In which of the following diseases structure of haemoglobin produced is normal but their amount reduced?

Question

The options provided are-

1. Chronic blood loss
2. Sickle cell anaemia
3. Haemolytic anaemia
4. Thallasaemia
5. Transfusion reactions -

*Q-15: pg-785; **Review of Medical Physiology - William F. Ganong; International 22nd Edition***

Here, the answer provided is (4), i.e Thallasaemia... My point is that, Thallasaemia is essentially a genetic defect resulting in mutation of either alpha or beta or both the chains, thus rendering the structure of haemoglobin fragile....the disease as far as I know don't cause any reduction in blood volume...

According to me option (1) i.e chronic blood loss is more feasible as in case of diseases resulting from nematodes like Hookworm (Ancylostoma duodenale)....

So, where am I wrong???

Answer 1

You are correct, Thalassemia is the wrong answer.

In Thalassemia and Sickle Cell Anemia, the structure of Hemoglobin is altered.

1. Chronic Blood Loss: Here the hemoglobin and packed cell values will be low, however there is no alteration in structure of either RBC or Hemoglobin

2. Hemolytic Anemia: This is a host of conditions which can cause hemolytic anemia. Some mechanisms where Hemoglobin structure remain normal would be:

   • The structure of RBC membrane is altered, this will make RBCs less maleable and cause early destruction - Example: Spherocytosis

   • G6PD Deficieny - In this the deficiency of G6PD will decrease the ability of Red Blood Cells to handle oxidative stress and when subjected to sudden oxidative stress, hemolysis will occur. Here the structure of both RBC membrane and Hemoglobin are normal.

3. Transfusion reaction (I am talking about only hemolytic transfusion reaction, there are other transfusion reactions too): Here the problem is the host reaction to transfused Red Cells. The host was initially severly anemic (Therefore low Hb) for which transfusion was done, now the host immunity is reacting against transfused RBCs which have normal Hemoglobin, resulting in reduced RBC counts and Hemoglobin. So this too can be taken as a correct answer as the end-result will be severe normochromic normocytic anemia.