PBC (Primary Biliary Cholangitis) – Top USMLE Diseases

Acute cholangitis refers to acute inflammation in the bile duct system; it is a life-threatening condition characterized by fever, jaundice, and abdominal pain. This condition develops as a result of stasis and infection of the biliary tract. Septic shock, liver abscess, and multi-organ dysfunction are potential serious complications. The diagnosis is confirmed with ultrasound (or other hepatobiliary imaging studies) showing dilation of the common bile duct (CBD) or gallstones, elevated liver function tests, and leukocytosis. Treatment includes hemodynamic stabilization, broad-spectrum antibiotics, urgent biliary drainage, and addressing the underlying etiology (e.g., cholecystectomy for gallstones).

Cholecystitis is the inflammation of the gallbladder (GB) usually caused by the obstruction of the cystic duct (acute cholecystitis). Mechanical irritation by gallstones can also produce chronic GB inflammation. Cholecystitis is one of the most common complications of cholelithiasis (calculous cholecystitis) but inflammation without gallstones (acalculous cholecystitis) can occur in a minority of patients. The acute type usually presents with right upper quadrant (RUQ) pain, fever, and leukocytosis. The diagnosis is made clinically and confirmed via ultrasound (US). The definitive management is cholecystectomy, preferably performed within 72 hours. This condition can present as a mild condition or as a severe disease (with complications such as gallbladder gangrene, perforation, empyema) which require emergent intervention.

Cholelithiasis (gallstones) is the presence of stones in the gallbladder. Most gallstones are cholesterol stones, while the rest are composed of bilirubin (pigment stones) and other mixed components. Patients are commonly asymptomatic but may present with biliary colic (intermittent pain in the right upper quadrant). The diagnosis is established by ultrasound. Management options include supportive care to prevent and control associated symptoms. When indicated, cholecystectomy is the definitive treatment. Gallstones may lead to complications such as choledocholithiasis (a stone trapped in the common bile duct), cholecystitis (inflammation of the gallbladder), or cholangitis (biliary sepsis). These conditions require urgent medical attention.

Primary biliary cholangitis (PBC) is a chronic disease resulting in autoimmune destruction of the intrahepatic bile ducts. The typical presentation is that of a middle-aged woman with pruritus, fatigue, and right upper quadrant abdominal pain. Elevated liver enzymes and antimitochondrial antibodies (AMAs) establish the diagnosis. Medical management includes ursodeoxycholic acid as the 1st-line treatment and for symptom management. Definitive treatment is liver transplantation, which is performed in late stages (cirrhosis).

The hepatobiliary system is composed of the liver, gallbladder, and bile ducts (within the liver and external to the liver). The liver produces bile, which is a fluid made of cholesterol, phospholipids, conjugated bilirubin, bile salts, electrolytes, and water. Bile, which assists in digestion and helps eliminate waste products, is stored in the gallbladder. The hepatobiliary system can be affected by infections, cysts, solid masses, ischemia, and mechanical flow obstruction, which mandate the presence of reliable imaging tests to determine the etiology. The methods that evaluate structural changes in the liver and biliary tract include ultrasonography, CT scan, and MRI (including magnetic resonance cholangiopancreatography). Additionally, cholescintigraphy, a functional imaging study, helps identify gallbladder pathology by tracking the biliary pathway.

Liver function tests, also known as hepatic function panels, are one of the most commonly performed screening blood tests. Such tests are also used to detect, evaluate, and monitor acute and chronic liver diseases. Liver function tests assess the levels of various hepatic proteins and enzymes to determine the state of liver metabolic activity, homeostasis, bile metabolism, and protein synthesis capacity. The standard hepatic panel includes the levels of total protein, bilirubin, albumin, ALT, AST, AST/ALT ratio, and alkaline phosphatase (ALP).

Primary biliary cholangitis (PBC) is a chronic disease resulting in autoimmune destruction of the intrahepatic bile ducts. The typical presentation is that of a middle-aged woman with pruritus, fatigue, and right upper quadrant abdominal pain. Elevated liver enzymes and antimitochondrial antibodies (AMAs) establish the diagnosis. Medical management is limited to using ursodeoxycholic acid, a disease-modifying agent. Definitive treatment is liver transplantation, which is performed in late stages (cirrhosis).

Acute cholangitis is a life-threatening condition characterized by fever, jaundice, and abdominal pain which develops as a result of stasis and infection of the biliary tract. Septic shock, liver abscess, and multi-organ dysfunction are potential serious complications. The diagnosis is confirmed with ultrasound showing dilation of the common bile duct (CBD) or gallstones, elevated liver function tests, and leukocytosis. Treatment includes hemodynamic stabilization, broad-spectrum antibiotics, urgent biliary drainage, and cholecystectomy to prevent recurrence.

The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Bile is secreted by hepatocytes into thin channels called canaliculi. These canaliculi lead into slightly larger interlobular bile ductules, which are part of the portal triads at the “corners” of hepatic lobules. The bile leaves the liver via the right and left hepatic ducts, which join together to form the common hepatic duct. The common hepatic duct joins with the cystic duct to form the common bile duct, which empties into the small intestine. If the sphincters leading into the intestines are closed, bile will travel via the cystic duct into the gallbladder for storage.

Cholecystitis is the inflammation of the gallbladder (GB) usually caused by the obstruction of the cystic duct (acute cholecystitis). Mechanical irritation by gallstones can also produce chronic GB inflammation. Cholecystitis is one of the most common complications of cholelithiasis (calculous cholecystitis) but inflammation without gallstones (acalculous cholecystitis) can occur in a minority of patients. The acute type usually presents with right upper quadrant (RUQ) pain, fever, and leukocytosis. The diagnosis is made clinically and confirmed via ultrasound (US). The definitive management is cholecystectomy, preferred to be performed within 72 hours. This condition can present as a mild condition or as a severe disease (with complications such as gallbladder gangrene, perforation, empyema) which require emergent intervention.

Cholelithiasis (gallstones) is the presence of stones in the gallbladder. Most gallstones are cholesterol stones, while the rest are composed of bilirubin (pigment stones) and other mixed components. Patients are commonly asymptomatic but may present with biliary colic (intermittent pain in the right upper quadrant). The diagnosis is established by ultrasound. Management options include supportive care to prevent and control associated symptoms. When indicated, cholecystectomy is the definitive treatment. Gallstones may lead to complications such as choledocholithiasis (a stone trapped in the common bile duct), cholecystitis (inflammation of the gallbladder), or cholangitis (biliary sepsis). These conditions require urgent medical attention.