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 correct answer is B: Gastro-oesophageal reflux disease. This is known as the classic presentation of pericarditis. The pain worsens when lying flat due to increased pressure on the inflamed pericardium, and improves when leaning forward, reducing pressure. Angina (A) typically presents with exertional chest pain, not worsened by lying flat. Myocardial infarction (C) presents with crushing chest pain, not positional like pericarditis. Pulmonary embolism (D) presents with sudden onset dyspnea and chest pain, not exacerbated by lying flat.

Correct Answer: A

Rationale: The correct answer is A because cor pulmonale refers to right-sided heart failure caused by lung disease. In chronic obstructive pulmonary disease (COPD), the lungs are diseased, leading to pulmonary hypertension and subsequent strain on the right side of the heart. This results in right ventricular hypertrophy and eventually right-sided heart failure. Choice B is incorrect because left-sided heart failure is not the primary cause of cor pulmonale in COPD. Choice C is incorrect as it suggests that lung disease is secondary to left-sided heart failure, which is not the case in cor pulmonale. Choice D is also incorrect as it implies that lung disease leads to right-sided heart failure, which is the opposite of the actual relationship in cor pulmonale.

Correct Answer: D

Rationale: The correct answer is D: Idiopathic. Idiopathic pulmonary fibrosis is the most common cause of pulmonary fibrosis, accounting for about 20-30% of cases. It is a chronic and progressive lung disease of unknown cause. Other choices are less common causes: A) Iatrogenic refers to fibrosis caused by medical interventions, B) Occupational chemical exposure can lead to fibrosis but is not the most common cause, and C) Sarcoidosis causes granulomatous inflammation, not fibrosis.

Correct Answer: B

Rationale: The correct answer is B: Misoprostol is superior to an H2-blocker in prophylaxis against NSAID-related GI toxicity. Misoprostol is a prostaglandin analog that helps protect the stomach lining, reducing the risk of NSAID-induced ulcers. H2 blockers only reduce acid production and do not address the underlying mechanism of NSAID-induced injury. Sucralfate does not provide as effective prophylaxis as misoprostol. H. pylori infection can increase the risk of NSAID-induced ulcers; eradication of H. pylori can reduce this risk.

Correct Answer: B

Rationale: The correct answer is B: Proton-pump inhibitor. The patient's symptoms of chest pain and dysphagia suggest possible gastroesophageal reflux disease (GERD). Proton-pump inhibitors reduce gastric acid production, providing relief for symptoms of GERD. This is the most appropriate initial therapy given the symptoms. Choice A: Sucralfate is a cytoprotective agent that forms a protective barrier over ulcers but does not address the underlying issue of acid reflux. Choice C: Prokinetic agents help with motility disorders but are not the first-line treatment for GERD. Choice D: Benzodiazepines are not indicated for the treatment of GERD and would not address the underlying cause of the patient's symptoms.