Liver Flashcards
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
Pathogenesis of HCC
Chronic inflammatory process, ongoing hepatocellular damage w high cell regeneration, increased rates of genetic mutation -> accumulates & leads to carcinoma
How to predict prognosis in pts with cirrhosis?
Model for End Stage Liver Disease (MELD) score
MELD score 15 = 6% mortality in 3 months
TIPSS: <14 good outcome, poor >24
Signs & symptoms of HCC
- Jaundice (5-10%)
- Fever from central tumour necrosis
- LOW, LOA
- Budd-chiari syndrome -> ascites
- Decompensated liver: hepatic encephalopathy, coagulopathy
- Rupture -> peritonitis
- Features of portal HTN
What is hepatorenal syndrome?
Acute renal failure in pts with advanced liver disease from cirrhosis
Portal HTN + splanchnic arterial vasodilation -> reduce resistance -> “hypovolemia”
Kidneys hypoperfused -> RAAS activated and efferent arterioles constrict to improve GFR. Afferent arterioles also constrict -> kidneys hypoperfused
How to diagnose HCC?
Triphasic CT
MRI - distinguish HCC from nodules in cirrhotic pts
What is a biomarker used in HCC?
Alpha fetoprotein
No longer used officially in diagnosis, but a rise in AFP in those w cirrhosis should raise suspicion for HCC
Child Pugh Score classifications
Class A: 5-6 points (better survival function), surgical mortality 10%
Class B: 7-9 points (still can resect), surgical mortality 20-30%
Class C: 10-15 (not for resection), surgical mortality 75-80%
Used to evaluate risk of portocaval shunting procedure in pts with portal HTN, also used for other procedures in cirrhotic pts
Indocyanine green test is for?
Assessing adequacy of remaining liver function post resection
Percentage of ICG dye left after 15 mins should be <10%
Hepatectomy of HCC in pts with cirrhotic liver has ____
high recurrence rates
cirrhosis = “field change” effect in the liver, new tumour can still develop in remnant liver
Only Child’s __ and ___ can undergo liver resection
A, good B
Use indocyanine green to determine extent of resection
Palliative therapies for HCC
1) Radiofrequency ablation
- destroy tissue with heat
2) Trans-arterial chemoembolisation
- selective intra-arterial administration of chemo agents + emoblise major tumour artery
What are secondary liver malignancies?
Metastatic liver tumours with cells originating from cancer elsewhere
Most common: colorectal cancer
Others: neuroendocrine tumour from GIT/pancreas, other cancers
Metastasis can be to the ___ or the ___. LFT changes in each? Jaundice in each?
liver parenchyma or porta-hepatis lymph nodes
Parenchyma LFT: deranged liver enzymes + obstruction
LN LFT: obstructive pattern (jaundice would present early)
Presentation of liver abscess
-*Spiking fevers with chills (90%)
- Jaundice, hepatomegaly
5 routes of infection for liver abscesses
1) Portal vein: from gut
2) Biliary tree: ascending infections
3) Hepatic artery: sepsis
4) Direct inoculation: trauma, iatrogenic
5) Adjacent organ infection
Pyogenic liver abscess appearance on CT
Rim-enhancing lesion on triphasic scan
Irregular lesion w central necrosis, air-fluid levels, could be multiloculated
How to treat pyogenic liver abscess
Empirical Abx: IV ceftriaxone + metronidazole
Drainage for >3cm (percutaneous or open)
Common pyogenic abscess organisms
Klebsiella
E.coli
Proteus vulgaris
Strep faecalis, staph epidermidis
Common amoebic abscess organisms
Entamoeba histolytica - faecal oral transmission, enters the gut and into the liver
Diagnosis of amoebic abscess
CTAP - round lesion abutting liver capsule, WITHOUT rim enhancement (unlike pyogenic)
Serum antibody test for E.histolytica
Treatment for amoebic abscess
metronidazole
needle aspiration not routinely done
