Clinical Assessment of Anemia
Tuesday, December 4th, 2007Signs and symptoms of anemia vary with the rapidity of onset and with underlying disease of the cardiovascular system (Table 51-2). Thus, rapid blood loss, especially if plasma volume decreases rapidly, or brisk hemolysis may result in cardiovascular compensatory reactions, including tachycardia, postural hypotension, vasoconstriction in skin and extremities, dyspnea on exertion, and faintness. Slowly developing anemias, such as those resulting from nutritional deficiency, permit gradual expansion of the plasma volume so that increased cardiac output gradually compensates. The subject may remain asymptomatic, noting only slight exertional dyspnea or, in the case of pre-existing coronary artery disease, increased angina. Pallor of skin and mucous membranes, jaundice, cheilosis (fissuring of the angles of the mouth), a beefy red, smooth tongue, and koilonychia (spoon-shaped nails) are signs that accompany more advanced anemias of different types. The level of anemia at which signs of cardiovascular decompensation occur varies considerably with underlying disease, age, level of activity, and the individual’s stoicism. For example, in the sedentary elderly person, a change in mentation can be an important clue to anemia, whereas decreased activity can mask exercise intolerance.
Evaluation of the anemic patient is best served by a systematic evaluation of the clinical and laboratory findings together (Fig. 51-1). First, is the patient truly anemic? Increased plasma volume, fluid overload, or congestive heart failure may produce a dilutional anemia that disappears when fluid balance is restored. Second, is the anemia acquired or inherited? Family history is important, especially in hemolytic anemias, and a positive family history of jaundice, splenomegaly, or gallstones may suggest such a condition. Hemoglobinopathies are frequent in Mediterranean, African, and Far Eastern populations, making ethnic background pertinent. For the immediate problem, a lifelong history versus recent onset is a key differential point. Third, is there evidence for blood loss? The most common reason for anemia is iron loss and iron deficiency. While in growing children and pregnant women iron deficiency may result from dietary lack, the overwhelming cause of iron deficiency in adults is loss of blood from the gastrointestinal or genitourinary tract. Fourth, is there evidence for nutritional deficiency or malabsorption? In the urban Westerner, folic acid deficiency is a common form of malnutrition, seen especially in the elderly living alone and in alcoholics. Fifth, is there evidence for hemolysis? Inherited hemolytic anemias are common in certain populations, whereas acquired hemolytic anemia is rare, occurring mainly in settings of autoimmune disease and drug ingestion. Sixth, is there evidence for toxic exposure or drug ingestion that could cause bone marrow depression and anemia? Finally, does the patient have a chronic inflammatory disease, renal insufficiency, or cancer, each of which is associated with secondary mild anemias, the “anemia of chronic disease”?