LE5 Flashcards
(218 cards)
- The arterial supply to the common bile duct is derived from which of the following?
a. Left hepatic artery
b. Right hepatic artery
c. Gastroduodenal artery
d. Right hepatic and gastroduodenal arteries
d. Right hepatic and gastroduodenal arteries
Rationale: The common bile duct receives its blood supply primarily from the right hepatic artery (superior portion) and the gastroduodenal artery (inferior portion). These anastomose along the duct, ensuring a dual supply.
- Relaxation of the sphincter of Oddi in response to a meal is largely under the control of which hormone?
a. Gastrin
b. Cholecystokinin (CCK)
c. Motilin
d. Secretin
b. Cholecystokinin (CCK)
Rationale: CCK is released from the duodenum in response to fats and proteins, stimulating gallbladder contraction and relaxation of the sphincter of Oddi, allowing bile flow into the duodenum.
- What percentage of the bile acid pool is reabsorbed in the ileum through the enterohepatic circulation?
a. 25%
b. 50%
c. 75%
d. 95%
d. 95%
Rationale: Bile acids are extensively reabsorbed in the ileum via active transport (Na⁺-dependent bile acid transporter), with only 5% excreted in feces—a key step in the enterohepatic circulation.
- Acute cholecystitis is best described as:
a. A primary infectious process with secondary inflammation
b. A sterile primary inflammatory process
c. A primary inflammatory process with occasional bacterial contamination
d. A primary autoimmune process
c. A primary inflammatory process with occasional bacterial contamination
Rationale: Acute cholecystitis is caused by cystic duct obstruction (usually from gallstones), leading to bile stasis, mucosal injury, and inflammation. Secondary bacterial infection may occur but is not the initiating event.
- The most common type of gallbladder cancer is:
a. Oat cell carcinoma
b. Adenocarcinoma
c. Adenosquamous carcinoma
d. Squamous cell carcinoma
b. Adenocarcinoma
Rationale: Adenocarcinoma accounts for 85–90% of gallbladder cancers, arising from chronic inflammation (e.g., gallstones, chronic cholecystitis). It has a poor prognosis due to late diagnosis.
- The best initial test for a suspected postoperative bile leak is:
a. Percutaneous transhepatic cholangiography (PTC)
b. Endoscopic retrograde cholangiopancreatography (ERCP)
c. Magnetic resonance imaging (MRI)
d. Ultrasound (US)
b. Endoscopic retrograde cholangiopancreatography (ERCP)
Rationale: ERCP is the best initial test for a suspected postoperative bile leak, as it provides both diagnostic imaging (contrast study of the bile ducts) and therapeutic options (stenting, sphincterotomy).
- In the early postoperative period, what is the most common presentation of a patient with a biliary injury?
a. Fever
b. Abdominal pain
c. Steatorrhea
d. Elevated transaminases
b. Abdominal pain
Rationale: Biliary injury postoperatively often presents with abdominal pain, bile leakage, or jaundice. Fever can develop if infection occurs, but pain is typically the earliest symptom.
- A patient presents with biliary colic. On ultrasound, multiple stones are noted in the gallbladder, and the common bile duct measures 9 mm in diameter, but no stone is visualized in the common bile duct. What is the most reasonable next step?
a. Repeat ultrasound in 24-48 hours
b. Magnetic resonance cholangiopancreatography (MRCP) with contrast
c. Percutaneous cholangiography
d. Laparoscopic cholecystectomy with intraoperative cholangiography
d. Laparoscopic cholecystectomy with intraoperative cholangiography
- The gallbladder can store only a small fraction of the bile produced by the liver. What is the primary mechanism that prevents the gallbladder from becoming distended and developing high pressure?
a. Bile continuously secretes into the duodenum once gallbladder pressure increases
b. Gallbladder contraction in response to eating empties the large volume of bile
c. The gallbladder concentrates the bile to reduce its volume
d. The liver decreases bile production when gallbladder pressure increases
c. The gallbladder concentrates the bile to reduce its volume
- After a cholecystectomy, the surgeon opens the gallbladder specimen and observes a milky content. What is the most likely cause?
a. Secretion of pancreatic juice into the common bile duct
b. Reabsorption of bile pigments by the gallbladder mucosa
c. Reduced bile pigment production in the liver
d. Absence of bilirubin glucuronidase
b. Reabsorption of bile pigments by the gallbladder mucosa
- A 45-year-old female presents with fever, jaundice, and right upper quadrant pain. What is the most likely initial diagnosis?
a. Acute cholecystitis
b. Acute hepatitis
c. Acute pancreatitis
d. Ascending cholangitis
d. Ascending cholangitis
Rationale: Charcot’s triad (fever, jaundice, RUQ pain) is highly suggestive of ascending cholangitis, a life-threatening biliary infection often caused by obstruction (e.g., CBD stones), leading to bacterial overgrowth and systemic infection.
- A patient presents with fever, jaundice, and right upper quadrant pain. What is the most likely initial diagnosis?
a. Ascending cholangitis
b. Hepatitis
c. Pancreatitis
d. Acute cholecystitis
a. Ascending cholangitis
Rationale: Charcot’s triad (fever, jaundice, RUQ pain) is classic for ascending cholangitis, a biliary tract infection due to obstruction (often from choledocholithiasis).
- What is the half-life of cholecystokinin (CCK)?
a. 2-3 minutes
b. 20-30 minutes
c. 1-3 hours
d. 12-24 hours
a. 2-3 minutes
Rationale: Cholecystokinin (CCK) has a short half-life (2-3 minutes), ensuring rapid regulation of gallbladder contraction and bile secretion in response to meals.
- A 53-year-old patient is admitted with 24 hours of pain from acute cholecystitis. He is placed on NPO, IV antibiotics, and given analgesia. When should he undergo a cholecystectomy?
a. Urgently
b. In 1-3 days
c. In 7-10 days
d. In 6-8 weeks
b. In 1-3 days
Rationale: Early laparoscopic cholecystectomy (within 72 hours) is preferred for acute cholecystitis to reduce complications and shorten hospital stay. Delayed surgery increases the risk of recurrent attacks.
- Choledochal stones are primarily composed of:
a. Cholesterol stones
b. Black pigment stones
c. Brown pigment stones
d. Mulberry stones
c. Brown pigment stones
Rationale: Choledochal (bile duct) stones are usually brown pigment stones, formed due to biliary stasis and infection, with calcium bilirubinate and bacterial debris as key components.
- Which of the following is a major component of gallstones?
a. Biliverdin
b. Hemoglobin
c. Lecithin
d. Myoglobin
c. Lecithin
Rationale: Lecithin (phosphatidylcholine) is a major component of gallstones, along with cholesterol and bile salts. A deficiency in lecithin can promote gallstone formation.
- The primary stimulus for gallbladder contraction is:
a. Somatostatin
b. Cholecystokinin (CCK)
c. Vasoactive intestinal polypeptide
d. Enkephalin
b. Cholecystokinin (CCK)
Rationale: CCK is the primary hormone that stimulates gallbladder contraction, triggered by the presence of fats and proteins in the duodenum.
- A patient presents with biliary colic. Ultrasound shows small stones in the gallbladder, and the common bile duct measures 9 mm in diameter. No stone is visualized in the common bile duct. What is the most reasonable next step?
a. MRCP with contrast
b. Laparoscopic cholecystectomy and intraoperative cholangiography
c. Percutaneous cholangiography
d. Repeat ultrasound in 24-48 hours
b. Laparoscopic cholecystectomy and intraoperative cholangiography
- The gallbladder differs histologically from the rest of the gastrointestinal tract by:
a. Absence of serosa
b. Lack of muscularis mucosae and submucosa
c. Presence of villi
d. Presence of crypts
b. Lack of muscularis mucosae and submucosa
Rationale: Unlike the rest of the gastrointestinal tract, the gallbladder lacks a muscularis mucosae and submucosa, which makes it more prone to perforation in inflammation.
- Which of the following is an indication for cholecystectomy in an asymptomatic patient with an incidental finding of gallstones?
a. Porcelain gallbladder
b. Single gallstone larger than 1 cm
c. Presence of sludge in the gallbladder
d. Thickened gallbladder wall without symptoms
a. Porcelain gallbladder
Rationale: Porcelain gallbladder (intramural calcification) is a strong risk factor for gallbladder cancer, warranting prophylactic cholecystectomy.
- Which theory explains how gallstones can cause pancreatitis?
a. Common channel theory
b. Bile reflux theory
c. Ischemic ductal injury theory
d. Autoimmune activation theory
a. Common channel theory
Rationale: The common channel theory explains gallstone-induced pancreatitis, where an impacted stone at the ampulla of Vater causes reflux of bile into the pancreatic duct, leading to pancreatic inflammation.
- Which of the following is TRUE regarding splenic abscess?
a. It is a common condition with a high incidence.
b. It usually arises from a systemic infection.
c. Clinical manifestations appear early and are easily diagnosed.
d. Splenectomy is rarely required for treatment.
- b. It usually arises from a systemic infection.
🔹 Rationale: Splenic abscesses are rare but often result from hematogenous spread of infection (e.g., endocarditis, septicemia). Risk factors include immunosuppression, IV drug use, and trauma.
- Which of the following is NOT a common indication for splenectomy?
a. Myeloproliferative disorders
b. Disorders of red blood cells
c. Acute viral infections
d. Disorders of platelets
c. Acute viral infections.
🔹 Rationale: Splenectomy is not indicated for acute viral infections, as most resolve spontaneously. Common indications include:
Myeloproliferative disorders (e.g., myelofibrosis, CML)
RBC disorders (e.g., hereditary spherocytosis, sickle cell disease)
Platelet disorders (e.g., ITP, TTP)
- What is the primary function of Tuftsin?
a. Stimulates phagocytic function
b. Activates the coagulation cascade
c. Enhances red blood cell production
d. Acts as an enzyme in digestion
a. Stimulates phagocytic function.
🔹 Rationale: Tuftsin is a tetrapeptide produced in the spleen that enhances phagocytosis by neutrophils and macrophages, aiding immune defense.