Transcript Aplastic and Hypoplastic Anemias

Normocytic Normochromic
Anemias
M H Qari, MD, FRCPA
Associate Professor of
Hematology
Aplastic anemia
Aplastic anemia is a severe, life
threatening syndrome in which production
of erythrocytes, WBCs, and platlets has
failed.
Aplastic anemia may occur in all age groups
and both genders.
The disease is characterized by peripheral
pancytopenia and accompanied by a
hypocellular bone marrow.
Hypocellular bone marrow in
aplastic anemia
Aplastic anemia
Pathophysiology:
The primary defect is a reduction in or
depletion of hematopoietic precursor stem cells
This may be due to quantitative or qualitative damage
to the pluripotential stem cell.
In rare instances it is the result of abnormal
hormonal stimulation of stem cell proliferation or the
result of a defective bone marrow microenvironment
or from cellular or humoral immunosuppression of
hematopoiesis.
Aplastic anemia
Etiology
Acquired
Most cases of aplastic anemia are idiopathic
Exposure to ionizing radiation – hematopoietic
cells are especially susceptible to ionizing
radiation. Whole body radiation of 300-500
rads can completely wipe out the bone marrow.
Chemical agents – include chemical agents
with a benzene ring, chemotherapeutic agents,
and certain insecticides.
Idiosyncratic reactions to some commonly
used drugs such as chloramphenicol or
quinacrine.
Aplastic anemia
Infections – viral and bacterial infections
such as infectious mononucleosis, infectious
hepatitis, cytomegalovirus infections, and
miliary tuberculosis ;Pregnancy (rare)
Paroxysmal nocturnal hemoglobinuria – this is
a stem cell disease in which the membranes of
RBCs, WBCs and platlets have an abnormality
making them susceptible to complement
mediated lysis.
Other diseases – preleukemia and carcinoma
Aplastic anemia
Congenital disorders
Fanconi’s anemia – the disorder usually becomes
symptomatic ~ 5 years of age and is associated
with progressive bone marrow hypoplasia.
Congenital defects such as skin hyperpigmentation
and small stature are also seen in affected
individuals.
Familial aplastic anemia – a subset of Fanconi’s
anemia in which the congenital defects are absent.
Clinical manifestations
Fatigue
Heart palpitations
Pallor
Infections
Petechiae
Mucosal bleeding
Aplastic anemia
Lab findings
Severe pancytopenia with relative lymphocytosis
(lymphocytes live a long time)
Normochromic, normocytic RBCs (may be slightly
macrocytic)
Mild to moderate anisocytosis and poikilocytosis
Decreased reticulocyte count
Hypocellular bone marrow with > 70% yellow
marrow
Treatment – in untreated cases the prognosis is poor
Remove causative agent, if known
Multiple transfusions
Bone marrow transplant
Pure Red Cell Aplasia
Pure red cell aplasia s characterized by a
selective decrease in erythroid precursor
cells in the bone marrow. WBCs and
platlets are unaffected.
Acquired
Transitory with viral or bacterial infections
Patients with hemolytic anemias may suddenly halt
erythropoiesis
Patients with thymoma – T-cell mediated responses
against bone marrow erythroblasts or erythropoietin
are sometimes produced.
Pure Red Cell Aplasia
Congenital
Diamond-Blackfan syndrome – occurs in
young children and is progressive. It is
probably due to an intrinsic or regulatory
defect in the committed erythroid stem cell.
Other causes of Normocytic
Normochromic Anemia
Myelopthesic anemia – replacement of
bone marrow by fibrotic, granulomatous,
or neoplastic cells
Hypersplenism – why can this lead to
pancytopenia?
Severe Chronic infection or inflammation
Myelodysplastic syndromes – are primary, neoplastic
stem cell disorders that tend to terminate in acute
leukemia. The bone marrow is usually normocellular, or
hypercellular with evidence of qualitative abnormalities in
one or more cell lines resulting on ineffective
erythropoiesis and/or granulopoiesis and/or
megakaryopoiesis. The peripheral smear shows
dysplastic (abnormality in development) cells including
nucleated RBCs, oval macrocytes, pseudo-Pelger-Huet
PMNs (hyposegmented neutrophils) with hyperchromatin
clumping, hypogranulated neutrophils, and giant bizarre
platlets.
Other hypoproliferative anemias
Renal disease – due to decreased
erythropoietin
Endocrine deficiencies – may lead to
decreased erythropoietin production.
For example: hypothyroidism leads to
decreased demand for oxygen from
tissues; decreased androgens in
males; decreased pituitary function