Correct Answer: C

Rationale: The correct answer is C: Truncus arteriosus. In this condition, there is a single large vessel arising from the heart that gives rise to the systemic, pulmonary, and coronary arteries. This results in mixing of oxygenated and deoxygenated blood, leading to severe cyanosis and inadequate oxygenation of the body, causing immediate death after birth. A: Pulmonary stenosis and B: Aortic coarctation typically do not cause immediate death after birth. D: Ductus arteriosus is a normal fetal structure that closes shortly after birth and its presence would not directly cause immediate death.

Correct Answer: B

Rationale: The correct answer is B, Gestational diabetes mellitus. This condition is diagnosed when a pregnant woman exhibits symptoms of diabetes and has elevated fasting blood sugar and abnormal oral glucose tolerance test results. This specific combination of symptoms and test results during pregnancy points towards gestational diabetes mellitus. A: Potential diabetes mellitus - Incorrect. The symptoms combined with abnormal test results suggest an active condition, not potential. C: Clinical diabetes mellitus - Incorrect. While the symptoms and test results indicate diabetes, the context of pregnancy suggests gestational diabetes. D: Chemical diabetes mellitus - Incorrect. This term is not commonly used in medical practice and does not specifically address the condition in the given scenario.

Correct Answer: D

Rationale: The correct answer is D (>90%). Mr. Mettenberger had a reexpansion of his second spontaneous pneumothorax this year, indicating a high recurrence risk. Spontaneous pneumothorax recurrence rates are high, especially in young males. Factors such as smoking history, gender, and prior occurrences contribute to increased risk. Mr. Mettenberger's cessation of smoking reduces but does not eliminate the risk. Choices A, B, and C are too low, given his history and current situation. Choice D is the most appropriate due to the high likelihood of recurrence based on his medical history and risk factors.

Correct Answer: C

Rationale: The correct answer is C: Fever. Physiologic stress ulcers are often associated with systemic stress response, leading to an increase in body temperature. Fever is an early sign of stress-related ulcers before other symptoms like epigastric pain or hemorrhage manifest. Change in mental status is more indicative of neurological issues rather than stress ulcers. Epigastric pain typically occurs after the ulcer has progressed, and hemorrhage is a severe complication of untreated stress ulcers.

Correct Answer: B

Rationale: The correct answer is B (3000 ml) because polyhydramnios is defined as an excessive amount of amniotic fluid, typically exceeding 2000-2500 ml. A level of 3000 ml is commonly used as a cutoff point for clinical diagnosis. Choices A, C, and D are incorrect because they fall below the threshold typically considered diagnostic for polyhydramnios. Answer A (1500 ml) is too low, while choices C (1900 ml) and D (2500 ml) are below or at the lower end of the range typically associated with polyhydramnios. Therefore, the most appropriate threshold for diagnosing polyhydramnios is when the amount of amniotic fluid exceeds 3000 ml.