Correct Answer: D

Rationale: The correct answer is Hemangiomas, congenital dermal melanocytosis (i.e., Mongolian spots), and macular stains. These three types of birthmarks are known to fade or regress as the child gets older. Hemangiomas are vascular birthmarks that often shrink and disappear over time. Congenital dermal melanocytosis, commonly known as Mongolian spots, usually fade by adolescence. Macular stains, also called salmon patches, tend to lighten and fade as a child grows. The other choices are incorrect because they do not typically fade or regress with age.

Correct Answer: B

Rationale: In this scenario, the rising lactic acid levels in a 65-year-old man after a coronary artery bypass graft could indicate bowel ischemia. Bowel ischemia can lead to anaerobic metabolism, causing an increase in lactic acid levels. Excessive sedation may cause respiratory depression but would not directly lead to rising lactic acid levels. Excessive volume infusion in the operating room might cause fluid overload but would not typically result in rising lactic acid levels. Mild hypothermia postoperatively could lead to shivering and increased oxygen consumption, but it is less likely to be the primary cause of rising lactic acid levels in this context.

Correct Answer: A

Rationale: Alpha-1 antitrypsin deficiency is a genetic cause of chronic obstructive pulmonary disease (COPD). It is more common in younger patients with a history of smoking at a younger age, like the 30-year-old who has smoked for 3 years. Choices B, C, and D are less likely to be associated with alpha-1 antitrypsin deficiency as COPD in these cases is more likely due to smoking and environmental exposures.

Correct Answer: A

Rationale: Abrupt withdrawal or discontinuation of prednisone, a corticosteroid, can lead to adrenal crisis. This occurs due to the suppression of the adrenal glands' natural cortisol production caused by prolonged exogenous steroid administration. Adrenal crisis presents with symptoms such as weakness, fatigue, abdominal pain, and hypotension. Hypercortisolism (Cushing syndrome) results from chronic excessive exposure to cortisol, not abrupt withdrawal. ACTH stimulation would be expected in response to low cortisol levels, not as a direct consequence of prednisone withdrawal. Thyroid crisis (thyroid storm) is associated with severe hyperthyroidism and is not directly related to corticosteroid withdrawal.

Correct Answer: B

Rationale: Multiple dark bands on the nails can be associated with malignant melanoma, a serious type of skin cancer. While dark bands on the nails can sometimes be a normal variant, they should not be ignored as they could also be a sign of a serious condition like melanoma. Nail fungus typically presents with different symptoms such as thickened, discolored, or brittle nails. Dark bands on the nails are not directly associated with aging.