CASE HISTORY • Part 1
A 66-year-old woman presents with more than 6 months of pain and stiffness of the muscles of the neck, shoulders, and lower back. Within the past 2 weeks, she has also suffered from recurrent headaches, unresponsive to aspirin, acetaminophen, and nonsteroidals. Review of systems is negative for collagen vascular disease or vasculitis, but she has had a 10–15 lb weight loss, and is a heavy smoker. Examination is notable for sallow complexion and depressed mood. Neck and shoulder muscles are tender to palpation but no arthritic changes or temporal artery nodularity or tenderness are noted.
CBC: Hematocrit/hemoglobin - 29%/9 g/dL
MCV - 84 fL MCH - 30 pg MCHC - 30 g/dL
RDW-CV - 14%
WBC count - 9,500/μL
Platelet count - 210,000/μL SMEAR MORPHOLOGY
Normocytic/normochromic, with minimal anisocytosis, no poikilocytosis, and no polychromasia.
Reticulocyte count/index - 1.3%/<1
Sedimentation rate - 115 mm/h (Westergren)
C-reactive protein - 37 mg/L
How should the anemia be described and classified, given the above data?
What additional tests should be ordered?
Anemia is common in patients with acute and chronic inflammatory diseases, renal insufficiency, and hypothyroidism. In each situation, there is an apparent failure in the erythropoietin stimulation of the marrow. Serum erythropoietin levels, although not decreased below basal levels, are not appropriately increased for the severity of the anemia. Marrow cellularity and reticulocyte response are typically hypoproliferative.
The importance of this class of anemias cannot be overemphasized. The clinical incidence of hypoproliferative anemias associated with acute infection or chronic inflammatory disease (the anemia of chronic disease) is far greater than that of all other types of anemia. In some cases, appearance of a typical hypoproliferative anemia is the first sign of underlying disease. The pattern of the anemia can also be of considerable value in the diagnosis of the etiology and severity of the disease process. It is important, therefore, that clinicians be skilled in evaluating the patient with a hypoproliferative anemia, even when the anemia is mild.
NORMAL MARROW PROLIFERATION
The normal proliferative response of the erythroid marrow to anemia requires an appropriate erythropoietin response, an intact erythroid marrow, and an adequate supply of iron (Figure 4-1). Dedicated peritubular interstitial cells in the kidney are capable of sensing changes in oxygen delivery. A decrease in hemoglobin level to values less than 12 g/dL stimulates an increased production of erythropoietin. This process involves recruitment of additional peritubular interstitial cells rather than an upregulation of existing cellular production. The role of the kidney in regulating erythropoietin production is well maintained even with significant renal damage. However, end-stage renal disease is uniformly associated with a failure in the erythropoietin response. Since hepatocytes also produce some erythropoietin, anephric patients have measurable serum erythropoietin levels but markedly reduced red blood cell production.
Components of the normal marrow proliferative response. A full response ...