Anemia in a simplified translation means a “lack of blood cells”, but it involves a catalogue of complex symptoms. Just giving it a label without looking for the cause is a serious medical blunder. Anemia is like a warning flag that points to an underlying medical problem that needs to be investigated. Here a general overview of anemia is given based on what causes a particular type of anemia.
The patient may not notice mild forms, and only laboratory tests will show abnormalities. Severe forms of anemia can produce a host of signs and symptoms. Weakness, dizziness, headache, ringing in the ears (tinnitus), lack of energy, irritability and loss of libido may be part of the symptoms that send the patient to the doctor. Sometimes there are gastrointestinal complaints, jaundice or an enlarged spleen.
It is necessary to investigate the mechanisms that led to anemia. Acute blood loss is the most obvious reason. Chronic blood loss-even if the amounts are small- can lead to anemia. A deficiency in the production of red blood cells (erythropoiesis) may be the culprit or destruction of red blood cells (know as excessive hemolysis) could be responsible. Blood loss in its acute or chronic form have to be considered first. Any source of unrecognized internal bleeding (ulcers and gastrointestinal bleeding) can be at the source of anemia. Too frequent periods or heavy periods will lead to anemia in females. Iron deficiency anemia shows a similar laboratory pattern as anemia due to chronic blood loss. If blood loss has been excluded as a reason for anemia, only the other two mechanisms (deficient production of red blood cells and destruction of red blood cells) have to be considered.
Forms of Anemia
The changes in laboratory patterns, also known as morphological changes, and the special features make the condition of anemia a very complex one. For instance, the microcytic form of anemia caused by chronic blood loss and iron deficiency leads to a production problem of the bone marrow. The macrocytic form of vitamin B12 deficiency anemia and folate deficiency anemia comes from impaired DNA synthesis in the bone marrow leading to blown up appearing red blood cells (“macrocytic”), but overall there are insufficient numbers of them circulating in the blood because of a reduced production in the bone marrow. The latter one (folate deficiency) is often associated with celiac disease, pregnancy, malabsorption of nutrients and alcoholism. Other forms of anemia can have their origin in bone marrow failure, can stem from chronic infection or inflammation, or can be the result of a paroxysmal cold hemoglobinuria after exposure to a cold or an infection with syphilis. Hereditary forms include hereditary spherocytosis or there could be inborn or acquired defects (sideroblastic anemia.) Some specific anemias are more common in certain population groups. As an example, sickle cell anemia is almost exclusively found in blacks, and thalassemia is frequently found in patients of Mediterranean descent. Due to the complexity of this disease, it is imperative to seek a referral to a hematologist, who assesses and treats disorders of the blood.
Tests for Anemia
Blood tests give information about the severity of the condition and are the data source, which are needed for the proper diagnosis. In most cases the blood is collected in the laboratory by venipuncture. The so-called CBC, which stands for “complete blood count” is the basic test, which includes information about the composition of the blood. It includes a count of the white blood cells, the red blood cells, the white blood cell differential count, hemoglobin and hematocrit, as well as information about platelet spread. This test is valuable, as it may detect anemia, infection, bone marrow failure and adverse drug reactions. Blood smear examinations can help with the detection of other abnormalities. This test is important to check the appearance of red blood cells. Some abnormalities (thrombocytopenia and others) can be detected, even if the CBC showed normal counts. Automated technology makes test results available in about 30 seconds. Red blood count and reticulocyte count give more details about the red blood cells, the latter being the young cell population. An increased count in the young cells (reticulocytosis) is especially noticeable in hemolytic anemias and in acute and severe bleeding. Electronic and automated technologies have opened up new diagnostic possibilities. Variation in the shape of cells, portions of disrupted cells, membrane alterations and fragments of red blood cells can be found. Tests for red blood cell fragility (osmotic fragility) are another tool, and hemostasis (bleeding time, prothrombin time and others can provide further insight.
Bone Marrow Studies
The techniques of bone marrow aspiration and biopsy allow a direct observation of activity and maturation of the red blood cell precursors. The amount of distribution, the cellular pattern of iron content or abnormal maturity of the cells are all helpful tests in anemias. Bone marrow aspiration and biopsy are neither difficult nor invasive, can be done as a single procedure and for this reason should be part of the early diagnostic tools in suspected hematological diseases. These procedures typically are ordered by a hematologist.
1. Merck Manual (Home edition): Anemia
2. Noble: Textbook of Primary Care Medicine, 3rd ed., Mosby Inc. 2001
3. Goldman: Cecil Medicine, 23rd ed., Saunders 2007: Chapter 162 – APPROACH TO THE ANEMIAS