Anemia literally means “Lack of Blood”. However, it actually refers to a reduction in the capacity of Blood to carry oxygen to various body parts. It can be due to a reduced number/poor quality of Red Blood cells or Lack of Oxygen carrying chemical present in Red Blood Cells namely, Hemoglobin.
WHO criteria for the diagnosis of Anemia are Hemoglobin <13gm/dL in adult males and <11gm/dL in adult females.
Signs and Symptoms of Anemia include Pale skin, feelings of weakness or fatigue, poor concentration, shortness of breath, inflamed tongue (glossitis), Spoon nails, Restless leg syndrome, Fatigue, Irritability and Pica -A craving for peculiar substances such as soil or clay.
As discussed previously, anemia is related to RBCs and Hemoglobin. Though the simplest cells in the body, the main function of the RBCs is the creation and maintenance of physical integrity and functionality of hemoglobin, an oxygen-carrying molecule. Numerous substances are necessary for the creation of RBC & Hemoglobin, including metals (iron, cobalt, manganese), vitamins (B12, B6, C, E, folate, riboflavin, pantothenic acid, thiamin), and amino acids. Regulatory substances necessary for normal erythropoiesis include certain chemical substances known as hormones like erythropoietin, thyroid hormones, and androgens.
Thus, any condition that involves a deficiency of involved substances or excess destruction of RBCs may lead to anemia. Various conditions leading to anemia include Heavy periods, Pregnancy, Ulcers, Colon polyps or colon cancer, genetic disorders, a diet that does not have enough iron, folic acid or vitamin B12 [Iron, vitamin B12, and folic acid are three of the most important substances for RBC & Hemoglobin production], Blood disorders [sickle cell anemia and thalassemia, or cancer], Aplastic anemia [inherited or acquired] and G6PD deficiency, a metabolic disorder.
Anemia is typically diagnosed on a Complete Blood Count and the Hemoglobin Level. Examination of a stained blood smear [known as Peripheral Smear or P/S] using a microscope can also be helpful. Usually, in labs, four parameters (RBC count, hemoglobin concentration, MCV, and RDW) are measured, allowing others (hematocrit, MCH, and MCHC) to be calculated.
Usually, anemia is classified by the size of red blood cells which are assessed both by automatic analyzers as well as by Peripheral Smear examination. The size is reflected in the mean corpuscular volume (MCV). If the cells are smaller than normal (under 80 fl), the anemia is said to be microcytic; if they are normal size (80–110 fl), normocytic; and if they are larger than normal (over 100 fl), the anemia is classified as macrocytic. This scheme quickly exposes some of the most common causes of anemia; for instance, microcytic anemia is often the result of iron deficiency and macrocytic anemia is usually due to deficiency of Vitamin B12 or Folic acid. Normocytic anemia is usually due to more sinister causes like conditions leading to chronic blood loss like heavy periods, ulcers, cancers or due to reduced RBC production like Aplastic Anemia/Myelofibrosis.
Thus, after classifying the anemia certain specialized tests can be ordered depending on the type of anemia like Serum Iron and Ferritin levels as well as Total Iron Binding Capacity to assess for iron deficiency, direct estimation of Vitamin B12 and Folate levels as well as Intrinsic Factor or Stool for Occult blood and bone marrow studies for assessment of normocytic anemias.
Treatment of Anemia depends on severity and cause. First, the underlying cause of the anemia should be identified and corrected. For example, anemia as a result of blood loss from a stomach ulcer should begin with medications to heal the ulcer. Likewise, surgery is often necessary to remove colon cancer that is causing chronic blood loss and anemia.
Oral or Parenteral Iron supplements will also be needed to correct iron deficiency. In severe anemia, blood transfusions may also be necessary. Vitamin B12 injections and Folate therapy are needed for patients suffering from pernicious anemia or other causes of B12 deficiency.
In certain patients with bone marrow disease or patients with kidney failure, Erythropoietin injections as also repeated blood transfusions may be required as therapy.