A previously healthy 37-year-old woman, gravida 3, para 2, at 29 weeks' gestation comes to the physician because of colicky postprandial abdominal pain. Her vital signs are within normal limits. Physical examination shows a uterus consistent in size with a 29-week gestation. Ultrasonography of the abdomen shows multiple 5-mm hyperechoic masses within the gallbladder lumen. Which of the following processes is most likely involved in the pathogenesis of this patient's condition?

Increased secretion of cholesterol

Accelerated gallbladder emptying

Increased secretion of bile acids

A 42-year-old woman is brought to the emergency department because of intermittent sharp right upper quadrant abdominal pain and nausea for the past 10 hours. She has vomited 3 times. There is no associated fever, chills, diarrhea, or urinary symptoms. She has 2 children who both attend high school. She appears uncomfortable. She is 165 cm (5 ft 5 in) tall and weighs 86 kg (190 lb). Her BMI is 32 kg/m2. Her temperature is 37.0°C (98.6°F), pulse is 100/min, and blood pressure is 140/90 mm Hg. She has mild scleral icterus. On physical examination, her abdomen is soft and nondistended, with tenderness to palpation of the right upper quadrant without guarding or rebound. Bowel sounds are normal. Laboratory studies show the following: Blood Hemoglobin count 14 g/dL Leukocyte count 9,000 mm3 Platelet count 160,000 mm3 Serum Alkaline phosphatase 238 U/L Aspartate aminotransferase 60 U/L Bilirubin Total 2.8 mg/dL Direct 2.1 mg/dL Which of the following is the most appropriate next step in diagnosis?

Endoscopic retrograde cholangiopancreatography (ERCP)

Supine and erect X-rays of the abdomen

Computed tomography (CT) scan of the abdomen

Hepatobiliary iminodiacetic acid (HIDA) scan of the biliary tract

A 45-year-old woman comes to the emergency department complaining of abdominal pain for the past day. The pain is situated in the right upper quadrant, colicky, 8/10, and radiates to the tip of the right shoulder with no aggravating or relieving factors. The pain is associated with nausea but no vomiting. She tried to take over-the-counter antacids which relieved her pain to a certain extent, but not entirely. She does not smoke cigarettes or drink alcohol. She has no past medical illness. Her father died of pancreatic cancer at the age of 75, and her mother has diabetes controlled with medications. Temperature is 38°C (100.4°F), blood pressure is 125/89 mm Hg, pulse is 104/min, respiratory rate is 20/min, and BMI is 29 kg/m2. On abdominal examination, her abdomen is tender to shallow and deep palpation of the right upper quadrant. Laboratory test Complete blood count Hemoglobin 13 g/dL WBC 15,500/mm3 Platelets 145,000/mm3 Basic metabolic panel Serum Na+ 137 mEq/L Serum K+ 3.6 mEq/L Serum Cl- 95 mEq/L Serum HCO3- 25 mEq/L BUN 10 mg/dL Serum creatinine 0.8 mg/dL Liver function test Total bilirubin 1.3 mg/dL AST 52 U/L ALT 60 U/L Ultrasonography of the abdomen shows normal findings. What is the best next step in management of this patient?

Reassurance and close follow up

A 41-year-old G3P3 woman presents with acute on chronic right upper quadrant abdominal pain. She says that her current symptoms acutely onset 8 hours ago after eating a large meal and have not improved. She describes the pain as severe, sharp and cramping in character, and localized to the right upper quadrant. She also describes feeling nauseous. The patient says she has had similar less severe episodes intermittently for the past 2 years, usually precipitated by the intake of fatty foods. She denies any history of fever or jaundice. Vital signs are stable. Physical examination is unremarkable, and laboratory findings show normal liver function tests and normal serum bilirubin and serum amylase levels. Ultrasonography of the abdomen reveals multiple stones in the gallbladder. The patient is managed symptomatically for this episode, and after a few months, undergoes elective cholecystectomy, which reveals multiple stones in her gallbladder as shown in the figure (see image). Which of the following best describes these gallstones?

They are formed due to bile supersaturated with cholesterol.

These are usually radiopaque on X-ray imaging.

They are formed due to elevated uric acid in the blood.

These are seen in patients with chronic hemolysis.

They are formed due to the release of beta-glucuronidase from infecting bacteria.

A 45-year-old woman comes to the emergency department because of right upper abdominal pain and nausea that have become progressively worse since eating a large meal 8 hours ago. She has had intermittent pain similar to this before, but it has never lasted this long. She has a history of hypertension and type 2 diabetes mellitus. She does not smoke or drink alcohol. Current medications include metformin and enalapril. Her temperature is 38.5°C (101.3°F), pulse is 90/min, and blood pressure is 130/80 mm Hg. The abdomen is soft, and bowel sounds are normal. The patient has sudden inspiratory arrest during right upper quadrant palpation. Laboratory studies show a leukocyte count of 13,000/mm3. Serum alkaline phosphatase, total bilirubin, amylase, and aspartate aminotransferase levels are within the reference ranges. Imaging is most likely to show which of the following findings?

Dilated common bile duct with intrahepatic biliary dilatation

Enlargement of the pancreas with peripancreatic fluid

Decreased echogenicity of the liver

A 66-year-old woman comes to the physician because of a 1-week history of pruritic blister formation. Physical examination shows multiple 1–3 cm bullae on the palms, soles, lower legs, and inguinal folds. Gentle rubbing of the skin does not result in sloughing of the epidermis. Immunofluorescence studies of a perilesional skin biopsy specimen are most likely to show deposition of antibodies in which of the following areas?

Between epidermal keratinocytes

Gallbladder and biliary tract disorders for USMLE Step 2 CK: High-Yield Pathology Lessons

Biliary Anatomy - The Bile Route

Anatomy of the Gallbladder and Biliary Tree

Bile flows from liver to duodenum. Gallbladder stores & concentrates bile (30-50 mL).
Blood supply: Cystic artery, usually from the Right Hepatic Artery.
Innervation: Vagal fibers (contraction), splanchnic nerves (relaxation).

⭐ Calot's Triangle is a critical surgical landmark for cholecystectomy. Its boundaries are the cystic duct, common hepatic duct, and the inferior liver edge; it contains the cystic artery.

Cholelithiasis - Stone Cold Facts

Two main types:
- Cholesterol stones (>80%): Formed from cholesterol supersaturation in bile. Often solitary and large.
- Pigment stones: Composed of calcium bilirubinate.
  - Black stones: Associated with hemolysis (e.g., sickle cell) and cirrhosis.
  - Brown stones: Associated with biliary tract infections.
📌 Risk Factors (4 F's): Female, Fat, Fertile (multiparity), Forty.
Diagnosis: Abdominal ultrasound is the gold standard imaging test.

⭐ Most cholesterol gallstones are radiolucent on X-ray. Pigment stones are more likely to be radiopaque.

Ultrasound: Gallbladder with cholelithiasis and shadowing

Cholecystitis - Gallbladder Under Siege

Inflammation of the gallbladder, typically due to cystic duct obstruction.
Types:
- Calculous (90%): Gallstone impaction.
- Acalculous (10%): Critically ill patients (sepsis, trauma, burns); high mortality.

Dx: RUQ ultrasound shows thickened wall (>4 mm), pericholecystic fluid. Positive Murphy's sign.
Complications: Gangrene, perforation, empyema, fistula.

⭐ HIDA scan is the most sensitive and specific test for acute cholecystitis, especially when ultrasound is equivocal.

Anatomy of the Gallbladder and Biliary Tract

Choledocholithiasis & Cholangitis - Duct Drama

Choledocholithiasis: Gallstone in the common bile duct (CBD), causing biliary colic and obstructive jaundice.
Cholangitis: Ascending infection of the biliary tree, often due to CBD obstruction.
Clinical Syndromes:
- 📌 Charcot's Triad (Cholangitis): Jaundice, Fever, RUQ Pain.
- Reynold's Pentad (Suppurative Cholangitis): Charcot's triad + Hypotension & Altered Mental Status.
Labs & Dx: ↑ Direct bilirubin, ↑ ALP, ↑ GGT. Ultrasound/MRCP first, then ERCP (diagnostic & therapeutic).

Charcot's Triad and Reynolds' Pentad for Cholangitis

⭐ Reynold's pentad signifies severe, life-threatening cholangitis requiring urgent biliary decompression via ERCP.

Biliary Neoplasms - Sinister Growths

Cholangiocarcinoma: Malignancy of bile duct epithelium; adenocarcinoma.
- Risk Factors: Primary sclerosing cholangitis (PSC), liver flukes (Clonorchis, Opisthorchis), choledochal cysts, Thorotrast.
- Presentation: Obstructive jaundice (painless), pruritus, dark urine, pale stools.
- Markers: ↑ CA 19-9, ↑ CEA.
Gallbladder Carcinoma: Adenocarcinoma from gallbladder mucosa.
- Risk Factors: Gallstones (>3 cm), porcelain gallbladder (chronic inflammation & calcification).
- Presentation: Vague; cholecystitis-like pain, weight loss. Poor prognosis.

⭐ Klatskin tumors are cholangiocarcinomas occurring at the confluence of the right and left hepatic ducts, causing early biliary obstruction.

Types of Cholangiocarcinoma

High‑Yield Points - ⚡ Biggest Takeaways

Cholesterol stones (radiolucent) are linked to the 4 Fs; pigment stones (black/brown) to hemolysis or infection.

Acute cholecystitis features constant RUQ pain, fever, and a positive Murphy sign from cystic duct blockage.

Porcelain gallbladder, a finding in chronic cholecystitis, significantly increases risk for gallbladder adenocarcinoma.

Choledocholithiasis (stone in common bile duct) presents with painful jaundice and elevated alkaline phosphatase.

Ascending cholangitis is a surgical emergency defined by Charcot's triad: fever, jaundice, and RUQ pain.

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