A 28-year-old presents with left-sided pleuritic chest pain exacerbated by lying flat and relieved on leaning forward. Which of the following is the most likely diagnosis?

Correct Answer: B

Rationale: The most likely diagnosis for the given presentation is Gastro-oesophageal reflux disease (GERD). The chest pain exacerbated by lying flat and relieved by leaning forward is typical of GERD due to acid reflux when lying down. Angina and myocardial infarction typically present with exertional chest pain, while pulmonary embolism presents with sudden onset pleuritic chest pain often associated with shortness of breath. Therefore, the correct answer is B.

Correct Answer: A

Rationale: The correct answer is A: Right-sided heart failure secondary to lung disease. In cor pulmonale, chronic lung disease such as COPD leads to pulmonary hypertension, which in turn causes the right side of the heart to work harder and eventually fail. This is because the right side of the heart pumps blood to the lungs to pick up oxygen, and when the lungs are diseased, the heart has to pump harder to maintain adequate blood flow. Choices B, C, and D are incorrect because they do not accurately describe cor pulmonale. Left-sided heart failure (choice B) is not directly related to lung disease, whereas lung disease secondary to left-sided heart failure (choice C) and lung disease secondary to right-sided heart failure (choice D) are not accurate descriptions of cor pulmonale.

Correct Answer: D

Rationale: The correct answer is D: Idiopathic. Idiopathic pulmonary fibrosis (IPF) is the most common type of pulmonary fibrosis with unknown cause. It is a chronic, progressive, and irreversible lung disease. Iatrogenic causes refer to those induced by medical treatment, which are not as common as IPF. Occupational chemical exposure and sarcoidosis are known causes of pulmonary fibrosis, but they are not as prevalent as idiopathic cases. In summary, the most common cause of pulmonary fibrosis is idiopathic, followed by occupational exposures, sarcoidosis, and iatrogenic factors.

Correct Answer: B

Rationale: The correct answer is B: Misoprostol is superior to an H2-blocker in prophylaxis against NSAID-related GI toxicity. Misoprostol, a prostaglandin analog, helps protect the gastric mucosa by increasing mucus production and decreasing acid secretion. This makes it more effective than H2-blockers, which only reduce acid production. Choice A is incorrect because proton-pump inhibitors are more effective than H2-blockers in preventing NSAID-related GI toxicity. Choice C is incorrect as sucralfate is not recommended for prophylaxis against NSAID-related GI toxicity. Choice D is incorrect because H. pylori infection significantly increases the risk of NSAID-induced ulcers.

Correct Answer: B

Rationale: The correct answer is B: Proton-pump inhibitor. The patient's symptoms of chest pain and dysphagia are suggestive of gastroesophageal reflux disease (GERD). Proton-pump inhibitors (PPIs) are the first-line therapy for GERD as they reduce gastric acid secretion, alleviating symptoms and promoting healing of esophageal mucosa. Sucralfate is not effective for GERD symptoms. Prokinetic agents are used for motility disorders, not GERD. Benzodiazepines are not indicated for GERD and may even exacerbate symptoms. Therefore, the most appropriate initial therapy for this patient is a proton-pump inhibitor.