Anemia means decrease of red blood cells numbers and amount of hemoglobin in blood below normal range. The causes of this condition are numerous, although the most common is anemia probably due to iron deficiency. Anemia has many symptoms and it can significantly impair quality of life. Some forms of anemia are associated with other serious illnesses.
At first, let's mention some information about red blood cells (erythrocytes). These are special cells containing no nucleus. Red blood cells are produced in the bone marrow. Life length of an erythrocyte is about 120 days. Hemoglobin is vital substance contained inside every mature red blood cell. Hemoglobin is capable of binding breathing gases like oxygen and carbon dioxide, this function is enabled by a key element – a molecule of iron.
There are many possible causes and it is not easy to sort anemia types into a clearly arranged system.
I. Anemia due to decreased production of blood cells in the bone marrow
This is a whole group of congenital and acquired diseases that have one common feature - bone marrow stops producing red blood cells and often other types of blood cells and platelets. Anemic syndrome is often accompanied by sings of immunodefficiency (lack of white blood cells) and tendency to bleed (lack of platelets).
This is probably the most common cause of anemia, particularly typical among menstruating women. It usually combines chronic blood loss (see below, number III), or iron malabsorption in small intestine and lowered red blood cell production in bone marrow caused by iron deficiency.
Anemia of chronic diseases
Anemia is typical for many chronic diseases, including cancers. It manifestation is very similar to iron deficiency anemia. In this case, however, the body has enough of iron, but iron molecules are "locked" in cells. This is a defense mechanism that prevents iron to get into “wrong hands”. Chronic infections and tumors need iron supply to grow and proliferate.
As a side effect, hemoglobin and erythrocyte formation is also affected.
Anemia caused by vitamin B12 and folic acid deficiency
It is common in alcoholics, but can affect even people who have trouble of vitamin B12 absorption in their digestive tract. If associated with chronic inflammation of stomach this condition is designated as pernicious anemia.
II. Anemia caused by affection of bone marrow by another disease
These are classic situations where bone marrow is attacked by a cancer. It may be solid tumor metastases (e.g. lung cancer, breast cancer and others), but damage of healthy bone marrow cells production is more typical for hematological cancers (leukemia, lymphomas, multiple myeloma). Sometimes clinical manifestation may be similar to aplastic anemia. Especially in hematological tumors, by contrast, white blood cells are produce in large numbers, but they are poorly functional or totally non-functional.
III. Anemia caused by red blood cells destruction or losses
This includes all situations where red blood cells break down or are lost from our body.
It belongs among autoimmune diseases. Our own immune system starts to produce antibodies that begin to destroy red blood cells. If body is unable to replace these losses, anemia occurs.
This condition is also causes by breakdown of red blood cells. In this case it is due to presence of abnormal hemoglobin molecules inside red blood cells. Affected erythrocytes change their shape; they loose flexibility and tend to disintegrate when passing through small vessels and through spleen.
Thalassemia is a group of diseases that are genetically determined. The consequence of these conditions is a smaller quantity of a hemoglobin component that deteriorates red blood cells length of survival and increases their disintegration rate.
Anemia of acute or chronic blood loss
Anemia occurs when there is a sudden big blood loss, or chronic loss of red blood cells in quantities impossible to replace by our organism. Chronic losses are usually caused by conditions affecting digestive tract (see blood in stool article), urinary tract (see blood in urine article) or gynecologic tract (gynecological bleeding including menstruation). Colon cancer is a classic example of a chronic blood loss cause. Due to the fact that our body is capable of producing enough blood cells to replace chronic blood loss, iron deficiency (see above) becomes the biggest problem.
Anemia manifests by some typical symptoms. Most of them are related to reduced capacity of blood to transport the breathing gases. Symptoms are described as so-called anemic syndrome including weakness, fatigue, dizziness, pallor and shortness of breath. Muscles do not get enough oxygen, and therefore they get easily tired, fainting is caused by attacks of brain ischemia. Anemic people tend to be chilly. Anemic person suffers from shortness of breath during exertion and it may appear that he or she has a lung disease. Nevertheless, the lungs are healthy; they just try to breathe faster to oxygenate blood. Without sufficient blood hemoglobin this unfortunately doesn't have the desired effect.
Anemia is diagnosed from blood test by decreased number of red blood cells and lack of hemoglobin. If our diagnosis is confirmed, we should know serum iron and ferritin level (Ferritin is a protein that determines the amount of iron stored in cells). We should also check transferrin saturation with iron. Transferrin is a protein that serves as a carrier of iron in blood stream. More specific procedures are described in texts related to certain types of anemia. Here, I would only say that we use a lot of examination methods including sternal puncture, trephine biopsy, gastroscopy, colonoscopy, etc. Of course, their selection is dependent on individual case.
Therapy depends on the underlying cause. Sometimes we supply iron; sometimes we treat a tumor and so on. More information is present in relevant articles. Severe anemia that can cause a cardiovascular collapse can be in general treated by a blood transfusion.