Past Blast
This disease is failure of neural crest cell migration, leading to aganglionic cells in the distal colon, resulting in a functional obstruction as the smooth muscle in this area is unable to relax.
Hirschsprung disease
A 65-year-old man with hospital-acquired pneumonia is started on empiric antibiotics. Which of the following best describes the mechanism of action of piperacillin/tazobactam?
A. Inhibition of bacterial cell wall synthesis and β-lactamase inhibition
B. Disruption of bacterial DNA gyrase
C. Inhibition of bacterial protein synthesis at the 50S ribosomal subunit
D. Blockade of folate metabolism
E. Depolarization of bacterial cell membranes
(perplexity) Answer: A. Inhibition of bacterial cell wall synthesis and β-lactamase inhibition
Explanation: Piperacillin (a β-lactam antibiotic) inhibits cell wall synthesis by binding penicillin-binding proteins (PBPs), while tazobactam irreversibly inhibits β-lactamases, protecting piperacillin from degradation157. DNA gyrase disruption (B) is seen with fluoroquinolones. Protein synthesis inhibition (C) occurs with macrolides. Folate blockade (D) is a sulfonamide mechanism. Cell membrane depolarization (E) is caused by polymyxins.
A 55-year-old woman with obesity presents with right upper quadrant pain after eating fried foods. Ultrasound reveals gallstones. Which of the following is the most common component of gallstones in this patient?
A. Bilirubin
B. Cholesterol
C. Calcium carbonate
D. Protein
E. Mixed lipid-protein complexes
(perplexity) Answer: B. Cholesterol
Explanation: Cholesterol is the primary component of 80% of gallstones in Western populations, linked to obesity and supersaturated bile911. Bilirubin stones (A) account for ~20% of cases and are associated with hemolysis or infection. Calcium carbonate (C) and protein (D) are rare. Mixed complexes (E) describe micelles but not stone composition.
An elevation in this enzyme is the beginning of the end in acute pancreatitis, aka the great initiator. This leads to the autodigestion of the pancreas.
Trypsin
Name Charcot's triad associated with ascending cholangitis. Bonus if you can also name Reynold's Pentad.
Fever/chills, jaundice, RUQ ++++ AMS, and shock (hypotension)
A 66-year-old woman with a history of chronic alcohol abuse has had headaches and nausea for the past 4 days. She has become increasingly obtunded. On physical examination she has right upper quadrant tenderness, tachycardia, tachy-pnea, and hypotension. Laboratory studies show serum AST of475 U/L, ALT of 509 U/L, alkaline phosphatase of 23 U/L, total bilirubin of 0.9 mg/dL, albumin of 3.8 g/dL, and total protein of 6.1 g/dL. She is treated with N-acetylcysteine. Which of the following drugs has she most likely ingested in excess?
A Acetaminophen
B Aspirin
C Ibuprofen
D Meperidine
E Oxycodone
(Robbins & Contran 4th ed.) " B. Aspirin.
In the setting of chronic liver disease, ingestion of acetaminophen is more likely to produce hepatotoxicity because detoxification by conjugation is exceeded. This leads to metabolism by cytochrome P-450 to the toxic metabolite N-acetyl-p-benzoquinineimine (NAPQI), which accumulates beyond the capacity of glutathione. The N-acetylcysteine increases available glutathione. Aspirin ingestion is a cause for Reye syndrome in children. Ibuprofen, which is a non- steroidal anti-inflammatory drug (NSAID), meperidine, and oxycodone do not have significant hepatotoxicity."
A 45-year-old woman presents with right upper quadrant pain that worsens after fatty meals. Physical exam reveals tenderness at the gallbladder fossa (Murphy’s sign). Which of the following imaging studies is most appropriate for initial diagnosis?
A. Abdominal X-ray
B. CT scan of the abdomen
C. Abdominal ultrasound
D. Magnetic resonance cholangiopancreatography (MRCP)
E. Endoscopic retrograde cholangiopancreatography (ERCP)
(perplexity) Answer: C. Abdominal ultrasound
Explanation: Ultrasound is the first-line imaging for suspected cholecystitis due to its high sensitivity for gallstones, gallbladder wall thickening, and pericholecystic fluid. X-ray (A) lacks sensitivity. CT (B) is reserved for complications (e.g., abscess). MRCP (D) and ERCP (E) evaluate bile ducts, not the gallbladder itself.
T or F. Murphy's sign is a physical exam maneuver that looks for a sudden halt of expiration following contact of the gall bladder against an examiner's hand when placed underneath the breastbone in the RUQ.
False. The sudden halt is during inspiration. This action brings the gall bladder closer to the examiner's hand and illicits pain.
List 5 causes of acute pancreatitis
(Bootcamp) "Gallstones, ethanol, trauma, viral (mumps, coxsackie, hepatitis, HIV, mononucleosis), autoimmune, scorpions/snakes/spiders, hypercalcemia/hypertriglyceridemia, ECRP, drugs (protease inhbitiors, NRTIs, sulfa drugs, steroids)"
A 42-year-old woman from Lisbon, Portugal, has had fever, chills, and bouts of colicky right upper quadrant pain for the past week. On physical examination, her skin is icteric, and there is scleral icterus. Laboratory studies show a total serum bilirubin concentration of 7.1 mg/dL and direct bili- rubin concentration of 6.7 mg/dL. An abdominal ultrasound scan shows cholelithiasis; dilation of the common bile duct; and two cystic lesions, 0.8 cm and 1.5 cm, in the right lobe of the liver. Which of the following infectious agents is most likely to produce these findings?
A Clonorchis sinensis
B Cryptosporidium parvum
C Cytomegalovirus
D Entamoeba histolytica
E Escherichia coli
(Robbins & Contran 4th ed) E. E.coli
"this patient has a history of gallstones and has developed an ascending cholangitis caused by Escherichia coli. These bacteria reach the liver by ascending the biliary tree. Obstruction from lithiasis is the most common risk factor. Development of cystic lesions in the right lobe of the liver suggests that the patient has developed liver abscesses. Clonorchis sinensis is a liver fluke that is endemic to East Asia, and it is a risk factor for biliary tract cancer. Cryptosporidi- osis in immunocompromised patients occasionally can occur in the biliary tract and elsewhere. Cytomegalovirus infection also can be seen in immunocompromised patients; it produces a clinical picture similar to that of hepatitis, but without biliary tract disease. A patient with amebiasis involving the liver is most likely to present with a history of diarrhea with blood and mucus.
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A 58-year-old man with a history of gallstones develops severe right upper quadrant pain, fever (103°F/39.4°C), jaundice, hypotension, and confusion. Laboratory studies show leukocytosis and elevated total bilirubin. Which of the following is the most urgent next step in management?
A. IV fluids and antibiotics
B. Abdominal ultrasound
C. ERCP
D. CT abdomen with contrast
E. Laparoscopic cholecystectomy
(perplexity) Answer: C. ERCP
Explanation: This patient has Reynolds’ pentad (Charcot’s triad + hypotension and confusion), indicating severe ascending cholangitis with sepsis. ERCP is the gold standard for urgent biliary decompression and source control. IV antibiotics (A) are critical but insufficient without drainage. Ultrasound (B) or CT (D) may identify the obstruction but delay definitive treatment. Cholecystectomy (E) is deferred until after ERCP and infection resolution.
Name at least 3 risk factors for developing gallstones.
4 F's. Fat, female, fertile (pregnancy), forty
A 55-year-old woman with a history of gallstones develops acute pancreatitis. Laboratory studies show hypocalcemia (7.2 mg/dL) and a serum lipase >5x normal. Which of the following pathophysiologic mechanisms explains her hypocalcemia?
A. Hyperparathyroidism
B. Vitamin D deficiency
C. Saponification of peripancreatic fat
D. Renal calcium wasting
E. Malabsorption due to pancreatic insufficiency
(perplexity) Answer: C. Saponification of peripancreatic fat
Explanation: Hypocalcemia in acute pancreatitis results from saponification, where calcium binds to free fatty acids released during fat necrosis. Hyperparathyroidism (A) causes hypercalcemia. Vitamin D deficiency (B) and malabsorption (E) are chronic issues. Renal calcium wasting (D) is unrelated to pancreatitis.
Which patient is at highest risk for developing cholangitis?
A. A 30-year-old woman with gallstones
B. A 50-year-old man with choledocholithiasis
C. A 40-year-old woman with nonalcoholic fatty liver disease
D. A 60-year-old man with hepatitis C cirrhosis
E. A 70-year-old woman with Gilbert syndrome
(perplexity) Answer: B (A 50-year-old man with choledocholithiasis).
Rationale: Biliary obstruction (e.g., choledocholithiasis) is the primary risk factor. Gallstones (A) alone do not cause cholangitis unless they obstruct the bile duct. NAFLD (C), HCV (D), and Gilbert syndrome (E) do not predispose to cholangitis.
A 41-year-old woman who works as a tattoo artist has had increasing malaise and nausea for the past 2 weeks. On physical examination, she has icterus and mild right upper quadrant tenderness. Laboratory studies show serum AST of 79 U/L, ALT of 85 U/L, total bilirubin of 3.3 mg/dL, and direct bilirubin of 2.5 mg/dL. She continues to have malaise for the next year. A liver biopsy is done, and microscopic examina-tion shows minimal hepatocyte necrosis, mild steatosis, and minimal portal bridging fibrosis. An infection with which of the following viruses is most likely to produce these findings?
A HAV
B HBV
C HCV
D HDV
E HEV
(Robbins & Cotran 4th ed.) HCV. Necrosis with portal bridging suggests chronic hepatitis. Mild steatosis is seen in HCV infection. The incidence of chronic hepatitis is highest with HCV infection. More than50% of individuals infected with this virus develop chronic hepatitis, and many cases progress to cirrhosis. This is partly because the IgG antibodies against HCV that develop after acute infection are not protective."
A 35-year-old man presents with severe pain following major surgery. He is prescribed a full μ-opioid receptor agonist. Which of the following is the most common serious adverse effect of this medication?
A. Hypertension
B. Respiratory depression
C. Hyperreflexia
D. Diarrhea
E. Tachycardia
(perplexity) Answer: B. Respiratory depression
Explanation: Full μ-opioid agonists (e.g., morphine, fentanyl) cause dose-dependent respiratory depression due to direct suppression of brainstem respiratory centers. Hypertension (A) and tachycardia (E) are uncommon (opioids may cause bradycardia). Hyperreflexia (C) occurs in opioid withdrawal. Diarrhea (D) is not typical (opioids cause constipation)
In which of the following pathologies would I see a direct increase in ALP, GGT, and bilirubin?
A.) Cholelithiasis
B.) Choledocholethiasis
C.) Cholecystitis
D.) Cilliary collic
B.) Choledocholethiasis (look at the anatomy)
A 40-year-old man with acute pancreatitis develops tachypnea, hypoxemia, and bilateral lung infiltrates. Which of the following is the most likely underlying mechanism for his respiratory findings?
A. Aspiration pneumonia
B. Acute respiratory distress syndrome (ARDS)
C. Pulmonary embolism
D. Pleural effusion
E. Chronic obstructive pulmonary disease (COPD) exacerbation
(perplexity)
Answer: B. Acute respiratory distress syndrome (ARDS)
Explanation: ARDS is a severe complication of acute pancreatitis due to systemic inflammation and cytokine release, leading to alveolar damage. Aspiration pneumonia (A) would present with focal infiltrates. Pulmonary embolism (C) causes hypoxia without infiltrates. Pleural effusion (D) is common but does not explain hypoxemia or infiltrates. COPD exacerbation (E) typically occurs in smokers and involves wheezing.
Rationale: These questions assess diagnosis (easy), pathophysiology (medium), and complications (hard) in acute pancreatitis, emphasizing NBME’s focus on clinical reasoning and mechanistic understanding.
Which cholangitis is assoicated with middle aged women, autoimmune disorders, increased IgM and anti-mitochandrial autoantibodies, along with hypercholesterolemia?
A. Primary sclerosing cholangitis
B. Ascending cholangitis
C. Primary billiary cholangitis/cirrhosis
D. Seconday cholangitis
(bootcamp) C. primary billiary cholangitis
Primary sclerosing cholangitis is associated with middle aged men, UC, increased IgM, p-ANACA, and concentric "onion skin"--> periductal fibrosis of intra and extrahepatic bile ducts. Ascending cholangitis is due to an acute bacterial infection, with the primary risk factor being choledocholithiasis. Secondary biliary cholangitis is an extra hepatic obstruction of the bile ducts that leads to ductal fibrosis and bile stasis.
A 44-year-old man has had increasing arthritis pain, swelling of the feet, and reduced exercise tolerance over the past 3 years. Laboratory studies include serum glucose of 201 mg/dL, creatinine of 1.1 mg/dL, and ferritin of 893 ng/mL. A chest radiograph shows bilateral pleural effusions, pulmonary edema, and cardiomegaly. He undergoes a liver biopsy; the microscopic appearance of a biopsy specimen stained with H&E (right panel) and Prussian blue (left panel) is shown in the figure. Based on these findings, which of the following is the most appropriate therapy for this patient?
A Cholecystectomy
B Interferon-α
C Phlebotomy
D Prednisone
E Reduce alcohol intake
( Robbins & Contran 4th ed) C. Phlebotomy.
This patient has clinical, histologic, and laboratory features of genetic hemochromatosis. In this condition, iron overload occurs because of excessive absorption of dietary iron.The absorbed iron is deposited in many tissues, including the heart, pancreas, and liver, giving rise to heart failure, diabetes, and cirrhosis. It appears blue with Prussian blue stain, as seen in this figure. High serum ferritin concentration is an indicator of a vast increase in body iron. Genetic hemochromatosis is an autosomal recessive condition; siblings are at risk of developing the same disease. Phlebotomy removes 250 mg of iron per unit of blood, and over time can reduce iron stores.
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A 50-year-old woman with a history of recurrent pyogenic cholangitis develops intrahepatic gallstones. Which of the following pathophysiologic mechanisms is most likely responsible for stone formation in this condition?
A. Estrogen-induced cholesterol hypersecretion
B. Bacterial β-glucuronidase deconjugating bilirubin
C. Bile acid malabsorption due to ileal resection
D. Autoimmune destruction of biliary epithelial cells
E. Chronic alcohol-induced pancreatic insufficiency
(perplexity) Answer: B. Bacterial β-glucuronidase deconjugating bilirubin
Explanation: Recurrent pyogenic cholangitis involves bacterial infection (e.g., E. coli), which secretes β-glucuronidase, deconjugating bilirubin glucuronides into insoluble unconjugated bilirubin. This binds calcium to form pigmented stones. Estrogen (A) drives cholesterol stones. Bile acid malabsorption (C) causes cholesterol supersaturation. Autoimmune destruction (D) is seen in PBC/PSC. Pancreatic insufficiency (E) does not directly cause gallstones.
Rationale: These questions assess risk factors (easy), stone composition (medium), and disease-specific pathophysiology (hard), emphasizing NBME’s focus on clinical relevance and mechanistic reasoning.
Name the two skin changes associated with acute pancreatitis and their associated distribution.
( Bootcamp) Cullen's sign (bruising around umbilicus) & grey Turner's sign (flank bruising)
A 50-year-old man with a history of ulcerative colitis develops recurrent episodes of jaundice and pruritus. MRCP shows multifocal strictures of the intrahepatic and extrahepatic bile ducts. Liver biopsy reveals concentric periductal fibrosis ("onion-skinning"). Which of the following is the most likely diagnosis?
A. Primary biliary cholangitis (PBC)
B. Primary sclerosing cholangitis (PSC)
C. Wilson disease
D. Hemochromatosis
E. Hepatitis B infection
(perplexity) Answer: B. Primary sclerosing cholangitis (PSC)
Explanation: PSC is strongly associated with ulcerative colitis and presents with multifocal bile duct strictures and periductal fibrosis on biopsy. PBC (A) affects small intrahepatic ducts and is linked to anti-mitochondrial antibodies. Wilson disease (C) and hemochromatosis (D) cause hepatocellular damage, not biliary strictures. Hepatitis B (E) elevates transaminases and does not cause "onion-skinning" fibrosis.
Rationale: These questions assess etiology (easy), antibiotic selection (medium), and disease associations (hard), reinforcing core concepts in cholangitis pathophysiology and management.