Bile Duct Obstruction – Causes, Symptoms, Treatment

Bile Duct Obstruction /Biliary Obstruction refers to blockage of the bile duct system preventing bile from flowing from the liver into the intestinal tract. Bile is synthesized in the liver and transported via the bile ducts into the duodenum to assist with the metabolism of fats. Bile is a substance produced continuously by the hepatocytes consisting of bile salts, bilirubin, fats, water, and inorganic salts. Bile formed in the liver flows through the right and left hepatic ducts into the common hepatic duct. Nearly 50% of the bile flows into the cystic duct and is then stored in the gallbladder with the rest of the bile flowing through the common bile duct and converging and flowing through the main pancreatic duct in the head of the pancreas to empty into the duodenum through the sphincter of Oddi. Biliary obstruction can occur anywhere along this path and lead to serious complications such as hepatic dysfunction, renal failure, cardiovascular impairment, nutritional deficiencies, bleeding problems, and infection.[rx]

Biliary obstruction is generally referred to as blockage of the extrahepatic biliary system. Disruption in bile flow due to the hepatic or intrahepatic biliary system is generally referred to as cholestasis. All these can present as elevated bilirubin levels and Jaundice.

Bile obstruction is common and affects a large portion of the population around the world with significant morbidity and mortality. The most common etiology of biliary obstruction is from Choledhocholithiasis or gallstone causing extrahepatic bile duct blockage. The most serious manifestation of this is an infection of bile ducts or cholangitis which can be fatal if not treated promptly. [rx]

Pathophysiology of Bile Duct Obstruction

• Catabolism of hemoglobin is a normal function that releases heme molecules which then converts to biliverdin, a precursor to bilirubin. Biliverdin then transforms into unconjugated bilirubin within the reticuloendothelial system. Being that unconjugated bilirubin is lipid-soluble, the renal system does not eliminate it. Unconjugated bilirubin is bound in serum to albumin or exists as free unbound bilirubin. Unbound bilirubin is taken up by hepatocytes and converted to conjugated bilirubin which is water-soluble. Conjugated bilirubin becomes part of the bile which is secreted from the hepatocytes in the liver.
• Bile formed in the liver flows through the right and left hepatic ducts into the common hepatic duct. Fifty percent of the bile flows into the cystic duct and is then stored in the gallbladder with the rest of the bile flowing through the common bile duct and converging and flowing through the main pancreatic duct in the head of the pancreas to empty into the duodenum through the sphincter of Oddi.
• Biliary obstruction refers to blockage of the bile duct system preventing bile release. Biliary obstruction can occur anywhere along the path from the liver to the intestinal tract. Biliary obstruction is common and affects a large portion of the population around the world with significant morbidity and mortality. Gallstones are the most prevalent cause of biliary obstruction; they commonly manifest by dilatation of the common bile duct and jaundice.
• Jaundice, a physical exam finding of yellowish discoloration of the skin, conjunctiva, and/or mucous membranes is a consequence of obstruction leading to bile stasis and buildup of conjugated bilirubin in the blood.
• Normal total serum bilirubin values are 0.2-1.2 mg/dL. Jaundice is evident clinically at the level of 3 mg/dl.
• Normal urine contains no bilirubin; however, in patients with obstructive jaundice conjugated bilirubin is excreted in urine giving it a dark color. Urinary bilirubin is detectable at a lower level of bilirubin than that needed to cause clinical jaundice.
• The inability of bilirubin to reach the intestinal tract gives pale color to stools.
• Pruritus is common in biliary obstruction patients, but the cause of this is unknown. The deposition of bile acid into the skin is one postulation that could account for these symptoms. Percutaneous biliary drainage was found to decrease pruritis symptoms.[rx]

Causes of Bile Duct Obstruction

• Biliary obstruction can be divided into intrahepatic and extrahepatic etiologies. As described above, intrahepatic biliary obstruction is generally called cholestasis and not covered here in detail as is not the scope of this topic.
• Intrahepatic cholestasis [rx] can be from several diseases including any form of acute hepatitis (viral, drug, alcohol), drug-induced liver injury, primary biliary cholangitis, primary sclerosing cholangitis and infiltrative diseases (sarcoidosis, tumors, abscess, and cysts).
• The extrahepatic biliary obstruction which is the scope of this article can have various benign and malignant etiologies.
• These include Choledhocholithiasis, Choledochal cysts, Mirizzi’s syndrome, benign stricture disease (PSC, iatrogenic), neoplastic stricturing disease (cholangiocarcinoma, pancreatic head cancer, ampullary carcinomal or adenoma) and infectious diseases (Parasitic cholangiopathy), inflammatory and autoimmune disease (AIDS cholangiopathy, autoimmune cholangiopathy).[rx]

Causes of obstruction include the following

• Cysts of the common bile duct
• Enlarged lymph nodes in the porta hepatis
• Gallstones
• Inflammation of the bile ducts
• Narrowing of the bile ducts from scarring
• Injury from gallbladder surgery
• Tumors of the bile ducts or pancreas
• Tumors that have spread to the biliary system
• Liver and bile duct worms (flukes)
• Gallstones
• Tumors of the bile ducts or pancreas
• Other tumors that have spread to the biliary system
• Trauma including injury from gallbladder surgery
• Choledochal cysts
• Enlarged nodes in the porta hepatis
• Inflammation of the bile ducts
• History of any of these conditions:
  • Cholelithiasis (gallstones)
  • Chronic pancreatitis
  • Pancreatic cancer
  • Recent biliary surgery
  • Recent biliary cancer (such as bile duct cancer)
  • Abdominal trauma
• In immunosuppressed patients, obstructions can be caused by infections.

Symptoms of Bile Duct Obstruction

• Pale-colored stools (caused by lack of bilirubin)
• Dark urine (caused by bilirubin excreted in the urine)
• Jaundice (yellow skin color)
• Itching
• Abdominal pain in the upper right quadrant
• Fever
• Nausea and vomiting
• Most common symptoms can include light or clay-colored stools, dark urine and Nausea and vomiting typically present in Choledocholithiasis (at least one gallstone in the common bile duct), although many times initially conditions can be asymptomatic.
• Signs of jaundice (skin and icterus). Patients typically present with jaundice and pruritus can experience more generalized symptoms, such as weight loss, anorexia, and fatigue.
• The gallbladder may be palpable (Courvoisier sign). This may be associated with underlying pancreatic malignancy.
• Weight loss, adenopathies, and blood in the stool, suggesting a neoplastic lesion.
• Presence or absence of ascites (abnormal accumulation fluid in the abdominal (peritoneal) cavity) and collateral blood circulation associated with cirrhosis.
• High fever and chills suggest coexisting cholangitis.
• Abdominal pain in various areas dependent on cause. Pain can be intermittent, and may also spread to the back. Pains can be mild or intense, depending on the severity of the condition.
• Malignancy is more commonly associated with the absence of pain and tenderness during the physical examination.
• Irregular yellow patches or nodules on the skin (Xanthomata) associated with primary biliary cirrhosis (PBC).

Diagnosis of Bile Duct Obstruction

History and Physical

Presentation

• Biliary obstruction can have a very varied presentation depending on underlying etiology. It usually presents as Jaundice with clay-colored stools and dark urine. Patients can have pruritis if chronic and depending on underlying etiology can have Right upper quadrant abdominal pain, fever, nausea and vomiting, and weight loss. The onset of these symptoms can be variable ranging from acute development of symptoms to over months.
• A careful history of symptom duration, gradual or acute onset, accompanying symptoms, family, and social history is very important.

Physical Examination

• A detailed physical exam is of paramount importance. It is very important to check baseline vital signs, pallor, and scleral icterus.
• A detailed Abdominal Examination to examine for Right upper quadrant tendrness (Murphy’s sign), hepatomegaly and splenomegaly, presence of ascites, any palpable mass, stigmata of cirrhosis are very crucial for diagnosis.
• The cardiac exam to assess for signs of congestive heart failure with JVD elevation and displacement of heart sounds can be very important to determine underlying etiology.
• Similarly, a detailed lung pulmonary exam to assess for pleural effusions, determining one-sided or bilateral is helpful in determining etiology.

Digital Rectal Examination

• Sometimes rectal exam to assess for rectal cancer can be helpful.

Neck Exam

• Assessment of Left supraclavicular lymph node and other neck lymph nodes can provide helpful information.

Blood tests

Work up for biliary obstruction includes routine labs and some dedicated labs including:

• CBC
• CMP
• Total bilirubin
• Fractionated bilirubin
• Alkaline phosphatase and fractionated
• GGT
• viral hepatitis Serology
• Antimitochondrial antibody levels
• Antinuclear antibody
• Coagulation studies
• Tumor markers (CA19-9, CEA, AFP)[rx][rx][rx]

Urine test

• Urine bilirubin

Stool test

• Occult blood to rule out GI malignancy

Radiological tests

• Abdominal ultrasound – with doppler can be a starting radiological test due to low cost, non-invasive tests, and easy availability. Based on the results, and Abdominal CT Scan can be the next step.
• MRCP (magnetic resonance cholangiopancreatography) – is a very sensitive test to assess for intra and extrahepatic bile duct abnormalities.
• Based on the non-invasive tests – EUS (endoscopic ultrasound) and ERCP (endoscopic retrograde cholangiopancreatogram) can be further considered. Sometime Interventional Radiology based PTCA (percutaneous transhepatic cholangiogram) cen be useful to test.[rx][rx][rx]
• Once biliary dilation – or the presence of a common duct stone is noted on an imaging study or biliary obstruction is strongly suspected on clinical grounds despite negative imaging studies, endoscopic retrograde cholangiopancreatography (ERCP) is recommended. ERCP provides a means of visualizing the biliary tree and the opportunity for therapy.
• Abdominal CT scanning –  can also be helpful in evaluating patients with obstructive jaundice. It is as accurate as ultrasound in detecting common duct stones and may help localize the level of obstruction in the biliary tree.
• Cholangiography – A cholangiography is an X-ray of the bile ducts.
• Magnetic resonance cholangiopancreatography (MRCP) – a type of MRI scan is a non-invasive way to visualize the hepatobiliary tree.

Treatment of Bile Duct Obstruction

Initial management

• Initial management depends on patients’ clinical conditions and probable etiology. If the patient is stable, most of the work can be done as an outpatient with regular follow up. However, if patients are febrile and showing signs of hepatic compromise, admitting the patient for evaluation and treatment may be needed. This is needed in patients with Acute Cholangitis, Cholecystitis, and Acute Liver Failure.

Treatment

Treatment varies widely for biliary obstruction depending on the underlying cause. Some common etiologies are discussed below[rx]

Cholelithiasis and Choledocholithiasis

CBD stricture

Benign

Parasites

Choledochal cyst

• Excision and hepaticojejunostomy

Neoplasm

Differential Diagnosis

Benign diseases

• Acute cholecystitis and biliary colic
• Acute pancreatitis
• Alcoholic hepatitis
• Ascariasis
• Bile duct strictures
• Biliary trauma
• Choledochal cysts
• Chronic pancreatitis
• Cirrhosis
• Gallstones (cholelithiasis)
• Hepatitis B
• Hepatitis C
• Hepatocellular adenoma
• Mirizzi syndrome
• Primary biliary cholangitis
• Primary sclerosing cholangitis
• Unconjugated hyperbilirubinemia
• Viral hepatitis[rx]

Malignant diseases

• Ampullary carcinoma
• Bile duct tumors
• Cholangiocarcinoma
• Gallbladder cancer
• Gallbladder tumors
• Pancreatic cancer
• Primary hepatic carcinoma
• Enlarged malignant lymph node

Complications of Bile Duct Obstruction

Cholangitis

• One of the most feared complications of biliary obstruction is cholangitis which is an ascending infection of the biliary tree accompanying an obstruction

Presentation

• Charcot’s triad (right upper quadrant pain, fever, and jaundice)
• Reynold’s pentad (Charcot’s triad with mental status change and hemodynamic shock)

Laboratory evaluation

• Elevated white blood cell count
• Abnormal liver testing with elevated alkaline phosphatase and gamma-glutamyl transpeptidase
• Elevated bilirubin

Evaluation

• Abdominal ultrasound
• Helical CT-scan
• MRCP

Severe

• Hypotension requiring any vasopressor
• Mental status change
• PaO2/FiO2 less than 300
• Serum creatinine greater than 2.0 mg/dL
• INR greater than 1.5
• Platelet count less than 100000/mm[21]

Moderate

• Elevated white count greater than 12000
• Fever greater than 39 C, or 102.2 F
• Age older than 75
• Hyperbilirubinemia over 5 mg/dL
• Hypoalbuminemia

Treatment

General

• Admission
• IVF resuscitation and electrolyte replacement
• Pain control
• Antibiotics with activity against enteric streptococci, coliforms, and anaerobes

Low-risk community-acquired

• Single-agent: ertapenem or piperacillin-tazobactam
• Combination: ceftriaxone, ciprofloxacin, or levofloxacin with metronidazole

High-risk community-acquired

• Single-agent: imipenem-cilastatin, meropenem, or piperacillin-tazobactam
• Combination: cefepime or ceftazidime with metronidazole

Drainage

• ERCP (endoscopic retrograde cholangiopancreatography); Endoscopic removal of biliary stones with drainage of bile, often with sphincterotomy
• PTC (percutaneous transhepatic cholangiography); Insertion of a needle into biliary tract percutaneously for drainage, removal of stones, and possible placement of the biliary stent
• Surgical Drainage; Open or laparoscopic surgical intervention with biliary decompression, removal of the obstruction, and cholecystectomy if warranted and the patient is stable

Consultations

• Gastroenterology
• Radiology
• Interventional radiology
• Pathology
• Oncology
• General surgery
• Hepatology

Deterrence and Patient Education for Biliary Obstruction

Biliary obstruction

• Blockage within the biliary tract or the route bile uses to leave the liver and help metabolize fat

Most Common Cause

• Gallbladder stones that obstruct the biliary tract

Symptoms

• Right upper quadrant abdominal pain
• Pain in the back under the shoulder blade
• Nausea and vomiting
• Jaundice (yellowing of the skin)

Testing

• Laboratory evaluation and imaging
• Ultrasound of the abdomen
• Further testing will be chosen appropriately depending on the results of initial testing

Treatment

• Treatment for biliary obstruction depends on the cause but likely will be either surgical or non-surgical
• Surgical may include cholecystectomy to remove the gallbladder if the cause is gallstones along with ERCP with sphincterotomy to remove any gallstones from the biliary tract causing obstruction
• Non-Surgical may include stabilization and pain control along with medications to help dissolve any gallstones causing obstruction

Prevention of recurrence

• Maintain a healthy body weight with proper nutrition and exercise

References