Notes on Anaemia

1. Haematopoiesis
&
Approach to Anaemia

2. Haematopoiesis (1)
• Process by which formed elements of blood
– Produced & Regulated through series of steps
• Pluripotent haematopoietic stem cell
– Capable of producing red cells,
– All classes of granulocytes, monocytes, platelets
– Mechanism to become committed to a given
lineage
 Not fully known
13 Aug 2017

3. Haematopoiesis (2)
• Following lineage commitment
– Haematopoietic progenitor & precursor cells
 Come under regulatory influence of growth factors
and hormones.
– For red cell production
 Erythropoietin (EPO) is regulatory hormone
– EPO is required for Maintenance of
 Committed Erythroid progenitor cells
– In absence of EPO hormone
 Undergo programmed cell death (apoptosis)
13 Aug 2017

4. Factors Regulating RBC
Production
13 Aug 2017
Regulated process of RBC production is Erythropoiesis

5. RBC Characteristics
• Mature red cell is 8 micron in diameter
– Anucleate , Biconcave & discoid in shape
– Extremely flexible
 Needs to traverse microcirculation easily
– Membrane integrity maintained by
 Intracellular generation of ATP
• Average RBC lives 100–120 day
• 1% of all circulating RBC daily replaced
• Erythron: Organ for red cell production
– Pool of marrow erythroid precursor cells &
large mass of mature circulating RBCs
13 Aug 2017

6. RBCs : Normal Indices
• Mean cell volume (MCV)
(Haematocrit x10) / (RBC count x 106
) =90 ± 8 fL
• Mean Cell Haemoglobin (MCH)
(Hb x 10) / (red cell count x 106
) = 30 ± 3 pg
• Mean cell Hb concentration (MCHC)
(Hb x 10) / hematocrit or MCH/MCV = 33 ± 2%
13 Aug 2017

7. Leukocytes
• All Leukocytes derived from
– Common Stem cell in Bone marrow
– 3/4th
of nucleated cells of bone marrow
 Committed to production of Leukocytes
• Mediate Inflammatory / Immune Responses
– Include Neutrophils, T & B Lymphocytes
– Natural Killer (NK) cells, Monocytes
– Eosinophils & Basophils
• These cells have specific functions
– Antibody production by B Lymphocytes
– Destruction of bacteria by Neutrophils
13 Aug 2017

8. Granulocytes Development (1)
13 Aug 2017

9. Granulocytes Development (2)
13 Aug 2017

10. 13 Aug 2017
Eosinophil
Large bright orange granules
usually bilobed Nucleus
Basophil
Large purple-black granules
fill the cell & obscure nucleus

11. Bone marrow
13 Aug 2017
Normoblast Cell
Eosinophil Cell
Erythrocyte Cell
Myelocyte dividing
Myelocyte Cell
Normoblast
with dividing Nucleus
Fat CellFat Cell
Fat Cell
Myelocyte Cell

12. Bone Marrow: Erythroid Hyperplasia
13 Aug 2017

13. Bone Marrow: Myeloid Hyperplasia
13 Aug 2017

14. Anaemia: Introduction
• Hb level or haematocrit < expected value
for age & sex
• WHO criteria
– Adult men
 Blood Hb concentration <13 g/dL or
 Hematocrit <39%
– Adult women
 Blood Hb concentration <12 g/dL) or
 Hematocrit <37%
13 Aug 2017

15. Anaemia: Types
• Iron-Deficiency Anemia
• Vitamin B12 Deficiency Anemia
• Folate-Deficiency Anemia
• Anemia of Chronic Disease
• Haemolytic Anaemia
• Aplastic Anemia
• Myelodysplastic Syndromes
13 Aug 2017

16. Anaemia: Mechanisms
• 3 major physiologic mechanisms of anemia
• Marrow production defects (Hypoproliferation)
– Reflects absolute or relative marrow failure
– Erythroid marrow not proliferated appropriately
– Can result from
 Marrow damage
 Iron deficiency
 Inadequate erythropoietin stimulation
13 Aug 2017

17. Anaemia: Mechanisms
• Ineffective erythropoiesis (RBC maturation
defects)
– Nuclear maturation defects associated with
macrocytosis & abnormal marrow development
– Cytoplasmic maturation defects associated with
microcytosis and hypochromia, usually from
defects in hemoglobin synthesis
• Decreased erythrocyte survival: blood loss or
hemolysis
13 Aug 2017

18. Anaemia: Symptoms & Signs (1)
• Often recognized by abnormal results on
screening lab tests
• Signs and symptoms depend on
– Level of anaemia
– Time course over which it developed
 Acute onset Anaemia
 Chronic Anaemia
13 Aug 2017

19. Anaemia: Symptoms & Signs (2)
• Acute anaemia (nearly always due to
blood loss or haemoptysis)
• If Loss of 10–15% of total blood volume
– Hypotension
– Decreased organ perfusion
• Loss of >30% of blood volume
– Postural hypotension
– Tachycardia
13 Aug 2017

20. Anaemia: Symptoms & Signs (3)
• Loss of >40% of blood volume
– Hypovolemic shock
 Confusion
 Dyspnoea
 Hypotension
 Tachycardia
• Haemolytic Anaemia
– Presentation depends on mechanism that
leads to RBC destruction
13 Aug 2017

21. Anaemia: Symptoms & Signs (3)
• Chronic or progressive anaemia
– Presentation depends on age of patient
– Adequacy of blood supply to critical organs
• Possible Symptom / Sign
– Fatigue and Loss of stamina
– Breathlessness (specially on exertion)
– Pale skin and mucous membranes (Pallor)
– Palpitation (Tachycardia, after physical exertion)
– Forceful heartbeat (Heaving Apex beat)
– High Volume pulse & Systolic flow murmur
13 Aug 2017

22. Anaemia: DD (1)
• Hypoproliferative anaemias (75% of cases)
– Marrow damage
 Infiltration/fibrosis
 Aplasia
– Iron deficiency (mild to moderate)
– Decreased stimulation
 Inflammation
 Metabolic defect (Hypothyroidism)
 Renal disease
13 Aug 2017

23. Anaemia: DD (2)
• Maturation disorder
– Cytoplasmic defects
 Iron deficiency (severe)
 Thalassemia
 Sideroblastic
– Nuclear defects
 Folate deficiency , Vitamin B 12 deficiency
 Drug toxicity
– Methotrexate & Alkylating agents
– Alcohol
 Refractory anemia
– Myelodysplasia
13 Aug 2017

24. Anaemia: DD (3)
• Haemolysis / Haemorrhage
– Blood loss
– Intravascular haemolysis
– Metabolic defect
– Membrane abnormality
– Haemoglobinopathy
– Autoimmune defect
– Fragmentation haemolysis
13 Aug 2017

25. Anaemia: Diagnostic Approach (1)
• 02 questions need to be answered:
– Type of Anaemia & Cause of Anaemia
• Careful history
– Nutritional history
 Related to diet, drugs or alcohol
– Family history of anaemia (Genetic)
– Geographic backgrounds and ethnic origins
 G 6 PD deficiency
 Haemoglobinopathies
– Middle Eastern, Mediterranean, or African origin
– Exposure to toxic agents or drugs
13 Aug 2017

26. Anaemia: Diagnostic Approach (2)
• Physical examination
– May provide clues to mechanisms / cause of
anaemia
 Infection
 Blood in the stool
 Splenomegaly & Lymphadenopathy
 Petechiae suggest platelet dysfunction.
• Laboratory assessment
– Including review of past laboratory
measurements to determine time of onset
13 Aug 2017

27. Anaemia: Diagnostic Approach (3)
• Physiologic classification / Type of
anaemia
• Reticulocyte index <2.5 & Normocytic,
Normochromic anaemia
– Hypoproliferative
 Marrow damage:
– Infiltration / fibrosis
– Aplasia
 Decreased stimulation:
– Inflammation
– Metabolic defect
– Renal disease13 Aug 2017

28. Anaemia: Diagnostic Approach (4)
• Reticulocyte index <2.5 & microcytic or
macrocytic anemia
– Maturation disorder
 Cytoplasmic defects:
– Iron deficiency,
– Thalassemia, Sideroblastic
 Nuclear defects:
– Folate deficiency
– Vitamin B deficiency
– Drug toxicity
13 Aug 2017

29. Anaemia: Diagnostic Approach (5)
• Reticulocyte index ≥2.5
– Haemolysis / Haemorrhage
 Blood loss
 Intravascular haemolysis
 Metabolic defect
 Membrane abnormality
 Haemoglobinopathy
 Autoimmune defect
13 Aug 2017

30. Anaemia Algorithm
13 Aug 2017

31. Normal Blood Smear (Wright’s stain)
13 Aug 2017
Normal RBCs, single Neutrophil & few platelets seen

32. Reticulocytes (Supravital Stain)
13 Aug 2017
Reticulocyte count is key to initial classification of anemia
Reticulocytes are RBCs recently released from marrow

33. Severe Iron Def Anaemia
(Wright’s stain)
13 Aug 2017
Microcytic & Hypochromic RBCs smaller than nucleus of a
Lymphocyte + marked variation in size (Anisocytosis) &
shape (Poikilocytosis)

34. Macrocytosis
13 Aug 2017
RBCs larger than small Lymphocyte & well
haemoglobinized. Macrocytes are oval-shaped
(Macroovalocytes)

35. Howell-Jolly bodies
13 Aug 2017
In absence of functional spleen, nuclear remnants are not
expelled from RBCs & remain as small homogeneously
staining blue inclusions on Wright stain

36. Red cell changes in myelofibrosis
13 Aug 2017
A Teardrop-shaped RBC & a Nucleated RBC is seen. These
forms are seen in Myelofibrosis with Extramedullary
Haematopoiesis

37. Red cell changes in
Thalassemia & Liver disease
13 Aug 2017
Target cells have a bull’s-eye appearance &
are seen in Thalassemia & Liver disease

38. Red cell changes in
Sickle Cell Disease
13 Aug 2017
Sickle shaped cells are seen in Sickle Cell disease

39. Anaemia: Lab Tests
• CBC
– Erythrocyte count
 Haemoglobin & Haematocrit
 Reticulocyte count
 Erythrocyte indices
 Mean cell volume (MCV)
 Mean cell haemoglobin
 Mean cell haemoglobin concentration
– Leukocyte count
 Cell differential
 Nuclear segmentation of Neutrophils
13 Aug 2017

40. Anaemia: Lab Tests
– Platelet count
– Cell morphology
 Cell size
 Anisocytosis (variations in cell size)
 Poikilocytosis (variations in cell shape)
 Polychromasia
– Iron supply studies
 Serum iron
 Total iron-binding capacity (TIBC)
 Serum ferritin, marrow iron stain
13 Aug 2017

41. Maturation disorders Anemia: Tests
• Vitamin B12
• Folate
• Serum iron and iron-binding capacity
• Serum ferritin to assess iron stores
• Haemoglobin electrophoresis
13 Aug 2017

42. Haemolytic Anemia: Tests
• Haemoglobin electrophoresis
• Screen for red cell enzymes
• Direct or indirect anti-globulin test
• Cold agglutinin titre
13 Aug 2017

43. Anaemia Classification
• Based on defect in RBC production
– Marrow production defects: Hypo-proliferation
– Maturation defects: Ineffective Erythropoiesis
– Decreased survival: Blood Loss / Haemolysis
• Classification by MCV
– Microcytic: MCV <80 fL
– Normocytic: MCV 80–100 fL
– Macrocytic: MCV >100 fL
13 Aug 2017

44. Complications: Anaemia
• High-output Cardiac Failure
• End-organ ischemia or infarct
– Myocardial infarction
– Stroke
• Hypovolumic shock
• Death
13 Aug 2017