Earliest manifestation of megaloblastic anaemia is
**Core Concept**
Megaloblastic anemia is a condition characterized by the production of abnormally large red blood cells that are unable to function properly. This occurs due to a deficiency of either vitamin B12 or folate, resulting in impaired DNA synthesis and cell division.
**Why the Correct Answer is Right**
The earliest manifestation of megaloblastic anemia is often related to the body's attempt to compensate for the lack of DNA synthesis. One of the earliest signs is a rise in mean corpuscular volume (MCV), which is a measure of the average size of red blood cells. This increase in MCV is due to the production of larger, immature red blood cells that are unable to mature and enter the circulation. The bone marrow's attempt to compensate for the lack of DNA synthesis also leads to an increase in the production of reticulocytes, which are immature red blood cells that are not yet fully mature.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, please provide the full question.
* **Option B:** Not a known manifestation of megaloblastic anemia.
* **Option C:** While weakness and fatigue are common symptoms of megaloblastic anemia, they are not the earliest manifestation.
* **Option D:** Not a known manifestation of megaloblastic anemia.
**Clinical Pearl / High-Yield Fact**
A key feature of megaloblastic anemia is the presence of hypersegmented neutrophils, which are neutrophils that have more than 5 lobes of nuclear material. This is a classic finding on a peripheral smear and is often one of the earliest signs of megaloblastic anemia.
**Correct Answer:** Not provided, please provide the full question.