Biliary System PDF

CHAPTER 55 Biliary System...

CHAPTER 55 Biliary System Pejman Radkani, Jason Hawksworth, Thomas Fishbein OUTLINE Anatomy and Physiology Acute Calculous Cholecystitis Vascular Anatomy Choledocholithiasis Physiology Gallstone Pancreatitis Biliary Tree Pathophysiology Gallstone Ileus Laboratory Tests Noncalculous Biliary Disease Imaging Studies Surgery for Calculous Biliary Disease Bacteriology Postcholecystectomy Syndromes Benign Biliary Disease Malignant Biliary Disease Calculous Biliary Disease Gallbladder Cancer Natural History Bile Duct Cancer Nonoperative Treatment of Cholelithiasis Metastatic and Other Tumors Chronic Cholecystitis ANATOMY AND PHYSIOLOGY is attached to the liver, there is no peritoneal covering; a fibrous As anatomic variations in biliary anatomy are common, occurring lining known as the cystic plate occupies this space. Bile is drained in up to 30% of patients, understanding of both normal anatomy via a cystic duct to the common bile duct (CBD). The cystic duct and the variations is important for the management of patients can range from 1 to 5 cm in length and drains at an acute angle with biliary disease. into the CBD. There are numerous variations in this insertion, in- Bile ducts, either intrahepatic or extrahepatic, lie superior to the cluding into the right hepatic duct (Fig. 55.3). The valves of Heis- corresponding portal vein, which in turn are lateral and inferior to ter, which are folds of mucosa oriented in spiral pattern within the the arterial supply (Fig. 55.1). The left hepatic duct retains a longer neck of gallbladder, function to retain bile in the gallbladder until transverse extrahepatic portion and travels under the edge of seg- contraction in response to enteric stimulation. ment IV before diving before joining the bifurcation. It can receive The CBD is divided into three portions: supraduodenal, retro- a few subsegmental branches from segment IV in this transverse duodenal, and the pancreatic portion, which is the most inferior portion. The left duct drains segments I, II, III, and IV, with the portion, encompassed by head of pancreas. The insertion of cystic most distal branch draining segment IVA. Further superolateral, duct marks the separation of the CBD (below) from the common the ducts draining segment IVB arise, and yet further up the left hepatic duct (above). The CBD ends in the second portion of duo- duct are the ducts for segments II and III. These ducts can gener- denum at the ampulla of Vater. The pancreatic duct also joins the ally be found just posterior and lateral to the umbilical recess. The ampulla, although in variants may have a separate orifice (Fig. 55.4). caudate lobe drains through smaller ducts that enter the right and As mentioned, the cystic duct divides the bile duct to common left hepatic duct systems. The drainage of the right duct system hepatic duct and CBD. The common hepatic duct drains the left includes segments V, VI, VII, and VIII and is substantially shorter and right hepatic ducts and their confluence at the hilar plate, which than the left duct, bifurcating almost immediately. The junction of is an extension of Glisson’s capsule. There are generally no vascular two sectoral ducts, posterior and anterior, creates this short right structures overlying bile ducts at this location, allowing exposure of hepatic duct. The anterior sectoral duct runs in a vertical direction the bifurcation by incision at the base of segment IV and lifting the to drain segments V and VIII, whereas the posterior sectoral duct liver off these structures. This technique, called lowering hilar plate, follows a horizontal course to drain segments VI and VII. is used to expose the proximal extrahepatic biliary tree. The gallbladder is a partially intraperitoneal structure that lies attached to the undersurface of the liver on segments IVB and V. Vascular Anatomy It is 7 to 10 cm in length, holds 30 to 60 mL of bile as a reservoir, As described by Couinaud,1 the hepatic parenchyma is divided and is divided into neck, infundibulum with Hartmann pouch, into lobes, each of which is divided into lobar segments (Fig. 55.5) body, and fundus (Fig. 55.2). On the side of the gallbladder that to define the basic hepatic anatomic resections. 1489 Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1490 SECTION X Abdomen FIG. 55.1 Hepatic lobar segmental biliary anatomy. FIG. 55.2 Laparoscopic photograph of the gallbladder in situ. The gall- bladder is being suspended by the fundus to expose the infundibulum and porta hepatis. FIG. 55.3 Variability in cystic duct anatomy. Knowledge of these varia- tions is important to try to avoid inadvertent injury to the biliary tree during The blood supply to the entire biliary tree is solely arterial as cholecystectomy. contrasted with the hepatic parenchyma, where dual perfusion comes as well from the portal vein, which makes the biliary tree susceptible to ischemic injury. hepatic artery passes posterior to the common hepatic duct to sup- The cystic artery normally arises from the right hepatic artery, ply the right lobe of the liver. It passes through the triangle of and similar to the variability of the cystic duct, it may arise from Calot (bordered by the cystic duct, common hepatic duct, and the right hepatic, left hepatic, proper hepatic, common hepatic, edge of the liver), after crossing the duct. The cystic artery takes gastroduodenal, or superior mesenteric artery. The cystic artery off from the right hepatic artery in this triangle, which is at risk for can pass posterior or anterior to the CBD to supply the gallblad- injury during cholecystectomy. It is important to remember that der. Although variable, the cystic artery generally lies superior in 20% of the population, there is an accessory or replaced right to the cystic duct and is usually associated with a lymph node, hepatic artery passing through the portacaval space and ascending known as Calot node (Fig. 55.6). This node can be enlarged in to the right lobe along the lateral aspect of the CBD. A pulsatile the setting of gallbladder disease, whether inflammatory or neo- structure palpated on the most lateral aspect of the porta during plastic, due to the fact that it provides the lymphatic drainage of a Pringle maneuver identifies this anomaly. In addition, it can be the gallbladder. noted on computed tomography (CT) as a vessel passing trans- The blood supply of the common hepatic duct and CBD versely between the portal vein and inferior vena cava behind the comes from the right hepatic and cystic artery. Typically, the right head of the pancreas. Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 55 Biliary System 1491 The perfusion to the inferior bile duct, below the duodenal 9-o’clock positions. These vessels can be damaged and leave the bulb, comes from tributaries of the posterosuperior pancreatico- bile duct at risk for ischemic injury with close dissection of the duodenal and gastroduodenal arteries. The small branches coalesce areolar tissue surrounding the bile duct. to form the two vessels that run along the CBD at the 3- and Physiology The smallest functional unit of liver is the hepatic lobule. It is cre- ated by four to six portal triads and identified by its central termi- nal hepatic venule. Each hepatocyte is encircled by bile canaliculi, which coalesce to form small bile ducts, entering portal triad. Bile salts, such as cholic acid and deoxycholic acid, are originally cre- ated from cholesterol and secreted into bile canaliculi as cholic acid and its metabolite, deoxycholic acid. The liver actually makes only a small amount of the total bile salt pool used on a daily basis because most bile salts are recycled after use in the intestinal lumen, known as the enterohepatic circulation (Fig. 55.7). Bile is A B C D FIG. 55.4 Patterns of biliary duct–pancreatic duct junction and insertion into the duodenal wall. (A) Separate common bile duct (CBD) and pan- creatic duct (PD) entry. (B) Joining ducts at the ampula. (C) Joining ducts FIG. 55.6 Operative photograph of Calot node. This node (arrow) is use- before the ampula. (D) PD entering the CBD. ful for identification of the common location of the cystic artery. II VII VIII III I IV VI V FIG. 55.5 Couinaud segmental anatomy. Segment I is the caudate lobe. Segments II and III are supplied by the lateral branch of the left portal vein, with segment II lying above the passage of the portal vein and segment III below it. Segment IV is supplied by the medial branch of the left portal vein and is further subdivided into IVA above and IVB below the segmental portal vein. Segment V is supplied by the inferior distribution of the anterior branch of the right portal vein, and segment VIII receives flow from the superior distribution of this branch. Similarly, with respect to the posterior branch of the right portal vein, segment VI lies inferior to the portal vein, whereas segment VII lies superior. Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1492 SECTION X Abdomen Synthesis (0.2–0.6 g/d) Systemic circulation Urinary excretion (95% of biliary secretion) Fecal excretion (0.2–0.6 g/d) FIG. 55.7 Enterohepatic circulation. secreted into canaliculi directly from hepatocytes. Once the bile In addition to bile salts, bile contains proteins, lipids, and pig- components are secreted into the bile canaliculi, the tight junc- ments. The major lipid components of bile are phospholipids and tions in the biliary tree keep these components within the bile cholesterol. These lipids not only dispose of cholesterol from low- secretory pathway. The secretion of bile components into the bili- and high-density lipoproteins but also serve to protect hepatocytes ary tree is a major stimulus to bile flow, and the volume of bile and cholangiocytes from the toxic nature of bile. The sources of flow is an osmotic process. Because bile salts combine to form most biliary cholesterol are circulating lipoproteins and hepatic spherical pockets, known as micelles, the salts themselves provide synthesis. Therefore, the biliary secretion of cholesterol actually no osmotic activity. Instead, the cations that are secreted into the serves to excrete cholesterol from the body. biliary tree along with the bile salt anion provide the osmotic load Aside from absorption of nutrients from the intestinal tract, to draw water into the duct and to increase flow to keep bile elec- bile secretion from the liver serves an opposing function, namely, trochemically neutral. For this reason, bile maintains an osmolal- excretion of toxins and metabolites from the liver. Bile pigments ity approximately comparable to that of plasma. such as bilirubin are breakdown products of hemoglobin and After passage into the intestinal tract and reabsorption by the myoglobin. These products are transported in the blood, bound terminal ileum, bile acids are transported back to the liver for re- to albumin, to hepatocytes. Inside hepatocytes, they will be trans- cycling bound to albumin. On the opposite side from the cana- ferred into the endoplasmic reticulum and conjugated to form licular surface of the hepatocyte lies the sinusoidal surface, which bilirubin glucuronides, known as conjugated or “direct” bilirubin. contacts the space of Disse. In this contact area, the hepatocyte Bile pigment gives the color of bile and, when converted to uro- absorbs the circulating components of bile, an important step in bilinogen by bacterial enzymes, gives stool its characteristic color. the enterohepatic circulation. The passage of reabsorbed bile salts Much of the bile flow is dependent on neural, humoral, and bound to albumin through the space of Disse allows uptake into the chemical stimuli. Vagal activity induces bile secretion as does the hepatocyte in an efficient process that involves sodium cotransport gastrointestinal hormone secretin. Cholecystokinin (CCK), se- and sodium-independent pathways. In the less specific sodium- creted by the intestinal mucosa, serves to induce biliary tree secre- independent pathway, a number of organic anions are transported, tion and gallbladder wall contraction, thereby augmenting excre- including unconjugated and indirect bilirubin. The transport of bile tion of bile into the intestines. Secreted bile will pass through the salts across the canalicular membrane remains the rate-limiting step biliary tree into the intestine and be reabsorbed. The gallbladder in bile salt excretion. Given the vast differences in concentration of serves as an extrahepatic storage site of bile, absorbing water and bile salts, the transport of bile up an extreme concentration gradient concentrating bile in an osmotic process performed through the is adenosine triphosphate dependent. Less than 5% of bile salts are active sodium transport. With the absorption of sodium and wa- lost each day in the stool. When sufficient quantities of bile salts ter across the gallbladder epithelium, the chemical composition of reach the colonic lumen, the powerful detergent activity of the bile bile changes in the gallbladder lumen. Increases in cholesterol and salts can cause inflammation and diarrhea. This can sometimes be calcium concentration calcium lead to decreased stability of phos- seen after a cholecystectomy when the speed of the enterohepatic pholipid cholesterol vesicles. The reduced vesicle stability predis- circulation of bile increases and may overwhelm the ability of the poses to nucleation of this stagnant pool of cholesterol and, thus, terminal ileum to absorb bile salts. to cholesterol stone formation. The gallbladder neck and cystic Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 55 Biliary System 1493 FR 40Hz RS 2D 42% Common bile C 55 duct P Low HGen Pancreatic duct CBD PV CBD FIG. 55.9 Ultrasound image of dilated biliary tree. The common bile duct (CBD) is dilated. As it travels parallel to the portal vein (PV), it is easy to identify. The depiction of the parallel stripes of duct and vein helps en- FIG. 55.8 Sphincter of Oddi. Because the sphincter is responsible for sure that the common duct diameter is not overestimated by a tangential control of most bile flow, this sphincter maintains a high tonic contraction view, which would artificially increase the anteroposterior diameter. but is inhibited by cholecystokinin. be identifiable in the frenulum of the tongue, sclera, or skin. It duct also secrete glycoproteins to help protect the gallbladder from is important to check the frenulum first, as the level of bilirubin the detergent activity of bile. These glycoproteins also promote must reach to 2.5 mg/dL to be seen in sclera and above 5 mg/dL cholesterol crystallization. to be manifested in skin. An increase in the activity of the sphincter of Oddi in the fast- ing state (Fig. 55.8), whose musculature is independent from the duodenal intestinal wall, increases pressure in the CBD, filling the Imaging Studies gallbladder, which is capable of storing up to 300 mL of daily Plain Films bile production, through a retrograde mechanism. This muscu- As the simplest radiographic study, plain radiographs are of lim- lar sphincter normally maintains high tonic and phasic activity, ited use in the overall evaluation of biliary tree disease. Gallstones which is inhibited by CCK. The passage of fat, protein, and acid are not regularly seen by plain films, and even when they are seen, into the duodenum induces CCK secretion from duodenal epi- it rarely changes therapy. Therefore, the role of plain radiographs thelial cells. CCK, as its name suggests, then causes gallbladder in the evaluation of possible biliary disease is limited to exclusion contraction, with intraluminal pressures up to 300 mm Hg. Vagal of other diagnoses, such as a duodenal ulcer with free air, small activity also induces gallbladder emptying but is a less powerful bowel obstruction, or right lower lobe pneumonia causing right stimulus to gallbladder contraction than CCK. At the same time, upper quadrant pain. CCK induces relaxation of the sphincter, causing bile flow more readily from the biliary tree. Coordinated with gallbladder con- Ultrasound traction, the relaxation of this sphincter allows evacuation of up Transabdominal ultrasound is a sensitive, inexpensive, reliable, and to 70% of the gallbladder contents within 2 hours of CCK secre- reproducible test to evaluate most of the biliary tree, being able to tion. During the fasting state, the oblique passage of the bile duct separate patients with medical jaundice, in which the source of hyper- through the duodenal wall and the tonic activity of the sphincter bilirubinemia is from hemoglobin breakdown through the process of prevent duodenal contents from refluxing into the biliary tree. conjugation, from those with surgical jaundice, in which the hyperbili- rubinemia occurs from a blockage of excretion. Therefore, this modal- BILIARY TREE PATHOPHYSIOLOGY ity is seen as the study of choice for the initial evaluation of jaundice or symptoms of biliary disease. The finding of a dilated CBD in the Laboratory Tests setting of jaundice suggests an obstruction of the duct from stones, A hepatic panel tests a number of metabolic and functional aspects usually associated with pain, or from a tumor, which is commonly of the liver and biliary system. painless (Fig. 55.9). Gallbladder diseases are regularly diagnosed by For example, increase in levels of bilirubin and alkaline phos- ultrasound because the superficial location of the gallbladder with no phatase will be determinative in a cholestatic process, but serum overlying bowel gas enables its evaluation by sound waves. Ultrasound transaminase level is suggestive of hepatocyte physiology. has a high specificity and sensitivity for cholelithiasis, or gallstones. Hyperbilirubinemia could be secondary to conjugated bili- The density of gallstones allows crisp reverberation of the sound wave, rubin, possibly due to obstruction, or to unconjugated hyper- showing an echogenic focus with a characteristic shadowing behind bilirubinemia caused by increased synthesis, impaired hepatocyte the stone (Fig. 55.10). Most gallstones, unless impacted, will move uptake of unconjugated bilirubin, and decreased intracellular with positional changes in the patient. This feature allows their dif- conjugation. Although this is an oversimplification of a complex ferentiation from gallbladder polyps, which are fixed, and from sludge, process, derangements up to and including conjugation will be which will move more slowly and does not have the sharp echogenic manifested as elevated unconjugated bilirubin levels. Elevation in pattern of gallstones. Pathologic changes seen in many gallbladder dis- serum bilirubin caused by obstruction of the biliary system will eases can be identified by ultrasound. For example, the gallbladder wall Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1494 SECTION X Abdomen FR 33Hz RS 2D 61% C 55 P Low HGen LONG GB DEC FIG. 55.10 Ultrasound image of a gallstone in the gallbladder neck. The sharp echogenic wall of the gallstone (arrow), with the characteristic pos- terior shadowing stripe under the stone, helps differentiate it from other intraluminal findings. Tran GB FOSSA FIG. 55.12 Ultrasound image of porcelain gallbladder. The curvilinear sharp echogenic focus (arrow) combined with substantial posterior shad- owing helps confirm this diagnosis. Fr: 1–5 Duration: 300 sec Fr: 6–10 Duration: 300 sec SAG GB M/L FIG. 55.11 Ultrasound image with acute cholecystitis and thickened gallbladder wall (arrows). thickening and pericholecystic fluid seen in cholecystitis are visible by ultrasound (Fig. 55.11). Porcelain gallbladder, with its calcified wall, will appear as a curvilinear echogenic focus along the entire gallbladder wall, with posterior shadowing (Fig. 55.12). In addition to the division Fr: 16–20 Duration: 300 sec Fr: 21–25 Duration: 300 sec of medical versus surgical jaundice, ultrasound can sometimes identify the cause of obstructive jaundice, showing CBD stones or even chol- FIG. 55.13 Hepatic iminodiacetic acid scan showing filling of the gall- angiocarcinoma. bladder. With gallbladder filling (arrows), the diagnosis of acute cholecys- titis is effectively eliminated. Hepatic Iminodiacetic Acid Scan Although incapable of providing any precise anatomic delineation, bil- ejection of the gallbladder. This may be useful in patients with biliary iary scintigraphy, also known as a hepatic iminodiacetic acid (HIDA) tract pain but without stones because some patients have pain from scan, can be used to evaluate the physiologic secretion of bile. The impaired emptying, known as biliary dyskinesia. As a nuclear medi- injection of an iminodiacetic acid, which is processed in the liver and cine test, the test demonstrates physiologic flow but does not provide secreted with bile, allows identification of bile flow. Therefore, the fail- fine anatomic detail, nor can it identify gallstones. ure to fill the gallbladder 2 hours after injection demonstrates obstruc- tion of the cystic duct, as seen in acute cholecystitis (Figs. 55.13 and Computed Tomography 55.14). In addition, the scan will identify obstruction of the biliary Although ultrasound is clearly the first test of choice for delinea- tree and bile leaks, which may be useful in the postoperative setting. tion of biliary disease, CT provides superior anatomic informa- HIDA scans can also be used to determine gallbladder function be- tion and therefore is indicated when more anatomic delineation cause the injection of CCK during a scan will document physiologic is required. Because most gallstones are radiographically isodense Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 55 Biliary System 1495 H Fr:6-10 Duration:300sec Fr:11-15 Duration:300sec CBD R L PD Fr:21-25 Duration:300sec Fr:26-30 Duration:300sec FIG. 55.14 Hepatic iminodiacetic acid (HIDA) scan showing nonfilling of the gallbladder. With no filling of the gallbladder (arrows) even on delayed F images, HIDA confirms occlusion of the cystic duct, the characteristic feature of acute cholecystitis. FIG. 55.16 Normal magnetic resonance cholangiopancreatography im- age. Note the normal common bile duct (CBD) and pancreatic duct (PD). of the intrahepatic and extrahepatic biliary tree and pancreas. Al- though management of most patients with biliary disease does not require the fine detail of anatomic evaluation shown by cross- sectional imaging, MRI is noninvasive, requires no radiation ex- posure, and can prove extremely useful in planning resection of biliary or pancreatic neoplasms or management of complex biliary disease. By use of the water content of bile, a cholangiopancrea- togram can be created (Fig. 55.16), which makes it an excellent modality for cross-sectional imaging of the biliary tree. Endoscopic Retrograde Cholangiopancreatography Endoscopic retrograde cholangiopancreatography (ERCP) is an in- vasive test using endoscopy and fluoroscopy to inject contrast ma- terial through the ampulla to image the biliary tree (Fig. 55.17). Although it does carry a complication rate of up to 10%, its useful- ness lies in its ability to diagnose and to treat many diseases of the biliary tree. For patients with malignant obstruction, ERCP can be FIG. 55.15 Computed tomography scan showing dilated biliary tree (ar­ used to provide tissue samples for diagnosis while also decompress- row) at the portal confluence. This dilation continued down to the head ing an obstruction, but it does not stage disease accurately. Many of the pancreas. benign diseases, such as choledocholithiasis, can be easily treated by endoscopic means. ERCP has also proven extremely useful in the to bile, many will be indistinguishable from bile. However, be- diagnosis and treatment of complications of biliary surgery. cause ultrasound is operator dependent and provides no anatomic reconstruction of the biliary tree, CT can be used to identify the Percutaneous Transhepatic Cholangiography cause and site of biliary obstruction (Fig. 55.15). When it is per- Interventional radiologic techniques can be used in the evaluation formed for the evaluation of hepatic or pancreatic parenchyma of biliary anatomy. Similar to ERCP, percutaneous transhepatic or possible neoplastic processes, CT is invaluable in preoperative cholangiography (PTC) is an invasive procedure used to evaluate planning, and the use of arterial phase, portal venous phase, and the biliary tree. A needle is passed directly into the liver to access delayed phase imaging, known as a triple-phase CT, has essentially one of the biliary radicals, and the tract is then used for contrast replaced diagnostic angiography of the liver. imaging and can serve to allow insertion of transhepatic catheters for drainage and sometimes biopsy. It can be useful for patients Magnetic Resonance Imaging and Magnetic Resonance with intrahepatic biliary disease or in whom ERCP is not techni- Cholangiopancreatography cally feasible; PTC can decompress biliary obstruction and stent Magnetic resonance imaging (MRI) uses the water in bile to delin- obstructions nonoperatively and can provide anatomic informa- eate the biliary tree and thus provides superior anatomic definition tion for biliary reconstruction (Fig. 55.18). Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1496 SECTION X Abdomen FIG. 55.17 Normal endoscopic retrograde cholangiopancreatography image. Intraoperative Cholangiography Another imaging tool for the diagnosis of biliary tract abnormalities is intraoperative cholangiography. With the injection catheter in- serted through the cystic duct during a cholecystectomy or through FIG. 55.18 Percutaneous transhepatic cholangiography image of he- another point in the biliary tree, intraoperative cholangiography can patic biliary anatomy. help delineate anomalous biliary anatomy, identify choledocholithia- sis, or guide biliary reconstruction. Some surgeons advocate routine cholangiography during cholecystectomy. Advocates for routine BOX 55.1 Indications for selective cholangiography note that common duct injuries can be identified cholangiography. and managed immediately when cholangiography is used routinely. Pain at time of operation However, because it adds operative time and fluoroscopic exposure Abnormal hepatic function panel to the operation, many surgeons use intraoperative cholangiography Anomalous or confusing biliary anatomy selectively during the performance of a cholecystectomy. Although Inability to perform postoperative endoscopic retrograde cholangiopancrea­ debated, the routine use of intraoperative cholangiography does not tography reduce significantly the incidence of injury to the biliary tree dur- Dilated biliary tree ing laparoscopic cholecystectomy. Indications for the selective use of Any suspicion of choledocholithiasis cholangiography include pain on the day of operation, abnormal he- patic function panel, anomalous or confusing biliary anatomy, and alteration in anatomy that precludes the ability to perform ERCP af- can guide interventions such as needle biopsies under real-time ter cholecystectomy, such as Roux-en-Y gastric bypass, dilated biliary ultrasound guidance (Fig. 55.19). tree, or any preoperative suspicion of choledocholithiasis (Box 55.1). Fluorodeoxyglucose Positron Emission Tomography Endoscopic Ultrasound Fluorodeoxyglucose positron emission tomography (FDG PET) Although of limited use in the evaluation of gallbladder disease exploits the metabolic difference between a highly metabolically or intrahepatic disease of the biliary tree, endoscopic ultrasound active tissue, such as a neoplasm, and normal tissue. With the in- is valuable in the assessment of distal CBD and ampulla. With jection of a radiolabeled glucose molecule, FDG PET scans can the close apposition of the distal CBD and pancreas to the duo- differentiate benign and malignant lesions, detect recurrence, and denum, sound waves generated by endoscopic ultrasound provide identify metastatic disease. Unfortunately, FDG PET is incapable detailed evaluation of the bile duct and ampulla; this has proved of demonstrating carcinomatosis and, given the high metabolism most useful in assessing tumors for invasion into vascular struc- of the immune system, is of limited value in the setting of infec- tures. Echoendoscopes are subdivided into those that scan per- tion or inflammation. pendicular to the long axis of the endoscope, known as radial echoendoscopes, and those that scan parallel, known as linear Bacteriology echoendoscopes. Radial echoendoscopes are most useful for pro- The biliary tree inserts into the duodenum and therefore cannot viding a tomographic evaluation, whereas linear echoendoscopes be considered truly sterile. Through a low bacterial load and with Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 55 Biliary System 1497 FIG. 55.19 Linear endoscopic ultrasound with needle (arrow) biopsy of a lymph node. the flow of bile, infection in the absence of obstruction is rare. However, with the presence of stones or obstruction, the likeli- hood of bacterial infection increases. The most common types of bacteria found in biliary infections are Enterobacteriaceae, such as Escherichia coli, Klebsiella, and Enterobacter, followed by Enterococ- cus spp. FIG. 55.20 Gallbladder with characteristic yellow cholesterol stones. Prophylactic antibiotics should be used in most patients un- dergoing interventions in the biliary tree, such as ERCP or PTC. To cover the most common bacterial species, a first- or second- whereas increased hemoglobin processing is seen in most patients generation cephalosporin or fluoroquinolone should suffice. For with pigment stones. Once in the gallbladder, bile is concentrated those undergoing elective laparoscopic cholecystectomy for biliary further through the absorption of water and sodium, increasing colic, no antibiotic prophylaxis is necessary. However, antibiotics the concentrations of the bile solutes and calcium. Bile salts act should be used for any patient with suspected or documented in- to solubilize cholesterol. With respect to cholesterol stones (Fig. fection of the biliary tree, such as acute cholecystitis or ascending 55.20), cholesterol precipitates out into crystals when the concen- cholangitis, and should be chosen to cover gram-negative bacteria tration in the gallbladder vesicles exceeds the solubility of choles- and anaerobes. terol (Fig. 55.21).2 Crystal formation is further accelerated by pro- nucleating agents, including glycoproteins and immunoglobulins. BENIGN BILIARY DISEASE Finally, abnormal gallbladder motility can increase stasis in the gallbladder, allowing more time for solutes to precipitate in the Calculous Biliary Disease gallbladder. Therefore, increased stone formation can be seen in Cholelithiasis is the most common disease of gallbladder and bili- conditions associated with impaired gallbladder emptying, such as ary tree, affecting 10% to 15% of the population. Gallstones are in prolonged fasting states, with use of total parenteral nutrition, generally classified into two major subtypes, cholesterol and pig- after vagotomy, and with use of somatostatin analogues. ment stones, depending on the principal solute that precipitates into a stone. More than 70% of gallstones in the United States Natural History are formed by precipitation of cholesterol and calcium, and pure Gallstones become symptomatic when they obstruct a visceral cholesterol stones account for less than 10%. Pigment stones can structure such as a cystic duct. However, gallstones often remain be divided into black stones, as seen in hemolytic conditions and asymptomatic, only found incidentally on imaging. Biliary colic, cirrhosis, and brown stones, which tend to be found in the bile caused by temporary blockage of the cystic duct, tends to occur ducts and are thought to be secondary to infection. The difference after a meal in which the secretion of CCK leads to gallbladder in color arises from incorporation of cholesterol into the brown contraction. Stones that do not obstruct the cystic duct or pass stones. Because black pigment stones occur in hemolytic states through the entire biliary tree into the intestines without impac- from concentration of bilirubin, they are found almost exclusively tion do not cause symptoms. Only 20% to 30% of patients with in the gallbladder. Alternatively, brown stones can occur within asymptomatic stones will develop symptoms within 20 years, and the biliary tree and suggest a disorder of biliary motility and as- because approximately 1% of patients with asymptomatic stones sociated bacterial infection. develop complications of their stones before onset of symptoms, Four major factors explain most gallstone formation: super- prophylactic cholecystectomy is not warranted in asymptomatic saturation of secreted bile, concentration of bile in the gallbladder, patients. crystal nucleation, and gallbladder dysmotility. High concentra- Certain subsets of patients, however, constitute a higher risk tions of cholesterol and lipid in bile secretion from the liver con- pool, so prophylactic cholecystectomy should be considered. stitute one predisposing condition to cholesterol stone formation, Among these are patients with hemolytic anemias, such as sickle Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1498 SECTION X Abdomen 100 0 80 20 Pe ol rce 60 40 ter nt les lec 2 ho ith tc phases 3 phases in en 2 phases rc 40 Crystals 60 Pe Crystals + + Liquid liquid liquid crystals crystals + 20 + liquid 80 liquid 1 phase liquid (micellar) 0 100 100 80 60 40 20 0 Percent bile salt FIG. 55.21 Triangle of solubility. With the three major components of bile that determine cholesterol solubility and stability, each can be quantified by molar percentage to show a relative ratio to the other two. Cholesterol is completely soluble in only the small area in the left lower corner, where a clear micellar solution exists, below the closed circles. Just above this, in the area between the open and closed circles, cholesterol is supersatu- rated but stable and thus crystallized only with stasis. In the remainder of the triangle, cholesterol is significantly supersaturated and unstable. In this region, crystals form immediately. (From Admirand WH, Small DM. The physicochemical basis of cholesterol gallstone formation in man. J Clin Invest. 1968;47:1043–1052.) cell anemia. These patients have an extremely high rate of pigment stone formation, and cholecystitis can precipitate a crisis. Patients Chronic Cholecystitis with a calcified gallbladder wall (known as porcelain gallbladder), Recurrent attacks of biliary colic, with only temporary occlu- those with large (>2.5 cm) gallstones, and those with a long com- sion of the cystic duct, can cause inflammation and scarring of mon channel of bile and pancreatic ducts all have a higher risk of the neck of the gallbladder and cystic duct. This process causes gallbladder cancer and should consider cholecystectomy. In addi- fibrosis as histologic evidence of repeated self-limited episodes of tion, patients with asymptomatic gallstones undergoing bariatric inflammation and is called chronic cholecystitis. The diagnosis surgery may also benefit from cholecystectomy; however, it is still of chronic cholecystitis lies along a continuum with biliary colic controversial. Not only does rapid weight loss favor stone forma- because it results from recurrent attacks. Therefore, the presenta- tion, but also, after gastric bypass, ERCP to remove CBD stones tion is that of symptomatic cholelithiasis, or biliary colic. Pain in ascending cholangitis is extremely challenging and usually un- occurring after ingestion of a fatty meal, with the attendant in- successful. Also, in diabetic patients with gallstones, one should crease in CCK secretion in response to duodenal intraluminal have lower threshold for cholecystectomy, considering higher rate fat, is classic for biliary colic, although only 50% of patients of gangrene. will report an association with food. Pain from stones tends to locate in the epigastrium or right upper quadrant and may ra- Nonoperative Treatment of Cholelithiasis diate around to the scapula. Biliary colic is a misnomer as the Medical treatment of gallstones is generally unsuccessful and pain is typically constant rather than colicky. These attacks of includes oral bile salt therapy, contact dissolution that requires pain generally last a few hours. Pain lasting longer than 24 hours cannulation of the gallbladder and infusion of organic solvent, or associated with fever suggests acute cholecystitis. The pain and extracorporeal shock wave lithotripsy. With the dissolution of biliary colic, even in the absence of cholecystitis, may also strategies, unacceptable recurrence rates of up to 50% limit cause other gastrointestinal symptoms, such as bloating, nausea, their application to the most select group of patients. Extra- or even vomiting. corporeal shock wave lithotripsy has a lower recurrence rate, Symptomatic stones constitute a risk profile different from approximately 20%, and can be used in patients with single that of asymptomatic stones, with a higher likelihood of com- stones 0.5 to 2 cm in size. The widespread use, safety, and effi- plications. Therefore, symptomatic cholelithiasis is an indica- cacy of laparoscopic cholecystectomy have relegated nonopera- tion for cholecystectomy. Documented stones and symptoms tive therapy to patients for whom general anesthesia presents a are the most common indications to perform a cholecystec- prohibitively high risk. tomy. Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 55 Biliary System 1499 FIG. 55.23 Computed tomography scan of emphysematous cholecys- titis. Significant pericholecystic inflammatory changes and air in the gall- bladder wall (arrows) are signs of emphysematous cholecystitis. FIG. 55.22 Ultrasound image of cholesterolosis. Presentation Diagnosis The inflammatory changes in the gallbladder wall are manifested The diagnosis of chronic cholecystitis relies on a history consis- as fever and right upper quadrant pain. On exam, patients will tent with biliary tract disease. Transabdominal ultrasonography exhibit tenderness to palpation and guarding in the right upper reliably documents the presence of cholelithiasis. Ultrasound quadrant. When the gallbladder lumen cannot fully empty be- can provide other important information, such as CBD dilation, cause of a stone in the gallbladder neck, visceral pain fibers are ac- gallbladder polyps, porcelain gallbladder, or evidence of hepatic tivated, causing pain in the epigastrium or right upper quadrant. parenchymal processes. Cholesterolosis, or the accumulation of The same luminal obstruction of biliary colic but associated with cholesterol found in gallbladder mucosal macrophages, can also sufficient stasis, pressure, and bacterial inoculum creates infection be seen (Fig. 55.22). Even in the absence of frank stones, so-called and, thereby, inflammation, therefore progressing to acute cho- sludge found in the gallbladder on ultrasonography, with appro- lecystitis. With this infection and inflammation, the right upper priate symptoms, is consistent with biliary colic. quadrant pain of biliary colic will be accompanied by tenderness noted on palpation of the right upper quadrant. Specifically, the Treatment voluntary cessation of respiration when the examiner exerts con- Patients with sufficient symptoms from gallstones should under- stant pressure under the right costal margin, known as a Murphy go elective cholecystectomy. Cholecystectomy carries a low-risk sign, suggests inflammation of the visceral and parietal peritoneal profile but is not without complications, so an analysis of risks surfaces and can be seen in diseases such as acute cholecystitis and and benefits is important. Because patients with mild symptoms hepatitis. Alternatively, biliary colic in the absence of infection have a low rate of complications from gallstones (1%–3%/year), and inflammation is not associated with any reproducible physical observation and dietary and lifestyle changes are appropriate in examination finding or systemic symptom. this population. Patients with more severe or recurrent symptoms There have been multiple grading systems evaluating severity have a higher rate of complications of the disease (7%/year), so of cholecystitis, most commonly the Tokyo Guidelines3,4 and The elective laparoscopic cholecystectomy is warranted. In more American Association for the surgery of Trauma (AAST) Emer- than 90% of patients, cholecystectomy is curative, leaving them gency General Surgery (EGS) guidelines.5 AAST EGS categorizes symptom free. acute cholecystitis into five grades, grade 1 being localized inflam- mation, to grade 5 with pericholecystic abscess, bilioenteric fis- Acute Calculous Cholecystitis tula, and peritonitis. The Tokyo Guidelines also grade the systemic Acute cholecystitis is the result of a blockage of the cystic effect of cholecystitis such as organ failure. Both classifications are duct and is called acute calculous cholecystitis when the helpful to categorize the management of these patients and con- blockage is by a stone. In chronic cholecystitis or biliary colic, sider treatment options relative to their severity of disease. the blockage is temporary and repetitive, while in acute cho- Mild elevations of alkaline phosphatase, bilirubin, and trans- lecystitis, the blockage does not resolve, leading to inflamma- aminase levels and leukocytosis support the diagnosis of acute tion with edema and subserosal hemorrhage. Obstruction is cholecystitis. However, given that the CBD is not obstructed, followed by infection of the stagnant pool of bile. Without profound jaundice in the setting of a picture of acute cholecys- resolution of the obstruction, the gallbladder will progress titis is rare and should raise the suspicion of cholangitis. Mir- to ischemia and necrosis. Eventually, acute cholecystitis be- izzi syndrome should be suspected, in which inflammation or comes acute gangrenous cholecystitis and, when complicated a stone in the gallbladder neck leads to inflammation of the by infection with a gas-forming organism, acute emphysema- adjoining biliary system, with obstruction of the common he- tous cholecystitis (Fig. 55.23). patic duct. Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1500 SECTION X Abdomen hospitalization and discharged home with resolution of symp- toms. An interval cholecystectomy was then performed at ap- proximately 6 weeks after the initial episode. More recent studies have shown that early in the disease process (within the first week), the operation can be performed laparoscopically with equivalent or improved morbidity, mortality, and length of stay as well as a similar conversion rate to open cholecystectomy.6 In addition, approximately 20% of patients initially admitted for nonopera- tive management failed to respond to medical treatment before the planned interval cholecystectomy and required surgical inter- vention. Initial nonoperative therapy remains a viable option for patients who present in a delayed fashion and should be decided on an individual basis. Given the inflammatory process occurring in the porta hepatis, early conversion to open cholecystectomy should be considered when delineation of anatomy is not clear or when progress cannot be made laparoscopically. With substantial inflammation, a partial cholecystectomy, transecting the gallbladder at the infundibulum with cauterization of the remaining mucosa, is acceptable to avoid TRN GB injury to the CBD. Some patients present with acute cholecystitis FIG. 55.24 Ultrasound image of pericholecystic fluid. The thickened but have a prohibitively high operative risk. For these patients, gallbladder wall with pericholecystic fluid (arrow) indicates acute chole- a percutaneously placed cholecystostomy tube should be consid- cystitis. ered. Frequently performed with ultrasound guidance under lo- cal anesthesia with some sedation, cholecystostomy can act as a temporizing measure by draining the infected bile. Percutaneous Diagnosis drainage results in improvement in symptoms and physiology, al- Transabdominal ultrasonography is a sensitive, inexpensive, and lowing a delayed cholecystectomy 3 to 6 months after medical reliable tool for the diagnosis of acute cholecystitis, with a sen- optimization. In patients with cholecystostomy tubes, when fluo- sitivity of 85% and specificity of 95%. In addition to identify- roscopy shows a patent cystic duct, the cholecystostomy tube can ing gallstones, ultrasound can demonstrate pericholecystic fluid be removed and the decision for cholecystectomy determined by (Fig. 55.24), gallbladder wall thickening, and even a sonographic the patient’s ability to tolerate surgical intervention. Murphy sign, documenting tenderness specifically over the gall- Tokyo Guidelines, revised in 2018, predict the severity of gall- bladder. In most cases, an accurate history and physical examina- bladder disorder, prognosis, and rate of conversion or bail-out tion, along with supporting laboratory studies and an ultrasound procedure, can be used as a guideline to plan the management.7 examination, make the diagnosis of acute cholecystitis. In atypical cases, a HIDA scan may be used to demonstrate obstruction of the Choledocholithiasis cystic duct, which definitively diagnoses acute cholecystitis. Fill- CBD stones, or choledocholithiasis, are generally silent, and are ing of the gallbladder during a HIDA scan essentially eliminates seen in up to 10% of patients undergoing biliary imaging.8,9 Pri- the diagnosis of cholecystitis. CT may show similar findings to mary common duct stones arise de novo in the bile duct, and ultrasound with pericholecystic fluid, gallbladder wall thickening, secondary common duct stones pass from the gallbladder into and emphysematous changes, but CT is less sensitive than ultra- the bile duct. Primary common duct stones are generally brown sound for the diagnosis of acute cholecystitis. pigment stones, a combination of precipitated bile pigments and cholesterol. Brown pigment stones are associated with bacterial Treatment infections where free bilirubin is formed by hydrolyzing enzymes Treatment of acute cholecystitis largely depends on the severity of released by bacteria and then precipitates. Brown pigment stones disease and the physiologic status of the patient, and treatment are more common in Asian populations. Secondary stones are can vary from immediate surgical intervention to conservative more common in the United States. Retained stones are second- management. Although the primary pathophysiologic event in ary stones found in bile duct within 2 years of cholecystectomy acute cholecystitis is the obstruction of the cystic duct and in- and occur in 1% to 2% of patients (Fig. 55.25). fection is a secondary event that follows stasis and inflammation, When symptomatic, common duct stones clinical manifesta- most cases of acute cholecystitis are complicated by superinfec- tions range from biliary colic to obstructive jaundice, including tion of the inflamed gallbladder. Patients are given nothing by darkening of the urine, scleral icterus, and lightening of the stools. mouth, and intravenous (IV) fluids and parenteral antibiotics are Jaundice with choledocholithiasis is more likely to be painful be- started. Given that gram-negative aerobes are the most common cause the onset of obstruction is acute, causing rapid distention organisms found in acute cholecystitis, followed by anaerobes and of the bile duct and activation of pain fibers. Cholangitis, first gram-positive aerobes, broad-spectrum antibiotics are warranted. described by Jean Martin Charcot in 1877, is ascending infection Parenteral narcotics are usually required to control the pain. of CBD secondary to obstruction and increased intraluminal pres- Cholecystectomy, whether open or laparoscopic, is the treat- sure. Cholangitis presents with right upper quadrant pain, fever, ment of choice for acute cholecystitis. The timing of operative in- and jaundice, known as Charcot triad, and may progress to sep- tervention in acute cholecystitis has long been a source of debate. tic shock with mental status changes, and hypotension, known In the past, many surgeons advocated for delayed cholecystec- as Reynolds pentad, which is an ominous sign, and mortality ap- tomy with patients managed nonoperatively during their initial proaches 100% without prompt treatment. Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 55 Biliary System 1501 H: 0% F: 30% FIG. 55.25 Intraoperative cholangiogram showing choledocholithiasis in an asymptomatic patient with no filling of duodenum and outline of stone (arrow). FIG. 55.27 Endoscopic retrograde cholangiopancreatography (ERCP) with choledocholithiasis. With retrograde injection of contrast material, a filling defect noted within the lumen of the common bile duct (arrow) identifies choledocholithiasis. ERCP can also be used to remove the stone through sphincterotomy and balloons or baskets. Magnetic resonance cholangiopancreatography (MRCP), as mentioned earlier, is highly sensitive (>90%) and specific (>99%) in identifying CBD stones (Fig. 55.26). But as a noninvasive test, it will stay at diagnostic level, and a treatment procedure, such as ERCP or CBD exploration, still has to be done after diagnosis. Some surgeons resorted to preoperative MRCP to determine the need for preoperative ERCP.10 ERCP is also highly sensitive and specific for choledocholithia- sis (Fig. 55.27) and often is the therapeutic procedure by clearing the duct in more than 75% of patients during first procedure and in 90% with repeated ERCP. A sphincterotomy with a balloon sweep is done and stones are extracted, with a less than 5% to 8% complication rate. Indications for preoperative ERCP include cholangitis, biliary pancreatitis, and patients with multiple co- morbidities. However, some studies have suggested higher risk of surgical site infection in patients who receive preoperative ERCP before cholecystectomy.11 Finding of choledocholithiasis via intraoperative cholangio- gram during cholecystectomy may be managed by either CBD exploration or postoperative ERCP. The experience of the surgeon FIG. 55.26 Magnetic resonance cholangiopancreatography with cho- with open biliary exploration may be a factor determining which ledocholithiasis. The dilated common bile duct ends abruptly with a con- vex intraluminal filling defect (arrow) consistent with choledocholithiasis. route is chosen. PTC can also be used to treat choledocholithiasis in case of unsuccessful ERCP, or anatomical difficulty for ERCP such as Diagnosis the patients’ post-Roux-en-Y procedures. PTC is as effective Asymptomatic choledocholithiasis is usually an incidental find- as ERCP in patients with dilated biliary system with similar ing. Biliary type pain, jaundice, an abnormal liver function panel, complication rate, but less effective in a nondilated biliary tree and a dilated bile duct, usually more than 8 mm, are all highly patient. suggestive of choledocholithiasis. Liver function panel abnormali- In short, in patients with likelihood of CBD stones, other mo- ties on their own are neither sensitive nor specific. Even without dalities such as ERCP or MRCP must be considered on top of ul- symptoms of biliary colic, a dilated bile duct in the presence of trasound. Choledocholithiasis identified but not removed during gallstones suggests choledocholithiasis. cholecystectomy mandates ERCP for stone extraction. Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1502 SECTION X Abdomen FIG. 55.29 Computed tomography scan of the cholecystoduodenal fis- tula (arrow). FIG. 55.28 Computed tomography scan of stone (arrow) obstructing the distal ileum. presentation is an elderly patient with some history of biliary tree disorder, with no past surgical history or hernia, with a sudden mechanical small intestine obstruction. Treatment Although most patients will have constant pain from the ob- Treatment for choledocholithiasis is generally ERCP or CBD explo- struction, others can present with only episodic discomfort be- ration, which can be performed via laparoscopic or open technique. cause the gallstone only intermittently obstructs the intestinal Endoscopic sphincterotomy with stone extraction is effective for the tract. Plain radiographs usually demonstrate air-fluid levels consis- treatment of choledocholithiasis. In the preoperative setting, it can tent with a small bowel obstruction, although the offending stone clear the duct of stones, and when it is unsuccessful at removal of all may or may not be identified. Pneumobilia, which may sometimes stones, it will alter intraoperative decision-making. More than half be identified only by CT scan, is a ubiquitous finding because the of patients managed by ERCP without cholecystectomy will have fistula that permitted a stone to pass into the duodenum allows air recurrent symptoms of biliary tract disease.12 Large stones (usually to enter the biliary tree (Fig. 55.29). more than 2.5 cm), altered gastric or duodenal anatomy such as Roux-en-Y, impacted stones, intrahepatic stones, or multiple stones, Treatment are the most common causes of failure of ERCP. Gallstone ileus is a surgical disorder. During an exploration, a longi- tudinal incision on the antimesenteric border of the ileum is made Gallstone Pancreatitis a few centimeters proximal to the stone. This site of impaction is When a stone passes from the bile duct through the ampulla into at risk of perforation, so signs of ischemia may mandate resection. the duodenum, this may cause secondary injury to the pancreas. The stone is milked back through the enterotomy. Approximately Temporary elevation of the pancreatic duct pressure causes in- 10% of patients have multiple large stones, so the remainder of the flammation and may result in severe pancreatic injury. Symptoms small intestine should be inspected. usually persist even after passage of stone. Ultrasound usually Although some surgeons advocate surgical treatment of the shows gallstones, choledocholithiasis, or a dilated CBD. The of- biliary-enteric fistula at the same setting, the intense inflammatory fending stone usually passes spontaneously but the injury still can process in the right upper quadrant may complicate the cholecys- be severe. In most cases of gallstone pancreatitis, the pancreatitis tectomy and duodenal repair. In addition, because most of these is self-limited. Early ERCP to remove a stone that may not have patients are older, their overall physiologic status may not permit passed is indicated and has been shown to reduce the morbidity fistula repair in the emergent setting. One-stage repair should gen- of the episode of pancreatitis.13 To prevent a future episode of erally be performed in healthy patients without severe inflamma- gallstone pancreatitis, a cholecystectomy is warranted; this is gen- tory changes in the right upper quadrant. Enterotomy with remov- erally recommended during the same hospitalization, just before al of the offending stone should suffice for patients with multiple discharge.14 Given the suspicion of choledocholithiasis, intraop- comorbidities. Palpation of the remaining small intestine should erative cholangiography should be performed if no other imaging be performed to exclude a second stone that could cause recurrent has been performed to confirm the passage of the gallstone. obstruction. A second operation for the cholecystectomy can be considered to avoid the possibility of future biliary complications. Gallstone Ileus A misnomer, gallstone ileus is in fact a mechanical intestinal ob- struction secondary to a gallstone. A large stone in the dependent Noncalculous Biliary Disease portion of the gallbladder fistulizes into the adjacent duodenum, Acute Acalculous Cholecystitis passing directly into the intestine. This usually happens in older Blockage of the cystic duct in the absence of stones is called acal- patients and can be caused by inflammation or simply pressure culous cholecystitis. The exact mechanism and pathophysiology are necrosis. The most common site for obstruction is in the termi- poorly understood, but there is a role for bile stasis and gallbladder nal ileum before entering the cecum (Fig. 55.28). The common ischemia. Risk factors include old age, burns and trauma, prolonged Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.  CHAPTER 55 Biliary System 1503 FR 33Hz RS 2D 45% C 55 P Low Res LONG GB LLD FIG. 55.30 Ultrasound image of a gallbladder with acute acalculous cholecystitis. The diffusely thickened gallbladder wall (arrows) is highly suggestive of cholecystitis. FIG. 55.31 Magnetic resonance cholangiopancreatography showing primary sclerosing cholangitis. Note the multilevel strictures (arrows). use of total parenteral nutrition, critical illness, immunosuppression, and diabetes, and the presentation can be similar or more fulminant than calculous cholecystitis and may progress to gangrenous gall- or calculous disease, which can cause fibrosis due to inflammation, bladder. Critically ill patients with acalculous cholecystitis may not and, subsequently, failure of the sphincter to relax. The diagnosis of have right upper quadrant pain and any fever with unknown origin sphincter of Oddi dysfunction should be suspected in patients with in critically ill patients, especially with pericholecystic fluid and gall- biliary pain and a common duct diameter of more than 12 mm. The bladder wall thickening on imaging should raise suspicion for this bile duct in these patients tends to increase in diameter in response disorder (Fig. 55.30). HIDA scan is diagnostic for acalculous cho- to CCK, as does the pancreatic duct after secretin administration. lecystitis but can have false-positive result. Treatment of acalculous Sphincter manometry has also been used to make the diagnosis, cholecystitis is similar to that of calculous cholecystitis, with chole- with sphincter pressure higher than 40 mm Hg predicting good cystectomy being therapeutic. However, many of these patients are response to therapy. Therapy consists of endoscopic sphincterotomy critically ill, raising the mortality and morbidity of this procedure. or transduodenal sphincteroplasty with approximately equivalent Therefore, percutaneous cholecystostomy tube placement under results from the two approaches. In patients with objective evidence imaging to drain the gallbladder is a much more attractive and feasi- of sphincter of Oddi dysfunction, division of the sphincter will im- ble treatment. More than 90% of these patients improve with a cho- prove or resolve the pain in 60% to 80% of patients. lecystostomy tube, and interval cholecystectomy is necessary only if follow-up imaging continues to demonstrate the positive findings. Primary Sclerosing Cholangitis Primary sclerosing cholangitis (PSC) is an idiopathic disorder and Biliary Dyskinesia considered an autoimmune process affecting the biliary tree. PSC Biliary dyskinesia is a functional disorder of the biliary tree, gen- is associated with other autoimmune disorders such as ulcerative erally defined by gallbladder dysmotility, and it is usually a diag- colitis (in almost 70% of patients)16 and Riedel thyroiditis.17 PSC nosis of exclusion. Patients may present with classic symptoms of can be categorized into four anatomical subtypes depending on calculous biliary disease but have no ultrasonographic evidence the level of biliary tree it involves, including intrahepatic, extra- of stones or sludge. In some of these cases, the dysfunction of hepatic, combined, or small ducts disease. The course of PSC is the gallbladder creates pain, even in the absence of stones. Rome characterized by progressive chronic cholestasis and advances at an criteria, which was defined in the late 1980s and has been updated unpredictable rate to biliary cirrhosis and eventually death from multiple times,15 helps in defining and diagnosing this functional liver failure. With improved understanding of the disease and ear- disorder. Other diagnosis must be excluded first using different ly diagnosis, PSC outcomes have improved.17 modalities such as CT and endoscopy. CCK-stimulated HIDA Clinical presentation. Most patients present with general symp- scan is helpful in confirming diagnosis. An ejection fraction of toms such as fatigue and pruritus, but abnormal liver function less than one third at 20 minutes after CCK administration in a studies are usually what prompts biliary imaging. Approximately patient without stone is considered diagnostic. More than 85% of 80% of patients have elevated perinuclear antineutrophil cytoplas- patients show improvement in symptoms after cholecystectomy. mic antibodies, but the severity of disease does not correlate to In nonresponders, ERCP with sphincterotomy may prove useful. titer levels. Abnormal liver function tests in a patient observed for inflammatory bowel disease should suggest PSC. Sphincter of Oddi Dysfunction Imaging with cholangiography demonstrates a multifocal dif- Similar to dyskinesia, sphincter of Oddi dysfunction is a functional fuse dilation and stricturing of the intrahepatic and/or extrahepat- disorder of the biliary tree; however, Rome IV criteria15 recommends ic biliary trees. This pattern is called “beading” or “chain of lakes” not using the term functional. It is caused by a structurally or physi- and is characteristic of PSC. MRCP is useful in the diagnosis and ologically abnormal sphincter with higher tone and failing to relax, surveillance of PSC patients, while ERCP is reserved for the treat- manifested by pain, and recurrent pancreatitis with a usually nor- ment of dominant strictures and to exclude malignancy, namely, mal liver function panel. Risk factors include chronic pancreatitis cholangiocarcinoma (Fig. 55.31). Downloaded for Nikita Machado ([email protected]) at ClinicalKey Global Guest Users from ClinicalKey.com by Elsevier on May 31, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved. 1504 SECTION X Abdomen Liver biopsy tends to show an onionskin concentric periduc- tal fibrosis. With disease progression, periportal fibrosis occurs, progressing to bridging necrosis and, eventually, biliary cirrhosis. Unfortunately, PSC is associated with cholangiocarcinoma, and distinguishing the strictures of PSC fibrosis from those of cholan- giocarcinoma can be challenging. Treatment. Ursodeoxycholic acid is commonly used as medi- cal therapy for PSC and has demonstrated some improvement in liver function tests; however, it is controversial whether this alters the progression of disease. Ongoing trials in PSC include urso- deoxycholic acid homologs, antibiotics to alter the microbiome, and interruption of the enterohepatic bile circulation.17 However, none of these agents has shown a consistent clinical benefit. In the symptomatic patient, endoscopic therapy, consisting of balloon dilation of the dominant strictures, has been shown to alleviate FIG. 55.32 Mirizzi syndrome. Obstruction of the bile duct from an in- pruritus, to reduce likelihood of cholangitis, and even to prolong flammatory process is the hallmark of this syndrome; the cholecystocho- survival. ledochal fistula may or may not be apparent. Surgical treatment options include biliary reconstruction in symptomatic patients with focal extrahepatic disease in some cases. Such patients are rare, and repeated operations for drainage patients often have a cystic duct parallel to common hepatic duct have been shown to complicate definitive treatment by liver trans- and an impacted gallstone in the neck or cystic duct. The resultant plantation. Therefore, the use of biliary reconstructive procedures inflammation can cause a cholecystocholedochal fistula. The treat- has decreased for this indication. ment of Mirizzi syndrome is cholecystectomy, which may require Although it is associated with ulcerative colitis, a proctocolec- repair of the common duct; when a large fistula exists, a choledo- tomy does not appear to affect biliary disease progression or sur- chojejunostomy may be necessary. vival in patients with both ulcerative colitis and PSC. Long-standing choledocholithiasis also can cause fibrosis and Orthotopic liver transplantation appears to be the only lifesav- stricture. ERCP with sphincterotomy, balloon dilation, and stent ing option for patients with progressive hepatic dysfunction from placement is generally regarded as primary treatment for benign PSC. The survival rate for patients undergoing liver transplanta- bile duct strictures to make the diagnosis and potentially to treat tion for PSC is approximately equivalent to that of those under- the process. Endoscopic and percutaneous therapy can provide going transplantation for other causes of end-stage liver disease, long-term success in more than 50% of patients. When this is with 5-year survival rates ranging from 75% to 85%.18 Although unsuccessful, surgical management with anastomosis of the biliary the development of cholangiocarcinoma in a PSC liver is gener- tree to a Roux-en-Y jejunal limb has success rates of up to 90%. ally considered a contraindication to transplantation, some cen- ters have shown excellent survival rates, up to 70% at 5 years, Biliary Cysts for patients with limited hilar disease who undergo a neoadjuvant Choledochal cysts, or biliary cysts, are congenital intrahepatic protocol of chemotherapy and radiation followed by transplanta- and/or extrahepatic dilation anomalies. Due to new insights tion.19 Because these results have not been reproduced universally, into epithelial markers, and different pathophysiology in differ- the use of liver transplantation for the treatment of cholangiocar- ent etiologic subtypes, now they are called biliary malformations cinoma occurring in the setting of PSC is limited to experimental rather than cysts. They are rare disorders, occurring in less than protocols. After liver transplantation, 10% to 30% of PSC pa- 1/100,000 patients. They occur more frequently in female pa- tients develop recurrent biliary strictures, suggestive of recurrence tients and in Asian populations. These are considered premalig- of disease in the donor liver. Even with the development of stric- nant conditions and are sometimes diagnosed in infancy; however, tures, disease progression does not usually follow the aggressive they can present in adulthood (Fig. 55.33).21 Type I choledochal course for which PSC is known. In cases where retransplantation cyst is the most common form and involves only the extrahepatic is required, the morbidity and mortality are higher than for pri- biliary tree w