Diseases Of The Hepatobilliary Tract Flashcards
What are the microstructural features of the liver?
Sinusoids Bile canaliculi Bile duct Branch portal vein Branch hepatic artery Central vein
What forms the portal triad?
Hepatic artery
Portal vein
Bile duct
-> join together to make the central vein
What is the function of sinusoids?
Act like a filter aiding with the filtration process of the liver
What do bile canaliculi do?
Tubes that help drain the bile
What are the 3 main functions of the liver?
- Filter
2 Elimination of the filtrate - Metabolism
What forms the portal vein?
Splenic vein
SMV
IMV (attachment point is variable)
What are the clinical features of filter failure?
Portal vein hypertension (bleeding)
What are the clinical features of elimination failure?
Jaundice as you cannot get rid of bile
What are the clinical features of metabolic failure?
Acidosis
Muscle loss
Coagulopathy (more likely to bleed)
Hepatorenal syndrome
What is the clinical relevance of porto-systemic (portocaval) anastamosis?
Portal vein hypertension will effect + dilate these vessels at the anastomoses causing varicies which can potentially rupture (can be quickly fatal in some areas)
What are the 5 types of porto-systemic (portocaval) anastomosis?
- Oesophageal
- Rectal
- Paraumbilical
- Retroperitoneal
- Intrahepatic
What is cirrhosis? What does it look like?
An effect of liver scarring that has a characteristic nodular appearance - macronodular OR micronodular
What is caput medusae?
Umbilical veins re-open as a result of portal hypertension affecting the paraumbilical anastomosis
What is encephalopathy?
Failure of filter, elimination AND metabolism = hallmark of liver failure
What might the cause of encephalopathy be?
Nitro-amine type compound crossing BBB
What are the signs and symptoms of encephalopathy?
Signs: Liver flap (coarse/irregular flapping tremor) 5 pointed star/trail test Confabulate (mix up truths) Coma
Symptoms:
Reversal of sleep pattern
Shorted attention span
Constructional dyspraxia
What are the signs of chronic liver disease?
Spider naevi Clubbing Ascites Palma erythema Dupuytren's contracture Leuconychia Gynaecomastia Testicular atrophy Loss of body fair Caput medusa Splenomegaly Encephalopathy Parotid enlargement Jaundice Oedema Muscle wasting Coagulopathy/bleeding
What are the mechanisms of liver injury?
Acute (4-6 weeks)
Chronic (>6 weeks)
What is the general model of chronic diseases?
Organ function deteriorates over many years + at about 20% of functioning, you start to see clinical problems
What is the model of chronic liver disease?
Liver function deteriorates over a number of years, but the liver is a resilient organ (unlike the heart for e.g.) so compensates until the liver has 20% function left, which is when patients liver failure
Is ascites ever normal?
Yes, in women premenstruation
Why do you get coagulopathy as a symptom of chronic liver disease?
Because liver produces key proteins involved in blood clotting
What is decompensation of chronic liver disease? What can cause it?
2nd hit exposes the lack of liver reserve so liver deterioration speeds up showing a dramatic drop leading to liver failure directly as a result of infection (bacterial e.g. SBP), toxins (e.g. alcohol), trauma (e.g. surgery), drugs (e.g. sedatives), dehydration (e.g. diuretics), variceal bleeds/bleeding in general or malignant transformation (e.g. hepatoma)
What happens if chronic liver disease decompensation is treated?
Patients liver function can be brought back up so the patient is no longer in liver failure but the function will still be lower as a result of the event that caused decompensation
What will multiple decompensation episodes do to patients with chronic liver disease?
Bring them closer to liver failure quicker
What are the causes of liver injury (in order of most problematic to least)?
Fat
Alcohol
Virus
Iron
(factors often co-exist)
Why is hepatitis C not as big a cause of viral liver injury now?
Because there is now a treatment for it
What different types of fat problems can cause liver injury?
Non-alcohol fatty liver disease (NAFLD): T2DM, metabolic syndrome
Non-alcohol steatohepatitis (NASH)
What type of fat is more problematic?
Fat on the inside: peri-organ fat
What clinical tests are there of liver injury?
Blood tests
Imaging
Liver biopsy
What blood tests would you for the liver? What do they test for?
LFTs: indicating liver damage -> AST, ALT
Liver screen: determines the CAUSE of damage -> viruses, iron, genetic disorders
What blood tests are there for liver distress? What do they show?
ALT/AST: indicate hepatitis/hepatocyte damage
ALP/γGT: indicate obstructive/bile duct damage
What blood tests are done as true tests of liver function?
Prothrombin time Bilirubin (excretion) Albumin Urea/creatinine pH
What imaging/scans can be done on the liver?
US +/- liver biopsy CAT scan MRI MRCP (looks at bile duct specifically) Liver fibroscan (enhanced liver fibrosis; ELF)
What are CTs and MRIs good at picking up?
CT: large liver lesions e.g. cancers
MRI: bile duct problems e.g. inflammation, stones
Why type of imaging would not pick up gallstones?
X-ray as they as made of cholesterol which is a different constituent to kidney stones, which will show up on a X-ray
What 3 types of biliary problems exist?
- Gallstones
- Pancreatitis
- Cancer
What is jaundice?
Failure of body to EXCRETE bile
Clinically apparent when serum bilirubin is 2x above normal concentration ~ 34uM/L
What types of gallstones exist?
Gallbladder stones (cholelithiasis)
Bile duct stones (choledocolithiasis)
Gallstone pancreatitis
What is the gallbladder wall made up of?
Epithelium
Lamina propria
Fibromuscular layer
What is the gallbladder wall made up of?
Epithelium
Lamina propria
Fibromuscular layer
What are gallstones?
Stones associated with high fat diets/hypercholesterolaemia
Can be formed by reduced bile secretion or defective reabsorption of bile salts
Most are cholesterol based but other rare types as a result of RBC breakdown e.g. pigment stones found in those with haemolytic disorders (high serum bilirubin)
What are the pros and cons of ultrasound scan (UsS) investigation?
Pros: simple, non-invasive + widely available
Cons: operator dependent, poor specificity + poor views of pancreas
What is the appearance of gallstones on an ultrasound scan (USS) called?
Acoustic shadows
What is endoscopic retrograde cholangio pancreatography (ERCP)?
A scope on a catheter is put in + dye is squirted up the hepatic duct allowing you to see this duct + the pancreatic duct crossing the vertebrae (why patients present with back pain when they have pancreatic problems)
Stones can be cut out/grasped in this surgical procedure
What surgical procedure can patients get done if gallstones are a continuous problem?
Laparoscopic cholecystectomy
What effects may ensue if a patient has their gallbladder removed?
More likely to develop diarrhoea
Slight increased risk of colon cancer (due to increased exposure of bile acids to lining of bowel)
What are the pros and cons of endoscopic retrograde cholangio pancreatography (ERCP)?
Pros: high sensitivity + specificity (therapeutic too)
Cons: invasive, technically challenging + complication risk
What are the 2 types of pancreatitis?
- Acute
2. Chronic
What are the causes of pancreatitis?
I - idiopathic
G - gallstones
E - ethanol
T - trauma
S - steroids M - mumps/malignancy A - autoimmune S - scorpion sting H - hypertriglycerides/hypercalcaemia E - ERCP D - drugs
What are the functions of the pancreas?
- Endocrine: insulin
2. Exocrine: enzymes, amylase, trypsin, chymotrypsin, lipase + bicarbonate
What effects can chronic pancreatitis have?
Pain
Endocrine -> diabetes
Exocrine -> malabsorption
Pancreatic failure (if advanced)
What blood tests can be done acute and chronic pancreatitis?
Acute: amylase (lipase)
Chronic: none (diabetes)
What blood tests can be done for pancreatic cancer?
None (CA19.9, miRNA or volatile organic compounds)
What imaging interventions exist?
US EUS CT MRCP ERCP (therapeutic) PTC (therapeutic)
When is the commonest types of pancreatic cancer?
Adenocarcinoma
Neuroendocrine cancers affect function of pancreas too
Why is bile duct cancer becoming more common?
Increased cirrhosis makes cholangiocarcinoma more common which increases chances of cancer
Can patients get gallbladder cancer?
Yes but it is rarer than pancreatic or bile duct
What blood tests exist for biliary obstruction?
Bilirubin
ALP
What blood test exists for gallstones?
None
What tests are done as part of a liver screen?
Infection: viral hepatitis (HAV, HBV, HCV)
Metabolic: alcohol, haemochromatosis, Wilson disease, α-antitrypsin deficiency
Inflammatory: autoimmune hepatitis, primarily biliary cirrhosis, primary sclerosing cholangitis
Malignancy
What is the morbidity and mortality of liver biopsies?
Morbidity:
- 30% experience pain
- 0.35-0.5% get significant haemorrhage
- 0.01-0.1% get other organ punctures
Mortality = 0.1 - 0.01%
What are the causes of acute liver injury?
A sudden/recent insult resulting in:
- Filter failure
- Elimination failure -> jaundice
- Metabolic failure -> encephalopathy, acidosis, renal failure
What are the causes of chronic liver disease?
On-going low grade insult causing:
- Filter failure -> portal hypertension, ascites
- Elimination failure -> jaundice
- Metabolic failure -> weight/muscle loss, encephalopathy
What are the 4 consequences of non-alcoholic fatty liver disease (NAFLD)?
Fatty liver
NASH
(Cryptogenic) cirrhosis
Liver cancer (HCC)
What functional tests can be done on the pancreas?
Endocrine: blood glucose + glucose tolerance test
Exocrine: faecal fats, PABA test, pancreolauryl test + faecal elastase
Whats are the pros and cons of computerised tomography (CT)?
Pros: widely available, good views of pancreas + transferable images
Cons: radiation exposure + high demand
What are the pros and cons of Magnetic Resonance Cholangio-Pancreatography (MRCP)?
Pros: good mapping of ducts
Cons: limited (but increasing) availability
What interventions can be done on these problems?
ERCP
EUS
PTC
Surgery
What are the pros and cons of endoscopic ultrasound (EUS)?
Pros: very sensitive, good demonstration of vessels + biopsy can be done
Cons: limited availability + operator dependent
What are the pros and cons of percutaneous transhepatic cholangiography (PTC)?
Pros: specific + therapeutic
Cons: invasive + uncomfortable
