MSN 570 Advanced Pathophysiology Final 2024

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: C

Rationale: Multiple sclerosis is characterized by the immune system mistakenly attacking the myelin sheath in the central nervous system. This results in the formation of lesions that can occur in different parts of the central nervous system, leading to varied symptoms depending on the location of the damage. Choice A is the correct answer because it accurately describes the pathophysiology of multiple sclerosis. Choices B, C, and D are incorrect because they describe mechanisms or locations that are not associated with the pathogenesis of multiple sclerosis.

Correct Answer: B

Rationale: The correct answer is 'Herpes simplex I virus.' This disorder is known as Staphylococcal scalded skin syndrome (SSSS), where a Staphylococcus aureus organism produces an exfoliative toxin leading to skin exfoliation and large blister formation. Choices B, C, and D are incorrect. Herpes simplex viruses (I and II) cause different types of skin lesions and do not lead to exfoliation and blister formation. Necrotizing fasciitis is a severe soft tissue infection, while cellulitis is a bacterial skin infection that does not typically involve exfoliation and blister formation like in SSSS.

Correct Answer: D

Rationale: The correct answer is 'chronic gout.' Chronic gout is characterized by the presence of tophi, which are large, hard nodules that can develop around joints like toes and elbows. These tophi are a sign of longstanding, untreated gout. Choice A, 'asymptomatic,' is incorrect as the presence of tophi indicates a symptomatic phase. Choice B, 'acute flare,' is incorrect as acute flares are characterized by sudden and severe pain, inflammation, and redness in the joints, not the development of tophi. Choice C, 'the intercritical period,' is also incorrect as this phase occurs between acute attacks and is typically asymptomatic, without the presence of tophi.

Correct Answer: A

Rationale: In this scenario, the correct answer is the 55-year-old man with new onset headaches that worsen at night and reported mood swings according to his family. These symptoms, especially when combined with nighttime worsening and mood changes, could indicate a serious underlying disorder such as a brain tumor or increased intracranial pressure. Choice B is incorrect as the unilateral throbbing headache with photophobia and nausea is suggestive of migraine headaches, which are usually not associated with serious underlying disorders. Choice C describes symptoms that are more indicative of tension-type headaches rather than a serious underlying disorder. Choice D presents symptoms that are more likely related to hormonal changes and migraines rather than a serious underlying disorder.