Anatomy of Bile Ducts

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Questions and Answers

Where does the cystic duct drain into?

Left hepatic duct

Common bile duct (CBD) (correct)

Right hepatic duct

Pancreatic duct

What is the function of the valves of Heister?

To mix bile with pancreatic juices

To stimulate contraction of the gallbladder

To retain bile in the gallbladder (correct)

To drain bile from the gallbladder

What is the main source of the biliary cholesterol?

Bile salts

Circulating lipoproteins and hepatic synthesis (correct)

Hepatic glycogenolysis

Dietary cholesterol

What is the function of the tight junctions in the biliary tree?

To keep bile components within the bile secretory pathway Signup and view all the answers

What is the fate of the majority of the bile secreted into the bile canaliculi?

It is reabsorbed into the enteric circulation Signup and view all the answers

What type of bacteria is most commonly found in biliary infections?

Enterobacteriaceae Signup and view all the answers

What is the purpose of prophylactic antibiotics in biliary interventions?

To cover the most common bacterial species Signup and view all the answers

What type of antibiotics is recommended for prophylaxis in most patients undergoing biliary interventions?

First- or second-generation cephalosporin or fluoroquinolone Signup and view all the answers

What is the main function of bile salts in the gallbladder?

To solubilize cholesterol Signup and view all the answers

What is the process that occurs in the gallbladder to increase the concentrations of bile solutes and calcium?

Absorption of water and sodium Signup and view all the answers

What is the main function of the sphincter of Oddi?

To control the flow of bile into the duodenum Signup and view all the answers

What is the indication for antibiotic prophylaxis in patients undergoing elective laparoscopic cholecystectomy?

Presence of suspected or documented infection Signup and view all the answers

What is the effect of cholecystokinin on the sphincter of Oddi?

It inhibits the tonic contraction of the sphincter Signup and view all the answers

What is the role of glycoproteins in the biliary system?

To protect the gallbladder from the detergent activity of bile Signup and view all the answers

What is the effect of a high tonic contraction of the sphincter of Oddi in the fasting state?

It increases pressure in the common bile duct Signup and view all the answers

What is the maximum amount of bile that the gallbladder can store?

300 mL Signup and view all the answers

What is the primary reason for observing patients with mild symptoms of gallstones?

To monitor for potential complications Signup and view all the answers

What induces the secretion of cholecystokinin from duodenal epithelial cells?

The passage of fat, protein, and acid into the duodenum Signup and view all the answers

What is the significance of a level of bilirubin above 5 mg/dL in the skin?

It is a sign of jaundice Signup and view all the answers

What is the significance of a positive sign in cholecystectomy?

It suggests inflammation of the visceral and parietal peritoneal surfaces Signup and view all the answers

What is the limitation of plain radiographs in the evaluation of biliary tree disease?

They are of limited use in the overall evaluation of biliary tree disease Signup and view all the answers

What is the primary indication for elective laparoscopic cholecystectomy?

Presence of severe or recurrent symptoms Signup and view all the answers

What is the most common grading system used to evaluate the severity of cholecystitis?

The Tokyo Guidelines Signup and view all the answers

What is the outcome of cholecystectomy in more than 90% of patients?

They remain symptom-free Signup and view all the answers

What is the term for acute cholecystitis resulting from a blockage of the cystic duct by a stone?

Acute calculous cholecystitis Signup and view all the answers

What is the characteristic of biliary colic in the absence of infection and inflammation?

It is not associated with any reproducible physical examination finding or systemic symptom Signup and view all the answers

What is the highest grade of acute cholecystitis according to the AAST EGS guidelines?

Grade 5, pericholecystic abscess, bilioenteric fistula, and peritonitis Signup and view all the answers

What is indicated when more anatomic delineation is required in biliary disease?

CT scan Signup and view all the answers

What does the injection of CCK during a HIDA scan document?

Physiologic gallbladder function Signup and view all the answers

What is the characteristic feature of acute cholecystitis on a HIDA scan?

No filling of the gallbladder even on delayed images Signup and view all the answers

What type of stones are radiographically isodense?

Most gallstones Signup and view all the answers

What is the outcome of cholecystectomy in more than 90% of patients?

Cure of symptoms Signup and view all the answers

What is the term for acute cholecystitis resulting from a blockage of the cystic duct by a stone?

Acute calculous cholecystitis Signup and view all the answers

What is the limitation of plain radiographs in the evaluation of biliary tree disease?

Unable to diagnose most gallstones Signup and view all the answers

What is the sensitivity of transabdominal ultrasonography in diagnosing acute cholecystitis?

85% Signup and view all the answers

What is the primary indication for removing a cholecystostomy tube?

When fluoroscopy shows a patent cystic duct Signup and view all the answers

What is the use of a HIDA scan in diagnosing acute cholecystitis?

To diagnose obstruction of the cystic duct Signup and view all the answers

What is the significance of a positive Murphy sign in diagnosing acute cholecystitis?

It documents tenderness specifically over the gallbladder Signup and view all the answers

What is the role of Tokyo Guidelines in managing gallbladder disorders?

All of the above Signup and view all the answers

What is the incidence of CBD stones in patients undergoing biliary imaging?

10% Signup and view all the answers

What is the significance of gallbladder wall thickening in diagnosing acute cholecystitis?

It is a supporting diagnostic feature Signup and view all the answers

What is the outcome of delaying cholecystectomy in patients with acute cholecystitis?

Improvement in symptoms and physiology Signup and view all the answers

What is the primary use of biliary scintigraphy in the diagnosis of obstructive jaundice?

To evaluate the physiologic secretion of bile Signup and view all the answers

What is the significance of failed gallbladder filling 2 hours after injection on a HIDA scan?

Obstruction of the cystic duct Signup and view all the answers

What is the advantage of ultrasound in the diagnosis of obstructive jaundice?

It is a non-invasive and inexpensive test Signup and view all the answers

What is the role of a HIDA scan in the postoperative setting?

To identify bile leaks and obstruction of the biliary tree Signup and view all the answers

What is the limitation of computed tomography in the diagnosis of biliary disease?

It cannot provide fine anatomic detail Signup and view all the answers

What is the significance of gallbladder filling on a HIDA scan?

It effectively eliminates the diagnosis of acute cholecystitis Signup and view all the answers

What is the primary indication for using a HIDA scan in patients with biliary tract pain?

To evaluate the physiologic secretion of bile in patients with impaired emptying Signup and view all the answers

What is the role of ultrasound in the diagnosis of cholangiocarcinoma?

It can sometimes identify the cause of obstructive jaundice Signup and view all the answers

What can be identified by ultrasound in many gallbladder diseases?

Gallbladder wall thickening and pericholecystic fluid Signup and view all the answers

What is seen in ultrasound images of porcelain gallbladder?

Curvilinear echogenic focus with posterior shadowing Signup and view all the answers

What is the characteristic feature of acute cholecystitis on ultrasound?

Gallbladder wall thickening and pericholecystic fluid Signup and view all the answers

What can be seen in ultrasound images of gallstones in the gallbladder neck?

Sharp echogenic wall with posterior shadowing Signup and view all the answers

What is the significance of posterior shadowing in ultrasound images of the gallbladder?

Helps differentiate gallstones from other intraluminal findings Signup and view all the answers

What is the diagnostic role of ultrasound in gallbladder diseases?

To identify pathologic changes in the gallbladder Signup and view all the answers

What is the characteristic ultrasound feature of a gallstone in the gallbladder neck?

Sharp echogenic wall with posterior shadowing Signup and view all the answers

What is the ultrasound feature of porcelain gallbladder?

Curvilinear echogenic focus with posterior shadowing Signup and view all the answers

What type of gallstones are most common in the United States?

Cholesterol stones Signup and view all the answers

What is the primary reason for increased stone formation in conditions associated with impaired gallbladder emptying?

Increased stasis in the gallbladder Signup and view all the answers

What is the term for the temporary blockage of the cystic duct that causes pain?

Biliary colic Signup and view all the answers

What is the characteristic of pigment stones found in the bile ducts?

They are brown Signup and view all the answers

What percentage of the population is affected by cholelithiasis?

10% to 15% Signup and view all the answers

What accelerates crystal formation in the gallbladder?

Glycoproteins and immunoglobulins Signup and view all the answers

What is the typical composition of gallstones in the United States?

Cholesterol and calcium Signup and view all the answers

Why do gallstones become symptomatic?

When they obstruct a visceral structure such as a cystic duct Signup and view all the answers

What is the significance of a dilated bile duct in the presence of gallstones?

It suggests choledocholithiasis. Signup and view all the answers

What is the treatment for choledocholithiasis?

ERCP or CBD exploration. Signup and view all the answers

What is the indication for ERCP in patients undergoing cholecystectomy?

Choledocholithiasis identified but not removed during cholecystectomy. Signup and view all the answers

What is the presentation of an elderly patient with a sudden mechanical small intestine obstruction?

Small intestine obstruction due to a stone obstructing the distal ileum. Signup and view all the answers

What is the role of MRCP in patients with a likelihood of CBD stones?

It is considered when other modalities are inconclusive. Signup and view all the answers

What is the significance of a computed tomography scan in the diagnosis of biliary disease?

It can identify stones obstructing the distal ileum. Signup and view all the answers

What is the outcome of cholecystectomy in patients with choledocholithiasis?

More than 90% of patients experience resolution of symptoms. Signup and view all the answers

What is the role of ultrasound in patients with a likelihood of CBD stones?

It is used as an initial screening test. Signup and view all the answers

What is the primary use of ultrasound in the diagnosis of obstructive jaundice?

To identify CBD stones or cholangiocarcinoma Signup and view all the answers

What is the significance of failed gallbladder filling 2 hours after injection on a HIDA scan?

It demonstrates obstruction of the cystic duct Signup and view all the answers

What is the advantage of ultrasound in the diagnosis of obstructive jaundice?

It is a non-invasive and cost-effective test Signup and view all the answers

What is the role of a HIDA scan in the postoperative setting?

To diagnose bile leaks Signup and view all the answers

What is the primary indication for using a HIDA scan in patients with biliary tract pain?

To diagnose biliary dyskinesia Signup and view all the answers

What is the limitation of computed tomography in the diagnosis of biliary disease?

It does not provide fine anatomic detail of the gallbladder Signup and view all the answers

When is early conversion to open cholecystectomy considered?

When delineation of anatomy is not clear or progress cannot be made laparoscopically Signup and view all the answers

What is the significance of gallbladder filling on a HIDA scan?

It effectively eliminates the diagnosis of acute cholecystitis Signup and view all the answers

What is the purpose of a partial cholecystectomy?

To avoid injury to the CBD Signup and view all the answers

What is the role of biliary scintigraphy in the diagnosis of obstructive jaundice?

To identify obstruction of the biliary tree and bile leaks Signup and view all the answers

What is the characteristic of the gallbladder wall in acute cholecystitis?

Thickened with pericholecystic fluid Signup and view all the answers

What is the purpose of a percutaneously placed cholecystostomy tube?

To drain the infected bile Signup and view all the answers

What is the indication for a percutaneously placed cholecystostomy tube?

Patients with acute cholecystitis who have a high operative risk Signup and view all the answers

When is a partial cholecystectomy performed?

When there is substantial inflammation in the porta hepatis Signup and view all the answers

What is the role of ultrasound guidance in cholecystostomy?

To guide the percutaneous placement of the cholecystostomy tube Signup and view all the answers

What is the effect of cholecystostomy?

It acts as a temporizing measure by draining the infected bile Signup and view all the answers

Study Notes

Bile Ducts and Anatomy

Bile ducts, either intrahepatic or extrahepatic, lie superior to the corresponding portal vein, which in turn are lateral and inferior to the arterial supply.
The left hepatic duct retains a longer transverse extrahepatic portion and travels under the edge of segment IV before joining the bifurcation.
The left duct drains segments I, II, III, and IV, with the most distal branch draining segment IVA.
The ducts draining segment IVB arise further superolateral, and the ducts for segments II and III arise further up the left duct.
The cystic duct can range from 1 to 5 cm in length and drains at an acute angle into the CBD.
The CBD is divided into three portions: supraduodenal, retroduodenal, and the pancreatic portion, which is the most inferior portion.

Bile Production and Flow

Bile components are secreted into the bile canaliculi directly from hepatocytes.
The secretion of bile components into the bile tree is a major stimulus to bile flow, and the volume of bile flow is an osmotic process.
Bile salts combine to form spherical pockets, known as micelles, which provide no osmotic activity.
The cations that are secreted into the bile tree provide osmotic activity.
The sphincter of Oddi maintains a high tonic contraction, but is inhibited by cholecystokinin.

Enterohepatic Circulation

Bile salts are secreted into the bile canaliculi directly from hepatocytes.
The bile salts are then secreted into the bile duct and stored in the gallbladder.
The passage of fat, protein, and acid into the duodenum induces CCK secretion from duodenal epithelial cells.
CCK secretion increases the flow of bile from the gallbladder into the duodenum.

Bile Composition

Bile contains proteins, lipids, and pigments.
The major lipid components of bile are phospholipids and cholesterol.
Cholesterol is secreted into the bile duct and serves to excrete cholesterol from the body.
Glycoproteins are also secreted into the bile duct to help protect the gallbladder from the detergent activity of bile.

Imaging Studies

Plain radiographs are of limited use in the overall evaluation of biliary tree disease.
Ultrasound is used to evaluate the biliary tree and diagnose gallstones.
Endoscopic ultrasound with needle biopsy can be used to diagnose biliary disease.

Infection and Inflammation

Infection in the absence of obstruction is rare.
With the presence of stones or obstruction, the likelihood 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 Enterococcus spp.
Prophylactic antibiotics should be used in most patients undergoing interventions in the biliary tree, such as ERCP or PTC.

Cholecystectomy

Cholecystectomy carries a low-risk profile but is not without complications.
An analysis of risks and benefits is important before undergoing cholecystectomy.
In more than 90% of patients, cholecystectomy is curative, leaving them symptom-free.
Elective laparoscopic cholecystectomy is warranted for patients with more severe or recurrent symptoms.

Acute Calculous Cholecystitis

Acute cholecystitis is the result of a blockage of the cystic duct and is called acute calculous cholecystitis when the blockage is by a stone.
Acute calculous cholecystitis is associated with a higher rate of complications.
Elective laparoscopic cholecystectomy is warranted for patients with acute calculous cholecystitis.
There have been multiple grading systems evaluating the severity of cholecystitis, such as the Tokyo Guidelines and the American Association for the Surgery of Trauma (AAST) Emergency General Surgery (EGS) guidelines.

Biliary Disease Diagnosis

CT provides superior anatomic information and is indicated when more anatomic delineation is required.
HIDA scans can determine gallbladder function by documenting physiologic response to injection of CCK.

Gallbladder Function

HIDA scans can show non-filling of the gallbladder, indicating occlusion of the cystic duct, a characteristic feature of acute cholecystitis.
Filling of the gallbladder during a HIDA scan essentially eliminates the diagnosis of cholecystitis.

Biliary Scintigraphy

Hepatic iminodiacetic acid (HIDA) scan can evaluate the physiologic secretion of bile.
The scan identifies bile flow and can demonstrate obstruction of the cystic duct, biliary tree, and bile leaks.
HIDA scan does not provide fine anatomic detail, nor can it identify gallstones.

Computed Tomography

CT provides superior anatomic information, especially for the intrahepatic and extrahepatic biliary tree and pancreas.
CT can identify the cause of obstructive jaundice, showing CBD stones or cholangiocarcinoma.

Ultrasound

Transabdominal ultrasonography is a sensitive, inexpensive, and reliable tool for the diagnosis of acute cholecystitis.
Ultrasound has a sensitivity of 85% and specificity of 95% for diagnosing acute cholecystitis.
Ultrasound can identify gallstones, pericholecystic fluid, gallbladder wall thickening, and a sonographic Murphy sign.

Choledocholithiasis

CBD stones, or choledocholithiasis, are generally silent and are seen in up to 10% of patients undergoing biliary imaging.
Tokyo Guidelines, revised in 2018, predict the severity of gallbladder disorder, prognosis, and rate of conversion or bail-out procedure.

Gallbladder Diseases and Ultrasound

Ultrasound can identify pathologic changes in many gallbladder diseases, such as gallbladder wall thickening and pericholecystic fluid seen in cholecystitis.
Gallstones can be identified by ultrasound, with characteristic posterior shadowing stripe under the stone.
Porcelain gallbladder appears as a curvilinear echogenic focus along the entire gallbladder wall, with posterior shadowing.

Hepatic Iminodiacetic Acid (HIDA) Scan

HIDA scan can evaluate the physiologic secretion of bile and identify bile flow.
The scan can demonstrate obstruction of the cystic duct, as seen in acute cholecystitis.
It can also identify obstruction of the biliary tree and bile leaks, which may be useful in the postoperative setting.

Calculous Biliary Disease

Cholelithiasis is the most common disease of the gallbladder and biliary tree, affecting 10% to 15% of the population.
Gallstones are classified into two major subtypes: cholesterol and pigment stones.
Cholesterol stones account for more than 70% of gallstones in the United States, and pure cholesterol stones account for less than 10%.
Pigment stones can be divided into black stones, seen in hemolytic conditions and cirrhosis, and brown stones, found in the bile ducts and thought to be secondary to infection.

Natural History

Gallstones become symptomatic when they obstruct a visceral structure such as a cystic duct.
However, gallstones often remain asymptomatic, only found incidentally on imaging.
Biliary colic, caused by temporary blockage of the cystic duct, tends to occur early.

Treatment

ERCP or CBD exploration is generally the treatment for choledocholithiasis.
Laparoscopic or open cholecystectomy may be performed, depending on the severity of the condition.
Percutaneously placed cholecystostomy tube may be considered for patients with acute cholecystitis who have a prohibitively high operative risk.

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Description

Understand the normal anatomy of bile ducts and its variations in patients with biliary disease. Learn about the cystic duct, common bile duct, and their relations.