MICROCYTIC ANAEMIA
Dr. Babie Zirnunsangi
Anemia is defined as a reduction in the concentration of
blood circulating hemoglobin or oxygen carrying capacity
of blood below the level that is expected for healthy
persons of same age and sex in the same environment.
Hb or PCV level is below the lower limit of normal for the
particular age and sex.
Morphological Classification of anemia
1. Normocytic normochromic anemia
2. Microcytic hypochromic anemia
3. Macrocytic normochromic anemia
Normocytic MCV = 80-100 fL
Microcytic MCV = less than 80 fL
Macrocytic MCV = more than 100 fL
CAUSES OF MICROCYTIC HYPOCHROMIC
ANAEMIA
(SITA)
1. Iron deficiency anaemia
2. Thalassemia
3. Sideroblastic anaemia
4. Anaemia of chronic disease
Causes of iron deficiency anemia
(Type of nutritional anemia)
• Nutritional deficiency due to poor diet or increased
requirements: infants and children (6 months-2 years), women in
reproductive age group, pregnancy or lactation, elderly.
• Blood loss:
a. Gastrointestinal: Meckel’s diverticulum, esophageal varices,
peptic ulcer, carcinoma of stomach, hookworm infestation,
colorectal polyp or carcinoma, haemorrhoids, hereditary
hemorrhagic telangiectasia
b. Genitourinary tract: Menorrhagia, hematuria (RCC, transitional
Ca of bladder), hemoglobinuria (PNH)
• Malabsorption: Celiac disease, achlorhydria (gastrectomy,
atrophic gastritis)
Response to oral iron therapy:
Increased reticulocyte count beginning around 3rd day
and reaching maximum on 5th-10th day after starting
oral iron therapy indicates optimal response.
Hemoglobin rises at the rate of 0.5-1.0 gm/dl/week.
LABORATORY FINDINGS
1. Peripheral blood examination
• Red cell mass - decreased
Anisopoikilocytosis
• RBC size and appearance – Microcytosis (decrease in
MCV) and hypochromia (decrease in MCHC)
• Variation in shape – pencil cells, elongated cells, tear
drop cells
• White blood cells – Leucocytosis is common
• Platelets – often increased (reactive thrombocytosis)
2. RED CELL INDICES
• MCV – decreased
• MCHC – decreased
• RDW - increased
3. BONE MARROW EXAMINATION
• Erythropoiesis- Micronormoblastic reaction
• Myelopoiesis – Normal
• Megakaryocytes – Normal
• Iron stain i.e. Perls Prussian blue stain – depletion of
iron
4.Reticulocyte count – decreased
5. Serum iron profile
• Serum ferritin- <40mg/dl
• Serum Iron - <60 mg/dl
• Total iron binding capacity – increased
• Transferrin saturation – decreased
THALASSEMIA
This is a type of hemolytic anemia.
One of the hemoglobinopathies.
Heterogenous group of inherited disorders of
hemoglobin characterized by reduced or absent
production of one or more of the globin chains
CLASSIFICATION
According to the type of globin chain deficiency
- Alpha, beta thalassemia
According to clinical severity
- Thalassemia major, intermedia, minor/trait
LABORATORY FINDINGS
1. PERIPHERAL BLOOD EXAMINATION
• Red cell mass – markedly decreased.
• RBC size and appearance- microcytosis and
hypochromia
• Anisopoikilocytosis – plenty of target cells, Howell
Jolly bodies, basophilic stippling,
nucleated RBC (nRBC)
• WBC- within normal limits (WNL)
• Platelets - WNL
2. RED CELL INDICES
MCV- decreased
MCH – decreased
RDW – normal or increased
3.Hemoglobin electrophoresis /HPLC (high performance
liquid chromatography) – markedly elevated HbF.
(CONFIRMATORY TEST)
4.Test for inclusion bodies by methyl violet stain
5.Bone Marrow Examination – Erythroid hyperplasia
6.Osmotic fragility test - decreased
Sideroblastic Anemia
• Heme synthesis is deficient.
• There is a mitochondrial defect that leads to the
failure of incorporation of iron into heme.
• Iron accumulates in mitochondria that surround the
nucleus of erythroblasts forming ringed sideroblasts.
Sideroblastic anemia ischaracterized by:
• Dimorphic anemia (i.e. blood smear shows dual
population of cells: normocytic normochromic, and
microcytic hypochromic)
• Ringed sideroblasts in bone marrow
Sideroblastic anemia may be hereditary (X-linked) or
acquired.
Most cases are acquired and causes include:
(i) Drugs: isoniazid, chloramphenicol, cytotoxic drugs,
(ii) alcoholism,
(iii) lead poisoning,
(iv) Myelodysplastic syndrome, and
(v) acute myeloid leukemia.
Anemia of Chronic Disease
Anemia of chronic disease is the most common form of
anemia amongst hospitalized patients.
Diseases associated with anemia of chronic disease
1. Chronic infections: Tuberculosis, urinary tract
infection, bronchiectasis, osteomyelitis, subacute bacterial
Endocarditis (SABE)
2. Chronic inflammation: Rheumatoid arthritis, systemic
lupus erythematosus (SLE)
3. Malignancy
Laboratory Features
• Normocytic normochromic anemia (70% cases) or
microcytic hypochromic anemia (30% cases).
• Decreased serum iron, decreased total iron binding
capacity, and normal or raised serum ferritin.
Serum transferrin receptor level is normal.
• Increased marrow storage iron
• Erythrocyte sedimentation rate (ESR) is increased out of
proportion to the degree of anemia.
DIFFERENTIAL DIAGNOSIS OF MICROCYTIC HYPOCHROMIC ANEMIA
PARAMETER IDA ANEMIA OF Β SIDEROBLAS- LEAD
CHRONIC DS THALASSEMI TIC ANEMIA POISONING
A MINOR
1. MCV Low Normal or Markedly low Low Low
low
2. RBC on Microcytic NCNC,rarely Mild Dimorphic Coarse
blood smear hypochrom MCHC anisopoikilocytosis, basophilic
ic basophilic stipling stippling
3.Serum iron Low Low Normal Increased Increased
4. S. Ferritin Low Normal or Normal Increased Increased
increased
5. TIBC Increased Low Normal Normal Decreased
6. Storage Absent Normal or Normal Normal Increased
iron in increased
marrow
PARAMETER IDA ANEMIA OF Β SIDEROBLAS- LEAD
CHRONIC DS THALASSEMI TIC ANEMIA POISONING
A MINOR
7. Normal Normal Increased HbA2 Normal Normal
Hemoglobin
electropho-
resis
8. Iron in Absent Present Present Ringed Ringed
erythroblasts sideroblasts sideroblasts
9. Serum Increased Normal Normal or Normal or Normal
soluble increased increased
transferrin
receptor
