Anemia
Anemia is a medical condition characterized by a deficiency of healthy red blood cells (erythrocytes) in the body, which are responsible for transporting oxygen to the body’s tissues.
In anemia, the number of red blood cells, or hemoglobin, is below normal. Normal hemoglobin levels differ between men and women. The normal hemoglobin level for men should be greater than 13.5 g/dL, and for women, it should be greater than 12.0 g/dL. These definitions may vary slightly depending on the source and laboratory reference employed.
Anemia can lead to fatigue and weakness. It can cause pallor of the skin, palpitations, and an increased risk of heart failure, as well as hair loss.
As the body adapts to slow-developing and long-lasting anemia (chronic anemia), it may not exhibit any symptoms. Acute (rapidly developing) anemia is characterized by more noticeable and significant symptoms.
Classification of Anemia (Based on Production)
- Reduced erythrocyte or hemoglobin production
- Increased erythrocyte or hemoglobin destruction
Classification of Anemia (Based on MCV)
MCV (mean corpuscular volume) refers to the average volume of erythrocytes.
- Microcytic anemia: MCV < 80, indicating the cells are smaller than normal.
- Normocytic anemia: MCV 80-100, indicating the cells are normal size.
- Macrocytic anemia: MCV >100, indicating the cells are larger than normal.
Anemia Etiology (Causes)
There are several different causes of anemia, including:
- Iron Deficiency
- Blood Loss
- Vitamin Deficiency
- Chronic Disease
- Inherited disorders
- Hemolytic Anemia
- Other Factors
1. Iron Deficiency
The most prevalent form of anemia is iron deficiency anemia. Iron is a key component of hemoglobin, which is the protein in red blood cells that carries oxygen. Iron deficiency is a common cause of anemia, and it can occur due to inadequate dietary intake of iron, poor absorption of iron, or increased iron losses (such as from bleeding or chronic blood loss).
2. Blood Loss
Acute or chronic blood loss, such as from injury, surgery, or heavy menstruation, can lead to anemia.
Due to normal menstruation-related blood loss, young women are susceptible to mild iron deficiency anemia. Since the blood loss is relatively small and transient, there are usually no symptoms.
Chronic or recurrent bleeding due to conditions like colon cancer or stomach ulcers. In infants and young children, a diet devoid of iron is the primary cause of iron deficiency anemia. Erythrocytes in iron deficiency anemia are both small and pale (hypochromic microcytic anemia).
3. Vitamin Deficiency
Certain vitamins, such as vitamin B12 and folate, are essential for the production of red blood cells. Deficiencies in these vitamins can lead to anemia.
Pernicious anemia, which is caused by a vitamin B12 deficiency, is prevalent in alcoholics, vegetarians and vegans, and those with B12 absorption disorders (in the intestines). This results in macrocytic anemia.
Along with vitamin B12, folate plays a role in the production of heme molecules, which are an integral part of hemoglobin. Consequently, folate deficiency can also lead to anemia.
4. Chronic Disease
Chronic diseases, such as kidney disease, liver disease, and inflammatory bowel disease, can interfere with the production of red blood cells and cause anemia.
5. Inherited disorders
Some inherited disorders, such as sickle cell anemia and thalassemia, can cause anemia due to abnormal hemoglobin production.
6. Hemolytic Anemia
It is possible for erythrocytes (red blood cells) to break down due to antibodies adhering to the surface of the cells (hemolytic anemia), especially in the spleen. Hemolytic anemia may be acquired or inherited. Examples of hemolytic anemia include neonatal hemolytic disease and anemia caused by certain drugs.
7. Other Factors
Certain medications, such as chemotherapy drugs, can suppress the bone marrow’s ability to produce red blood cells, leading to anemia. Additionally, certain chronic infections, such as HIV/AIDS and malaria, can also cause anemia.
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