Anemia is one of the major Hematological complications in Chronic Kidney Disease (CKD). Although anemia in CKD is multifactorial by far the main cause of anemia is due to inadequate production of hormone Erythropoietin by the diseased kidneys.
As renal function declines, there is a progressive worsening of anemia, which becomes clear once serum creatinine rises above 300 µmol/L or GFR falls below 30 ml/min/1.73m² and its major cause is the loss of cells in the kidney responsible for the synthesis and secretion of erythropoietin.
Factors that cause renal anemia:
• Iron deficiency
• Blood loss
• Folate deficiency
• Hyperparathyroidism with marrow fibrosis
• Aluminum toxicity
• Suppression of erythropoiesis by “uremic inhibitors”
Morphology of red blood cells by peripheral blood film of a renal anemic patient usually shows normocytic (normal size RBC’s but less in number), normochromic (condition in which hemoglobin concentration in RBC is within standard range), and hypoproliferative (anemia caused by inadequate production of erythrocytes). Cellularity of bone marrow might be diminished, normal or expanded, and blood volume shows decreased red cells mass yet normal total blood volume.
Anemia in CKD is common by the time the renal failure patient reaches the stage of CKD5D (Chronic Kidney Disease stage 5 on Dialysis) the hemoglobin will be around 6-8 g/dl and very few have normal hemoglobin levels. In many patients, improvement is seen in hemoglobin level after the initiation of dialysis, particularly in peritoneal dialysis patients.
Hemodialysis patients have a tendency to have higher prevalence and increased severity of anemia than peritoneal dialysis patients, due to increased blood loss and hemolysis. Better management of anemia is seen in peritoneal dialysis patients due to increased clearance of middle molecules.
CKD patient with adult Polycystic Kidney Disease tends to have higher hemoglobin concentration due to increased production of erythropoietin by cells lining the cysts, resulting in enhanced serum erythropoietin levels. Serum erythropoietin levels in polycystic kidney disease are on average twice as high in patients with non-cystic end-stage renal disease.
Analysis for Anemia in Renal Failure
A renal failure patient is said to be anemic when hemoglobin is <10g/dl, the most valuable tests that reveal the cause of anemia in renal failure:
• Red blood cell indices
• Blood film
• White blood cells and platelets
• Reticulocyte count
• Serum iron and total iron binding capacity
• Transferring saturation
• Serum ferritin
• Stool occult blood.
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