MLAB 1415-Hematology
Keri Brophy-Martinez
Hypoproliferative Anemias
Overview

Disorders
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Anemia
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Acquired
Congenital
Normocytic or Macrocytic
Normochromic
Bone marrow hypocellularity
Defect

Depletion, damage or inhibition of stem and/or
progenitor cells
APLASTIC ANEMIA

Aplastic anemia


Disorder (or group of disorders) characterized
by aplasia of bone marrow or its destruction by
chemical agents or physical factors. All cell
lines are affected.
Aplasia
 Failure of a tissue or organ to develop
normally
Pathophysiology
Aplastic anemia is caused by an immune
process, either antibodies directed against
the stem cell or a cellular immune
mechanism (T-lymphocyte) that
suppresses stem cell prolieferation
 Bone marrow fails due to the
immunologically mediated tissue-specific
destruction

Phases

I: Onset


After an initiating event (i.e. viral infection)
the hematopoietic cells are destroyed by the
immune system
Small numbers of surviving stem cells can
support adequate hematopoiesis for some
time, but eventually the circulating cell counts
become very low and clinical symptoms appear
Phases

II: Recovery


Either a partial response or a complete response can
occur, initially, without increased number of stem cells
III: Late Disease


Years after recovery, blood counts may fall as
pancytopenia occurs or as abnormal clones of stem cells
emerge.
Often leads to PNH( paroxysmal noctural
hemoglobinuria), AML (acute myelogenous leukemia) or
MDS (myelodysplasia)
Aplastic Anemia

Two Groups

Acquired



Majority of cases
Surface after age 60
Congenital


2-5 years old
15-25 years old
APLASTIC ANEMIA

Acquired


Idiopathic or primary with no clear cause
Secondary due to
 Chemical agents such as benzene, insecticides, weed killers
 Drugs such as chloramphenicol (antibiotic) and
phenylbutazone (anti-inflammatory), chemotherapy drugs
(busulfan, vincristine), anticonvulsants (Dilantin)
 Ionizing radiation from nuclear fallout, x-rays or radiation
therapy, radium
 Infections such as hepatitis, Epstein-Barr virus, CMV, HIV
 Miscellaneous - pregnancy, malnutrition, immunologic
dysfunction
APLASTIC ANEMIA

Congenital/ Inherited Aplastic Anemia

Fanconi’s anemia
 Genetic predisposition to bone marrow
failure
 Chromosomal breaks, gaps, exchanges
 25- 30% cases of childhood aplastic anemia
 Twice as common in males than females
Clinical Features
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Low birth weight
Skin
hyperpigmentation
Short statue
Dyspnea
Bleeding
Infections
Skeletal disorders
Aplastic anemia
: Lab Features

Total Bone marrow failure
 Hypocellular: 70% fat
 Pancytopenia= all cell lines affected
Aplastic Anemia:
Lab Features

↓ RBC, hgb (<7), hct (<20), retic (absolute and corrected)

↓ WBC (<1.5) , absolute neutrophil count (<0.5)
 Relative lymphocytosis due to the neutropenia

↓ platelets (<20,000-60,000)

P.B
 Normocytic/macrocytic,normochromic
 Moderate anisocytosis, poikilocytosis
 NRBCs, teardrops*
Treatment



Treatment of choice is bone marrow
transplantation. If this is not an option,
immunotherapy is given. Spontaneous recovery
may occur if the offending agent is removed.
Prognosis is poor, high mortality rate..2 years
Complications include
 Bleeding
 Iron overload due to transfusions
Pure red cell aplasia
 Rare
condition
 Red cell precursors in the bone
marrow are decreased
 Presence of peripheral blood anemia
Pure Red Cell Aplasia
 Congenital

Diamond-Blackfan anemia
 Defect in erythroid precursors
 Acquired
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Hemolytic crises
Infection with parvovirus, EBV, viral hepatitis
Malnutrition
Certain drugs or neoplasms
Other Hypoproliferative Anemias
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Defective hormonal stimulation of
erythroid progenitor cells
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Kidney Disease
Endocrine Disorders
Lab findings reflect anemia and
pathologies of primary disorder
References
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Harmening, D. M. (2009). Clinical Hematology and
Fundamentals of Hemostasis. Philadelphia: F.A Davis.
http://www.aamdsglossary.co.uk/glossary/b
http://blass.com.au/definitions/aplastic%20anemia
McKenzie, S. B., & Williams, J. L. (2010). Clinical
Laboratory Hematology . Upper Saddle River: Pearson
Education, Inc.