A 50-year-old man presents with severe epigastric pain radiating to his back, nausea, and vomiting. He has a history of heavy alcohol use. Laboratory tests reveal elevated serum amylase and lipase. What is the most likely diagnosis?

Correct Answer: C

Rationale: The correct answer is C: Acute pancreatitis. The patient's symptoms of severe epigastric pain radiating to the back, along with nausea, vomiting, and a history of heavy alcohol use, are classic for acute pancreatitis. Elevated serum amylase and lipase levels further support this diagnosis, as they are key markers of pancreatic inflammation. Acute cholecystitis (A) typically presents with right upper quadrant pain and fever. Peptic ulcer disease (B) is characterized by burning epigastric pain that improves with food intake. Gastroesophageal reflux disease (D) presents with heartburn and regurgitation, not the severe symptoms seen in this case.

Correct Answer: C

Rationale: The most likely diagnosis for the 28-year-old woman with abdominal pain, diarrhea, weight loss, mouth ulcers, and perianal fistula is Crohn's disease. Crohn's disease is characterized by inflammation that can occur anywhere in the digestive tract, leading to symptoms like abdominal pain, diarrhea, weight loss, mouth ulcers, and fistulas. Ulcerative colitis primarily affects the colon, not the entire digestive tract like in this case. Irritable bowel syndrome typically presents with abdominal pain and changes in bowel habits but not with fistulas. Diverticulitis is inflammation of pouches that can develop in the colon, but it does not typically present with mouth ulcers or fistulas.

Correct Answer: B

Rationale: The correct answer is B: Esophageal cancer. This patient's symptoms of difficulty swallowing solids and liquids, along with unintentional weight loss, are concerning for a malignancy like esophageal cancer. The progressive nature of dysphagia and significant weight loss are red flags for cancer. Esophageal stricture (A) can cause dysphagia but typically presents with a history of chronic inflammation or injury. Achalasia (C) is characterized by dysfunction of the lower esophageal sphincter, leading to dysphagia, but it is less likely in this case due to the weight loss. Peptic ulcer disease (D) usually presents with epigastric pain and can cause weight loss, but it is less likely to cause progressive dysphagia.

Correct Answer: B

Rationale: The most likely diagnosis is B: Primary biliary cirrhosis. This condition commonly presents with fatigue, pruritus, jaundice, elevated bilirubin, and alkaline phosphatase levels in older women. Primary biliary cirrhosis is an autoimmune liver disease that leads to destruction of bile ducts. The other choices are less likely because Hepatitis C typically presents with acute symptoms, Hemochromatosis presents with iron overload symptoms, and Wilson's disease presents with copper accumulation symptoms, which do not match the patient's clinical presentation.

Correct Answer: B

Rationale: The most likely diagnosis in this case is B: Mesenteric ischemia. Given the sudden onset of severe abdominal pain in an elderly patient with atrial fibrillation, mesenteric ischemia is a crucial consideration due to the risk of thromboembolism from the heart condition leading to inadequate blood supply to the intestines. Acute pancreatitis (A) typically presents with epigastric pain radiating to the back and elevated serum amylase/lipase levels. Peptic ulcer disease (C) usually presents with a history of dyspepsia and is less likely to cause sudden severe abdominal pain. Diverticulitis (D) commonly presents with left lower quadrant pain and tenderness, which contrasts with the soft abdomen and minimal tenderness seen in this case.