Liver Disease Flashcards
what are the functions of the liver?
metabolism of carbohydrates, lipids, proteins, ammonia, vitamins, bilirubin
storage of carbohydrate, vitamin, minerals,
Coagulation
Endocrine function
Immune and inflammatory response (kupffer cells)
describe the role of the liver in carbohydrate metabolism?
Glucose homeostasis and maintenance of blood sugar
In periods of prolonged starvation ketone bodies and fatty acids are used instead
describe the role of the liver in protein metabolism?
- Synthesis and storage of proteins
- amino acids from intestine and muscles.
- Controls rate of gluconeogenesis and transamination
- controls albumin levels
- Synthesises coagulation factors and complement system
- Stores vitamins
- Degradation – nitrogen excretion. Ammonia, converted to urea and exctreted by the kidneys
describe the role of the liver in lipid metabolism?
Metabolising lipoproteins
• VLDL synthesis and HDL
• HDL substrate for conversion of free cholesterol to cholesterol ester
• Triglyceride removed from IDL to produce LDL
• Oxidation or de novo synthesis of FFA occurs in the liver
• Cholesterol can be dietary or produced from acetyl coa – free or esterified with FA. Occurs via LCAT enzyme which is reduced in liver disease, increasing free cholesterol to ester, altering membranestructures.
what should you ask about in a patient with a history of liver disease?
- Timing and duration of symptoms and associated symptoms
- Patients concerns
- RF: blood transfusion, IV drug use, surgery, contacts – sex, chemical exposure
- Med hx: prescribed, OTC, herbal/alternative
- FH
in general what can diseases of the liver be classified as?
- functional abnormalities
- pathological manifestations
what are the functional abnormalities that can cause problems with the liver?
- Metabolism – protein, carb, lipid, bile acid, bilirubin, hormone and drug
- Removal of microbes/toxin
- Excretion
- Immunological function
what are the pathological manifestations causing disease of the liver?
- acute hepatitis
- chronic hepatitis
- jaundice
- cirrhosis
- hepatocellular carcinoma
describe the features of acute hepatitis (causes and consequences)?
Toxic Drugs – paracetamol poisoning Viruses (hep A, B, C, D, E) Alcohol Vascular damage Biliary Obstruction – gall stones, tumours Metabolic
describe the features of chronic hepatitis (causes and consequences)?
Toxic, drugs – 24% alcohol related
Hep (B, C, D) – 57% Hep C
AI Disease (AI hepatitis)
Biliary Disease – primary biliary cirrhosis, sclerosing cholangitis, graft vs host disease, transplant rejection
Steatohepatitis (NASH – non-alcohol SH)
Steatosis is fatty infiltration of the liver. When inflammation is associated with fatty change, the term steatohepatitis is used.
RF: obesity, DM, hyperlipidaemia, jejunoileal bypass surgery
what are the causes of jaundice?
Drugs Viruses Alcohol AI Disease (primary biliary cirrhosis, Primary sclerosis cholangitis) Biliary obstruction Sepsis
what are the causes of crirrhosis?
Drugs Viruses Alcohol amyloidosis Biliary obstruction Others: haemochromatosis
what are the most common conditions associated with elevated LFTs?
hep C
NAFLD
what tests make up LFTs?
- Albumin
- Bilirubin (total and conjugated)
- Serum aminotransferases (AST and ALT)
- Alkaline phosphatase (APT)
- PT
what are synthetic liver function tests?
- Bilirubin
- PT
- Albumin
what is albumin?
– main protein synthesised by the liver and circulates in blood. Production is controlled by multiple factors including nutritional status, serum oncotic pressure, cytokines, and hormones. A serum albumin may be reflection of the synthetic function of the liver. Ability to make this and other proteins is affected in chronic liver disease.
Total protein - albumin and other in blood
what is bilirubin and why is it important clinically?
bile its yellow/green colour.
Used to determine liver’s ability to clear endogenous/exogenous substances from the circulation.
what are the types of bilirubin and when are these raised?
Indirect (unconjugated) bilirubin - Elevated with haemolysis, hepatic disease
Direct (conjugated) bilirubin - Elevated with biliary obstruction and hepatocellular disease.
what level does bilirubin need to be at for jaundice to develop?
≥ 3 mg/dL
what are aminotransferase enzymes?
Aminotransferase enzymes are intra-cellular enzymes
Also released from hepatocytes with hepatocellular injury.
examples: AST and ALT
what is the normal AST/ALT ratio and what is it in alcoholic hepatitis?
normal is 0.8
In alcoholic hepatitis, is usually > 2
what is ALT?
helps process proteins.
Large amounts occur in liver cells. When liver is injured or inflamed the blood level of ALT rises = hepatitis
ALT is usually considered more specifically related to liver problems than AST
what is AST?
enzyme in liver cells
involved in amino acid metabolism
High levels= liver is injured – hepatic necrosis.
AST can also be released if heart, liver, kidney, pancreas or skeletal muscle is
damaged – MI, CHF.
what is alkaline phosphatase?
a group of enzymes that catalyze the hydrolysis of a large number of organic phosphate esters.
In liver, believed to play an active role in down-regulating the secretory activities of the intrahepatic biliary epithelium.
what is gamma glutamyltranspeptidase?
induced by drugs and alcohol.
ALP normal and GGT raised = alcohol intake.
Mild GGT common with small alcohol consumption and fatty liver disease. In cholestasis ALP and GGT raised. Poor specificity. Sensitive huge.
what are the clotting factors that the liver synthesises?
Factor I (fibrinogen) Factor II (prothrombin) Factor V Factor VII Factor IX Factor X Factors XII and XIII
what is raised IgG suggestive off?
autoimmune hepatitis
what is raised IgM suggestive of?
primary billiary cirrhosis
what is raised IgA suggestive of?
alcoholic liver disease
in general what is the pattern of LFTs in patients with hepatocellular injury?
Very high AST, ALT with mild/moderately elevated alkaline phosphatase.
in general what is the pattern of LFTs in patients with cholestasis?
mild/moderately elevated AST/ALT with very high alkaline phosphatase
Bilirubin can be elevated with both combinations
What other specific blood tests can be performed in a patient with liver disease?
- Viral serology
- Blood alcohol
- Drug levels
- Liver auto antibodies
- Cu/Fe/a-1 anti-trypsin studies
- Unconjugated bilirubin, reticulocytes, hepatoglobulins/coombes test
what test is useful to perform for primary biliary cirrhosis?
anti-mitochondrial antibody
raised IgM
what test is useful to perform for autoimmune hepatitis?
anti-nuclear, smooth muscle(actin)
liver/kidney microsomal antibody
raised IgG
what test is useful to perform for hepatitis A, B, C, D, E
viral markers
what test is useful to perform for hepatocellular carcinoma?
alpha fetoprotein
what test is useful to perform for hereditary haemchromatosis?
serum iron, transferrin saturation, serum ferritin
what test is useful to perform for wilson’s disease?
serum and urinary copper
serum caeruloplasmin
what test is useful to perform for cirrhosis?
alpha1 antitrypsin
what test is useful to perform for primary sclerosing cholangitis?
anti nuclear cytoplasmic antibodies
what test is useful to perform for non alcoholic fatty liver disease and hepatits C?
markers of liver fibrosis
what test is useful to perform for HFE gene (hereditary haemochromatosis)?
genetic analysis
what steps need to be taken in diagnosing a patient with acute hepatitis?
- history and examination
- IgM anti HAV (if positive= hep A)
- HBsAg and IgM anti-HBc (if positive hepB then do anti HDV if risk factors)
- anti HCV (if positive=hep C)
- if all these are negative consider wilsons, EBV, CMV, autoimmune hepatitis, congestive heart failyre, biliary tract disease, metastases
- consider biopsy
what investigations would be performed in a patient with elevated ALT?
- history and examination
- HBsAg->IgM anti-HBc [if +ve=acute hep B] [If -ve=chronic hep B]
- anti-HCV->hepatitis C
- if above -ve consider wilsons, haemochromatosis, autoimmune hepatitis, alpha 1 antitrypsin deficiency, coeliac disease
- if all above -ve US or CT for fatty liver or biopsy
what investigations should be performed in a patient with mild diffuse LFT abnormalities?
- history and examination
- obesity, diabetes, hyperlipidaemia (non alcoholic fatty liver)
- viral hepatitis risk factors (serological tests)
- autoimmune features (serum globulins and auto antibodies)
- other considerations (test for haemochromatosis, wilsons disease, alpha 1 antitrypsin deficiency, coeliac disease)
- if all above consider US, CT, MRCP, ERCP, liver biopsy or transient elastography as suggested by results
what investigations should be performed in a patient with elevated alkaline phosphatase?
- history and examination
- GGT or isoenzymes normal ->extra hepatic source
- elevated = hepatobiliary disesae
- abdominal US (if normal->AMA, ACE level, serological tests for viral hepatitis, alpha fetoprotein.) gallstones, focal lesion, biliary tract abnormalities
- if all above negative consider biopsy, transient elastography
when would you take a liver biopsy?
- Acute and chronic liver dysfunction
- Hepatomegaly
- Space occupying lesions
- To find cause and severity (stage of progression)
what action would be taken if work up is negative and AST/ALP remain elevated?
Observe:
o Patients with two-fold or less increase in AST/ALT and no hyperbilirubinemia
Liver Biopsy
o Patients with > two-fold increase in AST/ALT, or abnormalities of other liver function tests
what causes hepatocellular injury?
viral hepatitis hepatitis due to other viruses drug induced liver injury toxins metabolic vascular events
what other viruses can cause hepatitis?
herpes viruses 1,2 and 6
adenovirus
epstein barr virus
CMV
what toxins can cause liver injury?
Amanita phalloides (death cap)
what metabolic issues can result in hepatocellular injury?
acute fatty liver of pregnancy
reye’s syndrome
what vascular issues can result in hepatocellular injury?
Acute circulatory failure
Budd-Chiari syndrome (occlusion of hepatic veins)
Veno-occulsive disease
Heat stroke
what other conditions can result in hepatocellular injury?
Wilson disease
Autoimmune hepatitis
Massive tumour infiltration
Liver transplant with primary graft dysfunction
describe the role of the liver in drug metabolism?
- Liver major site of drug metabolism
- between the splanchnic and systemic circulations and large amount of enzymes that are capable of transforming drugs into active compounds or degrading for elimination
- Converted from fat soluble to water soluble substances that are excreted in urine or bile
what is a phase I drug reaction?
oxidative and reductive processes
what is a phase II drug reaction?
oxidation, reduction and hydrolysis are couple with endogenous substrates such as glucuronic acid, sulfuric acid, glutathione. Render polar lipophilic compounds. Excreted in bile if molecules are large or in urine if small
what is a phase III drug reaction?
reactions actively transported from cell.
what are the 6 mechanisms that drugs can cause liver damage?
- Disruption of intracellular calcium homeostasis
- Disruption of bile canalicular transport mechanisms
- Formation of non-functioning adducts
- Present on surface of hepatocyte as new immunogens – attacked by T cells
- Induction of apoptosis -Inhibit mitochondrial function
describe drug induced hepatotoxicity?
- Intrinsic hepatotoxins = paracetamol
- Idiosyncratic (abnormal physical reaction to something) hepatotoxins = hypersensitivity and metabolic Can lead to hepatitis, cholestasis, fatty change and fibrosis
what affect can paracetamol have on the liver?
- Undergoes conjugation with glucuronide and sulphate. Remainder is metabolised by microsomal enzymes to produce toxic derivatives. Detoxified by conjugation with glutathione.
- Larger doses ingested, pathway becomes saturates and toxic derivative is produced at faster rate, binds to cell membranes. Can produce liver necrosis
what affect can halothane and other volatile anaesthetics have on the liver?
- Produces hepatitis in those having repeated exposures
* Hypersensitivity reaction
what affect can steroid compounds have on the liver?
- Cholestasis caused by natural and synthetic oestrogens
* Interfere with biliary flow
what affect can phenothiazines have on the liver?
- Cholestatic picture
* Hypersensitivity reaction
what affect can anti TB chemo have on the liver?
• Elevated AMT
• Hepatic necrosis with jaundice
• Rifampicin produces hepatitis, pyrazinamide
produces abnormal liver tests
what affect can amiodarone have on the liver?
steatohepatitis?
describe acetaminophen overdose?
• Toxicity is likely to occur with single ingestions greater than 250 mg/kg or those greater than 12 g over a
24-hour period
• AST/ALT elevation is first sign of liver damage (usually 24-hours after ingestion)
what is acute hepatitis and how does it present?
- Definition: Rapid development of hepatic synthetic dysfunction
- Presentation: jaundice, bleeding, confusion, abnormal LFTs
what is the aetiology of acute hepatitis?
- Drugs – isoniazid – first line treatment for TB
- Halothane (general anaesthetic)
- Viruses – hepatitis A, B, C, EBV, CMV, Adenovirus, Herpes
- Alcohol
what is the commonest cause of liver disease worldwide?
acute viral hepatitis
what effective vaccines are available for acute viral hepatitis?
o Enterically transmitted: HAV, HEV
o Blood borne: HBV, HCV, HDV, HGV
what are the symptoms of acute viral hepatitis?
- Asymptomatic
* Health screen in at risk populations
Is hepatitis A acute or chronic?
acute
what part of the history are important in a patient with hepatitis A?
travel recent outbreak nausea vomiting jaundice
what labs are useful to diagnose hepatitis A?
hepatitis A IgM
frequent elevated bilirubin
is hepatitis B acute or chronic
can be both?
what part of the history are important in a patient with hepatitis B?
See if patient from Asia, Subsaharan Africa; Sexual history, Drug use
what labs are useful to diagnose hepatitis B?
hepatitis B surface antigen
surface antibody
core antibody
what part of the history are important in a patient with hepatitis C?
IV drug abuse, blood transfusion prior to 1992, Sexual history, Tattoos
what labs are useful to diagnose hepatitis C?
Hepatitis C antibody (Hepatitis C viral load if HIV positive or immunocompromised)
what labs are useful to diagnose infectious mononucleosis (acute EBV)?
monospot
EBV IgM
what would LFTs show in a patient with HIV?
isolated elevated aminotransferases
what labs are useful to diagnose HIV?
HIV antibody test
what part of the history are important in a patient with HIV?
sexual history
IV drug use
what is the transmission of hepatitis A?
faecal oral
where are outbreaks of hepatitis A common?
schools
institutions
what is the incubation period of hepatitis A?
28 days (between 15-50)
describe the onset and symptoms of hepatitis A?
abrupt onset fever malaise anorexia nausea abdominal discomfort dark urine jaundice
how does age affect the symptoms presenting in a patient with hepatitis A?
age related
<6yrs 70% asymptomatic
>15yrs 70% icteric
what test is used to make a diagnosis of hepatitis A?
hep A IgM
what is the first sign of hepatitis A in smokers?
going of the fags
what is an effective way of preventing hepatitis A/
vaccination
describe the pre-icteric phase?
prodromal illness days to weeks
• Icteric = jaundice
• A prodromal phase from days to more than a week
• Characterised by appearance of symptoms like loss of appetite, fatigue, abdominal pain, N&V, fever,
diarrhoea, dark urine and pale stools (cholestatic phase)
• Malaise
• Anorexia
• Flu-like and GI like symptoms
• Few signs except for enlarged liver and jaundice