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Tuesday, October 4, 2011

Laboratory diagnosis of aplastic anaemia:


1. Routine haematological tests:

                -Haemoglobin-Reduced, maybe even less than 3g/dl.
                -MCV, MCH, MCHC are all normal
                -Erythrocyte sedimentation rate (ESR) is high(60-100 mm In first hour)
                -Peripheral blood film:
                                Leishmen stain:
                                                RBC: Normocytic normochromic with anisocytosis and poikilocytosis






Clinical presentation of aplastic anaemia:

1. Due to reduced RBC count(anaemia):
                Fatigue, Weakness, Pallor, Palpitation, Dyspnoea, Effort Angina

2. Due to reduced WBC count(leucopenia)
                Sore throat, ulceration of mouth and pharynx, malaise, fever, chills, chronic skin infection, recurrent chest infection


Aplastic anaemia

A disorder of unknown aetiology characterized by anaemia, leucopenia and thrombocytopenia resulting from aplasia of the bone marrow.

In reality aplasia of the bone marrow is absent and hypoplasia occurs.


Laboratory diagnosis of pernicious anaemia:

 Same as the laboratory diagnosis of megaloblastic anaemia plus the following:

Special tests for pernicious anaemia:

1. Gastric juice analysis.
2. Presence of anti-parietal cell antibody in the serum.
3. Presence of anti-intrinsic factor antibody in the serum.
4. Serum gastrin level
5. Pertagastrin fast acholrhydria

Treatment of pernicious anaemia:

Pathogenesis of pernicious anaemia:

Occurs due to gastric atrophy which in turn occurs due to genetic and autoimmune causes:


Pernicious anaemia / Addisonian Pernicious Anaemia:

A vitamin B12 deficiency megaloblastic anaemia which occurs due to deficiency of intrinsic factor of Castle due to gastric atrophy, characterized by one or combination of macrocytic anaemia, glossitis and nervous system involvement.


What is Schilling test?

It is a test to determine the cause of vitamine B12 defeciency. It is done by the measurement of urinary excretion of radio-isotope labeled oral vitamine B12 with and without the administration of intrinsic factor of Castle.


What is hypersegment neutrophil?


When more than 5% neutrophils have 5 lobed nucleus. Or if there is a single 6 lobed or more neutrophil in the peripheral blood then it is considered as hypersegmented neutrophil.




 



Laboratory diagnosis of megaloblastic anaemia

A. Routine haematological investigation
                1. Haemoglobin –Decreased. May decrease uptp 3 g/dl. Commonly found at 7-9 g/dl.

                2. MCV-Increased (Macrocytic)

                3. MCH-Increased

                4. MCHC-Normal (normochromic)

                5. Peripheral blood picture:


Folate deficiency is more common because:

1. Folic acid(60-90%) is more destroyed than vitamin B12(10-30%) by heating during cooking.
2. Folic acid (200µg) daily requirement is more than vitamin B12 (2-4µg).
3. Vitamin B12 can be stored in the liver for a long period of time(3 years)


Macrocytic anaemia

If mean corpuscular volume is more than normal then the anaemia is called macrocytic anaemia.

Classification of macrocytic anaemia:

1. Megaloblastic anaemia

2. Normoblastic macrocytic anaemia.