Liver Flashcards
(238 cards)
What organs are retroperitoneal
SAD PUCKER
S - Suprarenal (adrenal) glands
A - Aorta
D - Duodenum
P - Pancreas
U - Ureter
C - Colon (descending, ascending)
K - Kidneys
E - Oesophagus (lower 2/3)
R - Rectum
Functions of the liver
- Protein synthesis (albumin, clotting factors)
- Glucose and fat metabolism
- Defence against infection (reticuloendothelial system)
- Detoxification and excretion (ammonia, bilirubin, drugs/hormones)
Describe the blood flow around the liver
Blood enters via hepatic artery (oxygenated blood) and portal vein (deoxygenated blood from intestine containing nutrients), which lie together in lobules with a bile duct. Blood flows into sinusoids, bathing liver cells, before exiting via central hepatic vein. Liver cells within lobule can be divided into zones 1 to 3, receiving progressively less oxygenated blood
End points of liver injury (in acute and chronic)
Acute
- Recovery
- Liver failure
- Progression to Chronic
Chronic
- Recovery
- Cirrhosis
- Liver failure
- Varices
- Hepatoma
What are cellular consequences of acute and chronic liver failure
Acute - damage to and loss of cells, causing necrosis or apoptosis
Chronic - Fibrosis (called cirrhosis when severe)
Define cholestasis
Any condition where bile flow is blocked
What tests are used to assess liver function? (7)
- AST
- ALT
- ALP
- GGT
- Bilirubin
- Albumin
- Prothrombin time (and INR)
What do the LFTs help distinguish
AST, ALT, ALP, GGT differentiate hepatocellular damage (AST, ALT) and cholestasis (ALP, GGT)
Bilirubin, albumin, PT assess liver’s synthetic function
What does ALT stand for and show
alanine transaminase
Marker of hepatocellular damage; found in high concentrations within hepatocytes
What does ALP stand for and show
Alkaline phosphatase
Particularly concentrated in liver, bone and bile ducts. Shows liver pathology in response to cholestasis.
Also raised in bone pathology especially pagets and bone cancer
What does GGT stand for and show?
gamma glutamyl transferase
Raised GGT suggests biliary epithelial damage and bile flow obstruction. Can be used with ALP to suggest cholestasis.
How are ALT and ALP compared to find pathology
> 10x ALT, <3x ALP suggests predominantly hepatocellular injury
<10x ALT, >3x ALP suggests cholestasis
How is the AST/ALT Ratio used?
AST/ALT ratio
- ALT>AST - Chronic liver disease
- AST>ALT - Acute alcoholic hepatitis or cirrhosis
What blood test is a marker of pancreatitis
Serum amylase and lipase.
Lipase has a longer half life and is more specific, but takes longer to show as raised.
Define acute liver failure with 3 characteristic signs
Severe acute liver injury with impaired function and altered mental status in patient WITHOUT existing liver disease or cirrhosis
Jaundice
Coagulopathy (INR>1.5!!!!)
Hepatic encephalopathy
Causes of Acute Liver Failure
Drugs
- Paracetamol overdose
- Isonazid
- Alcohol
Infection
- Hepatitis A and B
- EBV
- CMV
- Herpes simplex virus
Vascular
- Veno-occlusive disease
- Budd-Chiari syndrome
- Autoimmune hepatitis
- Metabolic conditions (Wilson’s)
- Cancer
- Fatty liver of pregnancy
- PBC/PSC
Pathophysiology of acute liver failure
Depends on underlying cause
- Massive hepatocyte necrosis/apoptosis.
- Causes jaundice, coagulopathy (INR>1.5), hepatic encephalopathy (ammonia builds up in blood, travels to brain, clearance causes cerebral oedema)
- HE usually within 8-28 days of noticing jaundice but can be up to 28
Grading system for Hepatic Encephalopathy
West Haven criteria
1 - Change in behaviour with minimal change in consciousness
2 - Gross disorientation, drowsiness, asterixis, inappropriate behaviour
3 - Marked confusion, speech problems, incoherent speech, rousable to verbal stimuli
4 - Comatose, no response to stimuli
Signs/symptoms of Acute liver failure
- Jaundice
- Coagulopathy
- Hepatic Encephalopathy
Nausea, confusion, asterixis, abdominal pain
Investigations in Acute liver failure
- Serum bilirubin (high), albumin (low), prothrombin time/INR (raised)
- Serum transaminases (AST/ALT) suggest hepatocellular pathology
Others (to find cause)
- Abdominal US with dopper can be used to find vaso-occlusion
- ABG/paracetamol levels may indicate paracetamol overdose
- Blood culture to rule out infection
- EEG to grade HE
- Coagulation
- Lipase/amylase
- Serum ammonia
Management of acute liver failure
Raise head of bed, tracheal intubation and NG tube
Treat underlying cause/complications: - intracranial pressure - Mannitol IV
HE - Lactulose (NH3+ excretion)
Haemorrhage/bleeding (vit k)
Paracetamol overdose - N acetylcysteine
Complications of acute liver failure
Progression to chronic (Ascites, varices, oedema)
Bleeding
Hepatic Encephalopathy (confusion, coma, mood/behaviour change)
Pathophysiology of paracetamol overdose
- Paracetamol usually metabolised by liver, but small amount metabolised by cytochrome P450 system
- Toxic intermediate of p450 pathway (N-acetyl-p-benzoquinone imine (NAPQI)) is normally detoxified by conjugation with glutathione, when all glutathione used up, toxic intermediate remains and damages hepatocytes.
Treatment of paracetamol overdose
- N-acetylcysteine (replenishes glutathione stores, which bind to NAPQI)
or
- Activated charcoal if patient presents within 1 hour of ingestion