A 65-year-old woman presents with difficulty swallowing, weight loss, and a history of long-standing heartburn. She has been on proton-pump inhibitors for years, but her symptoms have worsened. What is the most likely diagnosis?

Correct Answer: B

Rationale: The correct answer is B: Esophageal cancer. Given the patient's age, symptoms of difficulty swallowing and weight loss, along with a history of chronic heartburn not responding to proton-pump inhibitors, esophageal cancer is the most likely diagnosis. Esophageal cancer commonly presents with dysphagia, weight loss, and a history of chronic reflux. Peptic stricture (A) typically presents with dysphagia but is less likely given the worsening symptoms despite treatment. Achalasia (C) presents with dysphagia and regurgitation, but not typically with weight loss. Esophageal spasm (D) presents with chest pain and dysphagia, but not typically with weight loss or chronic heartburn.

Correct Answer: C

Rationale: The most likely diagnosis is primary sclerosing cholangitis (PSC) based on the patient's symptoms of fatigue, pruritus, jaundice, and elevated bilirubin and alkaline phosphatase levels. PSC is commonly associated with inflammatory bowel disease, such as ulcerative colitis. The characteristic findings of elevated alkaline phosphatase and bilirubin levels are indicative of cholestasis, which is a key feature of PSC. Additionally, PSC is characterized by fibrosis and inflammation of the bile ducts, leading to bile duct strictures and subsequent liver damage. Hepatitis B would present with viral hepatitis symptoms and different lab findings. Primary biliary cirrhosis typically presents with elevated alkaline phosphatase and antimitochondrial antibodies. Autoimmune hepatitis would have elevated transaminases and autoantibodies. Therefore, based on the clinical presentation and lab results, PSC 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: Hemochromatosis. In this case, the patient's symptoms of fatigue, arthralgia, darkening of the skin, elevated liver enzymes, and high serum ferritin levels point towards iron overload disorder. Hemochromatosis is a genetic condition characterized by excessive absorption and accumulation of iron in various organs, leading to liver damage and skin pigmentation. Wilson's disease (A) presents with copper accumulation, not iron. Alpha-1 antitrypsin deficiency (C) primarily affects the lungs and liver, not causing iron overload. Autoimmune hepatitis (D) does not typically present with elevated ferritin levels.

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.