liver biochemistry Flashcards
where is the liver located?
Located under the diaphragm in the RUQ
what is the structure of the liver?
- 2 lobes
- Highly vascular structure
- Made up of about 300 billion cells
what are the functions of the liver?
- Homeostasis
- Metabolism
- Synthesis
- Immunological
- Storage
- Production of
bile
what does the liver homeostasis?
glucose
what does the liver control the metabolism of?
- Carbohydrates
- Protein
- Fats
- Steroid hormones
- Insulin
- Bilirubin
- Drugs
- Toxins
what does the liver control the synthesis of?
- Protein
- Clotting factors
- Cholesterol
what is the livers immunological function?
- Mobilise the macrophage system
- Kupffer Cells
what does the liver store?
- Fat soluble vitamins
- Glycogen
what does the liver secrete?
bile salts
what are the different types of liver diseases?
- Cholestatic
- Hepatocellular disease
– Steatosis
– Hepatitis - Fibrosis
- Cirrhosis
what is the difference between acute and chronic liver disease?
acute:
– Mild
– Self-limiting
– Develop into chronic disease
* Chronic
– Structural changes
→Compromise liver function
what are the symptoms of liver disease?
- Initially:
– Non-specific
– Easily fatigued
– Nausea - Often:
– Loss of appetite
– Weight loss
when are symptoms of liver disease most apparent? what are they?
- Apparent in decompensated liver disease
- Loss of muscle from arms and legs
- Swelling of the abdomen and lower body
- Abdominal pain
- Pruritus
- Bruising
- Bleeding – gums, nose
when are symptoms of liver disease most apparent? what are they?
- Apparent in decompensated liver disease
- Loss of muscle from arms and legs
- Swelling of the abdomen and lower body
- Abdominal pain
- Pruritus
- Bruising
- Bleeding – gums, nose
what are some signs of liver disease?
jaundice, fever, finger clubbing,white nails, oedema, varices, pigmentated ulceration of the skin
what are some causes of liver disease?
alcohol
viral infections- eg hep a,b,c,d,e
malignancy
immune disease
drugs and toxins
what is the marker of liver dysfunction?
Use a combination of factors:
–LFTs and additional tests
–Diagnosis
–Signs and symptoms
what are the standard LFTs?
– Albumin
– ALT
– AST
– GGT
– ALP
– Bilirubin
* Also need to remember:
– Clotting screen
what use would testing albumin be in liver disease?
Half life: 20 days
– Acute liver disease: normal
– Useful guide to the severity of chronic liver
disease
– Consider extrahepatic causes for low levels
when is alanine transferase released? - ALT
Released from hepatocytes when they are
damaged
what may ALT indicate?
a drug induced reaction
what is more specific to the liver ALT or AST?
ALT
when is asparate transferase released- AST
released from hepatocytes when they are damaged
where is AST primarily found?
in mitochondria- also in heart, kidnets, lung muscle and RBC
what markers in liver function tests tend to ruse and fall at the same time?
AST and ALT
what does the ratio of AST: ALT indicate?
may help in making a diagnosis more or less likely
what would the levels be in hepatocellular injury?
AST lower than ALt
chronic liver disease
what would the levels of established cirrhosis be?
AST>ALT
– AST:ALT of 2:1 or greater
* Alcoholic Liver Disease
* Especially if rise in GGT
what is GGT?
Gamma-Glutamyl transpeptidase (0 – 50 IU/L)
– Enzyme
where is GGT present? when is it released?
Hepatocytes, biliary epithelial cells, kidney,
pancreas, intestine, prostate
– Released in all types of liver dysfunction
what would the presence of GGT indicate?
indicate alcohol abuse
or if they are taking enzyme inducing drugs
what is ALP?
Alkaline phosphatase
it is an isoenzyme
where is ALP produced?
produced in hepatocytes
when would ALP be raised?
raised in cholestatic disease
Isolated rise may not be associated with liver
dysfunction
what is bilirubin?
breakdown product of RBC
what happens when bilirubin is transported into the liver?
bilirubin is conjugated
when would bile levels rise?
– When damage to the liver occurs, resulting in
jaundice
– Biliary tract obstruction
– Haemolysis
what are the clotting factors in the liver?
prothrombin- produced in the liver, vit K dependent
what is prothrombin time?
– Marker of synthetic function
– Time taken for a clot to form
– Exclude vitamin K deficiency
what additional tests can be preformed in addition to liver function tests?
– Ultrasound
– Doppler
– Biopsy
– Computed Tomography (CT)
– ERCP
– MRI
what are some of the complications with liver disease?
- Portal hypertension
- Ascites
- Encephalopathy
- Bleeding varices
- Spontaneous bacterial peritonitis (SBP)
- Pruritus
- Deranged clotting
- Hepatorenal syndrome (HRS)
what is portal hpt? how do you treat?
Increased pressure in portal venous
system
– Collateral veins develop
– Contribute to ascites and encephalopathy
* Treatment:
– Propranolol
what is ascites and how do you treat it?
- Swollen abdomen
– Accumulation of fluid
– Reduction in serum albumin
– Portal hypertension
– Decrease in aldosterone metabolism - Treatment:
– Low sodium diet
– Mobilise excess fluid - Diuretics
- Paracentesis
when does encephalopathy occur?
occurs with significant liver
dysfunction
– Altered permeability of the BBB
* Ammonia
– Altered mental state, asterixis
how do you treat encephalopathy?
– Aim is to reduce ammonia in circulatory system
– Lactulose
– Antibiotics
* Rifaximin
what is bleeding varices?
Upper GI bleeding
– Occurs in 50% of patients with end stage liver
disease
what are the aims of treatment with bleeding varices?
– Stop or slow down blood loss
– Treat hypovolaemic shock
– Prevent recurrent bleeding
how do you prevent bleeding varices?
– Propranolol and endoscopic ligation
– Carvedilol
how do you treat bleeding varices?
– Vasopressin or its analogue (terlipressin)
– Somatostatin or its analogue (octreotide)
– Balloon tamponade
what is the treatment and prophylaxis of spontaneous bacterial peritonitis?
– Acute
* IV antibiotics
– Prophylaxis
* High risk patients
* Quinolones
what is pruritis and how is it treated?
Deposition of bile salts within the circulation
* Treatment:
– Depends on severity
* Moisturising and cooling agents
* Ursodeoxycholic acid
* Antihistamines
* Anion exchange resins
what could be the underlying cause of muscle cramps?
diuretic induced
vitamin D deficiency
what treatment would you give for muscle cramps?
quinine sulphate
what are the s/e of quinine sulphate?
- Thrombocytopenia
- Cardiotoxicity
what pain relief can you give in liver disease?
DO NOT USE NSAIDs
* Opioids
– Morphine
– Oxycodone
– Fentanyl
* Paracetamol
what considerations should be made in liver disease?
hepatic blood flow
portosystemic shunting
reduced hepatic cell mass
reduction in protein binding
side effects
what are the main drug-induced liver diseases?
– Statins
– NSAIDs
– Penicillin’s
which may present weeks or months after stopping due to half life
