Clin Med- Small Animal Hepatobiliary System 1

kelseyfmeyer's version from 2015-11-30 13:40


Question Answer
what is the FUNCTIONAL unit of the liver?acinus
what is the ANATOMICAL unit of the liver?lobule
explain how blood flows in the liverfrom the hepatic artery and the portal vein, through the acinus (in the sinusoids) to the central vein
what are the three main parts of the anatomy of the liver?hepatocyte cords, sinusoids, space of disse
how do the hepatocyte cords, sinusoids, and space of disse relate to each other in location?hepatocytes arranged into cords running parallel to the space of disse which is between the cords and the fenestrated epithelium lining the sinusoids which are also running parallel
what are, like, 7 different awesome things the liver can do?Bile production, Glycogen storage, Urea synthesis, Metabolize fat, Synthesize plasma proteins (Including clotting and anti clotting factors), detox drugs and toxins, activates hormones
what are two cells unique to the liver and what is their function(1) kuppfer cells (macrophages tissue specific to the liver) (2) Stellate cells/ Ito cells (both antigen presenting cells and also responsible for fibrosis (cirrhosis) of the liver)
If you are hypoxic, where in the liver will be damaged first?cells nearest the central vein, because they are furthest from the hepatic artery/portal vein where the fresh O2 is coming from and it gets depleted by the time it gets to them
if there is a toxin in systemic circulation, where in the liver will be damaged first?cells nearest the portal triad (where the hepatic artery and portal vein are) because they are the first hepatocytes to be exposed to the toxin in the blood and attempt to filter it
what are some clinical signs of something wrong with the liver?(basically anything!) Anorexia, Depression, Lethargy, Weight Loss, Poor haircoat, Small body stature, Nausea, Vomiting, Hematemesis, Ulceration, Diarrhea, PU/PD, Dehydration, Hepatomegaly/microhepatica, Ascites, Icterus, Coagulopathies, Neurologic abnormalities, Acholic feces/steatorrhea, Bilirubinuria
Why is there PU/PD with liver problems?liver makes urea... how does kidney conc urine? uses urea in medulla of kidney so the concentration gradient will pull stuff towards it. So if no urea, no conc gradient, cant conc urine--> PUPD
why are you dehydrated with liver probs?bc not holding onto water bc of PU/PD (see other card)
when is there hepatomegaly/ when is there microhepatica? (basica cellular explination)megaly= cell swelling. Micro= cell death
why is there ascites in liver problems?not producing albumin--> low oncotic pressure--> fluid 3rd spaces
what are Acholic feces?white/light colored feces which are a result of lack of coloration with bile pigments (because bile not being produced because liver not working)
why is there steatorrhea in liver problems? fat in feces bc no bile--> not digesting fats--> stay in lumen--> stay in poop
how might the CBC (specifically how the RBCs look) look with liver problems? think to know?Microcytes and target cells-- however, these are not pathognomonic. CAN indicate liver problems, but not always means there's a liver problem if they are there
4 abnormalities present on a UA of an animal with liver problems?Dilute USG (think bc of PUPD), Ammonium biurate crystals (these are possible not always present), Bilirubinuria, Urobilinogen
what should you know about bilirubinuria?little bit ok in dogs, NONE ok in a little weary of this. Any pigments are NOT great for kidney, so careful, can have kidney dz because of that
how might bilirubinuria cause kidney problems?bile pigments bad for kidney
what should we know about urobilinogen?she doesnt care and wont ask us Qs. Know that if it is present, you don't have a bile obstrcution. That's about it.
Serum Chemistry values that can assess FUNCTION of liver? (4 maybe 5)Cholesterol, BUN, albumin, glucose, and MAYBE bilirubin if it isnt post or pre hepatic (is just hepatic)
explain when cholesterol would INC in hepatic dz, and DEC in hepatic dzcholesterol can INC in intraheaptic cholestasis, and can DEC in PSS and fibrosis
what does liver enzymes on a serum chemistry tell you?assess liver DAMAGE
explain the basics of entero-heaptic circulationif there is hemolysis (extra or intravascular) the unconjugated bilirubin attached to albumin travels in the blood to the hepatic sinusoid, where the bilirubin is taken up by the hepatocyte and turned into conjugated bilirubin. It is then excreted through the biliary system into the small intestine, where it is then absorbed by the intestine and it's taken to the portal vein, which goes to the heptic sinusoid, where it can be recycled again (some is lost in feces and urine, but there is always some being made by the hepatocytes as well)
how can a EXTRAHEPATIC BILE DUCT OBSTRUCTION (EBDO) cause a bleeding disorder??No bile--> fat in sm. intestine not emulsified--> fat not digested and absorbed, which means FAT SOLUABLE VITAMINS (ADEK) are ALSO not taken up, and Vitamin K is necessary for the clotting cascade
how can liver problems cause bleeding disorders? (3)(1) liver synthesizes most clotting proteins. (2) lack of K+ absorption (see other card for more on this) (3) Portal hypertension from the liver problem leads Vascular congestion and fragility (if inc volume, you can damage the vessels, can bleed in liver bc those)
what is a weird location of bleeding which is very often a direct correlation of liver dz?GI BLEEDING is a clear sign of liver dz, although we don't really know WHY it happens. two theories are due to Poor mucosal perfusion, or Reduced enterocyte turnover via portal hypertension
when is anti-clotting activated?AS SOON AS clotting is activated, so is anti-clotting. (Everywhere else around where the clotting is needed needs anti-clotting otherwise everything will clot)
what's the intrinsic clotting path again?12, 11, 9, 8
whats the common clotting path again?5, 10, 2
whats the extrinsic clotting path again?7
why are there all these clotting flashcards?LIVER MAKES CLOTTING PROTEINS--> so clotting tests can tell you about liver function
what does ACT test, what does ACT mean?activated clotting time- just tells you clot or no clot? It's a rough estimate, a broad tool
what does osPT (aka PT) test and what does the acronym stand for?(one step prothrombin time) which tests the EXTRINSIC pathway (*most accurate test for rodenticide poisoning)
what does aPTT (aka PTT) test and what does the acronym stand for?(Activated Partial Thromboplastin Time) which tests the INSTRINSIC pathway
what is fibrinogen? what does it test?it is a protein made by the liver, its an acute phase protein (when inflammed or sick, get lots of acute phase proteins turned on. (albumin dec in the same situation) ) and it means there could be inflammation, OR could be clotting (indicative of common pathway!)-- not a specific
what are FDPs? what does this test?fibrin OR fibrinogen degradation products, if its fibrin breakdown products then yes, could indicate clotting. but if its fibrinogen breakdown products, then could just be inflammation. so either inflammation OR bleeding (so not great for DIC)
what are D-dimers? what do they test?these are breakdown products of clots, which means the test is testing the presence of clot breakdown (this isn't specific for DIC because it could be ANY clot breaking down)
what should you know about Specific Factor analysis for dx tests?These are the tests you send off to Cornell
What is the test that can test best for liver production of clotting factors?PIVKA
what are the 4 dx tests which can specifically indicate liver function?aPTT, PIVKA, Fibrinogen, FDP
which tests are for intrinsic path?aPTT, PIVKA
which test is for the extrinsic path?osPT
which test is for the common path?fibrinogen
which tests are for breakdown?FDP (D-dimers)
when can hepatic encephalopathy occur?with any liver problem, really
hepatic encephalopathy can Marked reduction in what two things?Hepatic mass OR portal blood flow (PSS puppies usually have both!)
what are some of the clinical signs of liver problems?(can be systemic OR CNS signs) Anorexia/lethargy/depression, Ataxia, Dementia, Hysteria, Circling, Head pressing
why do PSS puppies have worse symptoms after they eat?bc stuff (implicated agents) getting absorbed by intestines--> portal vein that is supposed to take it to the liver for the liver can metabolize, but the liver is getting bypassed and those implicated harmful substances are staying in the system and reaching the brain (and of course the amount of them is higher after a meal because they just consumed them)
what is the basic reason that hepatic encepahlopathy is occuring?liver is sick, so there is Inability to detoxify GI toxins
6 implicated agents (not proven but suspected) in hepatic encephalopathy?Ammonia, Mercaptins, Short chain FA, Skatoles, Indoles, Aromatic amino acids
why is ammonia harmful to the CNS?in the CNS it is converted into glutamine
how good of a test is a bile acids test? how specific?fantastic test, its a good liver SPECIFIC function test
when should you NOT run a bile acids test?WHEN THEY ARE ICTERIC....of course it will be positive then, duh
what triggers gall bladder contraction to release the bile into the sm int?you eat/smell something yummy, and hormone that triggers the contraction is CCK (Cholechystokinin)
explain how you do a Serum Bile Acids Test?This is a FASTED TEST! Fast the animal for 12 hours and then draw blood (hour 0). Then, feed the animal a small snack, and two hours later take a post-prandial sample (hour 2). Send the blood to the lab (note: diff labs will have diff normal values)
what are the normal pre and post prandial values for the serum bile acids test? be aware of what?know that different labs might have slightly different normals. but in general, PRE-prandial should be <5 or 5-10 mmol/L (ie, should have very little). POST-prandial should be <15 or 25 mmol/L (should be more elevated)
what is an alternative to the serum bile acids test?there is a snap test, but it only tells you it's positive for ebing elevated and there is a low cut off. she didn't seem impressed with it
what exactly does the serum bile acids test tell you?It only tells you that you HAVE decreased function, not WHY.
although the serum bile acids test can't actually tell you why you have decreased function, what can the various values usually imply?Primary hepatic dz tends to be >100mmol/L of bile acids and then secondary hepatic dz tends to be <100mmol/L of bile acids. REMEMBER this is just a rough guide and there is grey area, but this can be useful to keep in mind
what does elevation of serum bile acids tell you? what does it NOT tell you? (examples to prove this point?)It tells you there is dec function, it DOESNT tell you why, and elevation DOES NOT correlate with reversibility!!! (ex: PSS in puppies will have SUPER high values but you can fix that easily. End stage liver in an old dog might give a low value but there is nothing you can do to help the problem )
If an animal is icteric, which liver function test cant you do?Serum Bile Acids Test
what if the pre-prandial value is higher than the post-prandial value on the serum bile acids test?either the owner actually did cheat and fed the animal during the 12 hour fast, OR, the SMELL of food was enough to trigger CCK to cause GB contraction
what are 4 sources of ammonia in the body?(there are Endogenous and dietary sources) Bacterial (bacteria make their own ammonia breaking down their food), intestinal (when we break down our food), High protein meals/GI blood (stomach can't differentiate between high protein meal and blood-- it's all protein), Lean body mass breakdown (proteins being broken down)
which is a better test for kidney fxn- BUN or creatinine?CREATININE better test for kidney fxn than BUN (bc lots of things affect BUN and not so many that affect creatinine)
If there is a bad kidney pt who's BUN is SUPER high but their creatinine is only a little high, what do you think the problem is, and why?It is a HIGH GI BLEED!!! This is because, first off, you know crt. is more accurate for kidney than BUN. which means sthing else is raising the BUN. It is REALLY COMMON to have a GI ulceration in kidney dz which could raise the BUN. Why is it common? Because first there is uremic gastritis to contend with, and MOSTLY because kidneys also clear gastrin (along with histamine and acetylcholine, gastrin is what turns on acid production in stomach) and in renal dz youre not CLEARING THE GASTRIN--> more gastrin in blood--> keep turning on acid--> ulcer