A 40-year-old woman presents with a history of chronic constipation, bloating, and abdominal pain. She notes that the pain is relieved with defecation. She denies any weight loss, blood in her stools, or nocturnal symptoms. Physical examination and routine blood tests are normal. What is the most likely diagnosis?

Correct Answer: B

Rationale: The correct answer is B: Irritable bowel syndrome (IBS). The key clues in the question are chronic constipation, bloating, abdominal pain relieved with defecation, and absence of alarming symptoms. These symptoms align with the Rome IV criteria for IBS. Inflammatory bowel disease (A) typically presents with more severe symptoms, including weight loss and blood in stools. Celiac disease (C) is associated with malabsorption symptoms and autoimmune features, not typically seen in this case. Lactose intolerance (D) presents with symptoms after consuming dairy, which is not mentioned in the patient's history. Therefore, based on the clinical presentation and exclusion of other conditions, the most likely diagnosis is IBS.

Correct Answer: B

Rationale: The correct answer is B: Achalasia. The presentation of difficulty swallowing, weight loss, regurgitation of undigested food, and 'bird beak' appearance on barium swallow are classic for achalasia. In achalasia, there is impaired relaxation of the lower esophageal sphincter and absent peristalsis in the esophagus. This leads to functional obstruction and dilation of the esophagus, causing the characteristic 'bird beak' appearance. Incorrect Choices: A: Esophageal cancer typically presents with progressive dysphagia, weight loss, and may show a mass or stricture on imaging. C: Peptic stricture is usually seen in patients with long-standing gastroesophageal reflux disease or esophagitis. Symptoms are often related to acid reflux. D: Gastroesophageal reflux disease commonly presents with heartburn, regurgitation, and chest pain. It does not typically cause weight loss or the 'bird

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.