Anatomy of the Liver and Hepatobiliary System: A Comprehensive Guide

1. Kingdom of BahrainArabian Gulf UniversityCollege of Medicine and Medical Sciences General Surgery The Hepatobiliary System Ali Jassim Alhashli

2. Anatomy of The Liver • Blood supply: • Arterial supply: • What are the branches of celiac trunk? • Left gastric artery. • Splenic artery. • Common hepatic artery, which divides to: • Hepatic artery proper → right and left hepatic arteries. Notice that these arteries supply 50% of liver oxygen while the remaining 50% is supplied by portal vein. • Gastroduodenal artery • Venous drainage: through IVC. • What are the important ligaments of the liver? • Falciform ligament: which attaches the liver to anterior abdominal wall and contains ligamentumteres (obliterated umbilical vein). • Coronary ligament: on the superior aspect of the liver and attaching it to the diaphragm. • Triangular ligaments (right and left): they are extension of the coronary ligament. • Hepatoduodenal ligament: contains common bile duct, portal vein and hepatic artery. • What is the bare area of the liver? • A posterior part of the liver against the diaphragm with no peritoneal covering.

3. Anatomy of The Liver

4. Anatomy of Biliary System • Parts of the gallbladder: • Infundibulum (Hartman’s pouch): proximal end near the cystic duct. • Fundus: distal larger end. • Valves within the cystic duct are called: valves of Heister. • Function of gallbladder: storage of bile which it collects from the liver via ducts of Luschka. • Biliary tree: right and left hepatic ducts converge to form common hepatic duct → which joins the cystic duct to form common bile duct → that empties in 2nd part of the duodenum through ampulla of Vater that is surrounded by sphincter of Oddi.

5. Bile: • It is composed of: cholersterol, lecithin, bile acids, bilirubin and water. • Function: emulsification of dietary fat facilitating its absorption. • Define enterohepatic circulation. • Bile acids which are released from the liver for emulsification of fat will be reabsorbed in the terminal ileum and transported back to the liver via hepatic portal vein. • What is cholecystokinin (CCK)? • It is a GI hormone which is released by the duodenum in response to the presence of fat in the duodenum. It causes contraction of the gallbladder and relaxation of sphincter of Oddi thus facilitating the release of bile. • Jaundice: • Definition: it is the yellowish discoloration of the sclera and mucous membranes due to increased bilirubin (< 3 g/dL). • Causes are classified to: • Pre-hepatic: hemolytic anemias (examples: spherocytosis, SCD and G6PD deficiency). Indirect bilirubin is increased. • Hepatic: hepatitis, cirrhosis or deficiency of UDP-glucouronyltransferase enzyme. Both direct and indirect bilirubin increased. • Post-hepatic: gallstone or tumor. Direct bilirubin is increased. In obstructive jaundice, alkaline phosphatase is also increased. • Gilbert’s disease vsCrigler-Najjar syndrome: • Gilbert’s disease: AR; ↓ acitivity of the enzyme UDP glucouronyltransferase; patients are usually asymptomatic. • Crigler-najjar syndrome: absence of the enzyme UDP glucouronyltransferase. Bile and Jaundice

6. Bile and Jaundice

7. Bile and Jaundice • Jaundice (continued): • Signs and symptoms: • Yellowish discoloration of sclera, mucous membranes and skin. • Patient might have hepatomegaly or tenderness in RUQ. • Obstructive jaundice: pale stool, dark urine and pruritis. • Courvoisier’s sign: jaundice with a PAINLESS, palpable gallbladder → seen in patients with cancer in the head of the pancreas. • Diagnosis: what investigations you will request for your patient? • CBC. • LFTs: • ALT: increased in viral hepatitis. • AST: increased in alcoholic hepatitis. • GGT: increased when there is intrahepatic or extrahepatic obstruction of bile flow. • Alkaline phosphatase: increased with obstructive jaundice. • Serum albumin, PT/PTT and ammonia. • Other investigations might include: ultrasound, CT-scan or ERCP.

8. As you receive patient in emergency with liver injury, how are you going to manage him? • First, ABC: Airway, Breathing and Circulation (resuscitate him). • Ask about the exact mechanism of injury to the liver. • Then depending on hemodynamics of the patient: • If he is stable: • Focused abdominal sonography for trauma. • CT-scan. • If he is unstable: take him to OT! • Non-operative management (for blunt trauma): • If patient is stable and there are no peritoneal signs. • CT-scan defines the injury and shows no other injuries to other organs. • Repeat CT-scan after 2-3 days to check for progression of injury in your patient. • Patients resumes normal activities after 2 months. • Operative management: • Penetrating trauma and patient is unstable. • Long midline incision with main goal being control of bleeding by packing and direct pressure. Then, patient is resuscitated as needed. • Some surgical options: • Pringle maneuver: occlusion of portal triad in hepatoduodenal ligament manually or via a clamp. This must no exceed 20 minutes. • Major hepatic resection: when part of the liver was totally destroyed by the trauma or it is the only way to control life-threatening hemorrhage. Liver Injury

9. Definition: collection of pus in the liver commonly occurring in the right lobe. • Types and risk factors: • Pyogenic (most common): caused by: E.coli, Proteus or Klebsiella. Risk factors include: bacterial sepsis, infection of portal vein or infection of biliary tree • Amebic: caused by Entamoebahistolytica. Risk factors include: alcoholics, central America, homosexual males and institutionalized patients. • Signs and symptoms: • Fever. • RUQ pain. • Jaundice. • Weight loss. • Diagnosis: • CBC: shows leukocytosis. • LFTs: elevated liver enzymes. • Ultrasound and/or CT-scan. • Serology for amebic abscess. • Treatment: • Pyogenic abscess: ultrasound or CT guided drainage + IV antibiotics. • Amebic abscess: IV metronidazole. Hepatic Abscess

10. Cavernous hemangioma: • Definition: it is a benign vascular tumor which commonly occurs in the right posterior segment of the liver and considered to be the most common tumor of the liver. • Signs and symptoms: • Usually ASYMPTOMATIC. • If symptomatic: RUQ pain, mass/hepatomegaly or biliary obstruction. • Diagnosis: • Usually discovered INCIDENTALLY. • Can be detected by: ultrasound or CT/MRI. • PAY ATTENTION NOT TO BIOPSY! • Treatment: • Surgical resection if: • SYMPTOMATIC. • There is a high risk for rupture. • Hamartoma: • Definition: it is a rare benign tumor of the liver consisting of normal hepatic tissue arranged in abnormal configuration. • Signs and symptoms: • Usually ASYMPTOMATIC. • If symptomatic: RUQ pain, mass. • Diagnosis: • Usually INCIDENTALLY by ultrasound or CT. • Histopathologic evaluation is needed for diagnosis. • Treatment: surgical removal (for diagnosis). Benign Liver Tumors

11. Hepatocellular adenoma: • Definition: it is a benign tumor of the liver caused by overgrowth of hepatocytes. • Epidemiology: 95% occurring in females of reproductive age. • Risk factors: OCPs, long-term anabolic steroid therapy and glycogen storage disease. • Signs and symptoms: abdominal pain, abdominal mass and risk of rupture and bleeding. • Diagnosis: • Ultrasound: well-demarcated, solitary and heterogenous. • CT-scan with contrast. • Treatment: • Stop OCPs. • Surgical excision due to high risk of rupture (especially with subsequent pregnancies). • Focal Nodular Hyperplasia (FNH): • Definition: it is a benign tumor of the liver arising from hepatocytes and bile ducts. • Epidemiology: premenopausal females. It is associated with long-term use of OCPs. • Signs and symptoms: • Usually ASYMPTOMATIC. • 10% might have: abdominal pain and/or RUQ mass. • Diagnosis: • INCIDENTALLY by ultrasound or CT-scan: classically showing central scarring. • Treatment: surgical excision if patient is symptomatic. Benign Liver Tumors

12. Benign Liver Tumors

13. Hepatocellular Carcinoma (HCC): • Definition: it is a malignant tumor of the liver arising from hepatocytes and associated with cirrhosis. • Epidemiology: • 80% of liver cancers. • More common in males between 50-60 years. • Risk factors: • Hepatitis B/C. • Cirrhosis. • Smoking/alcohol. • Hemochromatosis. • α1-antitrypsin deficiency. • Anabolic steroid use. • Signs and symptoms (those of the tumor + portal HTN due to cirrhosis): • RUQ pain. • Hepatomegaly. • Jaundice • Anorexia and weight loss. • Ascites (50%). • Splenomegaly (33%). • Nausea and vomiting. • Diagnosis: • Labs: increased liver enzymes (LFTs) and AFP. • Imaging: ultrasound or CT-scan with IV contrast. • Definitive diagnosis: ultrasound or CT guided biopsy with histopathologic evaluation. • Treatment: surgical resection (segmental or lobectomy) with 1 cm margin. • Prognosis: 5-year survival rate after resection is 25-40% Malignant Liver Tumors

14. Malignant Liver Tumors • Metastatic neoplasms: • From: lung, breast, stomach and colon. • Signs and symptoms: • Usually ASYMPTOMATIC until the disease becomes advanced. • Symptoms: RUQ pain, mass, jaundice, weight loss, and ascites. • Diagnosis: • Labs: increased liver enzymes (LFTs). • Imaging: CT-scan with contrast. • Most sensitive diagnostic tool: intraoperative ultrasound and palpation of the liver. • Treatment: resection if possible.

15. Definition: it is defined as portal venous pressure < 10 mmHg (measured indirectly by hepatic vein wedge pressure). • Causes: • Pre-hepatic: portal vein thrombosis. • Intra-hepatic: cirrhosis. • Post-hepatic: Budd-Chiari syndrome (thrombosis of hepatic veins). • Signs and symptoms (including both of portal hypertension and liver failure): • Portal hypertension: splenomegaly, ascites, dilated umbilical veins, hemorrhoids, esophageal varices. • Liver failure: jaundice, hepatic encephalopathy, palmarerythema, spider angiomata and flapping tremor. • What is the rule of 2/3 in portal hypertension? • 2/3 of patients with liver cirrhosis will develop portal hypertension → 2/3 of patients with portal hypertension will develop esophageal varices → 2/3 of patients with esophageal varices will bleed from them • Porto-systemic collaterals: • Left gastric vein to esophageal vein → esophageal varices. • Umbilical vein to epigastric veins → caput medusa. • Superior rectal vein to middle and inferior rectal veins → hemorrhoids. • Diagnosis: • History and physical examination. • Initially by ultrasound and then confirmed with CT-scan. • Treatment: reducing portal pressure by shunts: • Splenorenal vein: connecting splenic vein to left renal vein. • Total shunt (end-to-side): connecting end of portal vein to side of IVC. • Partial shunt (side-to-side): connecting side of portal vein to side of IVC. • Portocaval H graft: synthetic graft attached from portal vein to IVC. • Mesocaval H graft: synthetic graft attached from superior mesenteric vein to IVC. Notice that a major complications of creating a shunt is increased incidence of hepatic encephalopathy. Medical treatment: β-blockers to reduce portal pressure. Portal Hypertension

16. Portal Hypertension

17. Hepatic encephalopathy: • Definition: it is altered mental status which occurs in patients with liver failure due to increased level of ammonia in systemic circulation. • Precipitating factors: • Infections. • GI bleeding. • Opiates and sedatives. • Electrolytes depletion. • Excess intake of dietary protein • Signs and symptoms: • Altered mental status. • Flapping tremor. • Lethargy/coma. • Diagnosis: • Abnormal LFTs. • Elevated serum ammonia. • Altered mental status. • Treatment: lactulose and neomycin. • Ascites: • Definition: excess fluid in peritoneal cavity which increases the risk for spontaneous bacterial peritonitis. • Causes: • Decreased plasma oncotic pressure (deficient albumin production by the liver). • Increased hydrostatic pressure. • Signs and symptoms: distended abdomen, shifting dullness and fluid wave. • Treatment: • Decrease intake of sodium. • Potassium-sparing diuretic (e.g. spironolactone). • Abdominal paracentesis: don’t remove high volume of fluid otherwise patient will suffer from hypovolemic shock. Morbidities Resulting from Liver Failure

18. Esophageal varices: • Definition: dilated esophageal veins occurring in 2/3 of patients with portal hypertension. • Signs and symptoms: • ASYMPTOMATIC UNLESS THERE IS RUPTURE AND BLEEDING. • Rupture (upper GI bleeding):hematemesis, melena and/or hemtochezia (with massive bleeding). You might also notice features of shock! • Diagnosis: • Upper GI endoscopy. • Treatment: • To decrease risk of rupture: β-blockers. • When there is rupture: • Resuscitate the patient. • Give him octreotide. • Endoscopy with: sclerotherapy, injecting vasopressin, band ligation. • If you fail to control bleeding, try balloon tamponade (with Blakemore tube). • Caput medusa: • Definition: dilated veins around the umbilicus seen in patient with portal hypertension and accompanied by bruits. Morbidities Resulting from Liver Failure

19. Cholelithiasis: • Definition: it is the formation of stones in the gallbladder due to imbalance between contents of bile. • Types: • Cholesterol stones: 85%. • Pigmented stones: 15%. NOTICE THAT ONLY 15% OF GALLSTONES ARE RADIOPAQUE (BECAUSE THEY DO NOT CONTAIN SUFFICIENT CALCIUM). • Risk factors: • Remember the 4 F’s: Female, Forty, Fertile and Fat. • Others: pregnancy, OCPs, IBD and hyperlipidemia. • Signs and symptoms: • MOST PATIENTS ARE ASYMPTOMATIC. • If symptomatic: colicky pain in RUQ (radiating to back or epigastric area) which is worse when eating fatty food + nausea and vomiting. • Diagnosis: ultrasound. • Treatment: • ASYMPTOMATIC PATIENT: observation unless: • There is porcelain gallbladder (it has increased risk for cancer). • Patient is of pediatric age group. • Patient is immunocompromised. • Presence of large stones < 2-3 cm. • Patient has SCD. • SYMPTOMATIC PATIENT: cholecystectomy. Conditions of Gallbladder and Biliary Tree

20. Acute cholecystitis: • Definition: it is acute inflammation of the gallbladder due to a stone obstructing the cystic duct. • Mirizzi’s syndrome: it is external compression of common hepatic duct by a gallstone impacted in the cystic duct. • Signs and symptoms: • Fever. • Nausea and vomiting. • RUQ pain (which gets worse with fatty food) + presence of Murphy’s sign in 1/3 of patients (pain on deep inspiration upon palpation of RUQ). • Diagnosis: • Labs: CBC (leukocytosis), LFTs and bilirubin, amylase, BUN/creatinine and electrolytes. • Imaging: • Ultrasound: • Gallbladder wall < 4 mm. • Presence of stone. • Presence of fluid around gallbladder. • HIDA scan (most sensitive): filling defect of the gallbladder (not taking up the contrast due to obstruction of cystic duct). • Treatment: • NPO. • IV fluids. • Analgesia. • IV broad-spectrum antibiotics. • Cholecystectomy (laparoscopically preferred) if they present within 24-48 hours from the onset of symptoms. Conditions of Gallbladder and Biliary Tree

21. Conditions of Gallbladder and Biliary Tree

22. Emphysematous cholecystitis: • Definition: it is a severe form of cholecystitis caused by gas-forming bacteria (Clostridial species, E.coli or Klebsiella are the most common isolated organisms in such condition). • Epidemiology: commonly affecting elderly diabetic males. • Diagnosis: • AXR: might show a rimlike gas within galbladder. • CT-scan: gas within wall of gallbladder and in peritoneal cavity (there is a high risk of gallbladder perforation with emphysematous cholecystitis). • Acalculuscholecystitis: • Definition: it is acute inflammation of the gallbladder without the presence of a gallstone! • Causes: biliary stasis and ischemia. • Risk factors: • ICU patients with multiorgan system failure. • Trauma (especially after major surgery). • Burns. • Sepsis. • Total Parenteral Nutrition (TPN). • Diagnosis: • Labs: CBC (leukocytosis), amylase/lipase, LFTs/bilirubin, BUN/creatinine and electrolytes. • Imaging: • Ultrasound: increased thickness of gallbladder wall (without presence of a stone). • Diagnosis is confirmed with HIDA scan. • Treatment: urgent cholecystectomy • Open: kocher’s incision. • Laparoscopic: using 4 ports. Calot’s triangle contains cystic artery which has to be ligated before removing gallbladder. Conditions of Gallbladder and Biliary Tree

23. Conditions of Gallbladder and Biliary Tree

24. Choledocholithiasis: • Definition: presence of a stone in Common Bile Duct (CBD) thus obstructing it. • Signs and symptoms: • RUQ pain. • Obstructive Jaundice. • Cholangitis: bacterial infection superimposed on an obstruction of biliary tree most commonly due to a gallstone. • Recurrent attacks of acute pancreatitis. • Diagnosis: • Labs: ↑alkaline phosphatase, total and direct bilirubin. • ERCP: both • Diagnostic • Theraputic: endoscopic sphincterotomy (a basic technique which enables extraction of biliary stones by enlarging the papillary opening. IF ERCP fails → surgery (open bile duct and remove the stone). • Acute (ascending) cholangitis: • Definition: it is a bacterial infection superimposed on obstruction of CBD most commonly due to presence of gallstone. • What are the causes of CBD obstruction? SINGE • S: Strictures. • I: Iatrogenic. • N: Neoplasm. • G: Gallstone. • E: Extrinsic compression. • Signs and symptoms: • Charcot’s triad: fever, RUQ pain and obstructive jaundice. • Reynold’s triad: charcot’s triad + CNS symptoms + septic shock (hypotension). • Diagnosis: • Labs: CBC (leukocytosis), ↑alkaline phosphatase, total and direct bilirubin. • Initial study with ultrasound but ERCP provides defenitive diagnosis and is also therpautic. • Treatment: • NPO, IV fluids, analgesia and broad-spectrum IV antibiotics. • Patient is stable: conservative management with definitive treatment later. • Patient in shock: removing obstruction with ERCP. Conditions of Gallbladder and Biliary Tree

25. Conditions of Gallbladder and Biliary Tree

26. Conditions of Gallbladder and Biliary Tree

27. Sclerosingcholangitis: • Definition: it is a chronic, progressive inflammation of biliary tree of unknown etiology resulting in cirrhosis and liver failure. • Risk factors: • Most important: ulcerative colitis (70% of cases). • Trauma to common hepatic duct. • Pancreatitis. • Diabetes. • Signs and symptoms: • MOST PATIENTS ARE ASYMPTOMATIC AT TIME OF DIAGNOSIS. • If symptomatic: fever, weight loss, hepatomegaly, splenomegaly, jaundice, pruritis and hyperpigmentation. • Diagnosis: • Labs: ↑alkaline phosphatase. • ERCP: “beads on a string” appearance of bile ducts. • Treatment: • Palliative: balloon dilation with stent placement. • Definitive treatment depends on location of strictures: • Extrahepatic strictures: hepatoentericanastomosis with removal of extrahepatic ducts. • Intrahepatic strictures: liver transplantation. Conditions of Gallbladder and Biliary Tree

28. Conditions of Gallbladder and Biliary Tree

29. Gallstone ileus: • Definition: it is small bowel obstruction caused by a gallstone (mostly in ileocecal valve). This is caused by a large gallstone which creates a cholecystoenteric fistula thus entering the lumen of small bowel. • Epidemiology: elderly females. • Signs and symptoms (those of acute cholecystitis + those of small bowel obstruction): • Acute cholecystitis: RUQ pain, fever and nausea/vomiting. • SBO: abdominal distention, abdominal pain, nasuea/vomiting and constipation/obstipation. • Diagnosis: • AXR: shows dilated small bowel and might show a gallstone in RLQ. • Ultrasound: identifies the presence of cholelithiasis and fistula. • Abdominal CT-scan: shows dilated small bowel loops proximal to the site of obstruction with collapsed bowel loops distal to the site of obstruction. • Treatment: • Exploratory laparotomy: remove the gallstone. • If patient is stable: cholecystectomy and fistula repair in the same setting. • Carcinoma of the gallbladder: • Definition: it is malignant adenocarcinoma of the gallbladder. • Epidemiology: • EXTREMELY RARE! • Elderly females. • Risk factors: gallstones, PORCELAIN GALLBLADDER, choledochal cysts and gallbladder polyps. • Signs and symptoms: • PATIENTS ARE ASYMPTOMATIC UNTIL LATE IN THE DISEASE. • If symptomatic: RUQ pain/mass, jaundice, weight loss, nausea and vomiting. • Diagnosis: ultrasound, CT/MRI or ERCP. • Treatment: • Malignancy involving gallbladder mucosa: cholecystectomy. • Malignancy involving muscularis and serosa: radical cholecystectomy, wedge resection of overlying liver and dissection of portal lymph nodes. Conditions of Gallbladder and Biliary Tree

30. Conditions of Gallbladder and Biliary Tree

31. Cholangiocarcinoma: • Definition: it is a malignant neoplasm of biliary tree commonly occurring at the bifurcation of right and left hepatic ducts. • Epidemiology: • UNCOMMON! • Age: 55-65 years. • Risk factors: choledochal cysts, sclerosingcholangitis, ulcerative colitis, liver flukes, toxins and contrast dye. • Signs and symptoms: • RUQ pain. • Obstructive jaundice. • Weight loss. • Pale stool, dark urine and pruritis. • Diagnosis: • Ultrasound, CT/MRI. • Biopsy via ERCP under ultrasound guidance. • Staging (Bismuth classification): • Stage-I: involves common hepatic duct; spares bifurcation. • Stage-II: involves common hepatic duct and the bifurcation. • Stage-IIIa: extends to right hepatic duct. • Stage-IIIb: extends to left hepatic duct. • Stage-IV: extends to both right and left hepatic ducts. • Treatment: • Proximal tumors: resect with hepatojejunostomy. • Distal tumors: Whipple’s procedure. • Prognosis: 5-year survival rate 15-20% Conditions of Gallbladder and Biliary Tree

32. Conditions of Gallbladder and Biliary Tree