31 Liver Flashcards
Hepatic artery variants
Right hepatic artery off superior mesenteric artery (most common 20%) - courses behind pancreas, posterolateral to the CBD
Left hepatic artery off left gastric artery (20%) - found in gastrohepatic ligament medially
Falciform ligament
Separates medial and lateral segments of the left lobe
Attaches liver to anterior abdominal wall
Extends to umbilicus and carries remnant of the umbilical vein
Ligamentum teres
Carries the obliterated umbilical vein to the under surface of the liver
Extends from the falciform ligament
Cantlie’s line (portal fissure)
Line drawn from the middle of the gallbladder fossa to IVC
Separates the right and left liver lobes
Sections of the liver
Right lobe: anterior (8, 5) and posterior (7,6)
Left lobe: left medial section (1, 4) and left lateral section (2,3)
Liver segment - I
Caudate
Liver segment - II
Superior left lateral segment
Liver segment - III
Inferior left lateral segment
Liver segment - IV
Left medial segment (quadrate lobe)
Liver segment - V
Inferior right anteromedial segment
Liver segment - VI
Inferior right posterolateral segment
Liver segment - VII
Superior right posterolateral segment
Liver segment - VIII
Superior right anteromedial segment
Glisson’s capsule
Peritoneum that covers the liver
Bare area
Area on the posterior-superior surface of the liver not covered by Glisson’s capsule
Triangular ligaments
Lateral and medial extensions of the coronary ligament on the posterior surface of the liver, made up of peritoneum
Portal triad enters via:
Segments IV and V
Gallbladder lies under:
Segments IV and V
Relationship of structures within the hepatoduodenal ligament
Lateral - CBD
Portal vein (posterior)
Medial - Proper hepatic artery
Kupffer cells
Liver macrophages
Contents of the portal triad
Common bile duct (lateral)
Portal vein (posterior)
Proper hepatic artery (medial)
Come together in the hepatoduodenal ligament (porta hepatis)
Pringle maneuver
Porta hepatis clamping
Will NOT stop hepatic vein bleeding
Foramen of Winslow
Entrance to the lesser sac Anterior - portal triad Posterior - IVC Inferior - duodenum Superior - liver
Portal vein forms from:
Superior mesenteric vein joining the splenic vein (no valves)
Inferior mesenteric vein drains into the splenic vein
Portal vein branches
2 branches - providing 2/3 of hepatic blood flow
Left - segments II, III, IV
Right - segments V, VI, VII, VIII
Arterial blood supply to the liver
Right left and middle hepatic arteries
Middle hepatic artery is a branch of left hepatic artery
Hepatic artery supplies most primary and secondary tumors
Hepatic venous drainage
3 hepatic veins - drain into IVC
Left - II, III, superior IV
Middle - V, inferior IV
Right - VI, VII, VIII
Variation of the middle hepatic vein
80% drain into left hepatic vein
20% drain directly into the IVC
What do accessory right hepatic veins drain?
Medial aspect of the right lobe, directly into IVC
Blood supply of caudate lobe
Receives separate right and left portal and arterial blood flow
Drains directly into the IVC via separate hepatic veins
Alkaline phosphatase origin
Canalicular membrane
Where does nutrient uptake occur?
Sinusoidal membrane
Where is urea synthesized?
In the liver
What coagulation factors are NOT synthesized in the liver?
vWF, factor VIII (endothelium)
What vitamins are stored in the liver?
Fat soluble and B12
What are the most common problems with hepatic resection?
Bleeding
Bile leak
Which hepatocytes are most sensitive to ischemia?
Central lobular (acinar zone III)
What is bilirubin the product of?
Breakdown of hemoglobin
Hbg –> heme –> biliverdin –> bilrubin
How is the water solubility of bilirubin improved?
Conjugated to glucuronic acid (glucoronyl transferase)
Occurs in the liver
What form of bilirubin is actively secreted into bile?
Conjugated bilirubin
How is bilirubin processed after it is secreted in bile?
Free bilirubin is created via bacterial breakdown of conjugated bilirubin in the terminal ileum
It is reabsorbed and converted into urobiligen, which is released as urobilin in the urine
What causes cola colored urine?
Excess urobilinogen
What is the content of bile?
Bile salts (85%) Protein Phospholipids (lecithin) Cholesterol Bilirubin
What determines the final composition of bile?
Active resorption of water via Na/K ATPase
What is cholesterol’s role in bile?
Used to make bile salts/acids
What are bile salts conjugated to? Why?
Taurine, glycine
Improves water solubility
Primary bile acids (Salts)
Cholic and chenodeoxycholic
Secondary bile acids (salts)
Deoxycholic and lithocholic
Dehydroxylated primary bile acids via bacteria in gut
Role of bile in digestion
Bile solubilizes cholesterol and emulsifies fats in the intestine, forming micelles, which enter enterocytes by fusing with the membrane
Minimum bilirubin level for jaundice? Where do you see it first?
Bilirubin >2.5
Under the tongue
Maximum bilirubin level?
30
Unless underlying renal disease, hemolysis or bile duct-hepatic vein fistula
Causes of elevated unconjugated bilirubin
Prehepatic - hemolysis
Hepatic deficiencies of uptake or conjugation
Causes of elevated conjugated bilirubin
Secretion defects into bile ducts
Excretion defects into GI tract (stones, strictures, tumors)
Gilbert’s disease
Abnormal conjugation
Mild defect in glucuronyl transferase
Crigler-Najjar disease
Inability to conjugate
Severe deficiency in glucuronyl transferase
High unconjugated bilirubin - life-threatening disease
Physiologic jaundice of newborn
Immature glucuronyl transferase
High unconjugated bilirubin
Rotor’s syndome
Deficiency in storage ability
High conjugated bilirubin
Dubin-Johnson syndrome
Deficiency in secretion ability
High conjugated bilirubin
Fulminant hepatic failure - which viral hepatitis?
B, D and E (rare with A and C)
Chronic hepatitis and hepatoma - which viral hepatitis?
B, C and D
Hepatitis A
RNA
Fecal/oral
Serious consequences uncommon
Hepatitis B
DNA - funny replication with reverse transcriptase
Associated with both acute and chronic hepatitis
Anti-HBc antibodies (hep B)
Core antibody
IgM elevated first 6mo after exposure
IgG >6mo
NOT in vaccination
Hep B vaccination
Elevated anti-HBs (surface) antibodies only
Elevated anti-HBc antibody
Elevated anti-HBs antibody
Negative HbsAg
Patient had infection with recovery
Has immunity
Hepatitis C
RNA
Long incubation period
Not associated with acute hepatitis - associated with chronic hepatitis
Most common viral hepatitis leading to liver TXP
Hepatitis D
RNA
Cofactor for hepatitis B
Worse prognosis
Hepatitis E
RNA
Fulminant hepatic failure in pregnancy (3rd trimester)
Most common cause of liver failure?
Cirrhosis (palpable liver, jaundice, ascites)
Best indicator of synthetic function in patients with cirrhosis?
Prothrombin time (PT)
Mortality in acute liver failure?
Fulminant hepatic failure has 80% mortality
Outcome determined by course of encephalopathy
Criteria for urgent liver transplant listing?
King’s college criteria
Separated between acetaminophen-induced and other
King’s college criteria for acetaminophen-induced ALF?
Arterial pH <7.3 irrespective of coma grade OR, all of the following: - INR >6.5 - Creatinine >3.4 - Grade III/IV encephalopathy
King’s college criteria for Non-acetaminophen-induced ALF?
INR >6/5 OR, any 3 of the following: - Age <10 or >40 - Drug toxicity or undetermined etiology - Jaundice >7 days before encepholopathy - INR >3.5 - Bilirubin >17
Why does liver failure cause hepatic encephalopathy?
Inability to metabolize ammonia, mercantanes, and false neurotransmitters
Causes, apart from liver failure, for encephalopathy?
GI bleed
Infection (SBP)
Electrolyte imbalance
Drugs
Treatment of hepatic encephalopathy?
Possible emoblization of previous therapeutic shunts or other major collaterals Lactulose Limit protein intake (<70g/day) Add BCAA to diet No Abx unless specific infection Neomycin
How does lactulose help with hepatic encephalopathy?
Cathartic that gets rid of bacteria in the gut
Acidifies the colon - prevents NH3 uptake by converting it to ammonium
Titrate to 2-3 stools/day
How does neomycin help with hepatic encephalopathy?
Gets rid of ammonia-producing bacteria from the gut
How does chronic cirrhosis cause ascites?
Hepatocyte destruction --> Fibrosis and scaring of liver --> Increased hepatic pressure --> Portal venous congestion --> Lymphatic overload --> Leakage of splanchnic and hepatic lymph into peritonium --> Ascites
Albumin dose with paracentesis for ascites
1g albumin for every 100cc removed
Treatment of ascites
Water restrict ion(1-1.5L/day)
Decreased NaCl (1-2g/day)
Diuretics (spironolactone conteracts hyperaldosteronism seen with liver failure)
Paracentesis
TIPS
Prophylactics for SBP (Norfloxacin - if previous SBP or current UGI bleed)
Why is aldosterone elevated with liver failure?
Impaired hepatic metabolism
Impaired GFR
Hepatorenal syndrome
Progressive renal failure due to hepatic failure (end-stage)
Same lab findings as prerenal azotemia
Tx: Stop diuretics, give volume; liver TXP
Asterixis
Neurological changes due to liver failure
Sign that it is getting worse
Postpartum liver failure with ascites
Due to hepatic vein thrombosis - infectious component
Dx: SMA arteriogram with venous phase contrast
Tx: Heparin + abx
Diagnostic criteria for SBP?
Fever
Abdominal pain
PMNs >250 in fluid
+/- positive cultures
Bacteria causing SBP?
E. coli
Pneumococci
Streptococci
Differentiating between SBP and bowel perf?
SBP is mono-organism
If it is a poly infection - consider perf
Risk factors for SBP?
Ascites (required)
Prior SBP
Upper GI bleed (variceal hemorrhage)
Low-protein ascites
Treatment of SBP?
3rd generation cephalosporins
Patients respond in 48 hours
Treatment of esophageal varices
Banding and sclerotherapy (95% effective)
Vasopressin/octreotide (temporizing)
Sengstaken-Blakemore esophgeal tube
Propranolol (prevent re-bleed, not useful acutely)
TIPS for refractory bleeding
Vasopressin - MOA in esophageal varices
Splanchnic artery constriction
If patient has hx of CAD - add NTG
Octreotide - MOA in esophageal varices
Decreases portal pressures by decreasing blood flow
Late complication from sclerotherapy? Tx?
Strictures
Dilation
Causes of portal hypertension?
Pre-sinusoidal obstruction - schistosomiasis, congential hepatic fibrosis, portal vein thrombosis
Sinusoidal obstruction - cirrhosis
Post-sinusoidal obstruction - Budd-Chiari syndrome, constrictive pericarditis, CHF
Normal portal vein pressure
<12 mmHg
Which hepatic vein acts as collaterals between the portal vfein adn systemic venous system?
Coronary veins - portal vein to veins of lower esophagus (azygous vein)
Complications of portal hypertension?
Esophageal variceal hemorrhage
Ascites
Splenomegaly
Hepatic encephalopathy
Role of shunts in portal hypertension? Complications?
Decompress the portal system
Can increase risk of encephalopathy (bypassing the metabolism of liver)
Transjugular intrahepatic portosystemic shunt
TIPS
Indication: protracted bleeding, progression of coagulopathy, visceral hypoperfusion, refractory ascites
Allows antegrade flow
Complication - encephalopathy
Splenorenal shunt
Lower rate of encephalopathy
Ligate left adrenal vein, left gonadal vein, IMV, coronary vein and pancreatic branches of splenic vein
Indications - Child’s A cirrhotic presenting with just bleeding
CI: refractory ascites (can make it worse)
Child’s B or C with indication for shunt
Treat with TIPS
Child’s A with just bleeding symptoms
Consider splenorenal shunt (more durable)
Otherwise TIPS
Child-Pugh Score
Assessment of liver failure
Assesses:
- Albumin (>3.5 - 3-3.5 - <3.0)
- Bilirubin (<2.5 - 2.5-4 - >4)
- Encephalopathy (none - minimal - refractory)
- Ascites (none - tx with meds - refractory)
- INR (<1.7 - 1.7-2.3 - >2.3)
Give 1-2-3 points for each category
A - 5-6; B - 7-9; C 10+
Association of Child-Pugh Score with Shunt placement
Correlates with mortality after open shunt placement
Child’s A - 2%
Child’s B - 10%
Child’s C - 50%
Budd-Chiari syndrome
Occlusion of hepatic veins of IVC
Sx: RUQ pain, hepatosplenomegaly, ascites, fulminant hepatic failure, muscle wasting, variceal bleeding
Dx: angiogram with venous phase, CT angiogram; liver bx (sinusoidal dilation, congetsion, centrilobular congestion)
Tx: Porta-caval shunt (connecting to IVC above the obstruction)
Splenic vein thrombosis
Cause: Pancreatitis
Sx: Isolated gastric varices (without elevation of the rest of the portal system pressure), UGI bleed of the varices
Ts: Splenectomy if symptomatic
Amebic liver abscess
Single in right lobe of liver Entamoeba histolytica Reaches liver via portal vein Culture of abscess negative Dx: CT (rim enhancing lesion) Tx: Flagyl, aspiration (if refractory), surgery (free rupture)
Echinococcus liver abscess
Hydatid cyst
Positive Casoni skin test, positive serology
Right love of liver
Dx: CT (calcified, double-walled cyst); ERCP (jaundice, increased LFTs, cholangitis to assess for communication with biliary tract)
Tx: pre-op albendazole (2 weeks), surgical removal (inject cyst with alcohol, get entire cyst wall)
DO NOT aspirate - anaphylactic shock
Schistosomiasis liver abscess
Maculopapular rash, increased eosinophils
Sigmoid colon infection (fine granulation tissue, petechiae, ulcers)
Can cause variceal bleeding
Tx: praziquantel
Pyogenic liver abscess
Sx: Fever, chills, wt loss, RUQ pain, increased LFTs, WBC, sepsis
Right lobe
E. coli
Contiugous infection from biliary tract or bacteremia
Dx: aspiration
Tx: CT-guided drainage and abx; surgical drainage for unstable condition and continued sepsis
Benign liver tumors
Hepatic adenomas
Focal nodular hyperplasia
Hemangioma
Solitary cyst
Hepatic adenoma
Steroids/OCP
Sx: Pain, increased LFT, hypotension (rupture), palpable mass
Dx: Negative sulfur colloid scan (no Kupffer cells), MRI hypervascular tumor
Tx:
Asymptomatic - stop OPCs, if no regression –> resection
Symptomatic - resection for bleeding/malignancy risk; embolization if multiple and unresectable
Sulfur colloid scan
Used to liver tumors
Kupffer cells uptake sulfur colloid - positive scan
Hepatic adenomas have NO kupffer cells
Focal nodular hyperplasia does have kupffer cells
Focal nodular hyperplasia
Central stellate scar - looks like cancer
No malignancy risk, unlikely to rupture
Dx: Abdomina CT, positive sulfur colloid scan (has kupffer cells), hypervasular tumor
Tx: conservative (no surgery)
Hemangioma
Rare rupture
Avoid biopsy - risk of hemorrhage
Dx: MRI/CT - peripheral to central enhancement; hypervascular lesion
Tx: symptomatic - surgery +/- pre-op emobolization; steroids and possible XRT for unresectable
Kasabach-Merritt syndrome
Consumptive coagulopathy due to hemangioma (rare, children)
Rare complications of hemangioma seen in children?
Consumptive coagulopathy (Kasabach-Merritt) CHF
What type of CT do you use to assess the liver?
Triple phase
- Native
- Portal
- Arterial
Solitary liver cysts
Congenital Women Right lobe Characteristic blue hue Tx: nothing
Hepatoma (HCC)
Most common cancer worldwide
AFP level correlates with tumor size
Risk factors for HCC
Hep B, Hep C, ETOH, hemochromatosis, aslpha-1-antitrypsin deficiency, primary sclerosing cholangitis, alfatoxins, hepatic adenoma, steroids, pesticides
NOT - primary biliary cirrhosis, Wilson’s disease
Best prognosis forms of HCC
Clear cell
Lymphocyte infiltrative
Fibrolamellar type (adolescent, young adults)
Tumor marker for HCC
AFP
Margins for HCC
1cm
Risk factors for hepatic sarcoma
PVC, thorotrast, arsenic
Isolated colon CA metastases to liver - treatment
Resection if there is >35% of (good) liver remaining
Primary liver tumors CT apperance
Hypervascular
Metastatic liver tumors CT apperance
Hypovascular
