| Defining Alpha Thalassemia Alpha thalassemia demonstrates problems with alpha globin chain production. One to four loci that code for the alpha chain may be deleted from chromosome 16. The greater the number of loci deleted or inactivated, the greater the severity of the anemia which develops. Many different mutations exist that result from partial deletions of alpha genes. This unit of study deals only with the forms of alpha thalassemia that have entire loci deleted. | View Page |
| Anemia in Alpha Thalassemia In thalassemia there is often an excess production or accumulation of globin chains produced by genes that are not effected by the thalassemia deletion. In alpha thalassemia this may be seen as gamma chain tetramers (hemoglobin Bart's) in the unborn child and as beta chain tetramers (hemoglobin H) in adults. Tetramer accumulation often leads to red blood cell damage and hemolytic anemia. | View Page |
| Alpha Thalassemia Intermedia Alpha thalassemia intermedia (Hemoglobin H Disease) results from a deletion of three out of four alpha chain loci. Infants born with alpha thalassemia intermedia appear normal at birth but often develop anemia and splenomegaly by the end of their first year. Hepatomegaly is not a common finding and there may be some association with mental retardation. Due to the hemolytic nature of this anemia, there may be an increase in respiratory infections, leg ulcers and gallstones. Skeletal changes are not commonly seen in hemoglobin H disease. Every ethnic group can have occurrences of hemoglobin H disease; but it is most often seen in Southeast Asian, the Middle East and the Mediterranean islands. Development and life expectancy are usually normal, but some affected individuals may require splenectomy and transfusion therapy. | View Page |
| Case History A 29 year old female was seen by her physician for fatigue. She is of Philippine descent; and a relative told her that their family has a long history of anemia.She presented with sclera icterus and her spleen was palpable. Routine blood work was initially ordered. | View Page |
| What is the classification of this patient's anemia, based on the CBC results? | View Page |
| What is the differential diagnosis for this patient, based on the CBC results? | View Page |
| What laboratory tests should be performed to aid in the diagnosis of this anemia? | View Page |
| Summary The normal RBC count (4.84 x 1012/L) in this case, together with the decreased hemoglobin (8.4 g/dL) and MCV (59 fl) is an indicator of ineffective erythropoeisis that often points to thalassemia.The RBC morphology shows slight hypochromic microcytosis with codocytes, schizocytes, and basophilic stippling. Schizocytes form by several mechanisms, one being the removal of RBC inclusions.This patient's elevated bilirubin correlates with her presentation of sclera icterus; her splenomegaly is consistent with increased RBC destruction.The Hb electrophoresis demonstrated a normal pattern, initially, but the unstable Hemoglobin H was revealed upon repeat electrophoresis with reduced incubation time. Hemoglobin H is the result of beta globin chain tetramer formation due to the insufficient supply of alpha globin chains in alpha thalassemia intermedia.People with Hemoglobin H disease (alpha thalassemia intermedia) usually have a normal life expectancy without treatment. However, hemolysis may lead to moderate anemia that may be treated with splenectomy. | View Page |
| Alpha Thalassemia Major Anemia is fatal.Red blood cell (RBC) count is increased.Hemoglobin (Hb) is severely decreased.Mean corpuscular volume (MCV) is decreased. Mean corpuscular hemoglobin concentration (MCHC) is decreased.Red cell distribution width (RDW) is increased.RBC morphology shows slight hypochromic microcytosis with codocytes, schizocytes, nucleated RBCs.Reticulocytes are increased.Hb electrophoresis demonstrates abnormal pattern on cord blood: Hb A - absentHb Bart's - 80-90%Hb Portland - 0-20%Bone marrow demonstrates marked erythroid hyperplasia. | View Page |
| Alpha Thalassemia Intermedia Anemia is moderate.RBC count is increased.Hb is moderately decreased.MCV is decreased. MCHC is decreased.RDW is increased.RBC morphology shows slight hypochromic microcytosis with codocytes, schizocytes, and basophilic stippling.Reticulocytes are moderately increased.Hb electrophoresis demonstrates abnormal patterns in both adults and neonates.Adults:HbA decreasedHbA2 decreasedHbF normal to decreasedHb H -2-40% (beta chain tetramers)Neonates: 10-40% Bart's (gamma chain tetramers)Hb H inclusions are frequently seen.Bone marrow demonstrates erythroid hyperplasia. | View Page |
| Alpha Thalassemia Minor Anemia is mild to absent.RBC count is increased.Hb is slightly decreased.MCV is decreased. MCHC is slightly decreased.RDW is normal to slightly increased.Red Blood Cell morphology shows slight hypochromic microcytosis.Reticulocytes are normal to slightly increased.Hb electrophoresis demonstrates a normal pattern in adults:Hb A - 97-98% Hb A2 - 1-2.5% Hb F - <1%. Neonates have 5-15% Bart's Hemoglobin (gamma chain tetramers).Hb H inclusions are rarely seen.Bone marrow demonstrates erythroid hyperplasia. | View Page |
| Silent Carrier Anemia is absent.RBC count is within normal limits.Hb is within normal limits.MCV is normal to slightly decrease.MCHC is normal to slightly decrease.RDW is within normal limits.Red Blood Cell morphology is normal.Reticulocytes are within normal limits.Hb electrophoresis demonstrates a normal pattern in adults:Hb A - 97-98%Hb A2 - 1-2.5% Hb F - < 1%. Neonates have 1-2% Bart's Hemoglobin (gamma chain tetramers).Hb H inclusions are rarely seen.Bone marrow is normal. | View Page |
| Serum Bilirubin Bilirubin is formed as a result of hemoglobin degradation. Normally, senescent red blood cells are removed from circulation and the bilirubin that is formed is processed by the liver. The normal level of bilirubin in the serum of adults is 0.2-1mg/dl. Bilirubin levels increase with liver disorders and also in anemia that is a result of a hemolytic process. Patients may display jaundice when serum bilirubin levels exceed 2mg/dl.Persons with alpha thalassemia intermedia usually have an increased bilirubin level, because of ongoing hemolysis. This bilirubin is typically the unconjugated fraction of bilirubin. | View Page |
| Defining Beta Thalassemia Beta thalassemia demonstrates problems with beta globin chain production. One or two loci that code for the beta chain may be deleted from chromosome 11. The greater the number of loci deleted or inactivated, the greater the severity of the anemia which develops. Many different mutations exist that result from partial deletions of beta genes. This unit of study deals only with the forms of beta thalassemia that have entire loci deleted. Deletions of additional globin genes coded for on chromosome 11 can result in such combinations as delta-beta thalassemia. | View Page |
| Anemia in Beta Thalassemia In thalassemia, there is often an excess production or accumulation of globin chains whose genes are not affected by the deletion.In beta thalassemia, this may be seen as an increase in gamma chain and delta chain production, leading to increased levels of hemoglobin F and A2 respectively.Excess alpha chains may also form tetramers which often lead to red cell membrane damage and decreased red cell deformability. This leads to a hemolytic anemia. Adding to the anemia is a decrease in the total amount of hemoglobin produced in spite of the erythroid hyperplasia of the bone marrow. | View Page |
| Beta Thalassemia Major Children with beta thalassemia major, also called Cooley's anemia, usually develop clinical signs during their first year of life. They appear to be malnourished and may exhibit abdominal girth expansion. They show skeletal deformations, which are a result of increased erythropoiesis. A common finding is facial bone changes. Other clinical signs include frequent infections, hepatomegaly, splenomegaly, cardiomegaly, gall stones, leg ulcers, and poor growth and sexual development. Death usually occurs by the time these patients are in their early twenties unless treated with blood transfusions along with iron-chelating agents. If no chelating agent is used during treatment life will only be prolonged by about a decade.Beta thalassemia is found most often in populations of people from the Mediterranean, southern China, and India. | View Page |
| Hematologic Findings For Various Types of Beta Thalassemia Beta Thalassemia Silent Carrier Beta Thalassemia Minor Beta Thalassemia Intermedia Beta Thalassemia Major Delta-Beta Thalassemia Anemia Absent Mild to absent Moderate Severe Mild Red blood cell (RBC) count Normal Increased Decreased to normal Decreased Decreased to normal Hemoglobin(Hb) Normal Decreased to normal (10 - 12 g/dL) Decreased (7 - 10 g/dL) Marked decrease (<7 g/dL) Decreased to normal (8 - 13 g/dL) Mean corpuscular volume (MCV) Slight to no decrease Marked decrease Marked decrease Marked decrease May be slightly decreased Mean corpuscular hemoglobin concentration (MCHC) Slight to no decrease Marked decrease Marked decrease Marked decrease May be slightly decreased Red blood cell distribution width (RDW) Normal Normal to slightly increased Increased Increased Normal RBC morphology Normal Marked hypochromia and microcytosis Codocytes (target cells) Possible basophilic stippling Nucleated RBCs are usually not present Marked hypochromia and microcytosis Codocytes (target cells) Possible basophilic stippling Nucleated RBCs are usually not present Marked hypochromia and microcytosis Codocytes (target cells) schistocytes ovalocytes basophilic stippling polychromasia nucleated RBCs Possible hypochromia and microcytosis Codocytes (target cells) Basophilic stippling Reticulocyte count Normal May be slightly increased Slightly increased (<5%) Mildly increased (5 - 10%) Mildly increased Hb electrophoresis Normal pattern Decreased amount of Hb A Variable amounts of Hb A2 and Hb F Decreased amount of Hb A Variable amount of Hb A2 Hb F is usually increased Severly decreased amount of Hb A Variable amount of Hb A2 Usually an increased amount of Hb F Decreased amount of Hb A and Hb A2 Increased amount of Hb F (15 - 20%) If red blood cells are normochromic and normocytic, the RBC, Hb, and Hematocrit (HCT) test values follow in three-fold progression (i.e., RBC x 3 = Hb and Hb x 3 = HCT). This is sometimes referred to as "the rule of threes." This rule will usually not apply in cases of beta thalassemia, particularly beta thalassemia minor where the RBCs are not normochromic and are microcytic, and where there is a disproportionate number of RBCs for the amount of hemoglobin that is present. | View Page |
| Serum Bilirubin Bilirubin is formed as a result of hemoglobin degradation. Normally, senescent red blood cells are removed from circulation and the bilirubin that is formed is processed by the liver. The normal level of serum bilirubin for adults is 0.2-1mg/dL.Bilirubin levels increase with some liver disorders and also in anemia that is a result of a hemolytic process. Patients may display jaundice when serum bilirubin levels exceed 2mg/dL.Persons with beta thalassemia major usually have an increased bilirubin level. This bilirubin is typically the unconjugated fraction of bilirubin. | View Page |
| Why is it important to note that the red cell distribution width (RDW) in this case is normal ? | View Page |
| Case History Summary The laboratory findings in this case represent classic findings seen in beta thalassemia minor including: erythrocytosis, decreased hemoglobin, normal hematocrit, normal RDW, and the presence of codocytes (target cells). This patient does have a mild anemia, but some patients with beta thalassemia minor have no anemia. Hemoglobin electrophoresis confirms this diagnosis, showing an increased Hb A2 level and decreased Hb A.In addition, the slightly increased iron and slightly decreased TIBC contradict a suspicion of iron deficiency. These chemistry results are typical for beta thalassemia, even though the red blood cells are microcytic and hypochromic. | View Page |
| The RBCs found in this illustration are the result of: | View Page |
| The abnormal RBC indicated by the arrow in this illustration is indicative of: | View Page |
| The abnormal RBCs seen in this illustration are indicative of: | View Page |
| Which of the following conditions might give rise to the red cell abnormality depicted here: | View Page |
| The abnormal RBCs seen in this smear, such as those shown by the arrow are typically seen in: | View Page |
| Coarse basophilic stippling in all of the following EXCEPT: | View Page |
| The abnormal RBCs shape seen in this illustration is: | View Page |
| Identify the object contained in the cell in this illustration indicated by the arrow: | View Page |
| Identify the object contained in the cell in this illustration indicated by the arrow: | View Page |
| Which of the following conditions is frequently associated with these cells? | View Page |
| Howell-Jolly bodies are composed of: | View Page |
| Which of the following would not be represented in the usual classification of anemia: | View Page |
| Which two of the following are associated with macrocytic anemia? | View Page |
| Which of the following is not primarily a hemolytic process? | View Page |
| Spherocytes are associated with which two of the following conditions: | View Page |
| Aplastic anemia may be caused by all expect the following: | View Page |
| Eosinophilia is commonly found in which of the following disorder(s): | View Page |
| Which one of the following statements about iron deficiency anemia is false: | View Page |
| The reticulocyte count is used to assess which of the following: | View Page |
| Pappenheimer bodies are usually seen in patients who have had: | View Page |
| Cabot rings may be seen in rare occasions in patients who have: | View Page |
| More on Howell-Jolly Bodies Under normal conditions, Howell-Jolly bodies are thought to be remnants of nuclear fragments due to incomplete expulsion of the nucleus. In pathological conditions, they are aggregates of chromosomes which have separated from the mitotic spindle during abnormal mitosis. Single or multiple Howell-Jolly bodies may be found in a red cell. A single HJ body in a red cell may be seen in megaloblastic anemia, hemolytic anemia such as sickle cell anemia and after splenectomy. Megaloblastic anemia or abnormal erythropoiesis is usually present when multiple Howell-Jolly bodies are observed in a single cell. | View Page |
| In which of the following conditions would you expect to find Howell-Jolly bodies? | View Page |
| More on Pappenheimer bodies Pappenheimer bodies, while visible on a Wright's stained smear, should be Perls' Prussian blue stain, which is specific for iron. Pappenheimer bodies are seen in certain types of anemia characterized by an increase in the storage of iron, such as sideroblastic anemia and thallassemia. These inclusions are also seen in the peripheral blood following a splenectomy. In a healthy person with a normal spleen, Pappenheimer bodies are destroyed before the erythrocytes enter the peripheral circulation. | View Page |
| Stress Reticulocytes When the large reticulocytes normally found in the bone marrow are present in the peripheral blood, they are referred to as shift or stress reticulocytes. These cells may be up to twice the size of normal mature red cells and are an indication of the bone marrow’s response to severe anemia. In addition to recognizing their appearance as polychromatophlic cells on Wright’s stained smears, it is now possible to quantify stress reticulocytes using a flourescent stain. They are classified as high, medium or low using a fluorescent-sensitive flow cytometer. | View Page |
| Fine and Coarse Basophilic Stippling Fine basophilic stippling is associated with increased red cell production and is commonly seen when there is increased polychromatophilia. Coarse basophilic stippling is seen in megaloblastic anemia and other forms of severe anemias, lead poisoning, and thalassemia. Coarse basophilic stippling indicates impaired hemoglobin synthesis, probably due to the instability of RNA in the young cell. | View Page |
| Identify the conditions in which Cabot rings are occasionally seen. | View Page |
| What are Cabot rings? Thin, red-violet-staining strands in the shape of rings, figure eights, or shapes of the letter B may on rare occasions be seen in erythrocytes. These structures are called Cabot rings. Although the origin of Cabot rings continues to be ellusive, they are not nuclear fragments since they test Feulgen negative. The rings are probably microtubules remaining from a mitotic spindle. Cabot rings have been observed in a few cases of megaloblastic anemia, lead poisoning and other disorders of erythropoiesis, as well as, after a splenectomy. | View Page |
| References 1. Beutler E. Iron storage disease: Facts, fiction and progress. Blood Cells Mol Dis. 2007;39:140-7.2. Higgins T, Beutler E, Doumas BT. Hemoglobin, iron, and bilirubin. In: Burtis CA, editor. Teitz Fundamentals of Clinical Chemistry. 6th ed. Saunders Elsevier, 2008.3. Ganz T. Hepcidin, a key regulator of iron metabolism and mediator of anemia and inflammation. Blood 2003;102(3):78-8.4. Andrews NC, Schmidt PJ. Iron homeostasis. Annu Rev Physiolo. 2007;69:69-85.5. Murtagh LJ, Whiley M, Wilson S, et al. Unsaturated iron binding capacity and transferrin saturation are equally reliable in detection of HFE hemochromatosis. Am J Gastroenterol. 2002;97(8):2093-9.6. Haddy TB, Castro OL, Rana SR. Hereditary hemochromatosis in children, adolescents, and young adults. Am J Pediatr Hematol Oncol 1988;10:23-4.7. Edwards CQ, Ajoika RS, Kushner JP. Hemochromatosis: A genetic definition. In Barton JC, Edwards CQ, eds. Hemochromatosis: Genetics, Pathophysiology, Diagnosis and Treatment. Cambridge, UK:Cambridge Univ Pr 2000:8-11.8. Whitlock EP, Garlitz BA, Harris EL , et al. Screening for Hereditary Hemochromatosis: A Systematic Review for the U.S. Preventive Services Task Force. Ann Intern Med. 2006; 145: 209-23.9. Wallace DF, Subramaniam VN. Non-HFE haemaochromatosis. World J Gastroenterol. 2007;13(35):4690-8.10. Tavill AS. Diagnosis and management of hemochromatosis. Hepatology. 2001;33:1321-811. Qaseem A, Aronson M, Fitterman N, Snow V, Weiss KB, Owens DK, et al. Screening for hereditary hemochromatosis: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2005;143:517-21.12. Phatak PD, Bonkovsky HL, and Kowdley KV. Hereditary Hemochromatosis: time for targeted screening. Ann Intern Med. 2008; 149(4): 270 – 2.13. Brissot P, deBels F. Current approaches to the management of hemochromatosis. Hematology Am Soc Hematol Educ Program. 2006:36-41. 14. Guidance for industry: Variances for blood collection from individuals with hereditary hemochromatosis. http://www.fda.gov/cber/gdlns/hemchrom.htm Accessed 12/17/08. | View Page |
| Secondary Disorders of Iron Overload In addition to hereditary hemochromatosis (HH), there are other conditions of iron overload that must be considered in a differential diagnosis. Disorders such as sickle cell disease, thalassemia, sideroblastic anemia, congenital dyserythropoietic anemia, and liver disease may also cause iron overload. Transfusion-dependant patients and persons who abuse iron-containing vitamin supplements are also at risk. These conditions are usually described as secondary iron overload, in contrast to the primary iron overload of HH.Patient history, clinical signs and symptoms, biochemical and hematologic laboratory analyses, and possibly results of a liver biopsy may be needed to establish a diagnosis of a condition causing secondary iron overload. DNA tests for common HFE mutations are very likely the most important diagnostic tool for identifying HH as the cause of iron overload. In some patients, both secondary causes and HH may be contributing to iron overload. Differentiating the secondary causes of iron overload from HH is heavily dependent on the results of laboratory assays, but a complete discussion is beyond the scope of this course. | View Page |
| Which of the following is NOT considered to be a cause of secondary iron overload? | View Page |
| Serum Iron Serum iron (SI) is a measure of circulating iron bound to transferrin and is reflective of total body iron. SI is elevated in hereditary hemochromatosis (HH) and acute hepatitis. SI is decreased in iron deficiency anemia and chronic inflammation. SI concentrations exhibit diurnal variation, with the lowest values occurring around midnight. In addition, specimens collected from the same individual at the same time of the day may exhibit day to day variations as high as 40%. SI determinations are also affected by diet, menstrual cycle, pregnancy, ingestion of iron supplements, and oral contraceptive use. SI levels alone are considered insensitive indicators of HH. SI is typically measured on automated analyzers using spectrophotometric methods. Iron in the sample is released from transferrin with an acid reagent, reduced to the ferrous state, and reacted with a chromogen such as bathophenanthroline or ferrozine. The intensity of the color change is proportional to the iron concentration. Interference can arise from the use of a hemolyzed sample and contamination of reagents and water with iron. A typical reference interval for SI is 60 - 150 micrograms/dL. SI is usually ordered along with its companion test, the total iron binding capacity (TIBC), or with transferrin (Tf).(2) | View Page |
| Transferrin and Total Iron Binding Capacity The test for transferrin (Tf) measures the concentration of the primary carrier protein for iron. Measuring total iron binding capacity (TIBC) is an indirect method of assessing transferrin and provides comparable information. The TIBC (or transferrin) are typically performed along with the SI. Taken together, these determinations are useful in the differential diagnosis of many disorders affecting iron metabolism, including hereditary hemochromatosis (HH) and iron deficiency anemia. Tf and TIBC are typically low-normal or decreased in HH and are increased in iron deficiency. Serum transferrin can be measured directly using immunochemical methods such as nephelometry and turbidimetry. TIBC is performed in a 2-step method by adding ferric iron to the specimen in sufficient quantity to completely fill all of the iron binding sites on transferrin. Excess, unbound iron is removed by adsorption with magnesium carbonate, alumina, or ion resin. The iron content of the saturated binding protein is then measured as described for SI. Serum is the specimen of choice for Tf and TIBC. TIBC is less subject than SI to day-to-day variation and other causes of variability.A typical reference interval for TIBC is 300 - 360 micrograms/dL.(2) | View Page |
| Quantitative Phlebotomy An alternative to liver biopsy as a means of documenting iron overload may be provided by quantitative phlebotomy performed during treatment (See next section.) The removal of 4 to 5 grams of iron through documented successive phlebotomies (16 to 20 phleblotomies) without development of anemia is indicative of iron overload. (One unit, or 450 mL, of blood is assumed to contain approximately 200 to 250 mg of iron.) Quantitative phlebotomy is useful in patients for whom liver biopsy is contraindicated, refused, or not needed for other reasons. | View Page |
| Initial Treatment Phlebotomy is considered the treatment of choice for patients with iron overload due to hereditary hemochromatosis (HH). Each unit of blood contains approximately 200 to 250 mg of iron. As erythrocytes are removed by phlebotomy, iron stores are mobilized and utilized in the production of new, circulating erythrocytes. Through periodic phlebotomies, stored iron is removed until iron-deficient erythropoiesis is induced. The initial, or iron reduction, phase of treatment typically consists of removing one unit (450 mL) of whole blood once or twice weekly. Prior to beginning phlebotomy, the patient’s hemoglobin and hematocrit must be checked to ensure that the patient is not anemic. A sample for serum ferritin is also collected at this time.Initial treatment goals include inducing iron deficient hematopoiesis without the development of debilitating symptoms of anemia. A hemoglobin concentration of 10.0 to 12.0 g/dL is often used as a target range. The initial treatment phase continues until excess stored iron is removed and ferritin levels decrease to approximately 50 ng/mL. (13) Ferritin and hemoglobin levels are periodically monitored during this phase. The number of phlebotomies needed to reduce iron levels and induce anemia is related to the degree of initial iron overload. Patients may be referred to a hematologist or gastroenterologist during the initial treatment phase. Many patients receive therapeutic phlebotomy services in a hospital or doctor’s office, but patients may also undergo phlebotomy at a blood center. Blood collected from persons with HH may be used for transfusion or as blood products if it has been collected from a facility with an approved variance from the US Food and Drug Administration. Not all blood centers have applied for or been granted this variance.(14)The initial treatment phase continues until excess stored iron is removed and ferritin levels decrease to approximately 50 ng/mL. Removal of excess stored iron may take from one month to three years. | View Page |
| Other Treatments Deferoxamine (DFO), an iron chelating agent, may be used to reduce iron overload in patients for whom phlebotomy is contraindicated or not well tolerated. Examples include patients with sickle cell disease or thalassemia whose anemia would be exacerbated by phlebotomies. DFO is seldom used to treat hereditary hemochromatosis (HH) due to the low cost and efficacy of phlebotomy therapy. DFO is typically administered by intravenous or subcutaneous infusion.Patients with HH may be counseled to avoid alcohol use in order to avoid liver damage. With the exception of iron supplements, dietary restrictions on iron ingestion are rarely advised. | View Page |
| Note the view of a peripheral blood smear in the photograph. Pictured are scattered acanthocytes, echinocytes, target cells, spherocytes, and schistocytes. The condition in which each of these atypical RBC's may be found in varying numbers in the same peripheral blood smear is: | View Page |
| The condition most likely associated with the peripheral blood picture shown in the photograph is: | View Page |
| Match the form of red cell inclusions in each of the frames of photographs with a corresponding clinical condition. | View Page |
| The condition most likely associated with the peripheral blood picture in the photograph is: | View Page |
| Conditions in which erythrocytes as photographed here may be present in a peripheral blood smear include: | View Page |
| What are the erythrocyte inclusions that are indicated by the arrows on this blood smear? | View Page |
| An 8 year old girl is protected from severe hemolytic anemia by an elevated fetal hemoglobin level ( hemoglobin F). | View Page |
| Cells as shown in this iron-stained bone marrow preparation are found in each of the following conditions except: | View Page |
| The peripheral blood picture is consistent with each of the following conditions except: | View Page |
| Pappenheimer bodies Pappenheimer bodies are iron-containing granules that aggregate with mitochondria and are deposited in RBC or normoblast cytoplasm. Small and irregular, they are found only in pathological states as thalassemia and sideroblastic anemias(upper image). Wright-Giemsa stain defines the cytoplasmic content (protein), but Prussian blue staining is necessary to define the iron content, the essence of the Pappenheimer body (lower image). Pappenheimer bodies lie typically in small clusters (upper image) and tend to locate at the periphery of the red cell cytoplasm. A cluster is typically smaller than a single Howell-Jolly body. | View Page |
| The peripheral blood smear represented by this field was submitted for hematologic review. The RBC inclusions most likely are: | View Page |
| Leukoerythroblastosis Illustrated in this field is a normoblast and a myelocyte, representing leukoerythroblastosis, a term associated with the release of immature cells from a disrupted marrow. Metastatic disease in the bone marrow, particularly in patients with primary breast or prostate cancer, is usually the culprit. Leukoerythroblastosis in the absence of anemia or thrombocytopenia is a signal to search for cancer metastic to the marrow. Nucleated RBCs were not identified on the blood smear seen here but were detected by an automated analyzer.The mortality rate of elderly patients with increased NRBCs, especially following accidents or general surgery, is greater. | View Page |
| Schistocytes vs. bite cells Schistocyte is a general term for a fragmented red blood cell that may assume various shapes, some with horn-like projections (keratocytes), triangle-forms (triangulocytes), and helmet shapes, as illustrated in the upper photograph. Schistocytes are formed when erythrocytes are forced through a vessel blocked with interlacing fibrin strands and the red cells are sliced into fragments. True schistocytes are devoid of central pallor. These damaged cells continue to circulate while healing their torn edges. Finally, they are removed by the spleen. Bite cells (lower photograph) appear when an abnormal hemoglobin aggregate (Heinz body) is nibbled out of a red cell's cytoplasm by the spleen leaving a bitten apple appearance. Glucose 6-PD deficiency secondary to chemical poisoning or injury by oxidant drugs are settings for Heinz body formation, and the telltale bite cells remain as evidence. Hemolytic anemia associated with severe liver disease is another setting where bite cells are formed. | View Page |
| DIC: graft vs. host disease The peripheral smear illustrated in the photograph was obtained from a patient with a recent renal transplant. The patient developed a rash, accompanied by nausea and diarrhea. Graft vs. host disease was clinically suspected. The peripheral smear findings are consistent with that diagnosis. The presence of spherocytes suggests a hemolytic process which is supported by the presence of nucleated RBCs. A few scattered schistocytes and the decrease of platelets suggests DIC. The presence of target cells presents the possibility of associated liver disease. Additional tests, particularly coagulation studies, should confirm the diagnosis of microangiopathic hemolytic anemia. | View Page |
| The underlying condition where the defective erythrocytes marked by arrows are of diagnostic importance is: | View Page |
| Spherocytes and reticulocytes The photograph represents peripheral blood smear findings in another patient with hereditary spherocytosis. The red cells vary in size (anisocytosis)with a mixture of microcytes (red cells with central pallor) and microspherocytes (red cells with central staining). Macrocytes are conspicuous, some staining light blue. They are immature erythrocytes (reticulocytes)released from the bone marrow early. The bone marrow, geared up for rapid cell release in response to severe hemolysis, expels young red blood cells into the circulation before completing their 24 hour maturation cycle. Hemolysis, jaundice, and gall stone formation disappear following splenectomy. Gallbladder and stone removal eliminate the right upper quadrant pain. A serious consideration, especially in children with hereditary spherocytosis, is hemolytic crisis. A viral infection may allow red blood cell destruction to continue unabated. Anemia of such sudden onset and severity may become catastrophic, with death as the outcome. Splenectomy removes this possibility. | View Page |
| A 10-year-old child presents with jaundice and scleral icterus. The photograph captures a section of the peripheral blood smear. The report should direct attention to: | View Page |
| Considering the predominance of microspherocytes on the blood smear, and the patient's jaundiced condition, what is the most likely diagnosis? | View Page |
| Sickle cells This photograph of a peripheral blood smear from an 18-year-old North African woman with anemia reveals sickle cells. Target cells are not conspicuous. This shifts the diagnostic evidence away from HbSC disease. Cells tagged by arrows are variants of sickle cells. These may appear when multiple abnormal hemoglobin combinations are responsible for the clinical problem. The cell marked by the single arrow is an envelope formed not only in HbS disease but in HbC disease as well. Two arrows tag a blister cell, which, when seen in several fields, should prompt a hemoglobin electrophoresis to determine the presence of an undiagnosed hemoglobinopathy. Blister cells with fuzzy edged pseudo-vacuoles (see photo) are to be distinguished from the pseudo-vacuoles (blister)with razor sharp edges suggesting a microangiopathic state. | View Page |
| Atypical smear: Case follow-up The patient whose blood smear is shown in the photograph was a 32-year-old female from Virginia who came to the high country of Colorado to ski. The day after arrival, she experienced shortness of breath, fatigue, and upper abdominal pain. She was seen in a medical center in the mountains where a working diagnosis of altitude sickness was made. A CBC revealed RBCs 5.1 x 1012/L, hemoglobin 12.8g/dL, MCV 60fL, hematocrit 40.9%, and normal total WBC, differential, and platelet count. The RDW was normal. Further questioning revealed a previous diagnosis of heterozygous beta-chain thalassemia. No other abnormal hemoglobins were found on hemoglobin electrophoresis, but HbA-2 was elevated to 5%, supporting the diagnosis of beta thalassemia. The patient's poikylocytosis and anisocytosis may be a clue to an underlying erythrocyte abnormality. Persons with iron deficiency anemia may experience various degrees of hypoxia upon arriving at high altitudes. Those with sickle cell disease and thalassemia minor (as in this case) may experience bone pain or other symptoms of "crisis" and/or alteration in the appearance of their erythrocytes upon sudden high altitude exposure. The classic teaching is that in differentiating iron deficiency anemia from thalassemia, increased RDW would favor iron deficiency; normal RDW favors thalassemia. | View Page |
| A peripheral smear with red blood cells photographed in a typical field was submitted for review. Which of the following conditions might be eliminated because of the cell population found here? | View Page |
| Hb E disease (continued) The family (cited in the previous case history) was from a region of Thailand where the physician knew HbE carriers are prevalent. Homozygous hemoglobin E is common in Southeast Asia and presents with very mild anemia and seldom requires transfusion. Over 30 million people in the world are HbE carriers, making this abnormal hemoglobin almost as common as HbS. Hemoglobin E is uncommon in North America and in Europe, but with changing immigration patterns, hemoglobinopathy E cannot be ignored. Peripheral blood smear findings of target cells, microspherocytes, red cell hypochromia, a few red blood cell fragments, and nucleated red blood cells require evidence from hemoglobin electrophoresis to establish a diagnosis. Clinically, a very important and severe syndrome is hemoglobin E/beta thalassemia in which there is hemolysis requiring repeated transfusions. The patient has a severe anemia, low MCV (50's), and high RBC. This is characteristic of Hgb E/beta thalassemia. | View Page |
| Leptocytes and target cells The peripheral blood smear of HbH disease presented before is reviewed in the upper photograph.As mentioned, these leptocytes are pale-staining with hemoglobin confined to a thin, flat, cell membrane.Illustrated in the lower photograph are target cells or codocytes (a term derived from a Greek word for hat)Membrane accumulations of phospholipids and cholesterol (particularly in obstructive jaundice) promote target cell formation.When these cells are spread out on a glass slide, a central bump of hemoglobin appears to produce the target, a manifestation of excess cellular membrane compared to the amount of hemoglobin inside.The early descriptions of thalassemias, then called hereditary leptocytosis (Mediterranean anemia, Cooley's anemia), include description of leptocyes, which may have represented HbH disease. | View Page |
| The arrangement of the erythrocytes in this peripheral smear should be reported out as rouleaux formation. | View Page |
| A blood smear represented by the photograph was submitted for hematologic review. Based on the erythrocyte morphology and the accompanying histogram, which of the following choices is the most likely situation or condition? | View Page |
| Hereditary ovalocytosis and elliptocytosis Ovalocytes are rod shaped erythrocytes with nearly parallel lateral walls. If the long axis of an erythrocyte is no more than twice as long as the short axis, the cell is an ovalocyte. If the long axis is more than twice as long as the short axis, the cell is an elliptocyte. Hemoglobin tends to collect at each end of these cells. The ends of the cells are rounded and never pointed, to be differentated from sickle cells. Ovalocytes present in greater than 25% of red cells on the blood smear are characteristic of hereditary ovalocytosis. The oval shape is attributed to a defect in horizontal red cell membrane protein interactions. Lesser numbers of circulating ovalocytes may be present in various anemias including megaloblastic, sideroblastic, iron deficiency, and in thalassemias. A rare ovalocyte (less than 1%) may be found on almost any peripheral blood smear. Resistance to malarial infection may be a beneficial attribute of hereditary ovalocytosis. | View Page |
| Stomatocytes Stomatocytes are erythrocytes with a slit-like central pallor. Otherwise, they resemble typical RBC's in size and shape. Unless 10% or more of the RBC's are stomatocytes, their presence is probably artifactual. Stomatocytes form at a low blood acidic pH as seen in exposure to cationic detergents, and in patients receiving phenolthiazine. Hereditary stomatocytosis has some resemblance to hereditary spherocytosis, as stomatocytes may develop into spherocytes with further metamorphosis. In hereditary stomatocytosis, mild anemia and findings of on-going hemolysis should be evident if the condition presents as a clinical problem at all. | View Page |
| The arrow on this photomicrograh points to a macrocyte. The oval shape should be noted on the patient report. | View Page |
| Another View Another view taken from the same patient's slide. Although no lymphocyte is seen in this field, many of the cells appear quite small with increased areas of central pallor. This patient had iron deficiency anemia. | View Page |
| Microcyte with Normal Hemoglobin Content The arrow points to a microcyte with normal hemoglobin content (one-third of central pallor). Since many of the other cells in this field are normal or larger than normal, the mean corpuscular volume (MCV) would be within the normal range although the diameter and volume of this individual cell would be lower than normal. This type of microcyte can be seen in some hemolytic anemias and the rare enzyme deficiency, pyruvate kinase deficiency anemia. | View Page |
| Another Example of Macrocytosis This peripheral blood smear is from a patient with pernicious anemia, which results from an inability to absorb the vitamin B12 needed for DNA synthesis. Since many cells are destroyed in the bone marrow, decreased numbers of red cells are present in the circulating blood, resulting in anemia. However, the red cells that are present are generally macrocytes and are filled with hemoglobin. | View Page |
| Anisocytosis Anisocytosis is a general term used to describe increased variation in size of the red cell population present on a blood smear. The normal size of red cells varies from approximately 6 to 9 microns. Notice that normal, small, and large cells can be seen in this field. Since several populations of cells are present, this abnormality will not be reflected in the mean corpuscular volume (MCV) value, which is the average size of all the red cells that are counted. However, anisocytosis will affect the red blood cell distribution width (RDW), which is a measure of red cell size variation. As the severity of an anemia increases, the amount of significant anisocytosis present may also increase. | View Page |
| Summary of Anisocytosis Anisocytosis is a general term reflecting increased variation in the size of red blood cells. The MCV will be within normal limits, but RDW will be increased. Variation usually affects a continuum of red cell sizes, but occasionally two distinct red cell populations can be observed(for example in sideroblastic anemia, or after red cell transfusion.) | View Page |
| Microcyte Diameter The diameter of microcytes is less than 7 microns and the MCV is below 80 cubic microns. Notice that many of the red cells shown in this field are smaller than the nucleus of the lymphocyte and, in addition, have a greater area of central pallor. This type of microcyte can be seen in iron deficiency anemia and thalassemia. | View Page |
| Another Example of Microcytes Another example of microcytes seen in a slide from a patient with hemolytic anemia. Compare the two microcytes in the center of the field with the lymphocyte to the right. Notice the larger red cell just below the microcytes is about the same size as the lymphocyte. Several other microcytes can also be seen in this field. | View Page |
| Conditions Causing Teardrop Cells Conditions in which teardrop cells can be found include myelofibrosis/myeloid metaplasia, bone marrow metastases, thalassemias, and anemias causing Heinz body formation. Dacryocytes are not diagnostically indicative of any specific condition. | View Page |
| Another Knizocyte Another example of a knizocyte is seen in this slide. These forms are seen in conditions in which spherocytes are visible and in some types of hemolytic anemia. | View Page |
| Conditions Associated with Spherocytes Examples of conditions in which spherocytes can be seen include hereditary spherocytosis and immune hemolytic anemias (i.e., ABO incompatibility). Spherocytes can also form in conditions where there has been a direct physical or chemical injury to the cells. An example would be a smear from an individual who has suffered severe burns. In hereditary spherocytosis, a condition where spherocytes are numerous, the MCHC value will be at the upper limits of normal, or about 36. The identification of spherocytes on the smear of a patient with hereditary spherocytosis can aid significantly in the diagnosis of the disorder. In Artifactual spherocytes can appear when blood is stored for a prolonged period of time. | View Page |
| Another Echinocyte Another example of an echinocyte is seen in the center of this slide. In rare instances, echinocytes circulate in vivo in uremia, following heparin injection, in certain congenital anemias and in pyruvate kinase deficiency. Plastic slides must be used to verify the presence of in vivo echinocytes. Since echinocytes do not aid in the diagnosis of these conditions, their main importance lies in the fact that they are artifactual and reversible and must be distinguished from acanthocytes. | View Page |
| Sickle Cell Anemia Sickle cells can be seen in the peripheral blood of patients who have homozygous sickle cell anemia; however other tests are needed to make the diagnosis. Most sickled cells can revert back to the discoid shape when oxygenated. About 10% of sickled cells are unable to revert back to their original shape after repeated sickling episodes. | View Page |
| Another Target Cell Another example of a target cell (or codocyte) is seen in the center of this slide. Notice that the hemoglobin in the center of this cell is somewhat lighter in appearance than in the previous slide. A second codocyte can be seen in the upper left portion of the slide. Codocytes appear in conditions which cause the surface of the red cell to increase disproportionately to its volume. This may result from a decrease in hemoglobin, as in iron deficiency anemia, or an increase in cell membrane.
Target cells have excess membrane cholesterol and phospholipid and decreased cellular hemoglobin. Examples of other conditions in which target cells may be present include thalassemias, hgb C disease, post splenectomy and obstructive jaundice. Since their presence can be the result of an in vitro artifact, their value in clinical diagnosis is limited. | View Page |
| Elliptocytes Another example of elliptocytes as seen in hereditary elliptocytosis. Other conditions which may have varying numbers of elliptocytes include thalassemias, iron deficiency, megaloblastic anemia and anemia associated with leukemia. | View Page |
| Another Keratocyte Another example of a keratocyte (helmet cell) is seen in the center of this field. Examples of conditions in which keratocytes can be seen include intravascular coagulation, microangiopathic hemolytic anemia, glomerulonephritis, and rejection of renal transplants. The diagnosis of these disorders is not based on the presence of keratocytes. | View Page |