Liver Flashcards
Liver Functions
- ELIMINATION OF BILIRUBIN
- PRODUCTION OF BILE
- FAT METABOLISM
- VIT AND MINERAL STORAGE
- PROTEIN METABOLISM
- CARBOHYDRATE METABOLISM:
GLUCOSE STORAGE, GLYCOGENOLYSIS,
GLUCONEOGENESIS - BREAKDOWN OF HORMONES AND
STEROIDS - SYNTHESIS OF COAGULATION FACTORS
- DRUG/TOXIN METABOLISM
- INFECTION CONTROL
- HEAT PRODUCTION
Classifications of Liver Failure
Acute / Chronic Liver Failure
Stages of Acute liver failure timescales
Hyper Acute 8d
Acute 8-28 days
subacute 4-26 weeks
Causes of Liver Failure
Poisons/Chemicals/Drugs
infections
liver tumors
Stages of Alcohol liver disease
Fatty Liver > Liver Fibrosis > Cirrhosis
Fatty Liver stage of ALD is?
Deposits of fat causes liver enlargement. strict abstinence can lead to a full recovery
Fibrosis of the liver in ALD is ?
Scar tissue forms on the liver. Recovery is possible but scar tissue remains
Cirrhosis of the liver in ALD is ?
Growth of connective tissue destroys the liver cells. The damage is irreversible
Secondary causes of liver disease include
Ischaemia
liver tumours
acute on chronic
galactosaemia
reyes syndrome
wilsons disease
fatty liver in pregnancy
Clinical manifestations of liver disease
RESPIRATORY DYSFUNCTION
* CARDIOVASCULAR DYSFUNCTION
* ELECTROLYTE DISTURBANCES
* METABOLIC DISTURBANCES
* COAGULOPATHY/BLEEDING/DIC
* PORTAL HYPERTENSION
* RENAL DYSFUNCTION
* ASCITES
* JAUNDICE
* HEPATIC FOETER/PALMAR
ERYTHEMA/SPIDER
NAEVI/SPLENOMEGALY
* IMMUNOSUPPRESSION
* RARE COMPLICATIONS
Liver blood supply is from
Hepatic artery carrying oxygenated blood from the heart and the portal vein which delivers blood from organs such as stomach and intestines to your liver for processing.
The liver stores what
Glycogen, iron, copper, vit A, and many B-complex vitamins and vitamin D.
The liver produces what
albumin and other proteins, including clotting factors prothrombin and fibrinogen and anticoagulant heparin
what happens to amino acids in the liver
amino acids are deaminated (nitrogen removed)
What happens to nitrogen in the liver
it is used to produce new protein from carbohydrates or fat
The liver can make what from carbohydrates/proteins
It can make fat which is then stored and released as free fatty acids which can be utilised for energy
What can the liver do with cholesterol
Synthesizes cholesterol
In the liver, what is the purpose for phagocytes
To remove foreign substances and bacteria in the blood
What does the liver do to drugs
detoxifies drugs
what does the liver secrete
Cholesterol, bilirubin and enzymes
Liver generates what
Heat
What is Hepatitis?
Hepatitis: denotes any inflammation of the liver, usually due to acute viral infection. Lifelong immunity to the causative virus usually follows, but since several distinct viruses cause the disease, immunity to one type does not confer immunity to the others
Hepatitis A causes
Also known as infectious hepatitis, is transmitted by contaminated food or other objects taken into the mouth, or by unsterile hypodermic needle.
Hepatitis B cause
Also known as serum hepatitis, recognised since WWII. Hep B is transmitted by contaminated injections/transfusions and by sexual contact.
Hepatitis C cause
‘non-A’ ‘non B’, transmitted in blood or body fluids and caused by a virus which has been cloned, is most common cause of post-transfusion hepatitis.
Hepatitis D cause
Hep D, Delta virus, cannot replicate on own needs hep B, has caused epidemics and may be chronic.
Hepatitis E cause
Hep E, is transmitted in contaminated drinking water and can cause epidemic form of hepatitis C
Hepatitis Symptoms
All begin with fever, usually followed by weakness, loss of appetite, digestive upsets, and muscle pains. The upper abdomen may be painful and tender. Jaundice appears gradually, reaching maximum intensity at two weeks.5% goes on to chronic form. Fatality rate from all types of hepatitis is about 1% but may be higher for Hep B.
What is Jaundice
(icterus) yellowing of the skin, conjunctivae and mucous membranes due to raised plasma bilirubin, which is formed from breakdown of haemoglobin.
How many types of Jaundice
Two. Unconjugated and conjugated
4 Causes of Jaundice
Haemolytic jaundice due to red blood-cell damage
Newborns can have hyperbilirubinemia due to temporary defect in synthesis of enzyme that breaks bile down
Heptocellular due to damaged liver cells either by virus or excessive alcohol.
Obstructive due to physical block of ducts, can be due to gallstones, tumour or inflamation
History taking with jaundice
Duration
Previous attacks
Pain
Chills, fevers, systematic symptons
Itching
Exposure to drugs (prescribed or illegal)
Biliary surgery
Anorexia, weight loss
Colour of urine and stool
Contact with other jaundiced people
History of injections or blood transfusions
Occupation
Examination of the Jaundiced patient should include
Depth of jaundice
Scratch marks
Signs of chronic liver disease; palmar erythema, clubbing, white nails, dupuytrens contracture, gynaecomastia
Liver; size, shape, surface
Enlarged gallbladder
Splenomegaly
Abdominal mass
Colour of urine and stools
Liver function tests are
A variety of blood tests that assess general state of liver and bilary system
True LFT’s serum albumin, prothrombin time.
Tests that are simply markers of liver or bilary tract disease, measuring activity of various enzymes
Specific liver tests e.g. viral serologic tests or autoimmune tests to determine specific cause of liver disease
What are total serum protein levels
Concentration of total serum proteins outside normal range may occur in variety of circumstances
Increase in serum protein reflect increases in the levels of either of the two major serum proteins albumin and globulin, or increase in both. Generally, significantly increased total protein is seen if blood volume is reduced or in hypergammaglobulinaemia
A decrease in serum total protein reflects decreases in either albumin or globulin, or in both, and indicates a problem with liver function.
What is Serum Albumin
Serum proteins are only produced in the liver.
Albumin levels are best test of medium to long-term hepatic function.
Reduced levels of albumin are a useful indicator of
hepatic disease
Albumin is made ?
Albumin is synthesised by the liver, making 10 to 14g daily to replace albumin degraded.
Fluctuating albumin can be caused by
Albumin levels may fluctuate for many reasons,of which liver disease is one.
In liver disease, particularly more advanced cases, the amount of all liver proteins decreases and serum albumin levels drop to less than 35 g/l
Half life of albumin
The half-life is 17 to 20 days, as a result impaired synthesis may take months to become apparent.
Increased serum albumin is caused by
Increased serum albumin is not natural; Absolute increase may occur artificially by infusion of hyperoncotic albumin. Relative increase may occur if blood becomes concentrated.
Decreased level of albumin causes
In states of decreased synthesis due to malnutrition, malabsorption, liver disease
Increased loss due to nephrotic syndrome, many GIT conditions, thermal burns.
Increased catabolism due to thyroidtoxicosis, cancer chemotherapy.
Serum Globulin is
Globulin is increased disproportionately to albumin in states characterised by chronic inflammation and B-lmphyocyte neoplasm.
Decreased serum globulin is caused by
Decreased globulin may be seen in congenital or acquired hypogammaglobulinaemia
Prothrombin time is
Defined as the time taken for a fibrin clot to form in plasma under standard conditions. Normal range is approx. 11-13 seconds,
Prolonged prothrombin time is caused in which conditions
but this is prolonged when liver damage occurs, caused by; bile duct obstruction, cirrhosis, hepatitis, malabsorption of nutrients, vit k defiency, warfarin therapy.
Prothrombin time is the best test of short term hepatic function, what factors are produced in the liver
factors 11, V11, 1X & X are produced in liver and have short half-lives.
Prolonged PT can be caused by what
Prolonged PT can be caused by acute liver dysfunction or Vit K deficiency. Retesting 24 hrs after administration of Vit K can eliminate the latter.
Gamma-glutamyltransforase (Gamma-GT) tests for
Very sensitive test for liver damage,
Markedly increased GGT Levels indicate
Markedly increased in lesions which cause intrahepatic or extrahepatic obstruction of bile ducts.
Slight increase in GGT indicate
Lesser elevations are seen in other liver disease and in infections, mononucleosis, hyperthyroidism, myotonic dystrophy
Drugs causing hepatocellular damage and cholestasis may also raise gamma-GT.
although unexpected, unexplained mild elevations are common. Alcohol is often the culprit.
Increased Bilirubin levels are caused by
Infectious hepatitis
chemically induced damage from alcohol, hydrocarbons and other substances
drugs may damage liver or interrupt bile flow
neoplasm
biliary tract obstruction
Decreased bilirubin levels indicate
Not usually of any clinical significance although has been observed in IDA
Aminotransferase Enzymes types
Alanine aminotransferase(ALT)
and
aspartate aminotransferase(AST) are indicators of liver disease.
Aminotransferase Enzymes location, cause of increase levels
ALT AST Both are located in liver cells and leak out into general circulation when cells damage
Which aminotransferase enzyme is more liver specific
ALT is more specific to liver as AST may be elevated in heart or muscle disease
Difference between acute and chronic ALT AST levels
in acute injury ALT & AST may be 100+ times normal, in chronic elevation may be minimal
Mild / Moderate elevations of ALT AST causes
Mild or moderate elevations are nonspecific and may be caused by wide range of liver disease
ALT & AST are often used to monitor the course of chronic hepatitis and response to treatments, such as prednisolone and interferon
Alkaline Phosphatase ((ALP)) increasing indications
Elevated in large number of disorders that affect the drainage of bile, gallstones, tumours, alcoholic or drug induced.
It is also found in other organs (bone, intestine) and for this reason GGT is utilized to ensure raised levels is due to liver. GGT will not be elevated in other organ disease.
Imaging in acute/chronic liver disease
Plain radiography has limited role.
Chest may show subphrenic gas, abnormalities of diaphragmatic contour and related pulmonary disease, including metastes
Abdominal may be useful to show calcified or gas containing lesions (gallstones, chronic pancreatitis, liver abscesses)
USS in acute/chronic liver disease is
First line imaging in patients with jaundice, right upper quadrant pain, or hepatomegaly.
Non-evasive, inexpensive and quick but requires experience in technique and interpretation.
Good identifying cysts, tumours, pancreatic masses and fluid collections. Visualisation of lower common bile duct and pancreas can be hindered by overlying bowel gas.
Computed Tomography in acute/chronic liver disease is
Complementary to ultrasongraphy, provides information on liver texture, gallbladder disease, bile duct dilation, and pancreatic disease.
Particularly valuable for detecting small lesions in the liver and pancreas.
Liver biopsy is useful when
Provides information regarding hepatic lobular architecture and is most helpful in patients with undiagnosed persistent jaundice
Bilirubin > 100mol/l =
= urgent referral to hospital (Primary care)
Bilirubin < 100mol/l + ALP + GGT ^ =
obstruction
Bilirubin < 100mol/l + ALT^ =
hepatitis
Hepatitis A IgM + =
treat for Hep A
Cirrhosis features
Focal or diffuse inflammation and liver cell necrosis that causes severe changes in the structure and function of liver cells
Inflamed liver cells compress the liver lobule and cause increased resistance to blood flow and portal hypertension
Liver tissue is regenerated, but not in the normal fashion
Fibrotic changes are irreversible causing liver dysfunction; same clinical S & S of liver failure
Causes of Liver Cirrhosis
Alcoholic: results from long-term alcohol abuse; (most common)
Biliary: caused by a decrease in bile flow; commonly caused by long-term obstruction of bile ducts
Cardiac: caused by long-term right-sided CHF
Postnecrotic: result from hepatoxins, chemicals, or infection with hepatitis B or C
Portal HTN features
Fibrosis of the liver structures causes an increase resistance to blood flow within the liver, therefore an elevation in the portal venous pressure
This increase in pressure can cause
varices
ascites
splenomegaly
Varices features/ causes
Increased pressure in the portal vein is transmitted back to veins which supply it
Most commonly affected are those from the oesophagus and rectum
Increased pressure in these vessels causes varicosities
Varices may rupture causing massive bleeding, exacerbated by disordered clotting
Ascities is
Accumulation of fluid in the peritoneal cavity
Ascities mechanisms include
Mechanisms include:
an increase in portal venous pressures
sodium and water retention
decreased blood osmotic pressure due to decreased production of albumin
Splenomegaly mechanism
Increased portal pressure is transmitted to splenic vein causing enlargement
Increased transit time of blood through enlarged spleen causes increased destruction of all types of blood cell
Hepatic failure mechanism
Occurs when the liver is unable to perform its many functions
May happen acutely or as result of progressive degeneration
Most often caused by viral hepatitis or cirrhosis
Features of Hepatic Failure
Hepatomegaly at first and then atrophy of liver
Cause of paleness/lethargy in hepatic failure
Anaemia due to decreased production or increased haemolysis
Cause of Bruising/Haematuria/ GI Bleeds in hepatic failure
Clotting disorders due to thrombocytopenia, decrease in clotting factor production and vitamin K absorption
Cause of Amenorrhoea, gynaecomastia
Fluid retention in hepatic failure
- Endocrine disorders due to abnormal metabolism of sex hormones and aldosterone
Features of hepatic failure : skin disorders include
Spider naevi, palmar erythema
Jaundice
Features of hepatic failure :Kidney disorders include
renal failure
Features of hepatic failure :neurological disorders include
Hepatic encephalopathy due to failure to convert ammonia
Tremor
Deterioration of mental function leading eventually to coma
Features of hepatic failure :portal hypertension complications/ disorders include
varices, ascities
