GI Medicine - Liver Disease Flashcards
what is failure of liver detoxification due to?
hepatic dysfunction and/or abnormal blood supply (PSS)
what does build up of ammonia lead to?
hyperammonaemia
hepatic encephalopathy
what is caused by hepatic dysfunction and/or abnormal blood supply (PSS)?
failure of conversion of ammonia to urea
failure of drug detoxification
what is a key effect of the failure of drug detoxification in the liver?
anaesthetic agents have a prolonged effect
what is the effect of encephalopathic toxins?
forebrain dysfunction
when is hepatic encephalopathy made worse?
following high protein meal
GI haemorhage
why is hepatic encepalopathy worse after a high protein meal?
increased ammonia produced due to bacterial fermentation and enterocyte glutamine metabolism
what are the precipitating events for hepatic encepalopathy?
feeding high protein meal
vomiting diarrhoea
diuretics (lead to dehydration)
what laboratory tests are used to diagnose liver disease?
liver enzymes (may be primary or reactive) bilirubin bile acids blood glucose blood clotting parameters
what is bilirubin a marker of?
jaundice
what are bile acids a measure of?
liver function
what diagnostic tests are used in liver disease?
laboratory tests
imaging
liver cytology (FNA)/biopsy
what are the most common causes of acute liver disease?
toxins or infections
what are the most common toxins which cause liver disease?
xylitol
mushrooms
blue green algae
aflatoxins
what are the most common drugs which cause acute liver disease?
phenobarbitone paracetamol azathioprine doxycycline lomustine (CCNU)
what are the most common bacteria which cause acute liver disease?
leptospirosis
ascending biliary infection
what are the most common viruses which cause acute liver disease?
canine adenovirus
what happens during ascending biliary infection?
bacteria from the gut move into bile duct and cause infection
what are the main nursing considerations associated with acute liver disease?
management of hepatic encephalopathy anti-emetics for nausea manage hypoglycaemia consider implications for venepuncture due to coagulopathy risk specific therapies barrier nursing?
how is hepatic encephalopathy managed in acute liver failure?
lactulose
seizure management if needed
maintain and monitor hydration and electrolytes (esp. K+)
how may lactulose be administered?
oral
retention enema
how does retention enema work?
foley catheter used to introduce and hold Lactulose in the colon
what must be remembered about drug dosing in patients with acute liver disease?
dose will need to be reduced due to reduced liver function
how can hypoglycaemia be managed?
glucose infusion
feed complex carbohydrates little and often
what are the specific therapies for acute liver disease?
antioxidants
antibiotics
describe nutritional management of acute liver disease
restricted animal protein diet
copper restricted diet
antioxidant supplementation
what si the best diet for acute liver disease?
replete protein, plant or soy based (e.g. Purina HA)
why is reduced or alternative to animal protein diet needed in liver disease patients?
to reduce ammonia
what diet can be used if plant (soy) based diets cannot be used?
hepatic (or less ideally renal) prescription diets are appropriate
cottage cheese added to give more, safe protein
what are the overarching causes of inflammatory liver disease?
sterile
infectious
what are the sterile causes of inflammatory liver disease?
chronic hepatitis (dogs) lymphocytic cholangitis (cats)
what causes chronic hepatitis?
idiopathic
copper
why does copper cause inflammatory liver disease?
toxic to hepatocytes
what happens during lymphocytic cholangitis (cats)?
immune system attacks bile ducts
what are the infectious causes of inflammatory liver disease?
cholangitis / cholangiohepatitis (chronic and acute)
leptospirosis
chronic FIP
what are the specific treatments for inflammatory liver disease?
de-coppering therapy for copper excess
antibiotics - if indicated
what are the general treatments for inflammatory liver disease?
dietary moification liver supportive therapies (anti-oxidants) steroids choleretics hepatic encephalopathy therapies ascites management (spironolactone)
what do choleretics do?
support bile flow
what is involved in de-coppering therapy?
chelating agent
restrict copper intake
what chelating agents may be given during de-coppering therapy?
D-penicillamine
zinc therapy - long term use
how does zinc aid de-coppering?
competes with copper for uptake into liver
how can copper intake be restricted?
diet (prescription and avoid red meat, offal, eggs and cereals)
check water source doen’t have copper pipes
what is the role of antioxidants?
facilitate repair and recovery of hepatocytes
what are the main antioxidants given to inflammatory liver disease patients?
Silymarin / silibinin / sylibin
S-Adenosyl-L-methionine (SAMe)
what is the most commonly used choleretic?
ursodeoxycholic acid (UDCA)
what is UDCA?
hydrophilic, beneficial bile salt
how is UDCA derived?
synthetic
how does UDCA work as a choleretic?
stimulates bile flow (reduces viscosity)
modulates inflammatory response in liver
what animal should not be given UDCA?
rabbits - not safe
what are 2 examples of metabolic liver disease?
gall bladder mucocoeles
feline hepatic lipidosis
what happens in the gall bladder during gall bladder mucocoeles?
gall bladder is full of inspissated bile and mucus
what does the gall bladder of a patient with gall bladder mucocoeles look like?
kiwi fruit
what are the signs of gall bladder mucocoeles?
asymptomatic
obstruction of bile flow
rupture of gall bladder
how are gall bladder mucocoeles managed?
medical
surgical
what happens during feline hepatic lipidosis?
triglyceride deposition within hepatocytes leading to liver failure
what are the reasons for feline hepatic lipidosis?
primary
secondary
what predisposes a cat to feline hepatic lipidosis?
obesity high fat diet high carbohydrate diet systemic illness DM
what does feline hepatic lipidosis lead to?
massive intracellular fat accumulation
liver failure
death
what are the risks associated with diagnosis of feline hepatic lipidosis?
coagulopathies may mean that clotting is slow - risk of bleeding during FNA
how can risk of bleeding in a patient with coagulopathy be reduced?
check clotting
provide vitamin K therapy (aid clotting factor production)
monitor CVS parameters closely during and after procedure
how is feline hepatic lipidosis treated?
treat underlying cause (primary vs secondary)
lipidosis treatment
6-8 weeks of home tube feeding
what is the most essential part of FHL treatment?
nutritional support
how should cats never be fed?
syringe or force
what nutritional support may be needed for FL patients?
tube feeding high protein antioxidants UDCA L-carnitine
how much food should FHL patients receive per day?
40-60 kcal/kg/day
what are the signs of congenital PSS?
small dull lethargic inappetant history of waxing and waning GI signs picky eater
what abnormal liver findings would you expect in a patient with congenital PSS?
low albumin
low cholesterol
high bile acids
high ammonia
what is a portosystemic shunt?
bypassing of liver by blood due to a shunt (extra vessel)
what are the 2 types of PSS?
single congenital
multiple aquired
how are multiple PSS acquired?
chronic hepatitis leads to increased resistance to blood flow in portal vein leading to opening of shunts
what is happening in portovascular anomalies?
blood from GI tract bypasses liver and goes straight into systemic circulation
toxins are not removed and liver does not receive nutrients
what does lack of nutrient supply to the liver during PSS lead to?
liver dysfunction
what is the result of blood from GI tract not being filtered by the liver if a PSS is present?
toxins will accumulate
hepatic encephalopathy and so brain dysfunction
how is PSS treated?
ensure hydration ensure serum K+ normal restricted protein or plant based protein diet Lactulose antibiotics anti seizure surgical closure of shunting vessel
how does lactulose work?
traps ammonia in the colon
what are the signs of hepatic neoplasia?
asymptomatic
primary hepatic or obstructive signs
rupture leading to haemoabdomen
what may be obstructed by a hepatic tumor?
vessels or ducts
what are the 3 main types of liver neoplasia?
primary tumors
inflitrative
metastatic
how are primary liver tumors treated?
surgery
what is an example of infiltrative liver neoplasia?
lymphoma
how is infiltrative liver neoplasia treated?
chemo
what is an example of metastatic liver neoplasia?
carcinoma
how is metastatic liver neoplasia treated?
no treatment as secondary to tumor elsewhere
