Hepatobiliary Flashcards
What are most common organisms in cholecystitis
E. coli, Enterococcus, Bacteroides, Clostridium
Which gas producing bacteria cause emphysematous cholecystitis
E. coli, Clostridium
What are the 3 types of necrotizing cholecystitis?
Type 1- necrosis without rupture
Type 2- acute inflammation with rupture
Type 3- chronic inflammation with adhesions and/or fistulae
What bilirubin concentration in effusion is consistent with bile peritonitis?
bilirubin 2x that of serum
What are the two types of parasites in the gallbladder and what is the treatment of choice?
Life cycle?
Platynosomum conciccum
Amphimerus pseudofelineus
Praziquantel
Eggs in snail, ingested by arthropod intermediate host, which is ingested by cat.
How long after obstruction does it take for gall bladder and cystic duct to become dilated? Intrahepatic bile ducts?
GB, CD: 24 hours
Intrahepatic BD- 5-7 days
What is the difference in composition of choleliths in dogs and cats vs humans?
Calcium carbonate and bilirubin vs. cholesterol in people
What mutation has been identified in shelties associated with gallbladder mucocele formation?
Insertion mutation on ABCB4 gene, which encodes for a protein that translocates phosphatidylcholine from the hepatocyte to the biliary canalicular lumen
What conditions are associated with an increased risk of developing GB mucocoele?
HAC.
Also associated with dyslipidemias.
MOA of ursodeoxycholic acid (ursodiol)
Causes choleresis
Immunomodulatory properties
May decrease mucin secretion
May improve gallbladder motility
List at least 10 hepatotoxins
acetaminophen aflatoxin amiodarone nsaids- aspirin and carprofen azathioprine azole antifungals cycads diazepam (oral, cats) halothane lomustine methimazole anticonvulsants- phenobarbital, phenytoin, zonisamide t/c TMS xylitol blue green algae mushrooms (aminita) canine adenovirus type 1 hepatic lipidosis (cats) stazolol - cats
% of cats with neutrophilic cholangitis who have fever?
19%-37.5%
~20-40%
% cats with neutrophilic cholangitis with positive bacterial culture and what bugs?
20-60% or more
E coli, enterococcus, clostridium, staph.
Classifications of hepatic encephalopathy?
Type A- [A]cute liver failure
Type B- [B]ypass - PSS
Type C- [C]irrhosis, portal hypertension, or acquired shunting
Type C is sub classified into episodic, persistent, or minimal/covert (i.e., normal mental/neuro status but abnormal test results on psychometric tests)
Two main causes of HE in cats
congenital PSS
Arginine deficiency secondary to hepatic lipidosis
Major c/s of cat with HE?
ptyalism
2 sources of ammonia in the GIT
Ureas producing bacteria- esp colonic, but also helicobacter pylori in stomach.
Enterocyte production of ammonia from glutaminase catalyzed reaction glutamine -> glutamate + NH3
2 pathways of ammonia detoxification in liver and differences in terms of affinity and capacity
Urea cycle- low affinity, high capacity
High glutamine synthetase activity- high affinity, low capacity
What cells in the brain have the highest glutamine synthetase activity and what have the highest glutaminase activity?
Astrocytes- glutamine synthetase
Neurons- glutaminase
Precipitating factors for HE?
sepsis, GI hemorrhage, constipation, excess dietary protein, dehydration, drugs, hypokalemia, hyponatremia, alkalosis, uremia, hepatic injury, blood transfusion, arginine deficiency in cats.
How does sepsis precipitate HE?
inflammatory mediators have synergistic effect with ammonia
inreased BBB permeability
How does constipation precipitate HE?
Dehydration
Electrolyte abnormalities
Bacterial overgrowth and bacterial translocation
How does dehydration precipitate HE?
Electrolyte changes
Increased renal ammoniagenesis
How does hypokalemia precipitate HE?
Movement of intracellular potassium into the extracellular space leads to intracellular acidosis and trapping of ammonium ions within cells
How does hyponatremia precipitate HE?
enhanced astrocyte swelling
How does alkalosis precipitate HE?
Increased access of ammonia to neurons (due to shift in equilibrium from ammonium ions to ammonia, which can pass through cell membrane)
How does uremia precipitate HE?
increased renal ammoniagenesis
Benefits of lactulose
- trapping of ammonium
- inhibition of ammonia production by colonic bacteria
- incorporation of ammonia within bacterial proteins
- reduced intestinal transit times
- increased fecal excretion of nitrogenous compounds
Antibiotic used in humans for HE
rifaximin
Efficacy of L-ornithine-L-aspartate (LOLA) for treatment of HE and MOA?
L-ornithing- substrate of urea cycle and L-aspartate substrate of reaction converting ammonia-> glutamine. LOLA is thought to increase rate of ammonia detoxification through both pathways.
Metaanalysis in humans should good efficacy for mild-mod overt HE.
What is role of manganese in HE ?
Neurotoxin believed to synergize with ammonia in causing HE. Dogs. w/ PSS have increased levels compared to healthy dogs, and evidence of manganese deposition in brain on MRI.
What aromatic amino acid is increased in HE in dogs?
phenylalanine.
Lester Retrospective evaluation of acute liver failure in dogs (1995-2012): 49 cases.
Definition of ALF? Incidence of neuro signs? Top causes? Survival? What factors associated with survival?
ALF: acute onset of clinical signs, hyperbilirubinemia, coagulopathy (PT>1.5 times ref), +/- HE
Neuro signs in 57%
Neoplasia- 27%, Lepto- 8%, Ischemia 2%, remainder idiopathic with ~50% of those having exposure to possible hepatotoxins
14% survival
Survivors had higher ALT, more likely to maintain normal albumin concentrations and not develop clinical bleeding or ascites.
What is the current definition of acute liver failure in human medicine (ALF in dogs and cats, JVECC 2015)
1- Absence of pre-existing liver disease
2-HE occuring within 8 weeks after onset of hyperbilirubinemia (>2.9mg/dL)
3- Presence of coagulopathy, (INR> 1.5)
Prognostic indicators for cycad ingestion (JVIM 2011)
Higher bilirubin and lower albumin at presentation negative indicator. Higher proportion of nonsurvivors had prolonged PT/PTT. Administration of charcoal as part of initial treatment plan had protective effect.
MOA of blue green algae toxicosis
Microcystins disrupt hepatocyte cytoskeleton leading to hepatic necrosis.
Stages of toxicity with amanita mushrooms
1- Latency period
2- 6-12 hours: GI signs
3 - False recovery - few hours to few days
4- fulminant hepatic, renal, MOF 36-84 hours after ingestion