A 34-year-old woman presents with intermittent abdominal pain, bloating, and diarrhea. She notes that her symptoms improve with fasting. She has a history of iron deficiency anemia. What is the most likely diagnosis?

Correct Answer: B

Rationale: The correct answer is B: Celiac disease. The patient's symptoms of abdominal pain, bloating, diarrhea, and improvement with fasting are classic for celiac disease, an autoimmune condition triggered by gluten ingestion. Her iron deficiency anemia can be attributed to malabsorption common in celiac disease. Irritable bowel syndrome (A) typically presents with abdominal pain relieved by defecation, not fasting. Lactose intolerance (C) results in symptoms after consuming dairy, not necessarily improved by fasting. Crohn's disease (D) may present similarly, but the improvement with fasting and iron deficiency anemia point more towards celiac disease in this case.

Correct Answer: B

Rationale: The correct answer is B: Hyperthyroidism. In this case, the low TSH and high free T4 levels indicate overproduction of thyroid hormones, leading to symptoms like fatigue, weight gain, and constipation. Low TSH is a result of negative feedback due to high T4 levels. Hyperthyroidism is characterized by an overactive thyroid gland, resulting in excess thyroid hormone production. Other choices are incorrect because hypothyroidism would show high TSH levels, thyroiditis typically presents with thyroid tenderness and inflammation, and thyroid cancer usually does not cause these hormonal imbalances.

Correct Answer: A

Rationale: The correct answer is A: Ulcerative colitis. This chronic inflammatory condition affects the colon and rectum, leading to symptoms like abdominal pain, diarrhea, and rectal bleeding. The patient's recurrent episodes and history of similar symptoms point towards ulcerative colitis. Irritable bowel syndrome (choice B) typically presents with abdominal pain, bloating, and changes in bowel habits but not rectal bleeding. Celiac disease (choice C) presents with gastrointestinal symptoms after consuming gluten. Diverticulitis (choice D) presents with localized abdominal pain and fever due to inflammation or infection of the diverticula, not typically with rectal bleeding.

Correct Answer: C

Rationale: The most likely diagnosis for a 65-year-old man with weight loss, jaundice, palpable mass in the right upper quadrant, elevated bilirubin, and alkaline phosphatase levels is pancreatic cancer. This is because the symptoms and findings are classic for pancreatic cancer, which commonly presents with obstructive jaundice due to compression of the common bile duct by the tumor. Weight loss is also a common symptom of pancreatic cancer. Gallstones typically present with acute episodes of biliary colic, not a palpable mass. Hepatitis typically presents with elevated liver enzymes, but not a palpable mass. Primary biliary cirrhosis presents with chronic cholestasis and autoimmune features, not a palpable mass.

Correct Answer: A

Rationale: The most likely diagnosis for a 40-year-old woman presenting with fatigue, polyuria, polydipsia, hyperglycemia, and ketonuria is Type 1 diabetes mellitus. 1. Age: Type 1 diabetes commonly presents at a younger age. 2. Symptoms: Polyuria, polydipsia, fatigue are classic symptoms of uncontrolled diabetes. 3. Laboratory tests: Hyperglycemia and ketonuria indicate insulin deficiency. 4. Clinical presentation: Presence of ketonuria suggests metabolic derangement due to lack of insulin. In summary, Type 1 diabetes is the correct choice due to the age of the patient, symptoms, laboratory findings, and clinical presentation. Diabetes insipidus (choice C) presents with polyuria and polydipsia but lacks hyperglycemia and ketonuria. Type 2 diabetes (choice B) typically presents at an older age and rarely with ketonuria. Hyperthyroidism (choice D)