Small Ani. Med 2- Canine Liver Dzs 1

drraythe's version from 2016-04-29 15:20

Intro/ Acute hepatitis/ Destructive Cholangiolitis

Question Answer
what are some primary canine liver dzs?Acute Hepatitis, Chronic Hepatitis (idiopathic/breed associated), Cirrhosis, vasculat dzs
2 dzs which can cause hepatic lipidosis in dogshypoT4, DM
liver congestion is 2* to...heart failure
what is "reactive hepatitis" reacting to?comes from portal tract to portal area--- reactive dz of liver: AKA CHOLANGIOHEPATITIS
what are some secondary canine liver dzs?Steroid induced hepatopathy, Hepatic lipidosis, Congestion, Idiopathic vacuolar hepatopathy, Reactive hepatitis, LEPTO
what are some biliary dzs of the canine?Cholangitis, Destructive Cholangiolitis, mucocele, Caroli dz, Hepatocutaneous syndrome
best way to know if what you are looking at is hepatocutaneous syndrome?look at the food pads! If they aren't affected, it's not this
3 most specific clinical signs of possible liver dzIcterus, encephalopathy, change in liver size
Explain how Acute vs Chronic can me two different things (what are the 2 separate parameters in which we can say sthing is acute vs chronic)(1) HISTOLOGY: CHRONIC= FIBROSIS! Acute= no fibrosis. (2) CLINICALLY: ACUTE= <1-2wk Chronic: >2wk
what makes sthing Acute Liver failure?Sudden severe impact: 70 - 80% liver damage
**what infection is gonna make you think ACUTE LIVER FAILURE?LEPTO
if there is hypoperfusion, where will the damage be?Zone 3 centrolobular
Hepatic emergencies-- Intraabdominal bleeding-- what are some traumatic and non-traumatic causes?Traumatic: HBC, highrise, kick/shock. NON-traumatic: Ruptured hepatic mass
what is the emergency ABCs again?Airway, breathing, circulation
ER fluids: obv 2 large caths (14-18) and what is the shock dose for dogs, cats? (when is the exception and you will need a lower dose?)DOG: 90ml/kg/h. CAT: 60ml/kg/h. (*bolus in quarters and reassess) ....exception is need lower amount in pulmonary continusions
Hepatotoxins: what are the 2 situations where you do NOT want to induce vomiting/do an enema?(1) decreased consciousness (risk of Aspiration pneumonia) (2) bleeding
how do you induce vomiting in dogs? Cats?DOG: apomorphine. CAT: A-2 agonists (so dexmedetomidine, xylazine)
5 Radical scavengers against oxidative damage in cases of hepatotoxins?N-Acetylcystein (BOLUS NOT CRI) (donates SH group to assist GSH), Vitamin E ( disabling the production of damaging free radicals in tissues, by reacting with them to form a tocopheryl radical, which will then be reduced by a hydrogen donor (such as vitamin C) and thus return to its reduced state), Plasma, Vitamin K1, Cimetidine
what are some pathological changes lepto causes?Petechia on lungs, ACUTE LIVER DAMAGE, Acute interstitial nephritis
*which breed tends to get acute hepatitis?Cockers
which virus causes acute hepatitis, edema of the gall bladder? how can you ID?Canine-adenovirus-1 aka Infectious canine hepatitis (lol)... ID inclusion bodies on histo
If you see this, what do you think caused this acute hepatitis? Intranuclear inclusion bodies= DNA virus= CANINE ADENOVIRUS 1 AKA infectious canine hepatitis
Therapy: Acute Hepatitis--- What is DEF a drug you should give?Ursodiol!! aka UDCA/Ursodeoxycholic acid
explain how Ursodiol works again?It is a Synthetic primary bile acid which Influences balance of natural bile acids (more lipophilic BAs are more toxic, esp lithocholic bc causes apotosis and oxidative damage) MOA includes: (1) Displacement of toxic bile acids (flush effect) (2) Increased bile flow (active secretion from hepatocytes) (3) “immunemodulation” to prevent autoimmune reactions (4) Increased production of glutathione + metallothionein
**WHAT SHOULD YOU NEVER EVER GIVE IN ACUTE HEPATITIS?*** Corticosteroids !!!!! DONT GIVE PREDNISOLONE or PREDNISONE ! ! ! (ok so no steroids in laminitis or acute hepatitis) (Maybe bc bacterial infections, since the liver gets all the bact from the gut?)
*what is a follow up you must do if you are going to treat acute hepatitis?Control biopsy after 3-6 weeks to exclude chronic hepatitis
***WHEN IS URSODIOL C/I?Contraindicated in biliary duct obstruction (bc has flushing effect and inc BA flow-- if there is a block this is bad news)
2 dzs ursodiol is particularly awesome in?(1) Especially useful in destructive cholangiolitis (2) Best choice for chronic hepatitis of unknown etiology ....... 7.5 mg/kg/day q 12 h (Start slowly, watch for abdominal cramping, diarrhea)
**Destructive Cholangiolitis: WHAT IS THIS? CSs? Idiosyncratic reaction during sulfonamide treatment in dogs... There is Acute severe destruction of biliary flow. You will see: intrahepatic CHOLESTASIS, nausea, vomiting, icterus
**how do you treat destructive cholangiolitis? prog?Immediate stop of sulfonamide treatment (duh), **Ursodeoxycholic acid.... 50% chance of recovery
****What is the meaning of “ Idiosyncratic reaction ” during sulfonamide treatment (destructive cholangiolitis)?Type B adverse drug reaction-- rarely and unpredictably amongst the population, Not dose dependent, Independent of pharmacological effect, and probably immune mediated. (“ they can occur in the beginning or at any time during a treatment, completely unpredictable")

Hepatic encephalopathy/ PSS/portal vein hypoplasia (PVH)

Question Answer
Hepatic Encephalopathy: Why do you see seizures in acute hepatic encephalopathy??This is bc the liver cannot convert the NH3 (ammonia) so there is too much NH3 in circulation-- increased (pre)synaptic release of glutamate (excitatory)-- over-activation of Glutamate receptors. ("mating is a frenzied seizure like activity")
how does acute hepatic encephalopathy cause brain edema and also CNS depression?So, from before, we learned that INC NH3 will cause inc presynaptic release of glutamate which is excitatory, so you get seizures. However, then astrocytes in the brain detoxify NH3 into glutamine. and then high levels of glutamine in the astrocytes causes them to accumulate fluid and swell--> brain edema--> Decreased neuronal transfer between CNS regions (CNS depression)
in CHRONIC NH3 toxicity, there is deranged balance of neurotransmitters-- which are high and which are low?inhibitory (GABA) HIGH (so CNS depression) and excitatory (glutamate) LOW (so really seizures are in the acute phase, not chronic)
in CHRONIC NH3 tox-- is GABA or glutamate downregulated? which is upregulated? what are the results of this?(1) GLUTAMATE (excitatory receptor) is DOWNREGULATED--> no reuptake in astrocytes--> extrasynaptic Glutamate Accumulation. (2) Increase of inhibitory γ-Aminobutyric acid (GABA)--> Hypercortisolemia
too much GABA can cause what condition?Hypercortisolemia (inc ACTH secretion from high GABA!!)
Non-hepatic Encephalopathy DDxs? Renal Encephalopathy (kidney not clearing waste products--> accumulate in brain), Hypo- / Hyperglycemia (brain not getting enough/too much glucose affects nerves bc they depend on glucose), Hypo-/ Hyperthyroidism (thyroid has everything to do with metabolism incld the brain), Hypocalcemia (need Ca for synapse vesicle release)
Differential diagnoses for high NH3 in dogs (4)(1) primary portosystemic shunt (intrahepatic (large breeds), Extrahepatic (small breeds) ), secondary portosystemic shunt, portal vein hypoplasia, (urea cycle enzyme deficiency)<--rare
how can you know its portal vein hypoplasia and not a shunt?can only dx if pt has no shunt. if shunt, close shunt, then see that the vessels dont work (portal system doesnt work)
in a liver shunt, what are levels of NH3 and Urea like?both high, or variation, depending on how much is actually getting through the liver ((either way you are seeing too much NH3 bc whatever gets through shunt isnt converted)
Small dogs tend to get what kinda shunt the most? Large dogs?SMALL: tend to get a portal vein to vena cava shunt.... LARGE: tend to get a Persistent Ductus Venosus
6 possible types of shunts(1) portal vein to vena cava shunt SMALL DOGS (2) Persistent Ductus Venosus LARGE DOGS (3) portal to azygous (4) portal vein hypoplasia (see mult collateral shunts) (5) L gastric to vena cava (6) portal vein and caudal vena cava and azygous
If you aren't sure if there is a PSS, what is a SUPER easy test you can do?POST-PRANDIAL WORSENING!!!!! (feed them see if it gets worse) <--she said this is a text book thing and in real life tends not to happen?
Textbook Clinical signs of shunt?(1) Ascites, edema from low albumin (2) Ataxia, incoordination, blindness, head pressing, circling, coma, seizures (very late), circling, salivation, pu/pd, dehydration (3) Vomiting, diarrhea, nausea, inappetence, anorexia in 30% (4) Dysuria / stranguria / fever (5) POSTPRANDIAL WORSENING!!
what is the typical dog patient for PSS like? What are their CS?Dogs < 8 month old! “small statue” , smaller than siblings, sometimes vomiting, vague signs of encephalopathy (e.g. lethargy after meal), and she said "in real life" not all worsen after feeding !
What are two big signs of possible PSS in CATS?(1) 75% salivation! (2) 20% copper colored iris(?)
what is liver size like with a PSS, most often?SMALL LIVER!!! She said "small liver small dog" for PSS like a million times. (also about 50% of cats will also have small liver)
what might kidneys look like with PSS?Bilateral Renomegaly
why do you see PU/PD in PSS?medullary washout, Increased ACTH Secretion from high GABA (Hypercortisolemia), Urate cristaluria
what will CBC be like with PSS?Microcytosis!!! (liver not making enough cholesterol to make up part of the RBC membrane I think?)
which chem values will be high and which will be low in a PSS?(1) HIGH: ALT & Alk Phos (liver damage) (2) UREA, TP, Alb, Gluc, Cholesterol (liver makes these things so if it's sick, they will be low)
what will pre and post prandial bile acids be like with PSS?INC bile acids pre and post prandial (bc liver is not able to clear them after they are reabsorbed from the gut)-- Cholestasis, Icterus, PSS
what can cause a false positive inc in bile acid serum test? (WHICH BREED ALSO)Lipemia & Hemolysis & Maltese dog breed
which dog breed just sorta always has high BAs?maltese
which breed just sorta has high ammonia?irish wolfhound
remember: LARGE dogs get which kind of shunt (intra/extra)? specifically what kind?INTRAHEPATIC, esp persistent ductus venosus. (Old English Sheepdog, Australian cattle dog, Irish wolfhound, Labrador Retriever)
Remember: SMALL dog breeds get which kind of shunt (intra/extra)?EXTRAHEPATIC (Dandie Dinmont terrier, Yorkshire terrier, Mini schnauzer , Cairn terrier, Havanese, Maltese, Pug)
how does portal vein hypoplasia compare to PSS clinically? histologically?Clinically indistinguishable from PSS, Histologically identical to PSS
**What do you want to warn owners about if you are gonna do shunt sx?PSS AND PORTAL VEIN HYPOPLASIA ARE OFTEN CONCURRENT--- anddddd we can't fix portal vein hypoplasia.
***which two breeds tend to get portal vein hypoplasia?Yorkshire terrier & Cairn Terrier
portal vein hypoplasia used to be called? microvascular dysplasia
what are some signs of portal hypoplasia?Portal hypertension, nodular liver growth, partial portal vein hypoplasia

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