After seven days of treatment with sulfonamides, a patient's hemoglobin had decreased from 14.7 gm/100ml to 10gm/100ml. The most likely cause of hemolysis in this patient is

Correct Answer: D

Rationale: The correct answer is D: Glucose 6-phosphate dehydrogenase deficiency (G6PD). Sulfonamides can trigger hemolysis in patients with G6PD deficiency due to oxidative stress on red blood cells. G6PD enzyme deficiency impairs the ability of red blood cells to combat oxidative damage, leading to hemolysis. In this case, the patient's hemoglobin decreased significantly after sulfonamide treatment, indicating red blood cell destruction. The other choices (A: Sickle cell disease, B: Thalassemia minor, C: Hereditary spherocytosis) are not directly associated with sulfonamide-induced hemolysis and would not explain the observed decrease in hemoglobin levels after treatment.

Correct Answer: B

Rationale: Step 1: Non-Hodgkin lymphoma (NHL) can arise from either B cells or T cells. B cell NHL is more common than T cell NHL. Step 2: The B cell phenotype is predominant in NHL, making choice B correct. Step 3: Classical Reed-Sternberg cells are characteristic of Hodgkin lymphoma, not NHL, making choice A incorrect. Step 4: NHL can involve non-contiguous lymph nodes, ruling out choice C. Step 5: NHL can present with leukemic involvement, refuting choice D. Overall, the B cell phenotype being more common in NHL makes choice B the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Promastigote. In the laboratory diagnosis of leishmaniasis, the parasite stage typically observed in vitro is the promastigote stage. This is because promastigotes are the infective form of the parasite found in the sandfly vector. When a sample is taken from a patient, it is cultured in a suitable medium where promastigotes develop. Amastigotes (choice A) are the intracellular form found in the host, not typically observed in vitro. Trypomastigotes (choice C) are the stage found in Trypanosoma species, not Leishmania. Schizonts (choice D) are a stage in the life cycle of Plasmodium species causing malaria, not Leishmania. Promastigotes are the stage most commonly used for laboratory diagnosis and research in leishmaniasis.

Correct Answer: C

Rationale: Rationale: Hereditary spherocytosis is associated with splenomegaly due to the spleen's increased destruction of abnormal red blood cells. In this condition, red blood cells have a spherical shape, making them more prone to destruction by the spleen. Chronic renal failure (A) is not typically associated with splenomegaly. Aplastic anemia (B) is characterized by bone marrow failure and does not directly involve the spleen. Sickle cell anemia (D) leads to splenomegaly in children but not in adults due to splenic sequestration crises, making it less likely to be the correct choice.

Correct Answer: D

Rationale: The correct answer is D: SLE. Non-thrombocytopenic purpura is characterized by skin bleeding without low platelet count. SLE does not typically cause this type of purpura, as it primarily affects multiple organs through immune complex deposition. Vasculitis, uraemia, and hereditary hemorrhagic telangiectasia can all lead to non-thrombocytopenic purpura due to various mechanisms involving blood vessel inflammation, kidney dysfunction, or genetic defects in blood vessel formation, respectively.