A 70-year-old man presents with weight loss, jaundice, and a palpable mass in the right upper quadrant. Laboratory tests reveal elevated bilirubin and alkaline phosphatase levels. What is the most likely diagnosis?

Correct Answer: C

Rationale: The most likely diagnosis in this case is pancreatic cancer (Choice C) based on the constellation of symptoms including weight loss, jaundice, palpable mass in the right upper quadrant, and elevated bilirubin and alkaline phosphatase levels. These findings are indicative of a pancreatic head mass causing obstruction of the common bile duct, leading to jaundice and elevated liver enzymes. Gallstones (Choice A) typically present with colicky pain, not a palpable mass. Hepatitis (Choice B) would present with different liver enzyme patterns and usually lacks a palpable mass. Primary biliary cirrhosis (Choice D) typically presents with pruritus and fatigue, not a palpable mass and jaundice.

Correct Answer: D

Rationale: The correct answer is D: Crohn's disease flare. Given the patient's history of Crohn's disease, symptoms of abdominal pain, diarrhea, weight loss, and abnormal lab findings (low hemoglobin, elevated ESR) are indicative of a flare-up of Crohn's disease. This is supported by the clinical presentation and the lab results. Ulcerative colitis (A) presents differently with rectal bleeding and mucous diarrhea. Irritable bowel syndrome (B) does not typically cause weight loss or abnormal lab findings. Celiac disease (C) would present with malabsorption symptoms and specific antibodies, not consistent with this patient's presentation. Crohn's disease flare (D) is the most likely diagnosis based on the information provided.

Correct Answer: A

Rationale: The most likely diagnosis for the 45-year-old woman with fatigue, pruritus, jaundice, elevated bilirubin and alkaline phosphatase levels, and dilated intrahepatic bile ducts is Primary Biliary Cirrhosis (PBC). PBC is an autoimmune liver disease that primarily affects middle-aged women, leading to bile duct destruction and liver damage. The elevated alkaline phosphatase levels and presence of pruritus are typical in PBC due to impaired bile flow. Imaging showing dilated intrahepatic bile ducts supports the diagnosis of PBC as it indicates bile duct damage. Summary of other choices: B: Primary sclerosing cholangitis typically presents with strictures and beading of bile ducts on imaging. C: Gallstones would typically present with a common bile duct obstruction and not dilated intrahepatic bile ducts. D: Pancreatic cancer would typically present with different imaging findings and symptoms such as

Correct Answer: B

Rationale: The most likely diagnosis is Celiac disease (Choice B) due to the patient's symptoms of abdominal pain, bloating, diarrhea, and improvement with fasting, which are consistent with malabsorption seen in Celiac disease. The history of iron deficiency anemia also supports this, as it is a common complication of Celiac disease due to impaired absorption of nutrients. Irritable bowel syndrome (Choice A) typically does not improve with fasting, lactose intolerance (Choice C) does not usually cause iron deficiency anemia, and Crohn's disease (Choice D) typically presents with more severe symptoms and different patterns of improvement.

Correct Answer: A

Rationale: The most likely diagnosis for a 60-year-old man with fatigue, polyuria, polydipsia, hyperglycemia, and ketonuria is Type 1 diabetes mellitus. The key clues are the presence of ketonuria, which indicates the body is breaking down fats for energy due to lack of insulin in Type 1 diabetes. Additionally, the acute onset of symptoms in an older individual suggests an autoimmune destruction of pancreatic beta cells seen in Type 1 diabetes. Type 2 diabetes is less likely due to the acute presentation and ketonuria. Diabetes insipidus presents with polyuria but not hyperglycemia or ketonuria. Hyperthyroidism typically presents with symptoms such as weight loss, tremors, and heat intolerance, not the classic symptoms seen in this case.