ANEMIA - PART II Anemia of Chronic Inflammation BY: Zorawar Noor 4/21/2014 Objectives Understand the pathogenesis of anemia of chronic inflammation (ACI) Review 4 Simple Laboratory Steps to diagnose anemia (from Part I) Learn the characteristics lab findings of ACI Learn how to find coexisting iron deficiency When to Suspect Anemia of Chronic Inflammation? In inflammatory, infectious, and malignant conditions (RA, SLE, osteomyelitis…) In cases with normocytic and normochromic anemia (usually mild and asymptomatic) Pathogenesis Inflammatory cytokine release (IL-6) triggers: Hepcidin Hepcidin decreases iron absorption in GI tract, and makes macrophages hold onto iron Bone marrow is hypoproliferative despite having slightly increased EPO levels EPO levels are not as high as they should be Unlike in iron deficiency anemia, where peripheral RBCs gain a longer circulating half-life, there is shorter RBC life span. 4 Steps to Classify Anemia (Review from Part I) Step 1 – Characterize by MCV Microcytic, normocytic, macrocytic Step 2 - Identify Morphologies on Peripheral Smear E.g. hypochromia, bite cells, etc. Step 3 – Calculate Reticulocyte Index Reticulocyte Index (RI) = ReticCount * 0.5(Hct/45) Step 4 – Use iron studies, bone marrow biopsy, etc. See presentation “Anemia, Part I” for more explanation of each step Diagnosis History: collagen vascular diseases, malignancies, osteomyelitis, etc. Step 1) MCV initially normal Step 2) if chronic, can see mirocytosis and hypochromia Step 3) Low Retic Count Step 4) normal or low iron, low TIBC, high ferritin Iron Studies in ACI Finding in Anemia of Chronic Inflammation Fe Mildly low TIBC Low % Sat Mildly low Ferritin High – very high MKSAP Case 2 A 22-year old woman undergoes a new patient evaluation. She was recently diagnosed with SLE. Her menstrual pattern is normal, and her medical history is otherwise noncontributory, her only medications are hydroxychloroquine and a multivitamin. On Physical exam: T37.2C, BP 126/78, P88, RR17, and the patient has a malar rash, thinning hair, but no joint abnormalities, oral lesions, pericardial or pleural rubs, or heart murmurs. Laboratory studies: Hgb 8.2, WBC 3900, Ferritin 556, Iron 18, Retic Count 2%, TIBC 180, Transferrin sat 10%, and creatinine 1.0. …MKSAP Case 2 …MKSAP Case 2 Which of the following is the most likely diagnosis? (A) inflammatory anemia (B) iron deficiency (C) microangiopathic hemolytic anemia (D) Warm Ab-associated hemolysis Answer Explanation History of SLE Step 1) MCV is low late in inflammatory anemia Step 2) Hypochromia is noticeable, also late finding Step 3) low RI is consistent with Inflammatory Anemia Step 4) Ferritin is high from inflammation, TIBC is low ( think of iron being stored away from pathogens needing it for their own use through hepcidin) Finding Coexisting Iron Deficiency Transferrin will often be reduced, not increased like it is in iron deficiency anemia (IDA) Unlike usual Inflammatory anemia, Soluble transferrin receptor (sTfR)-ferritin index Ration of the sTfR to logarithm of ferritin If index <1.0 suggests pure inflammatory anemia If index >2.0, could be IDA or combination Bone Marrow biopsy (macrophages with iron in ACD) Summary Just approach it one step at a time! Remember the pathogenesis of ACI, cytokines cause hypo-proliferation and low-iron because it stays in macrophages Always watch out for coexisting iron deficiency Treat the underlying cause. References Harrison’s Principles of Internal Medicine Adamson JW. Chapter 103. Iron Deficiency and Other Hypoproliferative Anemias. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J, eds. Harrison's Principles of Internal Medicine. 18th ed. New York: McGrawHill; 2012. http://www.accessmedicine.com/content.aspx?aID=91172 23. Accessed December 7, 2011 Wians, F.H. and Urban JE. “Discriminating between Anemia of Chronic disease Using Traditional Indices of Iron Status v. Transferring Receptor Concentration”. 2001. American Journal of Clinical Pathology. Volume 115. UptoDate