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Approach to the Patient with Anemia Author: Márcia Datz MD, Pediatrician

Introduction

Anemia is a commonly encountered clinical condition that is caused by an acquired or hereditary abnormality of red blood cells (RBC) or its precursors, or may be a manifestation of an nonhematologic disorder.

Definition

Anemia is defined as a decrease in the circulating RBC mass and a corresponding decrease in the oxygen-carrying capacity of the blood.
Normal values of the hemogram:

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TEST	            WOMEN	            MEN
           ----------------------------------------------------------           
Ht (%)	            36-48	            40-52
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Hg (g/dl)	    12-16	            13,5-17,7
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Hem	            4,0-5,4	            4,5-6,0
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VCM	            80-100	            80-100
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A decrease in any of this values (Ht, Hg, Hem) is called anemia. They can be altered by the plasmatic volumes.Diference between women and men values are due to androgen hormones.

Signs and Symptoms

The clinical manifestations vary with the age, degree and rapidity of onset, presence of subjacent illness and other factors. Mild anemia are often assymptomatic. The main symptoms are exercise dyspnea, fatigue, palpitation, pica (consumption of substances such as ice, starch or clay, frequently found in iron deficiency anemia), syncope (particularly following exercise) and bounding pulse. Dizziness, headache, syncope, tinnitus or vertigo, irritability, difficulty sleeping or concentrating are more frequent in severe chronic anemia.

Common signs are pallor (color of skin, palms, oral and conjunctival mucous membrane and nail beds), tachycardia, ejection sistolic murmur, mild peripheral edema and venous hums and wide pulse pressure. In old people, angina pectoris can be an important clinical manifestation. Females commonly develop abnormal menstruation, both amenorrhea and increased bleeding.Males can develop decrease in libido and impotence.

Cardiovascular Adaptations in Anemia

The main consequence of anemia is tissue hypoxia. If anemia has developed rapidly, there may not be adequate time for compensatory adjustments to take place, so there is a sudden marked contraction of intravascular volume, resulting in postural hypotension, fall in cardiac output, shunting of blood from skin to central organs, sweating, restlessness, thirst and air hunger. If anemia has slowly instalation, many adaptations occur for the oxygen mantainance, such as increasing of plasmatic volume and right shift of the oxygen-hemoglobin dissociation curve.

History and Physical Examination

In the hystory is important to ask about duration and time of onset, other subjacent illness, associated symptoms related with one specific etiology, family history, hemotransfusion, blood loss and drug exposure.Physical findings can inclue jaundice, splenic enlargement, neurologic symptoms (loss of vibration sensibility, abnormal march), tongue atrophy, lynphadenopathy, evidence of blood in feces or vomit, leg ulcers, petechiae and myriad signs of primary diseases that may cause a secondary anemia.

Basic Laboratory Exams