By | December 13, 2015


The anemia is a decrease in the concentration of hemoglobin in blood. This parameter is not fixed but depends on several factors such as age, sex and special circumstances such as pregnancy.

Diagnostic Criteria

According to WHO accepted that there is anemia when the hemoglobin concentration in the blood is less than the following values:

Children from 6 months to 6 years 11 g. / Dl
Children 6 to 14 years 12 g. / Dl
Adult males 13 g. / Dl
Adult women, not pregnant 12 g. / Dl
Adult woman, pregnant 11 g. / Dl

Classification of anemias

Anemia can be due to various reasons and they relate very well with variations in size and shape of red blood cells (RBCs). This size is different depending on the producing cause of anemia. The size of red blood cells is determined by an analytical parameter called Mean Corpuscular Volume (MCV), which allows to classify anemias in:

A) microcytic anemia (MCV <80 fl)

  • Iron deficiency anemia. Iron deficiency
  • Hemoglobinopathies: Thalassemia minor
  • Anemia due to chronic disease
  • Sideroblastic anemia

B) normocytic anemia (MCV 80-100 fl)

  • Hemolytic anemias
  • Aplastic anemia
  • Medullary invasion
  • Anemia due to chronic disease
  • Acute bleeding

C) macrocytic anemia (MCV> 100 fl)

    • Anaemias.
    • Aplastic anemia.
    • Hemolytic anemias. (Reticulocyte Crisis).
    • Myelodysplastic syndromes.
  • Nonhematologic.
    • Abuse drinking.
    • Chronic liver disease.
    • Hypothyroidism.
    • Hypoxia.


The anemia occurs in the body a series of general disorders that do not match a particular disease and that can be summarized in the following table:

  • General manifestations.
    • Fatigue.
    • Decreased sexual desire.
  • Manifestations cardio – circulatory.
    • Palpitations.
    • Fatigue after exercise.
    • Low tension.
    • Swelling in the ankles.
  • Neurological manifestations.
    • Headache.
    • Dizziness, vertigo.
    • Drowsiness, confusion, irritability.
    • Ringing in the ears.
  • Gynecological manifestations.
    • Menstrual disorders.
  • Skin manifestations.
    • Pallor.
    • Brittle nails.
    • Hair loss.
  • In severe and / or acute cases.
    • Clammy skin.
    • Decreased urine volume.
    • Chest pain (angina).
  • Other symptoms and signs specific to the type of anemia and / or causal factor.

Description of main anemias

ANEMIAS iron deficiency:

It is an iron deficiency anemia. This lack of iron can be caused by:

  • Increased blood loss:

Rule abundant, gastrointestinal bleeding, blood in urine, etc.

  • Increased requirements:

There are temporary circumstances in which the body needs more iron intake and yet, this does not increase in the diet: Pregnancy, lactation, growth etc.

  • Decrease in intestinal absorption:

Operated stomach, diarrhea and other digestive diseases.

  • Insufficient food:

Free milk supplements, diet low in protein (meat, fish etc.).

THALASSAEMIAS (hemoglobinopathies)

It is a form of anemia caused because hemoglobin is defective and therefore does not fulfill its function is to transport oxygen. It is an inherited disease and is caused by a genetic disorder.


Anemia is caused by a preexisting disease of chronic type to digestive level, renal, etc.


It is produced by an immune disorder that results in the creation of such cells to red blood cells that compete with these, either destroying them or impersonating its function.

Examples: incompatible blood transfusions, toxic substances, etc.

Medullary aplasia

Bone disorder that causes an alteration in the formation of RBCs causing them presenting immature and have therefore the altered function.

Megaloblastic anemia

It is caused by the lack of one or two of the elements involved in the formation of red blood cells, folic acid and vitamin B12.

As in the previous case, the lack of these elements is caused either by a lack of foods that have either a loss due to digestive disorders.

When to see a specialist

Urgent referral.

  • In case of acute anemia.
      • All acute anemia with circulatory disturbances.
      • Anemia, acute bleeding with difficulty controlling the bleeding and / or needs transfusion therapy (Htc <25%; Hb <7-8 g / dl).
      • Clinic of acute crisis of hemolysis.
  • In case of chronic anemia.

Poor clinical and / or hemodynamic tolerance for exacerbation of underlying disease or aggravating factors (generally well tolerated low Hb levels in the order of 7-8 g / dl).


  • Microcytic anemia.
    • Sideroblastic anemia.
    • Anemia of chronic disease origin is not clear and / or treatable in primary care level.
  • Normocytic anemia.
    • All hemolytic anemia.
    • All suspected anemia with bone marrow involvement. (Involvement of more than one hematologic cell number).
    • Anemia of chronic disease unclear cause and / or untreatable at the level of primary care.
  • Macrocytic anemias.
    • Megaloblastic anemia for etiology and starting specific treatment.
    • All suspected anemia with bone marrow involvement. (Involvement of more than one hematologic cell number).