Myelodysplastic syndromes are a group of clonal stem cell disorders. Which of the following type has the poorest prognosis according to the FAB system of classifications?

Correct Answer: D

Rationale: The correct answer is D: RA with excess blasts in transformation. This type has the poorest prognosis as it represents a progression to acute myeloid leukemia, which is associated with a high mortality rate. In the FAB system, this category indicates a higher blast count than RA with excess blasts (choice C), leading to a worse outcome. Choices A and B are associated with a lower risk of progression to AML compared to choices C and D. Therefore, D is the correct answer due to its direct association with the most aggressive form of the disease.

Correct Answer: A

Rationale: The correct answer is A: Phlebotomus species. Phlebotomus species are the main vectors of visceral leishmaniasis in the Asian region. These sandfly species are known to transmit the Leishmania parasite, which causes the disease. Phlebotomus species are prevalent in the Asian region and have been identified through various studies as the primary vector for visceral leishmaniasis transmission. Summary of why other choices are incorrect: B: Lutzomyia species are primarily found in the Americas and are the main vectors for leishmaniasis in that region. C: Anopheles species are known to transmit malaria, not visceral leishmaniasis. D: Mansonia species are primarily associated with transmitting diseases such as filariasis and dengue fever, not visceral leishmaniasis in the Asian region.

Correct Answer: A

Rationale: The correct answer is A: vasculitis. Thalassemia major is a genetic blood disorder that causes anemia. Vasculitis, inflammation of blood vessels, is not a common cause of abdominal pain in thalassemia. Splenic infarction, dragging pain at huge splenomegaly, and pigment stones in the gall bladder are associated with thalassemia major due to complications such as splenomegaly and increased bilirubin levels, leading to abdominal pain. Vasculitis is not typically seen in thalassemia major patients, making it the exception among the choices.

Correct Answer: A

Rationale: The correct answer is A: chronic phenytoin therapy. Phenytoin is an antiepileptic medication known to cause gum overgrowth (gingival hyperplasia), leading to swollen and enlarged gums, but not gum bleeding. Choices B, C, and D all involve conditions that are associated with gum bleeding. Aplastic anemia (B) is a blood disorder that can cause low platelet count and increased risk of bleeding. Scurvy (C) is a condition caused by vitamin C deficiency, leading to weakened blood vessels and gum bleeding. Haemophilia (D) is a genetic disorder that impairs blood clotting, resulting in excessive bleeding, including gum bleeding.

Correct Answer: B

Rationale: Correct Answer: B - Hydroxyurea Rationale: 1. Hydroxyurea is not a standard treatment for sideroblastic anemia. 2. Pyridoxine (A) is commonly used to treat pyridoxine-responsive sideroblastic anemia. 3. Desferroxamine (C) is used to remove excess iron in iron overload conditions, not specific to sideroblastic anemia. 4. Androgens (D) may be used to stimulate erythropoiesis in certain types of anemia, but not typically for sideroblastic anemia.