Which of the following is a factor that leads to increased risk for dehydration in the elderly?

Correct Answer: C

Rationale: The correct answer is C: Decline in kidney function. As people age, their kidneys may not work as effectively in conserving water and concentrating urine, leading to a higher risk of dehydration. Choice A is incorrect because more insensible losses do not directly relate to an increased risk of dehydration in the elderly. Choice B, an increase in muscle mass, is not a factor that leads to dehydration. Choice D, a decrease in fat, is also not a direct factor contributing to dehydration in the elderly.

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.

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: 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: A

Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of abnormally large and immature red blood cells. Lower extremity paresthesias, such as tingling or numbness, are common neurological symptoms associated with vitamin B12 deficiency. Folate deficiency can also cause megaloblastic anemia but is not typically linked to lower extremity paresthesias. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with bleeding tendencies, not megaloblastic anemia or paresthesias.

Correct Answer: B

Rationale: The correct answer is B: Underexcretion of uric acid. In gouty arthritis, the crystallization within the synovial fluid of the affected joint is caused by the underexcretion of uric acid, leading to the accumulation and subsequent crystallization of urate crystals. Choice A, destruction of proteoglycans, is incorrect as it is not directly related to the crystallization process in gouty arthritis. Choice C, overexcretion of uric acid, is incorrect because gout is primarily associated with underexcretion or decreased excretion of uric acid rather than overexcretion. Choice D, increased absorption of uric acid, is also incorrect as the primary issue in gouty arthritis is the body's inability to properly eliminate uric acid.

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: C

Rationale: The correct answer is Computed tomography (CT) scan. When screening for lung cancer, CT scans are recommended over chest X-rays due to their higher sensitivity in detecting lung nodules and early-stage cancers. Pulmonary function tests are not used for screening lung cancer but rather to assess lung function. Magnetic resonance imaging is not the preferred imaging modality for routine lung cancer screening, as CT scans are more commonly used.

Correct Answer: B

Rationale: The correct answer is 'Both an adult male with a history of alcoholism and a middle-aged male who smokes a pipe.' Alcohol consumption and tobacco use, such as smoking a pipe, are well-known risk factors for developing oral cancer. These two factors significantly increase the likelihood of developing oral cancer compared to the other choices. Taking oral contraceptives, eating spicy foods regularly, and chewing gum frequently are not established risk factors for oral cancer, making them less likely to lead to the development of this type of cancer.