Liver Flashcards
What are some causes of liver failure?
Viral hepatitis Alcohol Drugs e.g. paracetamol, halothane Industrial solvents Mushroom poisoning
Define and give examples of a portal system.
Vein(s) that terminate at both ends in a capillary bed (no valves) - two capillary systems in series
Hepatic portal system
Hypothalamo-hypophyseal portal system
What are some complications of liver failure?
Increased susceptibility to infections (bacterial & fungal)
Increased susceptibility to toxins, drugs, hormones
Hyperammonaemia —> hepatic encephalopathy (ammonia not cleared by urea cycle and produced by colonic bacteria)
How can cirrhosis affect the portal system?
Shrinkage of liver compresses capillaries and leads to increased pressure in the hepatic portal system -> portal hypertension
What are portosystemic anastomoses? List them.
Communication between two blood vessels without any intervening capillary network
PORTAL SYSTEMIC OESOPHAGEAL: left gastric vein azygos veins
RECTAL: superior rectal vein middle/inferior rectal veins
PARAUMBILICAL: ligamentum teres superior/inferior epigastric veins
RETRO-
PERITONEAL: colonic veins body wall veins
INTRAHEPATIC: hepatic/portal veins inferior phrenic veins
PATENT DUCTUS left branch of portal vein IVC
VENOSUS:
What are some of the complications of portal hypertension?
Portosystemic shunting: connections between portal system opens up
Oesophageal varices = enlarged veins in lower oesophagus —> rupture —> massive bleeding (black & tarry or bloody stools, anaemia, haematemesis)
Caput medusae = distended umbilical veins (ligamentum teres reopens) which radiate from the abdomen to join the systemic veins
Rectal varices = enlarged collateral submucosal rectal veins
Ascites (reduced albumin & increased portal pressure)
Spider Naevi (oestrogen dependent - dilated arteriole forming a red papule with radiating prominent capillaries resembles a spider)
What is the difference between rectal varices and haemorrhoids? What is the purpose of the veins in the anorectal junction?
Rectal varices only occur in patients with portal hypertension
Haemorrhoids occur equally in patients with and without portal hypertension - prolapse of rectal venous plexus
Increased pressure in veins prevent flatus from escaping (just as veins at the GOJ help close it off)
How can caput medusae be differentiated from IVC obstruction?
Harvey’s test
Block off umbilical vein below the umbilicus
Blood flows towards legs - caput medusae
Blood flows towards head via abdominal collaterals - IVC obstruction
What are some of the functions of the liver?
Bile production
Metabolism (inc. cholesterol synthesis, gluco/glycogenesis/lysis, lipogenesis)
Protein & vit. D synthesis (inc. albumin, fibrin, prothrombin)
Detoxification
Vitamin & mineral storage
Phagocytosis
Outline the different liver function tests and what each is testing for?
Hepatocellular damage —> aminotransferases (ALT/AST) & gamma-glutamyl transpeptidases (gamma-GT)
Cholestasis —> bilirubin & alkaline phosphatase
Synthetic function —> albumin & prothromin time (INR - clotting)
What are the causes of pre-hepatic jaundice?
Excessive haemolysis —> excess bilirubin
INHERITED:
- red cell membrane defects
- Hb abnormalities
- metabolic defects
ACQUIRED:
- immune
- mechanical
- acquired membrane defects
- infections
- drugs
- burns
CONGENITAL HYPERBILIRUBINAEMIAS:
- Gilbert’s syndrome (reduced glucuronyl transferase —> reduced conjugated bilirubin) - stress causes jaundice (non-haemolytic jaundice)
What are some typical laboratory findings in pre-hepatic jaundice?
Unconjugated hyperbilirubinaemia
Reticulocytosis (excess reticulocytes - immature RBCs)
Anaemia (haemolytic)
Increase LDH (lactate dehydrogenase found in RBCs)
Decreased haptoglobin (binds free Hb)
What are some of the causes of hepatocellular jaundice?
Deranged hepatocyte function + some cholestasis (swelling prevents substances leaving the gallbladder)
CONGENITAL:
- Gilbert’s syndrome
- …..???
HEPATIC INFLAMMATION:
- viruses e.g. hepatitis, Epstein-Barr
- autoimmune hepatitis
- alcohol
- haemochromotosis
- Wilson’s disease (enzyme impairment causing copper accumulation: cirrhosis, tremors, dementia, dysarthria, tubular degeneration, Kayser-Fleischer rings around iris)
DRUGS:
- paracetamol
- ….????
CIRRHOSIS:
- alcohol
- chronic hepatitis
- metabolic disorders
HEPATIC TUMOURS:
- hepatoceullar carcinoma
- metastases
What are some typical laboratory findings in hepatocellular jaundice?
Mixed conjugated and unconjugated hyperbilirubinaemia
Increased ALT/AST (hepatocyte breakdown)
Normal or increased ALP (cholestasis)
Reduced clotting factors
Reduced albumin
What are some of the causes of post-hepatic/cholestatic jaundice?
Obstruction of biliary system (intra or extrahepatic cause) which blocks the passage of conjugated bilirubin into the bile canaliculi
INTRAHEPATIC (hepatocyte swelling):
- hepatitis
- drugs
- cirrhosis
- primary biliary cirrhosis
EXTRAHEPATIC (obstruction distal to bile canaliculi):
- gallstones
- biliary stricture
- carcinoma (head of pancreas, bile duct, porta hepatis lymph nodes, liver metastases)
- pancreatitis
- sclerosing cholangitis
- ascending cholangitis
-> pale stools/dark urine (lack of sterobilinogen/urobilinogen)
What are some of the causes of hepatitis?
VIRAL: hep. A, B, C (+ D, Epstein-Barr, CMV, Yellow fever)
AUTOIMMUNE
DRUGS: methyldopa, isoniazid
HEREDITARY: alpha-1-antitrypsin disease, Wilson’s disease
Give some examples of the complications of alcoholic liver disease.
Hepatocellular carcinoma
Liver failure
Wernicke-Korsakoff syndrome (B1 deficiency - thiamine - which causes lesions in the CNS)
Encephalopathy
Dementia
Epilepsy
How does liver cirrhosis occur and damage the liver?
Liver cell necrosis —> nodular regeneration & fibrosis —> increased resistance in blood vessels —> deranged liver function
Causes:
- alcohol
- hepatitis B/C
- biliary cirrhosis (primary - autoimmune destruction of bile ducts -> jaundice, pruritis, xanthelasma, hepatosplenomegaly)
- autoimmune hepatitis
- haemochromotosis (iron deposition -> cardiomyopathy, diabetes, hypogonadism, hepatitis, hyperpigmentation)
- Wilson’s disease
What are some of the signs & symptoms of liver cirrhosis?
Jaundice Anaemia Bruising Palmar erythema Dupuytren's contracture Portal hypertension Spontaneous bacterial peritonitis Flapping
What are the typical laboratory findings in liver cirrhosis?
Normal or elevated ALT/AST
Increased ALP
Increased bilirubin
Reduced albumin
Deranged clotting
Reduced Na+
What is fulminant hepatic failure? What can it be caused by? What are the signs and symptoms?
Acute/severe decompensation of hepatic function due to increased metabolic demand, which leads to hepatic encephalopathy within 2 months of liver disease diagnosis
Causes:
- hepatitis A, D, E
- paracetamol, isoniazid, ecstasy
- Wilson’s disease
- pregnancy
- Reye’s syndrome (unknown aetiology, variable symptoms e.g. brain, liver, hypoglycaemia)
- alcohol
Signs & symptoms:
- jaundice
- encephalopathy (oedema/toxins)
- reduced level of consciousness
- hypoglycaemia (loss of glycogen stores)
- reduced K+ & Ca2+
- haemorrhage (coagulopathy)
- renal failure
What is hepatic encephalopathy? What can it be caused by? What are the signs and symptoms associated with it?
Reversible neuropsychiatric deficit due to inability of liver to remove ammonia (which shunts to the systemic and crosses the blood-brain barrier)
Precipitated by:
- sepsis/infection
- constipation
- diuretics
- GI bleeding
- alcohol withdrawal
- oedema
Signs & symptoms:
- flapping tremors
- reduced level of consciousness
- personality changes
- intellectual deterioration
Reduce confusion by treating cause, 10% dextrose + ionic supplements if required, lactulose to cause diarrhoea
Where are the common sites of hepatic tumour metastases?
Along portal venous drainage
- neuroendocrine
- pancreas
- breast
- stomach
- kidney
- lung
- ovary
What is the difference between the anatomical and functional lobes of the liver?
Anatomical: left and right lobes; separated by the falciform ligament
Functional: quadrate lobe (anterior surface) and caudate lobe (posterior surface); defined by ductal and vascular anatomy (right limb of gallbladder, sulcus of vena cava)
