General Surgery (Board Review Series) 1st Edition

15

Liver

Traves D. Crabtree

1. Structural and Functional Anatomy
2. Major structures and landmarks (Figure 15-1)
3. Glisson's capsule

• is the peritoneal covering that surrounds the liver.

1. The bare area

• is an area on the posterior superior surface of the liver that is not covered by Glisson's capsule.
• is where Glisson's capsule reflects onto the parietal peritoneal covering of the inferior surface of the diaphragm.

1. The coronary ligaments

• are the actual reflections of peritoneum on the posterior superior surface of the liver.

1. The triangular ligaments

• are the lateral extensions of the coronary ligaments on each side of the liver.

2. The falciform ligament

• attaches the liver to the anterior abdominal wall.
• extends from the umbilicus to the diaphragm and contains the obliterated remnant of the umbilical vein.

1. The pathway of the ligamentum teres, known as the umbilical fissure, extends from the falciform ligament on the undersurface of the liver.
2. The ligamentum teres contains the extension of the obliterated remnant of the umbilical vein.
3. The liver is functionally divided into eight segmentsbased on arterial and portal venous inflow and biliary drainage (Figure 15-2).

. Segment I

P.344

• is the caudate lobeof the liver.

1. Segments II to IV

• are segments of the left loberesected during left hepatic lobectomy.

Figure 15-1. Major landmarks of the liver. (From Gray SW, Skandalakis JE: Atlas of Surgical Anatomy for General Surgeons. Baltimore, Williams & Wilkins, 1985, p 183.)

Figure 15-2. Functional segments of the liver. (From O'Leary JP: The Physiologic Basis of Surgery, 2nd ed. Baltimore, Williams & Wilkins, 1996, p 442.)

1. Segments V to VIII

• are segments of the right loberesected during right hepatic lobectomy.

P.345

2. The falciform ligament does not divide the rightand left lobe.
3. The portal fissure, or Cantlies line,

• is a plane passing from the left side of the gallbladder fossa to the left side of the inferior vena cava.
• defines the division of the physiologic right and left lobes of the liver.

1. A right trisegmentectomy

• includes resection of the right lobe and segment IV (Figure 15-3).

1. A left lateral segmentectomy

• includes resection of segments II and III to the left of the falciform ligament.

1. Resection of 80% of parenchyma

• in a normal liver is compatible with life.

Figure 15-3. Surgical resection of the liver. (From Greenfield L J, et al: Surgery: Scientific Principles and Practice. Philadelphia, Lippincott, 1993, p 849.)

1. Arterial supply and venous system
2. The portal vein

• is a valveless veinformed at the junction of the superior mesenteric vein and the splenic vein behind the head of the pancreas.
• passes posteriorly to the bile duct and the hepatic artery in the hepatoduodenal ligament.
• provides 75% of the liver's blood supply.

2. The common hepatic artery

• arises from the celiac artery and becomes the proper hepatic artery after the gastroduodenal artery branches.

P.346

• passes medial to the common bile duct and anterior to the portal vein in the hepatoduodenal ligament.
• bifurcates into the right and left hepatic arteries within the hilum of the liver.

3. Hepatic arterial anatomyhas many common variants:

• The right hepatic arterymay arise from the superior mesenteric artery.
• The left hepatic arterymay arise from the left gastric artery.

4. The “Pringle maneuver”

• is used occasionally during hepatic surgery.
• involves compressionof the structures within the hepatoduodenal ligament.
• Compression of the portal veinand hepatic artery within the hepatoduodenal ligament helps to control hemorrhage during hepatic surgery.

5. Hepatic drainage

• The leftand right hepatic veins drain directly into the inferior vena cava posteriorly.
• The middle hepatic veincharacteristically drains into the left hepatic vein.

1. Histology of the liver
2. The hepatic arteriole, portal venule, and bile ductule

• run together to form the three components of the portal triad(Figure 15-4).

2. A hepatic lobule

• contains a central hepatic vein with the portal triads along the periphery of the lobule.
• Radially dispersed hepatocytes and sinusoids perfused by the portal venules and hepatic arterioles are located around the central vein, forming the lobule.

3. Endothelial cells within the sinusoids

• comprise over 50% of nonhepatocyte cells within the liver.

4. Kupffer cells

• are leukocytes attached to the luminal surface of endothelial cells within the liver that resemble macrophages.

1. Infections of the Liver (Table 15-1)
2. Pyogenic liver abscesses

• account for approximately 80% of all hepatic abscesses.

1. The major routes of infectioninclude

• the portal venous system.
• ascending biliary tree infections.

P.347

• bacteremia via the hepatic artery.
• direct extension from adjacent infection (i.e., appendicitis, diverticulitis).
• primary infection after hepatic trauma.

Figure 15-4. Functional hepatic lobule. (Adapted from Simmons RL, Steed DL: Basic Science Review for Surgeons. Philadelphia, WB Saunders, 1992, p 247.)

2. Etiology
3. Frequently, there is no obvious identifiable sourceof bacterial infection leading to the development of these abscesses.
4. Intra-abdominal infectionsare the most common identifiable source of bacteria for pyogenic liver abscesses.
5. Biliary tract diseaseand colonic infections

• are the most common associated intra-abdominal infections.

2. Sources include

• cholangitis.
• cholecystitis.
• appendicitis.
• diverticulitis.
• malignant biliary obstruction.
• regional enteritis.
• generalized sepsis.
• pelvic inflammatory disease.
• cryptogenic sources.

3. Abscesses most often contain

• enteric gram-negative aerobic rods (i.e., Klebsiella, Proteus, Escherichia coli) and/or anaerobes (i.e., Bacteroides).

4. Common signs and symptomsinclude

P.348

Table 15-1. Hepatic Infections

Organisms Primary Source Signs and Symptoms Diagnosis Initial Treatment Pyogenic abscess Enteric gram-negative rods with or without anaerobes Cryptogenic or intra-abdominal infections Fever, chills, RUQ pains, ↑WBC, sepsis CT scan, ultrasound Radiologic or surgical drainage and antibiotics Amebic liver abscess Entamoeba histolytica Recent intestinal infestation Fever, chills, RUQ pain, ↑WBC, hepatomegaly CT scan, ultrasound, serum antibody to E. histolytica Metronidazole (surgical drainage if rupture or secondary bacterial infection) Hydatid liver cyst Echinococcus granulosus, Echinococcus multilocularis Fecal/oral contamination from animal carriers Vague abdominal pain, jaundice, fever, eosinophilia CT scan, serum ELISA for echinococcal antibody Surgical drainage and injection of hypertonic saline and resection of cyst wall CT = computed tomography; ELISA = enzyme-linked immunosorbent assay; RUQ = right upper quadrant; WBC = white blood cell.

P.349

• fever.
• chills.
• weight loss.
• right upper quadrant (RUQ) pain.
• leukocytosis.
• elevated liver function tests.
• sepsis.

5. Treatment

• should include broad spectrum antibiotics andeither surgical or radiologically guided drainage of the abscess.

1. Amebic liver abscesses
2. Etiology
3. The parasite Entamoeba histolytica

• causesthese abscesses.
• is transported via the portal venous system after an intestinal infestationwith this organism.
• Its immature form—the trophozoite—is usually ingested and transported via the portal system.

1. Tropical climates and areas of poor sanitation

• have a higher incidence of amebic liver abscesses.

1. Intestinal infestation

• often precedes the abscess by several weeks.

2. Pathology
3. The abscess usually contains necrotic tissue and blood, giving the classic “anchovy-paste”aspirate.
4. Secondary bacterial infection may occur in 10%.
5. Most abscesses occur in the right lobe (75%–90%) and are solitary lesions (80%).
6. Signs and symptomsmay include

• fever.
• chills.
• nausea.
• RUQ abdominal pain or tenderness.
• hepatomegaly.
• jaundice.
• leukocytosis.

4. Diagnosis

• Computed tomography (CT) scan or ultrasound may help with the diagnosis; however, it is difficult to discern pyogenic versus amebic abscesses.
• A serum test for antibody to E. histolyticais highly specific.

P.350

5. Treatmentis initially nonsurgical.

. Most abscesses resolve upon initiation of the antibiotic of choice, metronidazole.

1. Surgical drainage is indicated if there is suspected ruptureor secondary bacterial infection.
2. Hydatid liver cysts (i.e., echinococcal cysts)

• are rare liver cysts.
• are caused by the parasite Echinococcus granulosusor, less commonly, Echinococcus multilocularis.
• most commonly occur in the right lobeof the liver.

1. Endemic areasinclude

• most of Europe.
• Australia.
• New Zealand.
• South America.
• Africa.

2. A major risk factor

• is contact with dogs that eat carrier animals (i.e., sheep).

3. Most patients present with

• vague abdominal pain.
• jaundice, fever, and nausea (more rare).

4. Diagnosis
5. Serum enzyme-linked immunosorbent assay (ELISA) testfor antibody against Echinococcus is accurate > 90% of the time.
6. Eosinophiliais present in 10%–30% of patients.
7. Liver function studies may be abnormal in 25% of patients.
8. A CT scan

• may show the characteristic calcified wallof the cyst peripherally.

5. Treatment

• is with surgical drainageof the cyst.
• is followed by injection of hypertonic salineto kill the remaining organisms, then resection of the cyst wall.
• Antibiotic therapy with mebendazole or albendazole may be used in conjunction with surgical drainage.

6. Complications

• Spillage of the cyst contents into the peritoneal cavityduring drainage can rarely result in a life-threatening anaphylactic reaction.

III. Benign Tumors of the Liver (Table 15-2)

1. Hemangiomas

• are the most common benign tumors of the liver.

P.351

P.352

• are more common in women(60%–80%).
• generally present between the ages of 40 and 60.

1. Histologically

• these tumors are simply dilated endothelial-lined vascular spaces.

2. Presentation
3. Most hemangiomas are asymptomatic, although symptoms of pain, nausea, and vomiting may be present, especially with giant hemangiomas (> 4 cm).
4. Ruptureof a hemangioma is very rare.
5. Kasabach-Merritt syndromeis a rare sequelae of hemangiomas associated with thrombocytopenia secondary to sequestration of platelets within the tumor.

Table 15-2. Hepatic Tumors

Risk Factors Signs and Symptoms Diagnosis Treatment Pearls Hemangioma Female > male Most asymptomatic; pain, nausea, vomiting, palpable mass CT scan, ultrasound,tagged-red blood cell scan, arteriogram Surgical excision if symptomatic Rarely associated with Kasabach-Merritt syndrome Hepatic adenoma Oral contraceptive, diabetes, type 1 GSD Most asymptomatic; RUQ pain, palpable mass, hypotension secondary to rupture CT scan, ultrasound Trial of discontinuation of oral contraceptives, surgical excision 10% may undergomalignant transformation to HCC Focal nodular hyperplasia Female > male Often asymptomatic Central stellate scar on CT scan, sulfur colloid radionuclide scan Surgical excision only if symptomatic Often confused radio graphically with adenomas Simple liver cysts Female > male Often asymptomatic; RUQ pain, palpable mass CT scan, ultrasound Surgical excision and oversewing cyst wall if symptomatic Characteristic blue hueon gross examination Polycystic liver disease Childhood form—autosomal recessive; adult form—autosomal dominant RUQ pain, palpable mass CT scan, ultrasound with multiple cysts in liver (> 10) Treat like simple cysts if symptomatic Prognosis related to associated polycystic kidney disease Hemangioendothelioma Infants < 2 years Palpable mass, CHF secondary to AV shunting, hepatomegaly, hypotension secondary to spontaneous rupture and hemorrhage CT scan If symptomatic, medical treatment of CHF, steroids; surgical excision for medical failures Half may developKasabach-Merritt syndrome; associated with cutaneous hemangiomas AV = arteriovenous; CHF = congestive heart failure; CT = computed tomography; GSD = glycogen storage disease; RUQ = right upper quadrant.

3. Diagnosiscan often be made

• by characteristic CT scan findings.
• with a tagged-red blood cell scan.
• Needle biopsyis generally avoided because of the risk of hemorrhage.

4. Treatment

• is by surgical excision.
• is generally only indicated when symptoms are present, or when the diagnosis of hemangioma is indeterminate.

1. Hepatic adenoma

• is a benign liver tumor seen almost exclusively in women 30–50 years old.

1. Risk factor
2. The greatest risk factor is the use of oral contraceptives.
3. Other risk factors include

• diabetes.
• type I glycogen storage disease.
• use of anabolic steroids.

2. Lesions are

• made of hepatocytes.
• generally solitary.
• found in the right lobe of the liver.

3. Signs and symptomsmay include

• RUQ pain.
• a palpable mass.
• hepatomegaly.
• As many as one third of patients may present acutely with abdominal pain and hypotension secondary to rupture of the tumor.

4. Complicationsinclude

P.353

• malignant transformationto hepatocellular carcinoma, which may occur in as many as 10% of adenomas.
• rupture.

5. Diagnosis

• is often made by CT scan or by ultrasound.

6. Treatment

. The risk of rupture and the potential for malignant transformation are generally considered indications for surgical excision of asymptomatic lesions.

1. Occasionally, adenomas may regress after a trial of discontinuing oral contraceptives or steroids in patients with small, asymptomatic tumors or in the high-risk surgical patient.
2. Focal nodular hyperplasia (FNH)

• is typically found in women 20–50 years old.
• is not associated with oral contraceptive use, unlike hepatocellular adenomas.

1. Diagnosis

• FNH is usually asymptomaticbut is often confused radiographically with adenomas.
• FNH is not associated with malignant transformation or rupture.
• A central stellate scaron CT scan is characteristic of FNH.
• A sulfur colloid radionuclide scancharacteristically identifies the Kupffer cells within the FNH nodule.

2. Treatment

• Surgical resection is not indicated unless the lesion is symptomatic or if the diagnosis is indeterminate.

D Benign cystic lesions of the liver

1. Simple cysts

• are generally solitary cysts occurring more frequently in women.

1. The cyst walls have a characteristic blue hue.

• They histologically contain von Meyenburg complexes, islands of biliary ductal epithelium.

1. Most are found incidentally by CT scan or ultrasound.
2. Treatmentis by surgical resection or unroofing of the cyst and oversewing the cyst wall.
3. Indications for resectioninclude the presence of

• symptoms.
• rupture.
• hemorrhage.
• infection.
• indeterminate diagnosis.

2. Polycystic liver disease

P.354

• includes both adult and childhood forms.

1. Childhood polycystic disease

• is an autosomal recessivedisorder with cyst formation in both the liver and kidney.
• High mortality in infancy and early childhood is attributed to progressive renal failure.

1. Adult polycystic disease

• is an autosomal dominantdisorder seen more commonly in women 30–80 years old.

2. Approximately half of the patients with polycystic livers will have polycystic kidneys.
3. Prognosis is generally related to the level of kidney involvement and subsequent renal impairment.
4. There is a rare association between adult polycystic disease and the development of cerebellar aneurysms.
5. Other rare lesions of the liver
6. Mesenchymal hamartomas

• are rare, benign, cystic tumors found in infants and children.

2. Hemangioendotheliomas

• are benign vesiculiform tumors seen in infants younger than 2 years old.

1. Arteriovenous (A/V) shunting within the tumor may cause congestive heart failure.
2. Medical treatment with steroids is appropriate.

• Surgery is reserved for medical failures.

3. Intrahepatic bile duct adenomas

• are generally small, benign lesions that require no treatment.

1. Malignant Tumors of the Liver (Table 15-3)
2. Hepatocellular carcinoma (HCC)

• is the most common primary malignant tumor of the liver.
• is 4–9 times more common in men, generally presenting at age 40–70.

1. Risk factors
2. The most common risk factorsare

• cirrhosis(macronodular type).
• hepatitis B infection.

1. Other risk factorsinclude

• hepatitis C infection.
• exposure to carcinogens[e.g., thorotrast, carbon tetrachloride, aflatoxins (Aspergillus flavus)].
• hemochromatosis.
• tyrosinemia.

P.355

P.356

• glycogen storage diseases.
• Wilson's disease.
• α₁-1 antitrypsin deficiency.
• porphyria cutanea tarda.
• hepatic adenoma.
• schistosomiasis.
• blood group B.

Table 15-3. Malignant Hepatic Lesions

Risk Factors Signs and Symptoms Diagnosis Treatment Pearls Hepatocellular carcinoma Males > females, cirrhosis, HBV and HCV Malaise, anorexia, weight loss, abdominal pain, ascites, palpable mass CT scan, ultrasound, occasionally MRI or intraoperative ultrasound for improved localization Partial hepatic resection for resectable tumors Associated with ↑ AFP Fibrolamellar hepatocellular carcinoma More common in adolescents and young adults Abdominal mass, RUQ pain CT scan, ultrasound Partial hepatic reresection for resectable tumors No clear association with cirrhosis; AFP usually not elevated Liver metastases Primary lesion elsewhere (colon, breast, lung) Often related to primary disease CT scan, clinical history of primary lesions elsewhere, increased CEA Partial hepatic resection for isolated colorectal metastases; chemotherapy Resection for other metastatic lesions more controversial Hepatoblastoma Seen in children < 2 years, male > female Palpable mass, nausea, vomiting, precocious puberty or virilization (rare) CT scan, AFP elevated in > 90% Partial hepatic resection and chemotherapy for resectable lesions; just chemotherapy for unresectable lesions Associated with hemihypertrophy and Beckwith-Wiedemann syndrome AFP = α-fetoprotein; CEA = carcinoembryonic antigen; CT = computed tomography; HBV = hepatitis B virus; HCV = hepatitis C virus; MRI = magnetic resonance imaging; RUQ = right upper quadrant.

2. Symptomsmay include

• fatigue.
• malaise.
• anorexia.
• weight loss.
• abdominal pain.
• shoulder pain.
• ascites.

3. Diagnosis

. α-Fetoprotein (AFP)

• is a tumor marker that may be elevated in 40%–70% of patients with HCC.
• may also be elevated with teratocarcinomas, yolk sac tumors, and with hepatic metastases.

1. Ultrasound, CT scan, and MRI

• are generally very reliable at identifying tumors as small as 1 cm.

4. Treatment

. Surgical management of resectable tumors

• provides 5-year survival of 31%.

2. Without treatment, mean survival from the onset of symptoms is 1–4 months.
3. The mean perioperative mortality rate is 11% and is much higher in cirrhotics.
4. Cirrhosis is a major limiting factor in the surgical resection of liver tumors.
5. Total hepatectomy with liver transplantation may benefit a select group of patients not amenable to partial hepatic resection although the rate of recurrence may be as high as 50%.
6. Systemic chemotherapy

• has shown little benefitin the treatment of HCC.
• Transarterial chemoembolization, and percutaneous ethanol injection of tumors may provide some survival benefit in unresectable tumors.

1. Fibrolamellar hepatocellular carcinoma (FHCC)

• is a variant of HCC seen most commonly in adolescentsand young adults.

P.357

• is not clearly associated with viral hepatitis or cirrhosis.

1. AFP

• is typically not elevated, unlike with HCC.

2. Treatment

• is with surgical resection.

3. Overall survival

• is generally better than HCC, potentially because of the greater likelihood of resectability of FHCC tumors at the time of diagnosis.

1. Liver metastases

• are the most common tumors of the liver.
• occur much more frequently than any of the primary liver tumors.

1. Tumors that frequently spread to the liverinclude

• colorectal, lung, and breast cancers.
• melanoma.
• neuroendocrine tumors (i.e., carcinoid).
• other visceral malignancies.
• renal cell carcinoma.

2. Diagnosis
3. Serum carcinoembryonic antigen (CEA)

• is a sensitive indicatorof metastatic colorectal lesions but lacks specificity (it may be elevated with other disease processes).
• is a reliable indicator for disease recurrence in patients with previously treated colorectal cancer.

2. Imaging techniques

• such as CT scan and, more recently, intraoperative ultrasound, reliably identify colorectal metastases to the liver.

3. Liver resection for metastatic lesions

• other than colorectal cancer have shown little survival benefit.

1. Five-year survival

• after partial hepatic resection for limited hepatic metastases from a colorectal primary is 30%–35%.
• with untreated hepatic metastases is < 5%.

2. Operative mortality

• for partial hepatic resection for metastatic disease is approximately 5%.

3. Factors that determine resectability include

• the size, number, and location of metastatic lesions.
• the extent of the primary tumor.
• Resectable lesions represent a small percentage of liver metastases.

4. Unresectable metastatic lesions

• in other regions of the body (i.e., lung, brain) are contraindications to hepatic resection of liver metastases.

P.358

4. Cystic lesions within the liver

• may represent malignant neoplasmssuch as ovarian and pancreatic cystadenocarcinomas, as well as cystic degeneration of metastatic solid tumors.

1. Other malignant lesions of the liver
2. Hepatoblastomas

• are primary malignant tumors of the liver seen primarily in boys younger than 2 years old(see BRS Surgical Specialties, Chapter 3).
• are associated with hemihypertrophy and Beckwith-Wiedeman syndromes (see Table 15-3).

2. Cholangiocarcinomas

• are primary malignant tumors of biliary ductal epithelium(see Chapter 6).
• can present as intrahepaticor extrahepatic lesions.

1. Portal Hypertension
2. Portal venous system (Figure 15-5)

• is valveless, unlike most other veins.
• This allows elevated venous pressure in this system to be transmitted to multiple venous beds via an extensive collateral network of veins.

1. Normal portal venous pressure

• is generally less than 12 mm Hg.

2. Elevated portal pressurecan lead to

• reconstitution and dilation of the umbilical vein leading to the characteristic caput medusa.
• varicosities around the umbilicus.

3. The coronary veins

• act as collaterals between the portal vein and the systemic venous system of the lower esophagus.

1. Causes of portal hypertension

• may be presinusoidal, sinusoidal, or postsinusoidal.

1. Presinusoidal causes

• Schistosomiasisis the most common cause of portal hypertension worldwide.
• Portal vein thrombosisaccounts for 50% of portal hypertension in children.

2. Sinusoidal causesinclude

• cirrhosis.
• congenital hepatic fibrosis (rare).
• Alcoholic cirrhosisis the most common cause of portal hypertension in the United States.

P.359

Figure 15-5. Portal venous system. (Adapted from Jarrell BE, Bruce RA, III: NMS Surgery, 2nd ed. Baltimore, Williams & Wilkins, 1991, p 216.)

3. The rare postsinusoidal causesinclude

• Budd-Chiari syndrome(hepatic vein occlusive disease).
• constrictive pericarditis.
• chronic heart failure.

1. The four major consequences of portal hypertension are

• ascites.
• portosystemic venous shunts and varices.
• congestive splenomegaly.
• hepatic encephalopathy.

P.360

1. Esophageal varices
2. Approximately 90% of upper gastrointestinal bleedingin patients with portal hypertension is secondary to bleeding varices.

• Mortality with acute variceal hemorrhage is approximately 50%.
• An algorithm for the management of acute variceal hemorrhage is outlined in Figure 15-6.

2. Endoscopic sclerotherapy

• is generally the initial treatment of acute variceal hemorrhage after initial resuscitative measures have been started.

2. The varices are injected with a sclerosing agentthat stops the bleeding in over 90% of patients.
3. Balloon tamponadeand repeat sclerotherapy may be performed if bleeding recurs or persists.
4. Late esophageal stricturemay occur in as many as 25% of patients after sclerotherapy.

• These strictures are often easily managed with dilation.

Figure 15-6. Algorithm for the management of acute variceal hemorrhage.

3. Medical treatment of esophageal varices

• may also include the use of vasopressinand somatostatin.

1. These agents cause visceral vasoconstrictionbut may affect other vascular systems as well.

P.361

1. Simultaneous nitroglycerin should be givenwhen vasopressin is administered to patients with coronary artery disease.

• This will counteract the coronary vasoconstrictive effects of vasopressin.

1. Propranololmay decrease portal pressure and prevent recurrent variceal bleeding but has no role in the treatment of acute variceal hemorrhage.
2. Balloon tamponadeof esophageal varices with a Sengstaken-Blakemore tube may stop acute variceal hemorrhage in 80%–85% of cases.

• Bleeding recurs in over 50% of patients with balloon deflation.
• Serious complications such as esophageal rupture may occur in as many as 10% of patients.

4. Transjugular intrahepatic portocaval shunts(TIPS)

• may be inserted percutaneously for refractory variceal bleeding.
• produces portosystemic shunting of blood using minimally invasive angiographic techniques.
• often serves as a bridge to hepatic transplantation and as an alternative to surgical shunting procedures.

5. Surgical portosystemic shunts

• are divided into selective and nonselective shunts (Figure 15-7.)

1. Nonselective shunts

• decompress the central portal venous system, thereby decreasing portal pressure.
• are most effective at decreasing ascites and stopping variceal bleeding.
• have a high rate of hepatic encephalopathyand progressive hepatic failure because portal venous perfusion of the liver is substantially reduced.
• include end-to-side portocaval shunts, side-to-side portocaval shunts, large mesocaval shunts, and interposition portocaval shunts with an artificial graft.

1. Selective shunts

• decompress esophageal varices while preserving some hepatic portal venous flow.
• are technically more difficult to perform;however, they have a lower risk of producing progressive hepatic failure or hepatic encephalopathy.
• The most common selective shuntis the distal splenorenal shunt, or Warren shunt.
• Refractory ascites is a contraindicationto the splenorenal shunt because selective shunts tend to precipitate worsening ascites.

6. Isolated elevation of portal venous pressure

• within the gastric portal venous system can be caused by splenic vein thrombosis.
• can lead to gastric variceswithout altering the rest of the portal venous system.

P.362

1. Splenic vein thrombosis

• is most commonly caused by pancreatitis.
• is also noted to occur more frequently in pregnancy.

1. Recognition is important

• because adequate treatment is by splenectomyalone without the need for portosystemic shunting.

Figure 15-7. Portosystemic shunts. (A) Nonselective shunt: end-to-side portal caval shunt. (B) Selective shunt: Warren distal splenorenal shunt. (Adapted from Blackbourne LH, Fleischer KJ: Advanced Surgical Recall. Baltimore, Williams & Wilkins, 1997, pp 462–463.)

1. Liver Failure and Ascites
2. The most common cause of liver failure

• is cirrhosis of the liver.

1. Child's Classification

P.363

• lists stages of liver failure based on five clinical parameters (Table 15-4).

1. Bilirubin level
2. Albumin level
3. Severity of ascites
4. Severity of encephalopathy
5. Nutritional status
6. Hepatic encephalopathy

• is a major complication of hepatic failureand of portosystemic shunts.
• can lead to neurologic changes, such as an altered level of consciousness, confusion, intellectual deterioration, and the end-stage characteristic flapping tremor, or asterixis.

1. The pathogenesis of hepatic encephalopathy is unknownbut is thought to be related to an unidentified cerebral toxin.
2. Encephalopathy is most often precipitated by

• gastrointestinal bleeding.
• dehydration.
• constipation.
• sedatives.
• excessive dietary protein intake.

3. Treatment is medical with

• enteral administration of neomycin and lactulose.
• protein restriction.
• treatment of precipitating events.

Table 15-4. Child-Turcot Risk Classification for Liver Failure

Class A Class B Class C Bilirubin (mg/dL) <2.0 2.0–3.0 >3.0 Albumin (g/dL) >3.5 3.0–3.5 <3.0 Ascites None Minimal (treatable) Severe (refractory) Encephalopathy None Minimal Severe Nutritional status Normal Fair Poor

1. Hepatorenal syndrome

• is renal insufficiency or renal failure associated with hepatic failure.
• The etiology
• has yet to be identified, although decreased renal perfusion and ischemia are thought to play a major role.
• Renal failure
• is clinically difficult to differentiate from prerenal causes of renal failure.

P.364

• Kidney function
• is restored after liver transplantation in hepatorenal syndrome.

1. Ascites

• is a complication of liver failure and portal hypertension.
• can result in a transudate formation within the peritoneal space.

1. Initial medical management

• with diuretics and dietary salt restrictionsuccessfully relieves ascites 95% of the time.

2. Spironolactone

• is often a first line diuretic because of the associated hyperaldosterone state often seen with ascites.

3. Denver and LeVeen shunts

• are subcutaneous shunts that drain ascitic fluid from the peritoneal cavity to the central venous system.
• Disseminated intravascular coagulation (DIC) is a known complication of peritoneovenous shunting of ascitic fluid.

4. Spontaneous bacterial peritonitis

• is frequently a fatal complication of persistent ascites.

1. Risk factorsinclude

• nephrotic syndrome.
• systemic lupus, particularly in children.

1. Infection is often monomicrobial.

• E. coliis the most common precipitating agent, followed by Pneumococcus.
• Hemolytic streptococci and Pneumococcusare the most common organisms in children.

1. Characteristic findingsinclude

• fever.
• abdominal pain.
• serum leukocytosis.

1. Diagnostic findings

• Elevated white blood cell count(> 500/mL)
• Large numbers of polymorphonuclear leukocytes within the ascitic fluid(> 250/mm³)
• Blood culturesand ascitic fluid cultures are often positive, but not always.

1. Treatment

• is with broad spectrum antibiotics.

P.365

Review Test

Directions: Each of the numbered items or incomplete statements in this section is followed by answers or by completions of the statement. Select the ONE lettered answer or completion that is BEST in each case.

1. A 22-year-old man sustained a gunshot wound to the right upper quadrant (RUQ) and was severely hypotensive on arrival to the emergency room. Intraoperatively, the patient was noted as having a large liver parenchymal injury with severe hemorrhage. A Pringle maneuver was performed to control the hemorrhage for better visualization of the injured parenchyma. After confirmation of appropriate placement of the vascular clamp for the Pringle maneuver, there is persistent bleeding of bright red blood from the liver parenchyma just medial to the falciform ligament. Which of the following structures would mostly likely cause the persistent hemorrhage from the liver parenchyma?

(A) Portal vein

(B) Common hepatic artery from celiac axis

(C) Left hepatic artery arising from left gastric artery

(D) Blood supply to the common bile duct

(E) Blood vessels within the hepatoduodenal ligament

1–C. The “Pringle maneuver” is a technique occasionally used in hepatic surgery to control persistent hemorrhage within the liver. It involves compression of the structures within the hepatoduodenal ligament, including the common hepatic artery, the common bile duct, and the portal vein. Typically, the portal vein is posterior to both the common bile duct and the hepatic artery. The hepatic artery is usually medial to the common bile duct. Although there are many anomalies within the hepatic vascular system, one of the most common is the left hepatic artery arising from the left gastric artery. This anomalous artery may not be occluded upon performing the Pringle maneuver and thus may result in persistent parenchymal hemorrhage despite this maneuver. In addition, persistent hemorrhage may also result from back-bleeding arising from injuries to the hepatic veins or to the inferior vena cava, which are not occluded with the Pringle maneuver.

Questions 2–4

A 62-year-old man with a well-known history of alcohol abuse presents to the emergency room with persistent hematemesis and hypotension. Endoscopic examination confirms the presence of diffusely bleeding esophageal and gastric varices.

2. Which of the following are characteristic of the portal venous system and portal hypertension?

(A) Normal portal pressure is generally greater than 12 mm Hg

(B) Esophageal varices arise from dilated branches of coronary veins

(C) The portal vein runs anterior to the common bile duct in the hepatoduodenal ligament

(D) Caput medusa is formed by periumbilical branches of the recanalized ductus arteriosum

(E) Portal pressure > 18 mm Hg may lead to valvular incompetence and subsequent varices

2–E. The portal venous system is a valveless system capable of transmitting elevated portal pressures throughout many collateral venous systems. Portal pressure is generally below 12 mm Hg, although wide variations may exist with and without the development of varices. The coronary veins are a collateral venous system draining blood from the esophagus and cardiac region of the stomach which, when dilated, can produce the characteristic esophageal varices. Increased portal pressure may also lead to dilated periumbilical veins and the characteristic caput medusa.

3. Which of the following treatment strategies would be inappropriate in the management of this patient?

(A) Endoscopic sclerotherapy or band ligation

(B) Emergent portosystemic shunt procedure for refractory bleeding

(C) Emergent splenectomy for the gastric varices

(D) Liver transplantation

(E) Placement of a Sengstaken-Blakemore tube

3–C. Initial management of the patient with actively bleeding varices involves evaluation and control of the airway and initiation of aggressive volume resuscitation. Endoscopy with sclerotherapy with or without band ligation of esophageal varices is an appropriate next step in the management of actively bleeding esophageal varices. In certain situations where endoscopy is not readily available, placing a Sengstaken-Blakemore tube to tamponade the bleeding varices is an acceptable alternative or it may be used as an adjunct to endoscopy. Emergent surgical formation of a portosystemic shunt (i.e., portocaval, mesocaval) to relieve portal pressure is performed less frequently now because of endoscopic therapies but is an appropriate alternative in the treatment of refractory bleeding from esophageal varices. Treatment of isolated gastric varices generally requires splenectomy to allow for selective decompression of the varices. However, performing a splenectomy in this patient with diffuse portal hypertension may worsen the hemorrhage from the esophageal varices and is not indicated. Definitive treatment of esophageal varices is liver transplantation.

4. Selective portosystemic shunts have which one of the following characteristics?

(A) Ineffective at lowering venous pressure within esophageal varices

(B) Contraindicated for refractory esophageal varices

(C) May cause worsening of ascites

(D) Higher risk of encephalopathy compared with nonselective portosystemic shunts

(E) Large side-to-side portocaval shunt

4–C. Selective and nonselective portosystemic shunts are both excellent at reducing portal venous pressure and may be used for treatment of esophageal varices. Other less invasive techniques that effectively control bleeding esophageal varices have decreased the need for surgical shunt procedures for the management of bleeding esophageal varices. Nonselective shunts are associated with a higher risk of hepatic encephalopathy when compared with selective shunts because almost all portal venous blood is shunted directly into the systemic venous system with nonselective shunts. Selective shunts are known to cause worsening ascites in patients and these shunts are typically contraindicated in patients with significant ascites. A side-to-side portocaval shunt is a type of nonselective shunt.

5. A 45-year-old woman presented to the emergency room with right upper quadrant (RUQ) abdominal pain and fever. The patient states that she had a cholecystectomy 2 years earlier. Computed tomography (CT) scan reveals a 6-cm, fluid-filled mass in the right lobe of the liver that was not noted to be present by ultrasound 2 years ago. Which of the following is the appropriate definitive treatment for the potential cause of this patient's condition?

(A) “Triple” antibiotics alone for a large pyogenic liver abscess

(B) Antibiotics alone for uncomplicated amebic liver abscess

(C) Percutaneous drainage of fluid from echinococcal cyst

(D) Antibiotics alone for a ruptured amebic liver abscess

(E) “Triple” antibiotics alone for a ruptured pyogenic liver abscess

5–B. Treatment of most liver abscesses requires adequate drainage, with medical therapy generally serving an adjunctive role. Complicated or large pyogenic liver abscesses such as this one almost always require drainage either percutaneously or surgically. Echinococcal cysts require surgical drainage of cyst fluid followed by instillation of hypertonic saline to kill the remaining organisms. Medical treatment alone is inadequate and drainage, without instillation of hypertonic saline, will not adequately treat the infection. Uncomplicated amebic liver abscesses are an exception in that they may be adequately treated with antibiotic therapy (i.e., metronidazole) alone, although complicated abscesses (i.e., rupture) still generally require surgical management.

6. A 63-year-old man underwent elective cholecystectomy for chronic biliary colic. Intraoperatively, a 2-cm, irregular mass was identified in the right lobe of the liver. Biopsy revealed a primary hepatocellular carcinoma. Thorough evaluation revealed no evidence of metastatic disease. The patient subsequently underwent resection of this lesion. All of these are potential risk factors for development of hepatocellular carcinoma EXCEPT

(A) Hemochromatosis

(B) Wilson's disease

(C) Hepatic adenoma

(D) Focal nodular hyperplasia

(E) Alcoholic cirrhosis

6–D. The most common risk factors for the development of hepatocellular carcinoma are cirrhosis secondary to hepatitis B or C infection and alcohol-induced cirrhosis. Other potential risk factors include various disease processes that affect the liver such as hemochromatosis, Wilson's disease, and glycogen storage diseases. There is approximately a 10% risk of malignant transformation of hepatic adenomas to hepatocellular carcinoma. An association between the development of hepatocellular carcinoma and blood-group B has also been demonstrated. Focal nodular hyperplasia is a benign liver lesion that has not been shown to undergo malignant degeneration or transformation.

7. Which of the following would be included in a true functional right hepatic lobectomy?

(A) Hepatic segment IV

(B) All hepatic segments to the right of Cantlies line and segment IV

(C) All hepatic segments to the right of Cantlies line and the entire quadrate lobe

(D) All segments to the right of the falciform ligament

(E) Hepatic segments V–VIII

7–E. A true functional right hepatic lobectomy would include all hepatic segments of the right lobe including segments V–VIII. A right hepatic trisegmentectomy would include hepatic segments IV–VIII. The quadrate lobe includes segments of both the true right and left hepatic lobes, while segment I is the caudate lobe and is not included in a right lobectomy. Cantlies line is an imaginary line to the right of the falciform ligament that divides the true functional right and left hepatic lobes.

Questions 8–9

A 57-year-old man with a history of alcohol-induced cirrhosis and chronic hepatic insufficiency presents to the emergency room with complaints of increasing shortness of breath and abdominal bloating worsening over the past 2 weeks. On physical examination, his abdomen is firm but nontender, with notable shifting dullness. In addition, breath sounds are decreased in both lung bases with bibasilar crackles noted. There is no evidence of infiltrate on chest radiograph. His white blood cell count is 9,000 with a normal differential. His prothrombin time is 18, blood urea nitrogen 68, creatinine is 3.5, and albumin is 1.4. Blood and urine cultures are negative.

8. Which of the following is an appropriate statement regarding the management of ascites and its associated complications?

(A) Spontaneous bacterial peritonitis requires prompt surgical drainage

(B) Diuretics should not be used in the initial management of ascites

(C) Peritoneovenous shunts have been shown to improve overall survival in patients with ascites

(D) Disseminated intravascular coagulation is a complication of peritoneovenous shunting

(E) Transjugular intrahepatic portosystemic shunts (TIPS) have no role in the management of refractory ascites

8–D. Most cases of ascites can be managed adequately with diuretic therapy. Other techniques for managing refractory ascites include periodic percutaneous drainage, transjugular intrahepatic portosystemic shunts (TIPS), and the surgical placement of peritoneovenous shunts. Peritoneovenous shunts such as the Denver or LeVeen shunts have not been shown to improve survival in patients with liver failure and severe ascites. These shunts are associated with an increased risk of disseminated intravascular coagulation. Spontaneous bacterial peritonitis can often be treated nonsurgically with antibiotic therapy.

9. The renal failure in this patient has which of the following characteristic findings?

(A) Renal arteriolar vasodilatation

(B) Urine osmolality < 1.010

(C) Many urinary casts on urinalysis

(D) Low urine sodium

(E) Renal function typically does not recover after liver transplantation

9–D. Renal insufficiency secondary to hepatorenal syndrome clinically resembles prerenal causes of renal failure. Characteristics include renal arteriolar vasoconstriction, high urine osmolality, and low urine sodium. Urinary casts typical of acute tubular necrosis are rarely seen in hepatorenal syndrome. Renal function often recovers upon liver transplantation.

Directions: Each set of matching questions in this section consists of a list of four to twenty-six lettered options followed by several numbered items. For each numbered item, select the appropriate lettered option(s). Each lettered option may be selected once, more than once, or not at all.

Questions 10–22

1. Simple cysts
2. Cystadenocarcinoma
3. Hepatic adenoma
4. Hepatocellular carcinoma
5. Hemangioendothelioma
6. Focal nodular hyperplasia
7. Pyogenic liver abscess
8. Cavernous hemangioma
9. Echinococcal cyst
10. Polycystic disease
11. Fibrolamellar hepatocellular carcinoma
12. Hepatoblastoma
13. Amebic liver abscess
14. A 48-year-old woman with a history of primary ovarian carcinoma 2 months after total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH BSO) and staging laparotomy presents with a new 2-cm mass in the right lobe of the liver. (SELECT 1 DIAGNOSIS)

10–B. Although cystic hepatic lesions are frequently infectious in nature or otherwise benign, they can include malignant metastatic tumors such as ovarian and pancreatic cystadenocarcinomas. In addition, other solid metastatic tumors may undergo central necrosis and appear as cystic lesions.

11. A 42-year-old woman is found to have a 2-cm, solid mass in the left lobe of the liver during an ultrasound evaluation for biliary colic. Before elective cholecystectomy, a positive red blood cell scan confirms that the lesion is benign. (SELECT 1 DIAGNOSIS)

11–H. Cavernous hemangiomas are benign tumors of the liver, and are the most common primary lesions of the liver. Hemangiomas may be adequately differentiated from other lesions by computed tomography (CT) examination, although the diagnoses are frequently confirmed by characteristic findings on a red blood cell radionuclide scan.

12. A 34-year-old man presents to the emergency room with a 3-day history of fever and worsening right upper quadrant (RUQ) abdominal pain. Ultrasound reveals a 4-cm, fluid-filled mass in the right lobe of the liver. Attempted percutaneous drainage resulted in a scant amount of thick fluid. Routine bacterial cultures of the aspirated fluid and of the blood were negative. The patient has complete resolution of symptoms with metronidazole therapy. (SELECT 1 DIAGNOSIS)

12–M. An amebic liver abscess caused by Entamoeba histolytica can frequently present with fever and right upper quadrant (RUQ) abdominal pain. A fluid-filled mass may be seen on ultrasound or by computed tomography (CT) scan. The fluid within the cyst is often very thick and tenacious and is described as having an “anchovy-paste” consistency. Although most infectious lesions of the liver require drainage, débridement, or both, amebic liver abscesses frequently resolve with metronidazole therapy alone.

13. During an elective cholecystectomy, a 43-year-old woman is noted as having a 1-cm, superficial, blue, smooth cystic mass in the right lobe of the liver. (SELECT 1 DIAGNOSIS)

13–A. Simple liver cysts are a common incidental finding identified radiographically or at the time of intra-abdominal surgery. These lesions are generally solitary and, upon direct visualization, have a characteristic blue hue. Asymptomatic lesions do not require resection.

14. During a routine complete blood count, a 43-year-old woman is found to have a platelet count of 53,000. During a thorough evaluation of the thrombocytopenia, an abdominal computed tomography (CT) scan reveals a 5-cm, benign-appearing mass in the right lobe of the liver. Additional laboratory tests are all unremarkable. (SELECT 1 DIAGNOSIS)

14–H. Kasabach-Merritt syndrome is a rare syndrome characterized by sequestration of platelets, potentially leading to a thrombocytopenic coagulopathy. This syndrome is occasionally associated with large cavernous hemangiomas because of platelet sequestration within these lesions. This syndrome may also occur in children with hemangioendotheliomas, although these benign tumors are rare in adults.

15. An 18-month-old healthy boy is noted as having a small palpable mass in the right upper quadrant (RUQ) of the abdomen. Ultrasound reveals a 1-cm, solid, benign-appearing lesion in the periphery of the right lobe of the liver. (SELECT 1 DIAGNOSIS)

15–E. Hemangioendotheliomas are benign vesiculiform tumors seen almost exclusively in children younger than 2 years old. These tumors can easily be differentiated from other tumors, such as hepatoblastomas, with routine radiographic techniques.

16. A 38-year-old woman has been in a motor vehicle accident. During a trauma evaluation, she is found to have a 3-cm, asymptomatic, solid mass in the left lobe of the liver by abdominal computed tomography (CT). The lesion is determined to be benign. However, an elective resection of the lesion is planned given the risk of malignant transformation. (SELECT 1 DIAGNOSIS)

16–C. Hepatic adenomas are benign tumors typically presenting as an asymptomatic lesion identified radiographically as an incidental finding. These tumors are almost exclusively found in women of child-bearing age and are associated with oral contraceptive use. Malignant transformation to hepatocellular carcinoma may occur in a small percentage of hepatic adenomas. In addition, there is a risk of spontaneous rupture of these lesions with significant hemorrhage resulting. These factors provide support for the elective resection of medium-sized or large asymptomatic hepatic adenomas.

17. A 52-year-old woman has a 2-cm, solid mass within the right lobe of the liver. A computed tomography (CT) scan reveals a lesion with a central stellate scar. (SELECT 1 DIAGNOSIS)

17–F. Radiographic evidence of a central stellate scar is a characteristic finding of focal nodular hyperplasia. Unfortunately, this finding is not always present and this lesion is often difficult to differentiate from a hepatic adenoma. Unlike a hepatic adenoma, these lesions are not associated with malignant transformation or rupture. Therefore asymptomatic lesions do not require resection. These lesions are composed of hyperplastic Kupffer cells that are easily identified by a sulfur colloid scan.

18. During attempted laparoscopic drainage of a benign, 4-cm cystic lesion in the right lobe of the liver, a 38-year-old patient developed rapid onset of hypotension with associated difficulty in ventilation. There was no obvious hemorrhagic source, and emergent chest radiograph was normal. (SELECT 1 DIAGNOSIS)

18–I. Upon drainage of an echinococcal cyst, great emphasis is placed upon avoiding peritoneal spillage of the cyst contents because of the risk of spread of the infection as well as the rare occurrence of anaphylaxis.

19. A 63-year-old man with a history of hepatitis B-induced cirrhosis presents with a 20-lb weight loss over the past 3 months. Abdominal computed tomography (CT) scan reveals a 4-cm, irregular, solid mass in the right lobe of the liver. Additional thorough evaluation of the patient is negative. (SELECT 1 DIAGNOSIS)

19–D. Hepatocellular carcinoma is the most common primary malignant tumor of the liver. Cirrhosis of the liver is the greatest risk factor for development of this tumor. However, metastatic tumors, overall, remain the most common lesions found in the liver.

20. A 34-year-old, thin woman has a large, palpable, irregular liver edge on physical examination. In addition, the left kidney is easily palpable and irregular on physical examination. All liver function tests are within normal limits. Blood urea nitrogen is 45 and creatinine is 3.2. (SELECT 1 DIAGNOSIS)

20–J. Adult polycystic disease is characterized by multiple cystic lesions in both the liver and kidney. It is inherited as an autosomal dominant trait and may present with an enlarged palpable liver or kidneys. Hepatic function (i.e., liver function tests, albumin level, prothrombin time, partial thromboplastin time) is typically unaffected despite extensive cystic involvement of the liver. Morbidity is characteristically associated with renal dysfunction secondary to cystic involvement of the kidneys.

21. A 33-year-old woman is brought to the emergency room by her husband after she had been complaining of abdominal pain and then suddenly collapsed. Her blood pressure on arrival is 70/40 mm Hg and her abdomen is noted to be tense. Intraoperatively, the patient is found to have a large hemoperitoneum. (SELECT 1 DIAGNOSIS)

21–C. Spontaneous rupture of a hepatic adenoma with hypotension and a hemoperitoneum is a characteristic complication of these benign tumors. These tumors are associated with oral contraceptive use. There is also an increased risk of rupture of hepatic adenomas with oral contraceptive use. Although other diagnoses may present with hypotension and a hemoperitoneum (i.e., ruptured ectopic pregnancy), a hepatic adenoma should always be considered as a potential source in women of child-bearing age.

22. A 63-year-old man presents to the emergency room with fever and right upper quadrant (RUQ) pain. He is currently being treated as an outpatient for a bout of diverticulitis. Ultrasound reveals a 4-cm, fluid-filled mass in the right lobe of the liver. (SELECT 1 DIAGNOSIS)

22–G. Pyogenic abscesses account for approximately 80% of all infectious lesions of the liver. Pyogenic liver abscesses can often present without an obvious source of infection elsewhere, although intra-abdominal infections such as appendicitis, diverticulitis, and biliary tree infections often serve as a primary source of bacteria.