Correct Answer: A

Rationale: The correct answer is A. Alpha-1 antitrypsin deficiency is a genetic condition that can lead to COPD at a young age, even in light smokers. Choice B is less likely as the patient's occupation does not directly correlate with alpha-1 antitrypsin deficiency. Choice C, a 70-year-old woman with a long smoking history, is more likely to have COPD due to smoking rather than alpha-1 antitrypsin deficiency. Choice D, exposure to secondhand smoke, is not a common cause of alpha-1 antitrypsin deficiency-related COPD.

Correct Answer: C

Rationale: Thyroid crisis in Graves' disease typically presents with hyperthermia (high body temperature) and tachycardia (rapid heart rate). These symptoms are a result of excessive thyroid hormone production and can lead to life-threatening complications if not promptly addressed. Choices A, B, and D are incorrect because constipation with gastric distension, bradycardia and bradypnea, and constipation and lethargy are not typical signs of a thyroid crisis in Graves' disease.

Correct Answer: B

Rationale: The correct answer is B: Underexcretion of uric acid. Gouty arthritis is primarily caused by the underexcretion of uric acid, leading to its accumulation in joints and subsequent crystallization. Choices A, C, and D are incorrect as they do not directly relate to the pathophysiology of gout. Destruction of proteoglycans, overexcretion of uric acid, and increased absorption of uric acid are not primary causes of gouty arthritis.

Correct Answer: A

Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia and neurological symptoms, including lower extremity paresthesias. Folate deficiency can also cause megaloblastic anemia but typically does not present with neurological symptoms. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with coagulation abnormalities, not megaloblastic anemia.

Correct Answer: B

Rationale: In chronic kidney disease, anemia commonly occurs due to decreased erythropoietin production. Erythropoiesis-stimulating agents, such as erythropoietin or darbepoetin, are the mainstay of treatment to stimulate red blood cell production. Iron supplementation is more appropriate for iron-deficiency anemia, not the anemia of chronic kidney disease. Blood transfusion is reserved for severe cases or acute blood loss. Vitamin B12 supplementation is indicated for megaloblastic anemia caused by vitamin B12 deficiency, not specifically in chronic kidney disease-related anemia.