Week 4 - GI Flashcards
What are some CS for liver dz?
anorexia
vomiting
weight loss
weakness
ascites
polyuria
icterus
seizures
melena
polydipsia
grey feces
lethargy
fever
dark urine
obtundation
Why would you get ascites with liver dz?
- hypoalbuminemia, decreased colloidal oncotic pressure
- portal hypertension
Why would you get seizures with liver dz?
hepatic encephalopathy
What are the 5 liver parameters that assess function?
- Albumin
-made exclusively by hepatocytes
-decreased - BUN
-decreased, since the formation of urea is related to the hepatic metabolism of ammonia (liver takes ammonia and makes BUN)
-would be increased with GI bleeding - Glucose
-decreased, reflecting impaired gluconeogenesis - Bilirubin
-might be normal or increased due to cholestasis - Cholesterol
-synthesized by liver, so severe liver dysfunction is
associated with decreased cholesterol synthesis (hypocholesterolemia)
-but with cholestatic dz – would see an increase
Increased liver enzymes tell NOTHING about liver function. What are the liver enzymes?
ALT
AST
ALP
GGT
What’s ALT?
-Alanine aminotransferase (ALT)
-cytosolic
-leakage enzyme – leaks from hepatocytes when cell membrane permeability increases and when the cell undergoes necrosis
-SPECIFIC to liver (small amt in heart, kidneys, muscle)
-t1/2 for dogs: 2.5days (60 hours), so a 50% decrease over 2 to 3 days is a good prognostic sign
-t/12 for cats: 6 hours, MUCH faster, should decrease faster
-anticonvulsants and corticosteroids can cause induction of ALT
-ALT elevation indicates a hepatic abnormality in both species, it provides little information regarding diagnosis, prognosis or appropriate therapy
What’s AST?
-Aspartate aminotransferase (AST)
-not as specific to liver, present in: liver, skeletal muscle, heart, kidneys, brain, plasma
-Serum AST is derived from liver, skeletal muscle, and cardiac muscle sources
-leakage enzyme
-cytosolic and mitochondrial liver isoenzymes
–cytosolic enzyme: released with reversible or irreversible damage to hepatocyte plasma membranes and usually parallels increases in ALT
–mitochondrial liver enzyme: released only with irreversible hepatocyte injury (necrosis)
-t/12 for dogs: 12 hours
-t/12 for cats: 77 minutes
–so AST should return to normal faster than ALT
-if serum AST is much higher than serum ALT, a muscle source of the enzymes should be explored
–usually and increase in AST + CK would mean skeletal muscle damage is playing a bigger factor
What’s ALP?
-Alkaline phosphatase (ALP/AP)
-produced by bile duct epithelium (PRODUCTION enzyme)
-found in liver, bone, intestinal mucosa, kidney, and placenta
–usually never released by other organs, so increased ALP can be specific, particularly in cats (nearly all cats with increased ALP will have liver dz)
–ALP bone isoenzyme increases due to osteoblast activity
-Glucocorticoid-induced isoform in DOGS (not cats)
-Mild increases in feline SAP are significant because cats have only one third the concentration of AP per gram of liver than dogs + shorter t1/2
-t/12 of dogs: 66-72hours
-t/12 of cats: 6hours
-ALP bone isoenzyme can increase with osteoblast activity
What’s GGT?
-Serum gamma-glutamyl transferase (GGT)
-increases due to obstructed bile flow
–most marked elevations in GGT result from diseases of the biliary epithelium, such as
bile-duct obstruction, cholangitis, and cholecystitis
-more sensitive/less specific when compared to ALP for necroinflammatory bile disease
-increases both after administration of glucocorticoids
-GGT»_space; ALP in inflammatory disorders of portal triad and bile ducts
-Both ALP and GGT should always be evaluated concurrently
-in CATS, GGT is more sensitive than ALP for bile dz
**Hepatic Lipidosis: increased ALP, normal-mild increase GGT
**Cholangitis: increased ALP, moderate-marked increased GGT
Why is bilirubinemia ALWAYS ABNORMAL in a cat?
- Higher renal threshold vs. dog - cat is a 9x threshold, so if bilirubin is high, it is truly high
- Cats cannot conjugate bilirubin in PCRT
Why is Increased ALP activity is ALWAYS ABNORMAL in cats?
- No corticosteroid-induced isoenzyme
- Short half-life of ALP (6 hours)
- Less ALP in hepatocytes vs. dogs
Is triaditis more common in dogs or cats?
CATS
liver, pancreas, bowels
Common causes of secondary (reactive) hepatopathies
- Diabetes mellitus
- Hypoxemia
- Hyperlipidemia
- Hyperthyroidism
- GI disease (e.g., IBD)
- Pancreatitis
- Drug-induced
- Right-sided congestive heart failure
What is the Diagnostic Utility of Serum Bile Acids Test?
- Relatively sensitive for diagnosing PSS – 88.9% in dogs
*value of function, so don’t need to run serum BA test if you know liver is already trash
- Improves the diagnostic performance of routine
tests for hepatic disease when used adjunctively - One should perform pre- and post-prandial bile
acid measurements
-BAs under enterohepatic circulation
-BA concentrations provide no information regarding the type or severity of the disease, nor does it differentiate primary from secondary liver disorders
-Serum BA test is not usually indicated w icterus unless you cannot differentiate between pre, hepatic, post
–serum BA test usually more indicated when normal
–NORMAL BAs - prehepatic
–HIGH BAs - hepatic or post
What is the Diagnostic Utility of Blood Ammonia Test?
-marker for liver disease in dogs, particularly
identification of those with HEPATIC ENCEPHALOPATHY due to portal vein vascular anomalies
-ammonia is produced in the GIT, due to microbial degradation of nitrogenous matter in the colon
-ammonia is removed by liver/hepatocytes and converted into BUN
–could be impaired in liver disease or when portal blood does not flow through liver normally
-Blood ammonia in cats is less useful than in dogs, since increases may occur in any disease that produces anorexia
-not routinely done
What are common liver dz in cats?
- Hepatic lipidosis (idiopathic vs. secondary – 26-50%)
- Cholangitis (inflammation of biliary system)/Inflammatory liver dz – 25%
- Neoplasia – 20%
-Hepatic cyst adenomas
-Lymphoma
-Carcinoma
-Mast cell tumor - Secondary reactive hepatopathies – 16%
- Vascular – 6%
- Toxic – 5%
- FIP - < 2%
What is Hepatic Lipidosis?
-accumulation of excess triglycerides in hepatocytes with resulting cholestasis and hepatic
dysfunction
->80% of hepatocytes would be vacuolated
What is the pathogenesis to Hepatic Lipidosis?
-not well understood
-takes up to 6 weeks to see CS
*protein deficiency
* Excessive fatty acid uptake
* Inability to oxidize fatty acids
* Excessive lipogenesis
* Inhibition of synthesis/secretion of very-low-density lipoproteins (VLDLs)
What is the prognosis for Hepatic Lipidosis?
good, improved over years. good outmode with long term enteral feedingprognosis for IHL is influenced to a large
prognosis affected by the ability of the clinician or owner to aggressively meet the cat’s caloric requirements via enteral feeding
poorer prognosis with pancreatitis
What are pre-disposing factors for Hepatic Lipidosis?
obesity
stress
anorexia
Should you restrict protein from a cat with Hepatic Lipidosis?
NO – you should NOT restrict protein from a cat with liver dz (ONLY if it has encephalopathy)
protein is needed for VLDL synthesis, which is already decreased during Hepatic Lipidosis, so help a cat out
How do you DIAGNOSE hepatic lipidosis?
- Signalment and history
- Moderate-marked increase in ALT and ALP
- Moderate increase in serum bilirubin
- Normal to mildly increased GGT
- Enlarged/hyperechoic liver on ultrasound - LIVER BIG AND BRIGHT
- Vacuolar hepatopathy on cytology and histology
-Most affected cats are clinically jaundiced; hence they will have concurrent hyperbilirubinemia.
How do you TREAT Hepatic Lipidosis?
- Food aversion plays important role in anorexia
- Do not force feed the cat!
- Appetite stimulants (benzodiazepines) have limited benefits and may exacerbate the hepatopathy
–benzos can be hepatotoxic - oxepezam, diazepam
–Elura, Mirtazapine, Cyproheptadine - Treat the underlying disease!
- Proactive nutritional and fluid support
- Nasoesophageal feeding tube - temp support of critically ill patient
1. small size, so only liquid diet
2. used in patients that can’t go under GA for other feeding tubes
*Esophagostomy or gastostomy feeding tube - need GA for placement - Avoid feeding orally for first 10-14 days following
tube placement - nothing by mouth
–after 10-14 days, try a novel food and see if cat wants to orally eat, if not, wait another 10-14 days and try again with a diff novel food - Do not restrict dietary fat or protein in cats with HL
- Diets containing 25-40% fat (DM) are well tolerated
Why is ensuring daily energy intake very important in a cat with Hepatic Lipidosis?
-Provision of adequate daily energy intake is the cornerstone of successful medical management
adequate supply of energy is needed to:
1) prevent catabolism of amino acids for energy
2) inhibit peripheral lipolysis
3) avoid excessive energy consumption which will promote hepatic triglyceride accumulation
commercial diets with:
-25-40% fat
-30-45% protein
What is one electrolyte that should be particularly assessed in cats with hepatic lipidosis?
POTASSIUM
-cats can be hypokalemic
-may develop due to inadequate potassium intake, vomiting, magnesium depletion, and concurrent
renal failure.
-Hypokalemia was significantly related to nonsurvival
-may prolong anorexia and exacerbate hepatic encephalopathy
-diet should have potassium/the cats should be supplemented with potassium
Why would CARNITINE be given to a cat with hepatic lipidosis?
-Carnitine transports long chain fatty acids across the inner mitochondrial membrane into the mitochondrial matrix for β oxidation
-removes potentially toxic acyl groups from cells and equilibrates ratios of free CoA/acetyl-CoA between the mitochondria and cytoplasm
-diets supplemented with L-carnitine can safely facilitate rapid weight loss in privately owned obese cats
How do you calculate the RER/resting energy requirements?
- RER = [BW (kg) x 30] + 70 (kCal/day)
-linear formula only good for 2-40kg - RER = 70 x BW 0.75 (kCal/day)
-logarithmic
-any weight in kg
must feed slow 3-4x a day, 20 min at a time
feed in 20-25% of RER increments
What is cholangitis?
-Inflammation centered on the biliary tree/inflammatory disorder of the hepatobiliary system
-often concurrently associated with duodenitis, pancreatitis, cholecystitis, and/or cholelithiasis
What are the 3 forms of cholangitis?
1.Neutrophilic (acute and chronic phases) – 80%
-bacterial infections
- Lymphocytic – 20%
-immune mediated or viral - Chronic cholangitis due to liver flukes
What are the CS for cholangitis?
non-specific
- Anorexia
- Weight loss
- Lethargy
- Icterus
- Vomiting
- Diarrhea
- Fever (neutorophilic bc infections)
What would cholangitis look like on US?
can be associated with:
-gall bladder
-common bile duct distension
-tortuosity
-cholelithiasis
-cholecystitis
-bile sludging
What is Neutrophilic Cholangitis?
-infiltration of large numbers of neutrophils into portal areas of the liver and into bile ducts
-Can begin as ascending bacterial infection from the GIT
-Secondary to pancreatitis, IBD, cholelithiasis?
-Predispositions: Congenital or acquired abnormalities of the biliary system, including anatomic abnormalities of the gall bladder or common bile duct and gall stones
What bacteria is associated with Neutrophilic Cholangitis?
E. coli
Clostridia
Bacterioides
Actinomyces
alpha-hemolytic Strep
You can have acute and chronic Neutrophilic Cholangitis. What’s the difference?
difference is histologically is based on:
-presence of increased plasma cells, acute
-lymphocytes ± macrophages with the chronic phase
-Cats with acute cholangitis tend to be younger than chronic cholangitis and HL
-Male cats are more frequently affected with acute neutrophilic cholangitis
What is Lymphocytic Cholangitis?
-later stage of neutrophilic cholangitis, or may represent a separate disease entity
-Small lymphocytes mainly restricted to portal areas, variable portal fibrosis, and biliary proliferation
-PORTAL TRIAD LESION
-associated diseases: inflammatory bowel disease
and pancreatitis
What is Chronic Cholangitis secondary to fluke infestations?
-happens in Florida, areas like that
-severe ectasia of the bile ducts
-mild to severe hyperplasia of the biliary epithelium
-severe concentric periductal fibrosis
-occasional presence of adult flukes and/or operculate eggs within bile duct lumina
What is Chronic Cholangitis secondary to fluke infestations?
-happens in Florida, areas like that
-severe ectasia of the bile ducts
-mild to severe hyperplasia of the biliary epithelium
-severe concentric periductal fibrosis
-occasional presence of adult flukes and/or operculate eggs within bile duct lumina
When is Surgical Management of Feline Cholangitis indicated?
Only if discrete choleliths or complete biliary
obstruction observed
Cholecystoduodenostomy or cholecystojejunostomy
How do you DIAGNOSE Cholangitis?
-Hematologic and biochemical testing are essential to establish a diagnosis of liver disease
-need BIOPSY to differentiate between cholangitis - liver cytology or histopathology is essential to establish a definitive diagnosis
-BW and imaging can help figure things out, but BIOPSY is needed for a definitive diagnosis
Which test is the test that is most consistently abnormal in all types of inflammatory liver diseases and hepatic lipidosis?
Serums Bile Acids / Serum BAs
Lab findings of acute cholangitis?
-mild neutrophilia and left shift
-normal to slight increase in serum bilirubin
-normal/slight increase in serum alkaline phosphatase (SAP/ALP)
-substantial increase in alanine aminotransferase (ALT)
This profile tends to differentiate acute cholangitis from chronic cholangitis, hepatic lipidosis, and hepatic neoplasia
______ cats frequently have elevations in serum ALT and SAP, although the
magnitude of the elevation tends to be less than that of inflammatory hepatopathies
Hyperthyroid cats
Culture of _____ is superior to culture of liver
parenchyma for the isolation of bacteria
BILE
done via US-guided FNAs
How do you TREAT cholangitis?
-Treat underlying disease!
-Fluid and electrolyte replacement therapy
-nutritional support
-antibiotics
-immunosuppressives (chlorambucil, prednisolone)
-Ursodeoxycholic acid (Actigall)
-antioxidants (Denamarin which contains SAMe and Silybin)
Why is nutritional support important when treating cholangitis?
-many cats undergo esophagostomy tube placement to facilitate enteral nutritional support