Equine Med- Liver 1

kelseyfmeyer's version from 2016-10-03 18:51

Leevor intro, dx's

Question Answer
unique features of equine liver?No gallbladder
how resilient is liver to damage?Can lose 80% and still function-- also Reversible and can regenerate
how much/which plasma proteins is the liver responsible for?Produces 90% of plasma proteins! including Fibrinogen, clotting factors, Albumin (would have to be in end stage for liver to stop producing albumin she said in class)
horses naturally produce a lot of ammonia. Why? what implications does it have for Mr. Liver?horses naturally produce a lot of ammonia bc of hindgut fermentation, so, common to see hyperammonemia common in horses with liver dz
explain liver's role in lipid metabolism-- which breeds esp have implications for with this?Ponies/Minis/Mini donkeys esp prone to having lipid metabolism in their liver. They can get fatty livers just like cats that don't eat-- but they also take it to the next step and give themselves raging hypertriglyceridemia
two things you should think about with fibrinogenclotting factor and inflammatory marker.
how does the liver usually handle digested fatty acids?liver converts them into triglycerides so they can be stored
what are clinical signs of liver dz?OFTEN NON-SPECIFIC: Weight loss, anorexia, depressed, +/- fever
does icterus= liver dz?MAYBE. can only say its icteric bc icterus can be prehepatic, hepatic (not really post hepatic bc no gall bladder lol)
usually the first thing to turn icteric is?vulva
aside from hemolysis, what is another PRE-hepatic reason horses can be icteric?ITS A HORSE---- ANOREXIA/FASTING CAN CAUSE ICTERUS BC NO GALL BLADDER TO STORE IT IN. Also about 5% of all horses are just mildly icteric. Because horse.
so how might you know if the icterus is from not eating, or from a sickness causing them to not eat?bc anorexia= mild rise in bili (2-3x) but if another problem more like 6x.
what should you remember about horse plasma?their normal plasma can be much more yellow than a small animals, and thats normal (remember no gallbladder so kinda just hanging out in there)
If you see a skin lesion like this, why might you think there is liver dz?photosensitization can be due to a liver prob!! bc dzed livers cant break down the phylloerythrin in the plants they eat. ***note the photosensitivity is only on the white areas bc not protected from UV by pigmented hair. So if you see white-haired areas with photosensitivity dermatitis, look at the liver to see if it is ok-- because could also be that they just ingested a photodynamic plant (st johns wort, ryegrass)
so you see a horse head-pressing the stall-- is it liver?might be-- liver usually filters out ammonia so it doesn't cause neuro signs (hepatic encephalopathy) also horses with awful colitis can get this bc of high ammonia bc bacteria going crazy in there
so owner has no moneyz and you want to know if it is liver dz versus colitis but only can look at this pic they sent you What is it doc?WEeeeeellll i cant dx from pic but considering it is bleeding everywhere and liver produces clotting factors, it is prollllly liver
you have an overconditioned pony with a young foal that is still nursing. What is this momma at risk of?she is probably in a negative energy balance, so she is at risk for hepatic lipidosis/lipidemia
what does ALT tell you about liver in horses?LOL NOTHING. according to Dr Google, ALT has very little significance in horses AND rumis
what are the HEPATOCELLULAR enzymes you look at to assess liver damage? which is the best?AST AND SDH!!! (ALT IS NOT USEFUL IN HORSES) of the two , SDH is very liver cell specific so it is the most accurate marker for liver problems, since AST also goes up with mm damage
pro and con of SDHsuper specific enzyme for liver damage-- buttttt it is the most unstable enzyme- w/in 4-9hours of collection, needs to be read.
what are the two BILIARY dz enzymes? which is better?GGT and ALP. GGT is the most specific for biliary damage, because ALP has many iso enzymes (bones etc)
what tells you about liver FUNCTION? (class discussion)NOT ENZYMES- THAT IS DAMAGE!!! Function is C-BAG: Chlosterol, BILE ACIDS, Albumin, glucose.
what does BUN tell you with liver function?nothing because it isn't useful in horses. Do BILE ACIDS. NOT BUN.
how would you check bile acids with a horse?uh not with a postprandial thing bc they don't have a gall bladder... just take a sample and go.
*which is more sensitive to look at for liver fxn- bilirubin or bile acids?Bile acids more sensitive than bilirubin!!
a concentration of _________ bile acids is a POOR PROGNOSTIC INDICATOR!!>20 umol/L = poor prognostic indicator (liver too damaged to regenerate)
(notes) what are the 3 liver FUNCTION tests you can do?(1) Bilirubin (look at conjugated and unconjugated) (2) Bile acids (More sensitive than bilirubin, >20 umol/L= poor prognostic indicator) ( DONT DO IT ANYMORE, BUT: (3) Dye Clearance Tests: BSP pre and post injection levels tested )
when will abdominocentesis be useful as a liver dx?if neoplasia, or bact infection....might be able to see abnormal cells being shed
if you have a headpressing horse, might wanna check...ammonia levels (And this will guide your therapy, tx changes depending on high ammonia vs not)
what is the difference between hyperlipidemia and hyperlipemia? how do you measure this?Diff in amount of triglycerides!! so measure tri's. If <500mg/dL=LIPIDEMA.. But if it is >500mg/dL= LIPEMIA (so lipemia worse than lipidemia.....shorter word, more fats) --> also usually see gross discoloration of serum (creamy)
why do we care about hyperlipidemia versus hyperlipemia?lipemia=more fats than lipidemia and is a neg prog indicator
how helpful are rads for dx in horses?not very helpful.... but might be able to see enteroliths and sand
US can be helpful to look at liver-- WHERE do you look ON LEFT SIDE and why? what do you wanna look for?small window on L side-- good interaction of liver and spleen (use to compare) wanna see biliary tract, look at echogenicity, look for masses...
US can be helpful to look at liver-- WHERE do you look ON RIGHT SIDE and why? what do you wanna look for?bigger window on R (cecum is tucked back), you can see the RDC, liver and duodenum.
which is darker on US-- liver or spleenliver darker than spleen (uhh spleen super dense so bounces more sound back?)
how common is it to bx a horse liver?pretty darn common- huge liver, nbd to take some
WHICH SIDE AND WHERE do you take a liver bx/FNA in a horse-- and how?on R side, use bx instrument, dorsally, 14-15th rib (or 13-14). Dont get a chunk of lung on accident!
before you take liver bx you should make sure...their clotting is fine lol (coag panel+platelets)
what is the best way to measure the prognosis of a liver dz? (2nd best choice?)Histopathologic score of the liver bx is the BEST prog indicator. A score (score usually related to fibrosis she said in class) of >2= negative prognostic indicator..... serum bile acids can also help with prognosis but bx histopath score is best.
what is the histopath score that is a neg prog indicator?>2

Cases and stuff

Question Answer
what are some plants toxic to horses?pyrrolizidine alkaloids, cassia seeds, agave
what are some toxic chemicals?arsenic, iron, copper
possible place bacterial infection in liver might have come from?ascending from GI
so from CBC how might you know its not hemolysis causing high bili?bc there would be a low PCV (and might have red serum)
what is the active phase protein which is chronic?fibrinogen
so what can cause liver to rot?theiler's dz aka serum sickness, iatrogenic hepatic dz
what are risk factors for developing theilers?previous xfusions or tetanus antitoxin (usually dz develops like 4-10 months after admin)
is theilers risk inc with the tetanus toxoid or antitoxin?ANTITOXIN--- the toxoid is the vx, much less reactive than the antitoxin.
who might be at higher risk of developing theilers?preg/lactating mares (can occur as an outbreak!)
what causes theilers?they think a virus is actually (but tetanus antitoxin/transfusions inc risk sig). TDAV virus
what is the VIRUS which might be associated with theilers?flavivirus TDAV associated with cases
if it is a liver rotting in a 1 mo old foal, it is _________ until proven otherwisetyzzer's
If you suspect aflatoxin as a reason for liver dz, what will you test?THE FOOD NOT THE ANIMAL.
how do you test for toxic plants and chemicals?there isnt one...just hx of exposure, and ruling out other things.
what causes Tyzzer’s Disease?Clostridium piliformis
average age affected by Tyzzer's?1-6 weeks of age -- ONLY SUSCEPTIBLE AT THIS TIME!!!!!
clinical presentation of Tyzzers?Found dead! or SUPER SICK with liver failure
how do you dx Tyzzers?RT-PCR at UCDavis
prog of Tyzzers?uniformly fatal
*so our horse with some hepatic encephalopathy is all freaked out and we want to sedate her-- DO NOT DO WHAT?NO benzodiazepines WITH HEPATIC ENCEPHALOPATHY– GABA plays a role in HE and may worsen
3 ways you can reduce ammonia in hepatic encephalopathy?(1) Vinegar (Acid kills NH3 forming bact) (Want to acidify GI tract, causes ion trapping when NH3-->NH4+) caution might cause diarrhea. (2) Lactulose (Want to acidify GI tract, causes ion trapping when NH3-->NH4+) (Acid kills NH3 forming bact) (3) Neomycin: This is a Aminoglycoside which has very little systemic absorption (so give it PO) and it kills off the ammonia-producing bacteria in gut. (might predispose to salmonella infxn too)
what is the abx we can give to kill off ammonia producing bact in the gut (if there is Hepatic encephalopathy) and what risk does it carry?Neomycin-- give PO- look out, risk of salmonella overgrowth then
3 things we can use to reduce inflammation in the liveR?NSAIDS, pentoxifylline, DMSO
lol whats pentoxifylline?Drug we use to reduce inflammation in the liver
what antioxidant can you use to protect the liver?SAMe
diet plan for acute liver dz ptFluids with dextrose, Small frequent meals, low protein & fat, Tube feed or TPN if necessary
Prognosis for Acute Liver Disease depends on what two factors?(1) MOST important: Histopathologic score (2) Serum bile acids