Internal Medicine experts define anemia as a decrease in peripheral blood hemoglobin concentration below 13 g/dL in adult males and 12 g/dL in adult females, or a decrease in hematocrit below 39% in males and 37% in females.
In situations such as pregnancy, heart failure and edematous states, the hemoglobin figures may be falsely decreased and it is not really anemia, and the opposite occurs in situations of dehydration.
In addition to hemoglobin concentration and hematocrit, there are other useful parameters to approach the causal diagnosis of anemias, such as mean corpuscular volume, which allows us to classify anemias as normocitic, microcytic or macrocytic, depending on the size of the red blood cells; the mean corpuscular hemoglobin concentration, which allows us to classify anemias as hypochromic or normochromic; the erythrocyte distribution range, which differentiates iron deficiency anemia from thalassemia; and the reticulocyte count, which allows us to know whether an anemia is regenerative or not, depending on the bone marrow response.
How do I know if I have anemia?
The clinical symptoms depend mainly on the intensity and speed of onset of the anemia. Thus, acute anemia is much worse tolerated and is generally due to hemorrhage or hemolysis.
Generally, patients report dizziness, tiredness, pallor, coldness, headache and even confusion. The physician may note coldness of the skin, hypotension, brittleness of hair and nails, as well as tachycardia and sometimes functional heart murmurs.
Causes of anemia
The patient with anemia should have a very complete medical history and a detailed physical examination to clarify the cause of the anemia, collecting data such as possible bleeding, characteristics of menstruation in women, altered bowel habits, drug intake, nutritional habits, etc., as well as personal or family history of anemia.
The most frequent causes of microcytic anemia are iron deficiency, due to insufficient dietary intake or alterations in iron absorption, gastrointestinal bleeding or bleeding at other levels, and intravascular hemolysis, which can be caused by infectious disease, valve prostheses or alterations in iron transport. Anemias due to hereditary alterations in hemoglobin synthesis, the most frequent being thalassemia, which is very common in our environment, also have a low corpuscular volume.
Normocitic anemias are very important, since they appear in a multitude of chronic diseases and hospitalized patients, the causes being very varied, from infectious, neoplastic to immunological diseases. Normocytic anemia can also occur in bone marrow disorders, when the bone marrow is unable to synthesize red blood cells, and in the case of hematologic diseases, such as leukemias, myeloma and myelodysplastic syndromes.
Hemolytic anemia, which can be primary or secondary to infectious, neoplastic or inflammatory diseases, is also a cause of normocytic anemia. Macrocytic anemias are mainly due to folic acid or vitamin B12 deficiency, generally related to nutritional habits or digestive diseases, although they can also be detected in patients with hypothyroidism, hepatic insufficiency or in cases of alcohol or drug abuse.
How anemia is diagnosed
The possible studies to be performed in a patient with anemia can be very varied, depending on the clinical data obtained in the anamnesis and physical examination, and should always be performed from less to more aggressive and expensive, to avoid abuse of studies and unnecessary expenses. All patients should have a complete blood count and standard biochemistry, urinalysis, iron, ferritin and transferrin.
In many cases, the reticulocyte count, haptoglobin and coombs test should be determined. If necessary, depending on the type of anemia, thyroid hormone, folic acid and vitamin B12 levels will be determined, and in certain situations an autoimmune and microbiological study will be performed, as well as a study of possible hemoglobinopathies and enzymes, to rule out congenital diseases. And if the clinical history is suggestive, imaging studies should be performed to detect tumor diseases.
In case of suspected gastrointestinal leakage, imaging studies and endoscopies should be performed. Sometimes it will be necessary to perform a bone marrow study, by aspiration or biopsy.
What is the treatment of anemia?
From what has been said above, it can be deduced that the treatment of anemia will be individualized for each patient, since we have seen that the causes can be very varied, and each one has its own specific treatment. The most commonly used treatments are the administration of iron, folic acid or vitamin B12, depending on the cause, without forgetting that the disease causing the anemia must be treated. If the anemia is very acute and important, a transfusion may be necessary, and in cases of chronic anemia, the administration of erythropoietin or derivatives may be necessary. When the cause is an immunological alteration, treatment with corticosteroids or immunosuppressants will be necessary.