2 Full Blood Count-Case C A 25 year old female:anaemiaNever pregnantNo change menstrual flow & intermenstrual bleedingNormal dietNo medicationsNo change in bowel habit or symptoms of GI/urinary blood lossNo abnormal physical change
5 Diagnosis: Iron deficiency QuestionsDiagnosis: Iron deficiencyIs the MCV consistent with the diagnosis? Explain.What do the presence of pencil cells, target cells & Howell-Jolly bodies suggest?Is B12 or folate deficiency suspected? evidence?Are the lab findings typical of iron deficiency anaemia?
6 Differential diagnosis Anemia is generally defined as a hematocrit <40% (hemoglobin <13.5 g/dL) in men or <37% (hemoglobin <12 g/dL) in womenMCV is a way of classifying anaemias morphologically, i.e. microcytic, normocytic and macrocyticMicrocytic anaemia can be caused byIron deficiencyThalassaemiaAnaemia of chronic diseaseSideroblastic anaemia
7 MCV and iron deficiency Microcytosis, or a decreased mean cell volume (MCV), is a characteristic feature of iron deficiency anaemia. Why?Iron deficiency anaemia manifests in 5 stages:Fe loss exceeds intake, causing progressive depletion of Fe storage.Exhausted Fe stores cannot meet the needs of the erythroid marrow.Anaemia with normal-appearing RBCs and indices occursMicrocytosis (small size, low MCV) and then hypochromia (pale colour, low Hb) is present.In advanced iron deficiency, anisocytosis (variable cell size) and poikilocytosis (variable cell shape) is seen.
8 MCV and iron deficiency Is the MCV result consistent with iron deficiency?MCV=74fL (80-100fL)Analysing result:MCV (mean cell volume) is a measure of the average volume of a single red blood cell.A value <80fL indicates microcytosis, i.e. the red cells are smaller than usual.Microcytosis in the presence of anisocytosis means indicates more advanced iron deficiency
9 MCV and iron deficiency So initially it can be said that the MCV value of 74fL supports the diagnosis of iron deficiency. However it is not as low as would be expected in iron deficiency.Since the MCV is an average value for the red cell volume, it must be considered in the context of the low folate level (which causes macrocytosis).The reason postulated for the slightly lowered MCV is that it is a result of a “balancing out” of the microcytosis caused by the iron deficiency with the macrocytosis caused by the folate deficiency.Therefore as in this case, patients with concurrent folate and iron deficiency may exhibit a normal or near normal MCVThe folate deficiency will be discussed later by roanna
10 A characteristic change that occurs in PENCIL CELLSAlso known as ovalocytes, cigar cells or elliptocytes.Are elongated hypochromic red blood cells.Consists of a central area of pallor and haemoglobin at both ends of cell.A characteristic change that occurs iniron deficiencyHypochromic defn: low conc of Hb in RBCs
12 TARGET CELLS Scientific name: Codocytes RBCs appear like a target with a bullseye.Erythrocytes are thin and have an increased surface membrane area to volume ratio (decrease in haemoglobin content).Have a central, haemoglobinised area surrounded by an area of pallor. The periphery of the cell contains a band of haemoglobin.
14 TARGET CELLSThe presence of excessive target cells may indicate chronic diseases that cause:Increases in surface membrane, associated with lipid disorders e.g. rare congenital deficiency of lecithin-cholesterol acyl transferase, and liver disease.Decreased cytoplasmic volume, is associated with decreased production of haemoglobin (iron deficiency), or manufacture of defective haemoglobin (thalassaemia).Note: target cells occur b/c of Altered (increased) surface membrane area to volume ratio, it can occur by either increase SA or decrease content
15 POST-SPELENECTOMYA major function of the spleen is the clearance of opsonized, deformed, and damaged erythrocytes by splenic macrophages.If splenic macrophage function is impaired or absent because of splenectomy (spleen removal), altered erythrocytes will not be removed from the circulation efficiently.Therefore, increased numbers of target cells may be observed.
16 HOWELL-JOLLY BODIESAre spherical inclusions of nuclear chromatin remnants in a RBCs (blue black appearance on Wright-stained smears).They are nuclear fragments of condensed DNA, 1 to 2 µm in diameter, normally removed by the spleen.They are seen in severe haemolytic anaemias, pernicious anaemia, thalassaemia, and in patients with dysfunctional spleens or after splenectomy.
18 Vitamin B12 and Folate Deficiency B12 and folate deficiency share the same haemotological changes including:Macrocytosis (MCV > 100fL)Anisocytosis (size variation)Megaloblastic bone marrow and anaemiaOval red cells (ovalocytosis)Hypersegmented neutrophilsMegaloblastic marrow – cell maturity is greater in the cytoplasm than the nucleus as a result of faulty DNA synthesis and normal RNA synthesis.
19 Evidence for Vitamin B12 Deficiency Vitamin B12 deficiency occurs when levels < 130 pmol/LThis patient has:Serum B12 reading of 220pmol/LMicrocytosis (MCV < 80 fL)These results are inconsistent with vitamin B12 deficiency.
20 Evidence for Folate Deficiency Folate deficiency occurs when:Serum folate < 11 nmol/LRed cell folate < 510 nmol/LThis patient has:Serum folate 2 nmol/LRed cell folate 100 nmol/LThese results are consistent with folate deficiency.Serum folate is not able to depict whether or not deficiencies are due to storage depletion or inadequate intake from dieting. Red cell folate is a means of measuring folate tissue storage. It is used in conjunction with serum folate levels to determine the cause of folate deficiency.
21 Folate and B12 Deficiency Conclusion This patient has serum and red cell folate levels consistent with folate deficiency.Deficiency associated with folate and/or B12 causes megaloblastic anaemia.Megaloblastic anaemia causes oval macrocytes, dyspoesis resulting in leukopenia and thrombocytopenia and hypersegmented neutrophils.Hypersegmented neutrophils is found in moderate amounts in this patient but may be due to folate malabsorption.
22 Iron Deficiency Anaemia Diagnosis will be based on:Reduced haemoglobin (man< g/dL, woman< g/dL)Reduced mean cell volume (<80fL)Reduced mean cell haemoglobin (<27pg)Reduced mean cell haemoglobin concentration (<300g/L)Blood film- microcytic, hypochromic red cellsReduced serum ferritin (<10ug/L)Reduced serum iron (man<14umol/L,woman <11umol/L)Increased serum iron binding capacity (>75umol/L)
23 The following investigation may be required: Full blood count and blood film examinationHaematinic assays (serum ferritin, vitamin B12 and folate)Faecal occult bloodsMid-stream urineEndoscopic or barium studies of GI tract
24 Blood FilmRed cells from iron deficient patients contain less haemoglobin than normal.The red cells appear pale (hypochromic) and smaller than normal (microcytic).Therefore microcytosis, hypochromia and pencil cells may be present in iron deficiency anaemia.The patient’s blood film presents hypochromic, microcytic cells, with moderate numbers of pencil cells.
25 HaemoglobinThe diagnostic criteria for iron deficiency anaemia vary (Hb< g/dL for women & < g/dL for men) between studies.The lower limit of the normal range of haemoglobin concentration should be used to define anaemia.The limitation of using haemoglobin as a measure of iron status are its lack of specificity and its relative insensitivity.To identify iron deficiency anaemia Hb must be measured together with more selective measurement of iron status.The patient’s Hb concentration is 65g/L.
26 Mean Cell Volume (MCV)Reduced MCV (microcytosis) occurs when iron deficiency becomes severe, following the development of anaemiaA cut off value of 80fL is accepted as lower limit of normal in adults.The patient’s MCV is 74fL
27 Serum FerritinThis is by far the most useful single measure of iron statusIt accurately reflects the body stores and it is usually the earliest laboratory measure to change in iron deficiencyIt is a sensitive test and is not affected by day to day fluctuation in iron intake.A low serum ferritin is a certain proof that patient is iron deficient.Appropriate lower limit of normal would be 15-16ug/L.The patient’s serum ferritin level is 5ug/L/Further tests is usually only required in patient when doubt still remains as to the presence of iron deficiency.
28 Other ResultsA raised platelet count is often seen in iron deficiency, but a normal or low count certainly doesn’t exclude diagnosis. The patient’s platelet count is raised at 500*109/LWCC and WCC differential is normal for this patient, which is expected in iron deficiency anaemia.Faecal occult blood testing for this patient is negative, which confirms there is no blood in faeces due to GI/Urinary blood loss.Red serum folate and red cell folate is also reduced below the normal range for this patient. Therefore patient has a folate deficiency.
29 Does patient have Iron deficient anaemia? Supportive results:Serum ferritin levels <5 ug/LDecreased hemoglobin (suggesting anaemia)Blood film: hypochromic (low Hb) and microcytic (low MCV) cellsPresence of pencil cells/target CellsHigh platelet count levelHence it can be concluded that the patient has iron deficiency anaemia.