HEMATOLOGY LECTUREAnemias(Chapter 19 of Rodak’s Hematology) /sqg

- decrease in oxygen carrying capacity of blood caused by decrease in RBCs, Hgb and Hct

- classic symptoms are fatigue and shortness of breatho patient history and physical examination are

important preliminary components of diagnosis- physiological adaptations occur due to anemia

o in acute blood loss blood flow is redirected to the brain, heart

and muscleso in chronic blood loss

↑ in 2,3-BPG to increase delivery of O2 to tissues

↑ in EPO

MECHANISMS OF ANEMIA- ineffective erythropoiesis

o production of defective erythroid precursor cellso causes cell to undergo apoptosis before

maturationo body ↑ EPO to compensate

useless if precursors are still defectiveo RBC circulating in blood is low

- inefficient erythropoiesiso decrease in number of erythroid precursor cellso associated with ↓ iron, ↓ EPO, ↓ of cells due to

autoimmune reaction, infection by parvovirus B19, and infiltration of bone marrow with granulomas and malignant cells

o RBC production is low- chronic blood loss

o induces iron deficiency- acute blood loss

o slow production of RBCs by bone marrow

LAB DIAGNOSIS OF ANEMIA- complete blood count (CBC) - routine

o RBC counto MCV

Hct x 10RBC count

reference range: 80-100 fLo MCH

Hgb x 10RBC count

reference range: 26-32 pgo MCHC

Hgb x 100Hct

reference range: 32-36 g/dLo RDW (in automated analyzers only)

- reticulocyte count – must be performed in every patient suspected with anemiao absolute reticulocyte count

retic100

x RBC count

reference range: 20-115 x 109/Lo corrected reticulocyte count

retic x Hct45

o reticulocyte production index better indication than corrected retic count

corrected retic countmaturation time

o reticulocyte counts determine the cause of anemia

o ↑ retics hemolytic anemia acute blood loss

o ↓ retics chronic blood loss insufficient/ineffective erythropoiesis

- peripheral blood film examination – describes size, shape, variations and inclusions of RBCs

RBC ABNORMALITIESAbnormality Appearance Associated Diseasemacrocyte macrocytic anemiasmicrocyte microcytic anemias

spherocytehereditary spherocytosis,

immune hemolytic anemia

elliptocytehereditary

elliptocytosis/ovalcytosis, IDA, thalassemia,

myelophthisic anemiaovalocyte

stomatocytehereditary

stomatocytosis, Rh deficiency

sickle cellsickle-cell anemia, sickle-

cell-beta-thalassemia

Hb C crystal Hb C disease

Hb SC crystal

Hb SC disease

target cell (codocyte)

hemoglobinopathies, thalassemia

schistocytemicroangiopathic hemolytic anemia

helmet cell (keratocyte)

acanthocytespur cell anemia,

neuroacanthocytosis

Burr cell (echinocyte)

uremia, pyruvate kinase deficiency

Teardrop cell

(dacryocyte)

primary myelofibrosis, myelophthisic anemia,

thalassemia, megaloblastic anemia

RBC INCLUSIONS

Inclusion CompositionAssociated

DiseaseDiffuse

basophiliaRNA hemolytic anemia

basophilic stippling

precipitated RNA

lead poisoning, thalassemia,

hemoglobinopathies, megaloblastic

anemia, myelodysplastic

anemias

Howell-Jolly body

DNA

megaloblastic anemia, hemolytic

anemia, thalassemia,

myelodysplastic anemia

Heinz body denatured Hgb G6PD deficiency

Pappenheimer bodies

iron

sideroblastic anemia,

hemoglobinopathies, thalassemias,

megaloblastic and myelodysplastic

anemias

Cabot ringmitotic spindle

remnants

megaloblastic anemia,

myelodysplastic anemia

Hb Hprecipitated β-globin chains

Hb H disease

CLASSIFICATION OF ANEMIAS ACCORDING TO MCV

1. Microcytic Anemias (MCV < 80 fL)o sideroblastic anemiao iron deficiency anemiao anemia of chronic inflammationo thalassemia

2. Macrocytic Anemias (MCV > 100 fL)o Nonmegaloblastic anemias

aplastic anemia chronic liver disease alcoholism

o Megaloblastic anemia vitamin B12 deficiency folate deficiency

3. Normocytic Anemias (MCV 80-100 fL)o ↑ Reticulocyte Count

acute blood loss hemolytic anemias

o Normal or ↓ Reticulocyte Count aplastic anemia anemia of renal disease myelophthisic anemia parvovirus B19 infection anemia of chronic inflammation

CLASSIFICATION OF ANEMIAS ACCORDING TO PATHOPHYSIOLOGY1. Anemia by Decreased RBC Production

o HSC failure aplastic anemia

o disruption of DNA synthesis megaloblastic anemia

o disruption of Hgb synthesis iron deficiency anemia thalassemia sideroblastic anemia anemia of chronic inflammation

o disruption of erythroid precursor proliferation anemia of renal failure anemia of marrow infiltration

2. Anemia by Increased RBC Destructiono membrane defects

hereditary spherocytosis hereditary elliptocytosis

o enzyme deficiency G6PD deficiency pyruvate kinase deficiency

o globin abnormality sickle cell anemia hemoglobinopathies

o immune causes warm-type autoimmune hemolytic anemia paroxysmal cold hemoglobinuria cold agglutinin disease hemolytic transfusion reaction hemolytic disease of the newborn

o non-immune causes microangiopathic hemolytic anemias

(thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, HELLP syndrome)

macroangiopathic hemolytic anemia

infection (malaria, babesiosis)o blood loss

acute blood loss anemia