Hemolytic Anemias: General Considerations
Harold R. Schumacher, William A. Rock, Sanford A. Stass in Handbook of Hematologic Pathology, 2019
4. Reticulocytosis. There are several ways to utilize the reticulocyte count (typically expressed as the percentage of red cells which are reticulocytes) to evaluate red cell production by the marrow. The reticulocyte count may be expressed as an uncorrected percentage, or as the absolute reticulocyte count (percent reticulocytes multiplied by the red cell count per cubic millimeter), or as the corrected reticulocyte count (percent reticulocytes multiplied by patient’s hematocrit/45), or as the reticulocyte production index (corrected reticulocyte count multiplied by a factor which reflects the increased shift of less mature cells to the peripheral blood) (8). All of these modifications are efforts to remind the clinician that a reticulocyte count of 1%, which is perfectly adequate to maintain a hematocrit of 45%, is too low if the patient’s hematocrit is 25% (see Table 4 for normal values of reticulocyte evaluations). An elevated reticulocyte count is considered a hallmark of hemolytic anemia. However, as many as 37% of patients with autoimmune hemolytic anemia can present with reticulocytopenia (as defined by a reticulocyte production index <2%), and it is important to remember that absence of reticulocytosis does not rule out a hemolytic anemia (9, 10). Individuals with mild chronic hemolysis (particularly patients with hemoglobinopathies or thalassemia) often have a relatively normal hemoglobin concentration and hematocrit but have an elevated reticulocyte count: The shortened red cell survival requires extra marrow production in order to maintain a near-normal hematocrit/hemoglobin. The phenomenon of transient aplastic crises in chronic hemolysis due to B19 parvovirus infection will be discussed elsewhere.
Transient Erythroblastopenia of Childhood
Stephen A. Feig, Melvin H. Freedman in Clinical Disorders and Experimental Models of Erythropoietic Failure, 2019
The absolute reticulocyte count (normal 50 to 150,000/|μl) is almost always low, although the percent reticulocytes may be elevated if the patient is seen at the beginning of recovery. In our patients we have observed that the reticulocyte count has a bimodal distribution. The majority (42 of 56 cases) had less than 1% reticulocytes and in many patients no reticulocytes were seen. A small fraction (14 of 56 cases) had a mean reticulocytosis of 7%, ranging from 1.6 to 15.8%. The presence of significant reticulocytosis can confuse the diagnosis with other disorders, such as the recovery from bleeding.32
Idiopathic Pulmonary Hemosiderosis
Lourdes R. Laraya-Cuasay, Walter T. Hughes in Interstitial Lung Diseases in Children, 2019
Chronic and acute blood loss occurs in IPH, and since the iron contained in hemosiderin trapped within the lung is only scantily reutilized for erythropoiesis, iron deficiency anemia develops in most cases. Red cells are microcytic and hypochromic, total iron binding capacity may be elevated, and iron is decreased in the serum and absent from the bone marrow,25,26 but paradoxically, reticulocytosis is not uncommon.27 Indirect hyperbilirubinemia and eos-inophilia sometimes occur.1
Severe acute kidney injury owing to rhabdomyolysis and intravascular haemolysis in an 11-year-old child with G6PD deficiency
Published in Paediatrics and International Child Health, 2019
Milan Talwar, Sriram Krishnamurthy, Narayanan Parameswaran, C. G. Delhikumar, Satish Haridasan, Bheemanathi Hanuman Srinivas
Haemoglobin was 3.3 g/dL, total leucocyte count 3.3 × 109/L and platelet count 260 × 109/L. Red blood cells were normocytic and normochromic with moderate anisopoikilocytosis. Blood film demonstrated many fragmented red blood cells and reticulocytosis (corrected reticulocyte count 5%). Blood urea was 68.2 mmol/L (2.9–8.2), serum creatinine 610 μmol/L (53–106), sodium 136 mmol/L and potassium 4.1 mmol/L. Urinalysis showed no RBCs but tested positive for blood by multistix on several occasions. Lactate dehydrogenase was 114.7 μkat/L (1.7–3.4) and creatinine kinase total (CPK) 136 μkat/L (0.67–2.5). The investigations were consistent with severe intravascular haemolysis in association with rhabdomyolysis, resulting in haemoglobinuria and myoglobinuria. Rhabdomyolysis was diagnosed on the basis of high levels of LDH, elevated blood CPK and the presence of myoglobin casts in the renal tubules demonstrated in the renal biopsy on immunohistochemistry.
Current and emerging treatment options for autoimmune hemolytic anemia
Published in Expert Review of Clinical Immunology, 2018
Wilma Barcellini, Bruno Fattizzo, Anna Zaninoni
Bone marrow is undoubtedly the fundamental hematopoietic organ and also a key element of the lymphatic/immune system. It produces approximately 500 billion blood cells/day, including both myeloid and lymphoid lineages. The latter, after completing their maturation in other lymphoid organs (e.g. thymus), and through trafficking in the circulation and tissues, may become true immune effectors even in the BM. BM examination is not routinely performed in benign hematology, as it is generally assumed that an effective compensatory activity (reticulocytosis) occurs constantly after a peripheral immune-mediated destruction. Indeed, reticulocytopenia/inadequate reticulocytosis is present in more than a half of AIHA patients, typically in very severe cases and in CAD and mixed forms. Reticulocytopenia has been reported particularly in children, representing a clinical emergency with an extremely high transfusion need, and also attributed to an autoimmune reaction against BM erythroblasts [66–69]. Erythropoietin has been shown effective in AIHA, particularly in the presence of reticulocytopenia and in chronic, transfusion-dependent CAD to avoid overtransfusion [2,4]. Moreover, the androgen danazol has recently received attention for its promising effects in aplastic anemia (AA), a disease known for an immunological attack against BM precursors [70,71]. In this setting, its efficacy has been possibly attributed to telomere elongation. As a matter of fact, this drug has been used since long time in autoimmune diseases including AIHA, without knowing a definite mechanism of action.
Mild erythrocytosis as a presenting manifestation of PIEZO1 associated erythrocyte volume disorders
Published in Pediatric Hematology and Oncology, 2019
Tristan Knight, Ahmar Urooj Zaidi, Shengnan Wu, Manisha Gadgeel, Steven Buck, Yaddanapudi Ravindranath
Case 1: Patient 1 was evaluated at age 17 years for mild polycythemia and reticulocytosis. Medical history included anxiety, depression, and attention-deficit hyperactivity disorder (ADHD), and medications included sertraline, methylphenidate, and minocycline. Family history was significant for heart failure of unknown etiology in the father and paternal grandfather. Peripheral blood smear showed both spherocytes and stomatocytes (Figure 1D), Osmoscan was consistent with mild spherocytosis and EMA MCF was reduced, suggesting reduced band 3 content (Figure 1E). Laboratory values are listed in Table 1. No abnormal hemoglobins were noted on hemoglobin evaluation; Hb p50 was 25.6 mmHg (reference range (RR) 24–28 mmHg). Serum erythropoietin was 18.7 mIU/mL (RR 4.3–29.0), giving a normalized value of +58.35.