Correct Answer: B

Rationale: The correct answer is B: Lung cancer. The patient's symptoms of chronic smoking, persistent cough, and weight loss are concerning for malignancy. Lung cancer is a common consequence of long-term smoking and can present with these symptoms. Chronic bronchitis (A) typically presents with cough and mucus production but not necessarily weight loss. Emphysema (C) is characterized by shortness of breath and is less likely to cause weight loss. Asthma (D) usually presents with wheezing and shortness of breath, not typically weight loss.

Correct Answer: A

Rationale: The correct answer is A because in an older adult with an indwelling urinary catheter, a fever >100°F can be a sign of urinary tract infection (UTI) or urosepsis. Given her acute decline in mental status and fever, empiric antibiotic therapy is warranted to treat a potential infection. Choice B is incorrect because older adults with indwelling catheters are at increased risk for UTIs and bloodstream infections. Choice C is incorrect as obtaining a urine culture is important to confirm the diagnosis and guide appropriate antibiotic therapy. Choice D is incorrect as the duration of antibiotic treatment for a UTI is typically longer than 3 days.

Correct Answer: B

Rationale: The correct answer is B: One breast larger than the other is most likely benign on breast examination. This is because breast asymmetry is a common and typically benign finding in women. It is important to note that a significant difference in breast size may warrant further evaluation, but in general, slight variations in size are normal. Now, let's discuss why the other choices are incorrect: A: Dimpling of the skin resembling that of an orange is concerning for peau d'orange appearance, which can be a sign of underlying breast cancer. C: One nipple inverted can be a sign of an underlying breast issue, such as a mass or tumor. D: One breast with a dimple when the patient leans forward can be a sign of an underlying breast abnormality, such as a tumor pulling on the skin. In summary, breast asymmetry (Choice B) is the most likely benign finding, while the other choices may indicate underlying breast issues that require further evaluation.

Correct Answer: B

Rationale: The correct answer is B: Funnel chest (pectus excavatum). Pectus excavatum is characterized by a depressed or sunken appearance of the sternum, which matches the description provided in the case. In this condition, the chest wall is abnormally shaped inward. This can be a congenital condition or develop during growth spurts in adolescence. The lack of symptoms such as shortness of breath, chest pain, or lightheadedness on exertion is consistent with pectus excavatum, as these symptoms are not typically associated with this condition. The other choices (A: Barrel chest, C: Pigeon chest, D: Thoracic kyphoscoliosis) do not match the specific findings described in the case and are not associated with the characteristic sternal depression seen in pectus excavatum.

Correct Answer: B

Rationale: The correct answer is B: Clonus. Clonus is a series of rhythmic, involuntary muscle contractions and relaxations that occur due to an abnormal response in the stretch reflex. In patients with neurological conditions like cerebral palsy, clonus is often observed due to increased muscle tone. Tremor (A) is a rhythmic shaking movement, not specifically associated with muscle contractions. Spasm (C) is a sudden, involuntary muscle contraction that is not typically rhythmic. Fasciculation (D) is a brief, spontaneous contraction of a small number of muscle fibers, not the rhythmic pattern seen in clonus.