In the laboratory diagnosis of leishmaniasis, the expected parasite stage in vitro is

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: 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.

Correct Answer: B

Rationale: The correct answer is B: lithium. Lithium does not cause hemolytic anemia because it does not affect red blood cell destruction. Penicillin (A), Quinidine (C), and Methyldopa (D) are known to cause hemolytic anemia by various mechanisms, such as immune-mediated destruction or oxidative damage to red blood cells. In contrast, lithium's mechanism of action does not involve direct harm to red blood cells, making it the correct choice in this scenario.

Correct Answer: D

Rationale: The correct answer is D, hereditary spherocytosis. In this condition, the presence of jaundice and splenomegaly is due to the destruction of red blood cells by the spleen, leading to increased MCH. In liver cirrhosis (choice A), jaundice is due to impaired liver function. Thalassemia major (choice B) presents with severe anemia, not jaundice. Paroxysmal nocturnal hemoglobinuria (choice C) is characterized by hemolytic anemia and not typically associated with splenomegaly and jaundice. Therefore, the presence of jaundice, splenomegaly, and increased MCH points towards hereditary spherocytosis.

Correct Answer: B

Rationale: Step-by-step rationale for choice B (pancreatitis) being correct: 1. Sickle cell anemia primarily affects red blood cells, leading to vaso-occlusive crises. 2. Pancreatitis is not a known complication of sickle cell anemia. 3. Complications of sickle cell anemia commonly involve organs affected by sickling, such as the bones (osteomyelitis), kidneys (papillary necrosis), and heart (CHF). Summary: A: Papillary necrosis - Correct, as it can affect the kidneys in sickle cell anemia. B: Pancreatitis - Correct, as it is not a typical complication of sickle cell anemia. C: Osteomyelitis - Incorrect, as it can affect the bones in sickle cell anemia. D: CHF - Incorrect, as it can affect the heart in sickle cell anemia.