Autoimmune hemolytic anemia is a group of disorders characterized by a malfunction of the immune system. Patients with this disorder produce autoantibodies that attack red blood cells as if they were substances foreign to the body. Which of the following causes about half of all cases of autoimmune hemolytic anemia?

Correct Answer: D

Rationale: The correct answer is D: An undetermined cause. Autoimmune hemolytic anemia often has an idiopathic or unknown cause. Here's a rationale: 1. Autoimmune hemolytic anemia is a complex disorder with various underlying mechanisms, making it challenging to pinpoint a single cause. 2. While some cases may be associated with certain factors like drug use (choice C) or coexisting autoimmune disorders (choice B), these do not account for most cases. 3. Genetic anomalies (choice A) may play a role in some instances, but they do not universally cause autoimmune hemolytic anemia. 4. Choice D is the most appropriate as it acknowledges the complexity of the disorder and the fact that a significant portion of cases lack a clear, identifiable cause.

Correct Answer: D

Rationale: The correct answer is D: Blood clotting factor transfusions. This is the appropriate treatment for bleeding episodes in people with hemophilia as they lack certain clotting factors. Transfusing these missing clotting factors helps to stop the bleeding. Explanation: 1. Aspirin (Choice A) is not recommended for hemophilia patients as it can increase the risk of bleeding due to its antiplatelet effects. 2. Blood clotting drugs (Choice B) may not be as effective as transfusions of specific clotting factors in treating bleeding episodes in hemophilia. 3. Gene therapy (Choice C) is a promising treatment for hemophilia, but it is not yet widely available and may not be the immediate solution for acute bleeding episodes.

Correct Answer: A

Rationale: The correct answer is A: Inadequate production of Hb. Anemia is classified based on the underlying mechanism causing decreased hemoglobin levels. Inadequate production of hemoglobin is one of the classifications, encompassing conditions like iron deficiency anemia. Decreased RBC production (choice B) is a broader classification that includes various causes like bone marrow disorders. Increased erythrocyte destruction (choice C) refers to hemolytic anemias where red blood cells are destroyed prematurely. Blood loss (choice D) is a separate classification related to acute or chronic bleeding. Therefore, the correct answer specifically addresses the primary issue of insufficient hemoglobin production in anemia.

Correct Answer: B

Rationale: The correct answer is B: FALSE. Aplasia is not directly caused by riboflavin deficiency. Aplasia refers to the failure of an organ or tissue to develop or function normally, while riboflavin deficiency is associated with conditions like glossitis and cheilosis, not aplasia. Riboflavin deficiency primarily affects mucous membranes and skin, not organ development. Therefore, there is no direct causal relationship between riboflavin deficiency and aplasia. Choices A, C, and D are incorrect as they suggest a potential link between riboflavin deficiency and aplasia, which is not supported by scientific evidence.

Correct Answer: D

Rationale: The correct answer is D: 2 and 3. Clopidogrel and dipyridamole are commonly used as prophylaxis for cardiovascular effects. Clopidogrel is an antiplatelet agent that helps prevent blood clots, reducing the risk of heart attacks and strokes. Dipyridamole is a vasodilator that helps widen blood vessels, improving blood flow and reducing the workload on the heart. Ticlopidine, on the other hand, is not commonly used due to its side effects and potential for serious complications. Therefore, choices A, B, and C are incorrect as they include ticlopidine, which is not typically used for cardiovascular prophylaxis.