Correct Answer: C

Rationale: The correct answer is dark urine. Rhabdomyolysis is a condition characterized by the breakdown of muscle tissue, leading to the release of myoglobin into the bloodstream. Myoglobin can cause the urine to appear dark or tea-colored, a condition known as myoglobinuria. This is a classic symptom of rhabdomyolysis. Choices A, B, and D are incorrect as they do not typically present as direct symptoms of rhabdomyolysis. Paresthesias refer to abnormal sensations like tingling or numbness, bone pain is not a primary symptom of rhabdomyolysis, and diarrhea is not a common complaint associated with this condition.

Correct Answer: D

Rationale: The correct answer is that ductal carcinoma in situ is characterized by malignant cells that have not invaded the stroma, making it a cancer precursor with a higher risk for invasive cancer compared to lobular carcinoma in situ. Choice A is incorrect because ductal carcinoma in situ is more common than lobular carcinoma in situ. Choice B is incorrect as it only partially describes ductal carcinoma in situ without mentioning its potential for progression to invasive cancer. Choice C is incorrect because it does not capture the complete characteristics of ductal carcinoma in situ, which include the risk for invasive cancer.

Correct Answer: B

Rationale: The correct answer is that the person is a sickle cell carrier. In HbAS, 'Hb' stands for hemoglobin, 'A' indicates normal hemoglobin, and 'S' indicates the sickle cell trait. Individuals with HbAS are carriers of the sickle cell trait but do not have sickle cell disease. Choice A is incorrect because having the sickle cell trait means carrying the gene for sickle cell disease. Choice C is incorrect as sickle cell anemia is a different condition where individuals have two copies of the abnormal hemoglobin gene, resulting in the disease. Choice D is incorrect because thalassemia is a separate genetic disorder affecting the production of hemoglobin, not related to the sickle cell trait.

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.

Correct Answer: C

Rationale: In nephritic syndrome, the presence of red blood cell casts in the urine is a characteristic finding, reflecting glomerular inflammation and damage. This differentiates it from nephrotic syndrome, where red blood cell casts are typically absent. Choice A is incorrect because nephritic syndrome usually presents with less albuminuria compared to nephrotic syndrome. Choice B is incorrect as hematuria is a common feature of nephritic syndrome. Choice D is incorrect as hypoalbuminemia is more commonly associated with nephrotic syndrome.