Liver Flashcards
Normal Functions of the Liver
- Processing and Storage of Nutrients Absorbed from the Gut
- Bile Synthesis and Excretion
- Synthesis of coagulation factors and other proteins
- Infection and Immunity
- Hormone Metabolism
- Drug Metabolism
Liver Blood Supply
Extremely vascular; receives:
- Approx. 30% of its blood supply from the HEPATIC ARTERY
- Approx. 70% of its blood supply from the PORTAL VEIN (which carries venous blood with nutrients absorbed
Causes of Liver Impairment and Failure
** Alcohol-induced cirrhosis
** Viral hepatitis
** Congenital causes -> Hereditary Haemochromatosis
Wilson’s Disease -> inappropriate deposition of copper in liver
a1-antitrypsin deficiency -> Liver cirrhosis
Hereditary Haemochromatosis associated risks:
Haemochromatosis results in inappropriate deposition of iron in tissues and organs from birth which with time may result in impaired organ function:
- Liver Cirrhosis
- Diabetes Mellitus
- Hepatocellular carcinoma
** A 55 year old man with hereditary heamochromatosis has a 200x increased risk of developing hepatocellular carcinoma (compared to someone without the condition)
Acquired pathology of the liver can be considered to arise from:
The bile ducts
The parenchymal cells of the liver (hepatocytes)
Blood vessels
Acquired disorders of the biliary tree:
Gallstones
Primary biliary cirrhosis
Primary sclerosing cholangitis
Acquired disorders of the liver parenchyma:
Hepatitis (if persists may lead to Liver cirrhosis)
Liver Cirrhosis
Liver Cancer
Hepatitis Causes
Infections
o Hepatitis A, B, C & E
o Herpes viruses - Epstein Barr Virus (glandular fever), Cytomegalovirus & Varicella Zoster Virus (chickenpox)
Drugs and toxins
o Alcohol í acute hepatitis
o Prescription (paracetamol) or recreational drugs (ecstacy)
Autoimmune diseases
o Autoimmune hepatitis
Errors of metabolism
o Haemochromatosis
o Wilson’s disease
o A1-antitrypsin deficiency
Cryptogenic (of obscure or uncertain origin)
o Cause for chronic hepatitis
Cirrhosis =
A diffuse abnormality of the liver characterised by inappropriate regeneration and fibrosis with formation of structurally abnormal nodules incompatible with normal liver function.
Liver Cancer Risk Factors
Chronic alcohol abuse (most)
Primary Biliary Cirrhosis
Haemochromatosis
- Chronic Hepatitis B or C infection
Acquired disorders of the liver vasculature:
Portal Hypertension
Gastro-Oesophageal Varices - **May haemorrhage
Splenomegaly
Clinical Features of CHRONIC LIVER FAILURE
- Jaundice
- Prolonged bleeding
- Hepatorenal syndrome - Chronic liver impairment can induce renal impairment and failure
- Malnutrition
- Fluid Overload -> Tisse Oedema e.g. swollen ankles
- Ascites
- Nail changes
- Palmar erythema
- Spider naevi
- Hepatic encephalopathy
- Altered steroid hormone metabolism -> increased levels of oestrogen
ACUTE LIVER FAILURE =
Abrupt loss (over days/weeks) of normal hepatic functions - associated with high morbidity and mortality
ACUTE LIVER FAILURE Causes
There are many causes including drug-induced necrosis:
- Paracetamol overdose = the commonest cause of acute liver failure in UK
- Idiosyncratic drug reactions account for 15-20% of cases of acute liver failure
- Recreational drugs e.g. ecstasy
Diagnosis and Monitoring of Liver Impairment and
Liver Function Tests (LFTs)
Prothrombin Time
Blood test e.g. if viral hepatitis suspected
Ultrasound or MRI scanning e.g. if biliary obstruction or malignancy are suspected
Liver biopsy
