Liver Flashcards
(45 cards)
Anatomical vs functional division of liver
Anatomical divided by falciform ligament
Functional divided by inferior vena cava & gallbladder fossa
Couinaud segments of the liver
How are the segments divided?
Segment I: caudate lobe
Segments II to VIII clockwise
Each has their own independent vascular inflow, outflow, biliary drainage
Divided by split of portal vein transversely, right/middle/left hepatic veins sagittally
Liver blood supply
75% by hepatic portal vein (splenic vein + superior mesenteric vein)
25% by hepatic artery
Functions of liver
1) Bile production
2) Metabolic functions - carbohydrate, lipid, protein, lactate
3) Clotting factor & protein synthesis
4) Vit D activation
5) Detoxification
6) Vitamin/mineral storage
7) Phagocytosis of bacteria
What is portal hypertension?
Chronic increase in portal pressure due to mechanical obstruction of portal venous system
When hepatic venous pressure gradient >=6mmHg (normal 3-5)
Pressure gradient between portal vein and hepatic vein
Portal vein formed by the union of the ___ and ___ at ___
splenic vein + superior mesenteric vein
behind the neck of pancreas
Causes of portal hypertension (divide into classifications)
1) Pre-sinusoidal
- splenomegaly -> increased splenic blood flow
- portal vein thrombosis
- splenic vein thrombosis
2) Sinusoidal
- CIRRHOSIS
- massive fatty change
- schistosomiasis
- Wilson’s disease, Caroli disease
3) Post-sinusoidal
- Hepatic vein thrombosis (Budd Chiari)
- Right heart failure, pericarditis
- IVC thrombosis
What is Budd Chiari syndrome?
Hepatic vein thrombosis that leads to post-sinusoidal portal hypertension
Where do portosystemic shunts occur?
1) Oesophageal branch of azygos (S) + left gastric vein (P)
2) Inferior rectal (S) + superior rectal (P)
3) Superficial epigastric (S) + paraumbilical (P)
4) IVC (S) + left branch of portal vein (P)
5) Renal/Gonadal (S) + Colic (P)
Complications of portal hypertension
Ascites
Portosystemic shunts - caput medusae, oesophageal varices
Portal hypertensive gastropathy - gastric mucosal friability & dilated blood vessels
Hepatic encephalopathy
Splenomegaly
What diuretic is used in ascites? Why?
Spironolactone - aldosterone antagonist
Portal HTN -> splanchnic vasodilation -> less effective blood volume in abdomen -> hypoperfused kidneys -> RAAS releases aldosterone to increase salt and water retention
What is SAAG?
Serum-ascites albumin gradient - directly correlates w portal pressure
SAAG >=1.1g/dL have portal HTN causing ascites (all the prepostsinusoidal stuff)
SAAG <1.1g/dL, non-HTN causes of ascites (malignancy, infection, inflammation, chylous ascites, nephrotic syndrome)
CT scan liver lesion features (HCC, adenoma, FNH, haemangioma)
HCC: hypervascular enhancement on arterial phase, portal venous washout
Hepatic adenoma: hypervascular enhancement on arterial phase, iso/hypointense on portal venous phase
Focal nodular hyperplasia: early arterial enhancement w centrifugal filling, sustained enhancement in portal venous phase (CHARACTERISTIC CENTRAL SCAR)
Haemangioma: early peripheral nodular enhancement in arterial phase, centripetal filling in, follows blood pooling
Most common benign liver tumour
Haemangioma - outgrowths of endothelium made of widened blood vessels
a/w with OCP, steroid, pregnancy
What can large haemangiomas cause?
Pain from liver capsule stretch, compression on surrounding structure
Rare: Kasabach-Merritt syndrome - consumptive coagulopathy -> thrombocytopenia
How do you diagnose haemangioma?
NOOOO BIOPSY - HAEMORRHAGE
Ultrasound, CT
What is focal nodular hyperplasia?
2nd most common benign tumour
CT shows characteristic central stellate scar
What are hepatic adenomas?
benign proliferation of hepatocytes - occurs in young females on OCP
Large lesions >5cm have high chance of rupture & haemorrhage
Resection of hepatic adenomas indicated in
Large lesions >4-5cm
Symptomatic
Cannot rule out malignancy
Male gender - high risk of malignant transformation
Hepatic cysts can be ___ or ___
Non-parasitic: simple liver cyst, PCLD, neoplastic cysts
Echinococcal cysts: most commonly Hydatid cyst (tapeworm)
Most common primary hepatic cancers
Hepatocellular carcinoma (85%)
Intrahepatic cholangiocarcinoma (6%)
HCC risk factors
1) Alcoholic cirrhosis
2) Non alcoholic cirrhosis
- hepatitis B, C
- NAFLD
- autoimmune: PBC, PSC
- metabolic: haemochromatosis, alpha1antitrypsin deficiency
- others: red meat, aflatoxins, diabetes, smoking, alcohol
What is primary biliary cirrhosis?
Inflammation & destruction of intrahepatic bile ducts
more common in middle aged women presenting w pruritus
anti-mitochondrial antibodies present
What is primary sclerosing cholangitis?
Inflammation & destruction of intra and extrahepatic bile ducts
More common in young men with IBD
