Tintinalli's Emergency Medicine - Just the Facts, 3ed.

135. EVALUATION OF ANEMIA AND THE BLEEDING PATIENT

Daniel A. Handel

PATHOPHYSIOLOGY

images Anemia is due to loss of red blood cells (RBCs) by hemorrhage, increased destruction of RBCs, or impaired production of RBCs.

images Bleeding disorders from congenital or acquired abnormalities in the hemostatic system can result in excessive hemorrhage, excessive clot formation, or both.

CLINICAL FEATURES

images The rate of the development of the anemia, the extent of the anemia, and the ability of the cardiovascular system to compensate for the decreased oxygen-carrying capacity determine the severity of the patient’s symptoms and clinical presentation.

images Patients may complain of palpitations, dizziness, postural faintness, easy fatigability, exertional intolerance, and tinnitus.

images On physical examination, patients may have pale conjunctiva, skin, and nail beds.

images Tachycardia, hyperdynamic precordium, and systolic murmurs may be present. Tachypnea at rest and hypotension are late signs.

images Use of ethanol, prescription drugs, and recreational drugs may alter the patient’s ability to compensate for the anemia.

images Risk factors for underlying bleeding disorders include a family history of bleeding disorder, history of liver disease, and use of aspirin, nonsteroidal anti-inflammatory drugs, ethanol, warfarin, or certain antibiotics.

images Signs of platelet disorders include mucocutaneous bleeding (including petechiae, ecchymoses, purpura, and epistaxis), gastrointestinal or genitourinary bleeding, or heavy menstrual bleeding.

images Signs of coagulation factor deficiencies include delayed bleeding, hemarthrosis, or bleeding into potential spaces (eg, retroperitoneum). Patients with combined abnormalities of platelets and coagulation factors, such as disseminated intravascular coagulation, present with both mucocutaneous and deep space bleeding.

DIAGNOSIS AND DIFFERENTIAL

images Decreased RBC count, hemoglobin, and hematocrit are diagnostic of anemia. Hemoccult examination, complete blood cell count, reticulocyte count, review of RBC indices, and examination of peripheral blood smear are necessary for the initial evaluation of the patient with anemia (Table 135-1).

images The mean cellular volume and reticulocyte count can assist in classifying the anemia and can aid in differential diagnosis (Fig. 135-1).

images Complete blood cell count, platelet count, prothrombin time, and partial thromboplastin time are necessary for the initial evaluation of the patient with a suspected bleeding disorder (Table 135-2).

EMERGENCY DEPARTMENT CARE AND DISPOSITION

images Emergent priorities remain airway, breathing, and circulation. Hemorrhage should be controlled with direct pressure.

images Type- and cross-matched blood should be ordered if blood transfusion is anticipated. Packed RBCs should be transfused in symptomatic patients and those who are hemodynamically unstable

images Patients with anemia and ongoing blood loss should with be admitted to the hospital for further evaluation and treatment.

images Patients with chronic anemia or newly diagnosed anemia with unclear etiology require admission if they are hemodynamically unstable, hypoxic, or acidotic, or demonstrate cardiac ischemia

images Hematology consultation is warranted in patients with suspected bleeding disorders and anemia of unclear. etiology.

TABLE 135-1 Laboratory Tests in the Evaluation of Anemia

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FIG. 135-1A. Evaluation of microcytic anemia. MCV = mean corpuscular volume; RBC = red blood cell; RDW = red cell distribution width. B. Evaluation of normocytic anemia. MCV = mean corpuscular volume; RDW = red cell distribution width. C. Evaluation of macrocytic anemia. MCV = mean corpuscular volume; RDW = red cell distribution width.

TABLE 135-2 Initial Tests of Hemostasis

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For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 226, “Anemia,” by Robin R. Hemphill; Chapter 227, “Tests of Hemostasis,” by Stephen John Cico and Robin R. Hemphill; and Chapter 232, “Acquired Hemolytic Anemia,” by Patricia Chu Klap and Robin R. Hemphill.