A 70-year-old woman has difficulty with driving, and she has been frequently getting lost. Her husband said she has also been acting strange and seems to want to sleep a lot. He said the other night she kept saying she was seeing animals such as lions in her room. He says her memory is not too bad, but he is very concerned about her health. Physical examination reveals an alert woman with stable vital signs. Bradykinesia and limb rigidity are noted. These findings are consistent with:

Correct Answer: C

Rationale: The symptoms described in the scenario, such as visual hallucinations, fluctuations in cognition, and parkinsonism (bradykinesia and limb rigidity), are classic features of dementia with Lewy bodies (DLB). DLB is characterized by the presence of Lewy bodies in the brain, which are abnormal protein deposits. Alzheimer's disease (Choice A) typically presents with memory loss as a predominant symptom, which is not a major concern in this case. Vascular dementia (Choice B) is associated with a history of cerebrovascular disease and is not supported by the symptoms described. Frontotemporal dementia (Choice D) usually presents with changes in behavior and personality, rather than the symptoms described in the scenario.

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: B

Rationale: Muscular dystrophy is primarily caused by mutations in the gene that provides instructions for making the protein dystrophin. Dystrophin plays a crucial role in maintaining the structure of muscle fibers. Glycoprotein is a general term for proteins with sugar molecules attached, not specifically related to muscular dystrophy. Troponin is a protein involved in muscle contraction regulation, and actinomyosin is not a specific muscle protein but a complex formed during muscle contraction. Therefore, the correct answer is dystrophin.

Correct Answer: C

Rationale: Osteosarcoma is an aggressive bone tumor that most commonly arises in the bone marrow of long bones, such as the femur or tibia. Choice A is incorrect as osteosarcoma is not a slow-growing tumor but rather a fast-growing one. Choice B is incorrect as osteosarcoma is not typically solitary but can involve multiple lesions. Choice D is incorrect as osteosarcoma primarily affects the medullary (marrow) cavity of bones, rather than infiltrating the trabeculae in spongy bone and surrounding tissue.

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.