of skin |
|
|
Term
| What signs are seen diagnostically in liver disease? |
|
Definition
Coagulopathies (intrinsic & extrinsic)
Hemoglobinuria
Hepatoencephalopathy
- altered neurotrans in brain due
to hyperammonia, aromatic AA,
hypoglycemia
-ALWAYS check liver function in a
horse with acute onset of neuro
signs
Icterus (liver dz, anorexia, hemolysis)
*NOT edema or ascities* (albumin is rarely low)
Chem: hepatocellular necrosis (SDH,AST)
cholestasis (GGT, ALP)
high bilirubin
high ammonia
BUN low
Glucose low |
|
|
Term
| How can you diagnose liver dz? |
|
Definition
CBC/Chem/UA
Bile Acids (high)
-horses do NOT have a gallbladder
Hepatic ultrasound
liver biopsy (on right side under diaphragm and lungs) |
|
|
Term
| How would you trx liver dz? |
|
Definition
supportive:
clean stall out of sunlight
avoid fresh alfalfa, first cut hay high
in protein
oral or IV fluids
add dextrose if hypoglycemic or
anorexic
xylazine or detomidine if manic (NO valium)
B vitamins (liver normally makes)
oral neomycin if hepatoencephalopathy
antibiotics (trimethorprim sulfa,
*enrofloxacin or gentamycin)
Corticosteroids
NSAIDs if painful |
|
|
Term
| What is the prognosis for liver disease |
|
Definition
guarded: hepatoencephalopathy, IV hemolysis, extensive fibrosis
response to treatment will help determine prognosis |
|
|
Term
| What are some liver disease's that affect foals and adults? |
|
Definition
foals:
tyzzer's dz
portocaval shunt
toxicity
adults:
theilers dz
pyrolizidine alkaloid toxicity
alsike clover
cholangeohepatitis*
choleoliths |
|
|
Term
| What is Tyzzer's disease? clinical signs? |
|
Definition
acute fatal disease of foals 7-42 d.o. caused by clostridium piliformis that is shed in soil by adults
common in foals of mares new to pasture in early spring
sudden death; fever, icterus, diarrhea, dehydration, seizures |
|
|
Term
| how to diagnose Tyzzer's? |
|
Definition
| necropsy: filamentour intracellular organisms in the liver |
|
|
Term
| what is Theiler's disease? clinical signs? |
|
Definition
acute hepatic necrosis: serum hepatitis
commonly occurs with tetanus anti-toxin
(4-10wks after)
common in summer months
signs (acute): depression, anorexia, colic, hepatoencephalopathy, icterus, dark urine, photosensitization, rapid progression->death; elevated liver enzymes |
|
|
Term
| how do you diagnose Theiler's dz? |
|
Definition
AUS: swollen rounded liver edges
Biopsy*: widespread centrilobular to midzonal hepatocellular necrosis w/ hemorrhage often the strongest Dx evidence |
|
|
Term
| List some examples of chronic liver disease |
|
Definition
toxicity: pyrrolizadine alkaloids, alsike clover, aflotoxin
fatty liver: mini horses, ponies
cholangiohepatitis
obstructive choleolithiasis
neoplasia (rare)
abscess (rare) |
|
|
Term
| list the clinical signs of chronic liver disease |
|
Definition
| anorexia, depression, photosens, scaly skin, hepatoencephalopathy, GGT and ALP elevated, BUN and glucose normal or low, high bile acids and ammonia |
|
|
Term
| Where do pyrrolizadine alkaloids come from? what are the stages of dz? |
|
Definition
From plants (ie-amsinckia); plants are unpalatable unless in hay
stages:
subclinical hepatic damage
gradual progression to liver failure
acute hepatic failure |
|
|
Term
| describe the pathogenesis of pyrrolizadine alkaloids |
|
Definition
| absorbed in intestine-> metabolized by liver to pyrroles-> pyrroles bind proteins and nucleic acids-> amtimitotic effect-> megalocyte formation-> megalocytes die and replaced by fibrin-> liver failure due to hepatocellular death and fibrosis |
|
|
Term
| how do you diagnose pyrrolizadine alkaloid toxicity? |
|
Definition
|
|
Term
| What is the pathogenesis of Alsike clover tox? and what are the clinical signs of Alsike clover toxicity? |
|
Definition
path: unidentified toxins cause proliferation of bile ducts and perilobular fibrosis
signs: photosens (transient), fever, jaundice, bilirubinuria, weight loss, colic, hepatoencephalopathy, sudden death |
|
|
Term
| what is the prognosis for Alsike clover tox? |
|
Definition
| may recover with removal of the alsike clover |
|
|
Term
| What is cholangiohepatitis? and what are the clinical signs? |
|
Definition
chronic active hepatitis in periportal regions
signs: intermittent fever, anorexia, icterus, colic, exfoliative dermatitis of coronary band |
|
|
Term
| how do you diagnose cholangiohepatitis? |
|
Definition
leukocytosis, hyperproteinemia, high bilirubin, fever, high GGT and ALP
ultrasound (look for hyperechoic areas)
liver biopsy: inflammation, neutrophilic, lymphocytic, mixed
liver culture: gram neg bacteria |
|
|
Term
| how do you treat cholangiohepatitis? |
|
Definition
NSAID for colic
antibiotics (ie-trimethoprim sulfa)
Baytril in adults
Corticosteroids (lymphocytic) |
|
|
Term
| what are choleoliths? how do you diagnose? prognosis? |
|
Definition
later stage of cholangeohepatitis
Dx:
high GGT and ALP and bilirubin
may be visible on AUS (hyperechoic masses)
Px: poor prognosis
- obstruction of common bile ducts
have been treated surgically with
modest success |
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