Definition and Classifications
What is anemia?
Anemia is defined as the reduced level of hemoglobin in the blood below the normal range appropriate for age and sex.
Anemia may be classified in two ways—etiological (based on cause) and morphological (based on morphology of RBC).
- Hemorrhagic anemia (due to blood loss):
- Acute—Trauma, postpartum bleeding, hematemesis, melena, epistaxis.
- Chronic—Hook worms, hemorrhoids, excessive menstrual loss, bleeding peptic ulcer, etc.
- Dyshemopoietic anemia (due to inadequate production of RBC):
- Deficiency anemia—Iron, vitamin B12, folate deficiency.
- Aplastic anemia (bone marrow failure which may be primary or secondary to some other diseases or drugs).
- Anemia of chronic disorder (ACD)—SLE, rheumatoid arthritis, CRF.
- Others—Hypothyroidism, sideroblastic anemia, malignancy.
- Hemolytic anemia:
- Genetic—Red cell membrane defect (e.g. hereditary spherocytosis, eliptocytosis, stomatocytosis), hemoglobin abnormality (thalassemia, sickle cell anemia) or enzyme defects (glucose-6-phosphate dehydrogenase deficiency, pyruvate-kinase deficiency).
- Acquired—Autoimmune, toxic, mechanical and infectious causes.
Morphological (depending on MCV and MCHC):
- Normocytic normochromic anemia (normal MCV and MCHC).
- Microcytic hypochromic anemia (low MCV < 76 fl, low MCHC < 30 g/dl).
- Macrocytic anemia (high MCV > 96 fl).
- Diamorphic anemia (two cell lines—macrocytes and microcytes).
What is dimorphic anemia?
When both microcytes and macocytes are found, this is called dimorphic anemia.
What is spurious anemia?
When plasma volume is increased, hemoglobin is relatively low, it is called spurious anemia. It is found in pregnancy.
What is spurious polycythemia?
Here hemoglobin is relatively increased due to low plasma volume. This is found in dehydration.
Etiology and Pathophysiology
What are the causes of normocytic normochromic anemia?
- Anemia of chronic disorder
- Chronic infection (e.g. tuberculosis)
- Collagen disease (e.g. SLE, rheumatoid arthritis)
- Endocrine disease
- Sideroblasitic anemia.
What are the causes of microcytic hypochromic anemia?
- Iron deficiency anemia
- b-thalassemia major
- Sideroblastic anemia
- Anemia of chronic disorder (ACD).
What are the causes of macrocytic anemia?
- Macrocytosis with megaloblastic marrow are found in:
- Vitamin B12 deficiency
- Folic acid deficiency.
- Macrocytosis with normoblastic marrow are found in:
- Chronic liver disease
- Chronic alcoholism
- Others—sideroblastic anemia, pure red cell aplasia, azathioprine therapy.
What are the causes dimorphic anemia?
- Combined iron, B12 and folate deficiency
- Sideroblastic anemia
- Treatment of anemia.
What are the causes or mechanisms of anemia of chronic disorder?
Actual mechanism is unknown. It is due to abnormality of iron metabolism and erythropoiesis. There is less erythropoietin. Also red cell survival is short.
What are the causes of dyserythropoietic anemia?
- Lack of iron, vitamin B12 or folate
- Invasion by malignant cells
- Renal failure.
What is the most common cause of anemia in female of Bangladesh?
Iron deficiency is the most common cause of anemia in female of Bangladesh.
What is the most common cause of anemia?
Iron deficiency is the most common cause of anemia.
What are the common causes of iron deficiency anemia?
- Hookworm infestation.
- Gastrointestinal blood loss—Peptic ulceration, gastritis, occult gastric or colorectal malignancy, inflammatory bowel disease.
- In women of childbearing age, menstrual blood loss, repeated pregnancy and breastfeeding.
What are the main causes of iron deficiency anemia worldwide?
Hookworm and schistosomiasis are the main causes of iron deficiency anemia worldwide.
What are the clinical features of anemia?
- Effort intolerance
- Exertional dyspnea
- Chest pain
- Peripheral edema
- Cardiac dilatation.
What are the specific features of iron deficiency anemia?
Unusual symptom—Picca, i.e. craving for unusual food, e.g. coal, earth.
Signs—Koilonychia, angular stomatitis and pale smooth tongue