Which of the following is a characteristic of osteosarcoma?

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: In a thyroid crisis resulting from Graves' disease, the patient typically experiences symptoms such as hyperthermia (elevated body temperature) and tachycardia (rapid heart rate). These symptoms are indicative of the hypermetabolic state seen in thyroid storm. Choices A and D are incorrect as constipation and lethargy are not typical signs of a thyroid crisis; instead, patients with hyperthyroidism often experience diarrhea and agitation. Choice B is incorrect because bradycardia (slow heart rate) and bradypnea (slow breathing rate) are more commonly associated with hypothyroidism rather than a thyroid crisis in Graves' disease.

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: Truncal obesity with thin extremities is a classic manifestation of Cushing syndrome due to the redistribution of fat. Enlargement of face, hands, and feet is seen in conditions like acromegaly, not Cushing syndrome. Cachexia is a state of severe weight loss and muscle wasting, typically seen in conditions like cancer or advanced infections. Thick scalp hair is not typically associated with Cushing syndrome.

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: A

Rationale: The clinical findings of thin hair, exophthalmos (bulging eyes), hyperreflexia, and pretibial edema are classic manifestations of Graves disease, an autoimmune condition that results in hyperthyroidism. Choice B is incorrect because weight gain and constipation are more indicative of hypothyroidism, not hyperthyroidism seen in Graves disease. Choice C is incorrect as the symptoms described are more characteristic of hypothyroidism, not hyperthyroidism. Choice D is also incorrect as the symptoms listed are not consistent with Graves disease but rather suggest hypothyroidism.

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: B

Rationale: Neutrophils are the first responders to a bacterial infection. They are phagocytes that engulf and destroy bacteria, playing a crucial role in the early stages of the immune response. Eosinophils are primarily involved in combating parasitic infections and allergic reactions, not bacterial infections. Leukotrienes are signaling molecules that contribute to inflammation and immune responses, but they are not cells. Monocytes are another type of white blood cell that differentiates into macrophages and dendritic cells, playing a role in immune response but not as immediate as neutrophils.

Correct Answer: A

Rationale: The correct answer is A: live and can cause infection. Patients who are immunocompromised, like those receiving long-term steroids after an organ transplant, should not receive live vaccines because the live attenuated organisms in these vaccines can cause infections in individuals with weakened immune systems. Choice B is incorrect because attenuated vaccines are live but weakened, not mutated. Choice C is incorrect because while inactive, attenuated vaccines are not infectious. Choice D is incorrect because attenuated vaccines are not pathogenic; they are attenuated (weakened) forms of the pathogen.