Pernicious Anemia Megaloblastic Anemia: Causes, Symptoms & Diagnosis
Anemia is a major killer in India .One in every maternal deaths is directly due to anemia. Anemia affects both adults and children of both sexes , although pregnant women and adolescent girls are most susceptible and most affected by this disease.
Anemia is the decrease in the RBC count , haemoglobin and /or Hematocrit values resulting in the lower ability from the blood to carry oxygen to blood tissue .
- Poor socio-economic class
- Teenage pregnancy
- Menstrual problems
TYPES OF ANEMIA
1. Iron deficiency anemia.
2. Vitamin B12 / folic acid deficiency anemia (Megaloblastic anemia )
a) Vitamin B12 deficiency anemia
b) Folic acid deficiency anemia
3. Aplastic anaemia.
4. Haemolytic anemia.
5.Congenital hemolytic anemia.
a) Sickle cell anemia
b) Thalassemia anemia.
1) IRON DEFICIENCY ANEMIA
- Most common form of anemia in many parts of the world .
- Caused due to excessive loss of iron.
- RBC count is often normal but cells are small , pale,contain less haemoglobin than normal .
- Dietary iron comes from red meat and highly coloured vegetable.
- Men require 1-2 mg of iron, whereas women require 3 mg of iron per day .
- Women are at risk as due to continuous menstruation and foetal growth.
2) MEGALOBLASTIC ANEMIA
- Deficiency of vitamin B12 and /or Folic acid impairs erythrocyte maturation.
- Abnormally large erythrocytes are found in blood .
- When deficiency of vitamin B12 and /or folic acid occurs , the rate of RNA and DNA synthesis is reduced , delaying cell division . The cell therefore grows larger then the normal cell division .
- The haemoglobin contend of each cell is normal or raised .
- The cells are fragile and their life span is reduced to between 40 – 50 days .
A ) PERNICIOUS ANEMIA
- Most common form of vitamin B12 deficiency .
- Commonest in women over 50 .
- It is an autoimmune disease in which auto antibodies destroy intrinsic factor (IF) and parietal cells in the stomach .
- Vitamin B12 deficiency occur in gastrectomy , chronic gastritis , malabsorption .
B ) FOLIC ACID DEFICIENCY ANEMIA
- Deficiency of folic acid causes a form of megaloblastic anemia identical to that in vitamin B12 deficiency , but not associated with neurological damage .
- Occurs due to malabsorption from jejunum .
- Due to prolonged loss of use of anticonvulsant drug and cytotoxic drugs.
3) APLASTIC ANAEMIA (HYPOPLASTIC ANAEMIA )
- Results in bone marrow failure .
- Erythrocyte number is reduced.
- Since the bone marrow also produce leukocytes and platelets, leukopenia (low white cell count ) and thrombocytopenia (low platelet count ) are also likely.
- Caused due to cytotoxin therapy , ionization radiation.
- Viral diseases including hepatitis .
- Some chemicals example benzene.
4 ) HEMOLYTIC ANAEMIA
- Circulation red cells are destroyed or are removed prematurely from the blood because the cells are abnormal or the spleen is overactive.
- Homolysis takes place in the liver or spleen so the normal erythrocyte life span of about 120 days can be considerably shortened.
- May be due to parasites , toxins etc.
- Hemolytic jaundice can cause additional symptoms such as jaundice or spleenomegaly.
5 ) CONGENITAL HEMOLYTIC ANAEMIA
Genetic abnormality leads to the synthesis of abnormal haemoglobin and increased red cell membrane fragility , reducing their O2 carrying capacity . Most common forms are :
(i) SICKLE CELL ANAEMIA
- The abnormal haemoglobin molecules become misshapen when deoxygenated , making the erythrocytes sickle shaped .
- The life span of cells is reduced by early hemolysis , which causes anaemia.
- Sickle cells do not move smoothly through the circulation .They obstract blood flow , leading to intravenous clotting , tissue ischemia and infarction .
- Black people are more affected than other .
- The inherited condition commonest in Mediterranean countries .
- Causes abnormal haemoglobin haemoglobin production , which in turn reduces erythropoiesis and stimulates hemolysis .
- severe form can be life threatening .