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Questions and Answers
What is the primary site of hemopoiesis during normal childhood and adult life?
What is the typical lifespan of platelets in the human body?
Which blood component is not produced during erythropoiesis?
What does RDW measure in blood parameters?
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What is the normal range for hemoglobin concentration in adult females?
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Which blood cells are considered granulocytes?
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Which of the following best describes thrombocytopoiesis?
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What percentage of white blood cells are typically lymphocytes in adults?
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What is the normal hematocrit value for a healthy adult?
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Which type of anemia is characterized by decreased hemoglobin synthesis?
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Which clinical sign is NOT typically associated with hyperdynamic circulation?
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What is the consequence of excess 2,3 DPG production in erythropoiesis?
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Which of the following is a common symptom of anemia?
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What type of anemia is characterized by an increase in the color index greater than 1?
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Which of these conditions would most likely result in decreased stem cell production?
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What is a typical laboratory finding in the case of chronic disease anemia?
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Which type of anemia is characterized by a defect in haem synthesis?
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What is a common cause of vitamin B12 deficiency?
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Which clinical manifestation is associated with vitamin B12 deficiency?
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Which condition is characterized by megaloblastic hyperplasia of the bone marrow?
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Which of the following is NOT a feature of megaloblastic anemia?
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What laboratory finding is typical in a complete blood count (CBC) for megaloblastic anemia?
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Which drug is known to potentially cause folic acid deficiency?
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In the classification of anemias, which type is characterized by macrocytic red blood cells?
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What serum B12 level indicates a deficiency?
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What does normal excretion of radioactive B12 after oral intrinsic factor indicate?
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Which test becomes positive in folic acid deficiency?
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What is the treatment regimen for vitamin B12 deficiency?
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Which vitamin is essential for the conversion of folic acid into its active form?
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What is the typical urinary sign for malabsorption of vitamin B12?
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Why can large doses of folic acid exacerbate vitamin B12 deficiency manifestations?
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Which condition is associated with a positive result in the Schilling test?
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Study Notes
Blood Consists Of:
- Red Blood Cells (RBCs)
- White Blood Cells
- Platelets
- Plasma
Hemopoiesis
- Bone marrow is the chief source of blood cells during normal childhood and adult life
- Lifetime of blood cells:
- RBCs: 120 days
- Platelets: 7 days
- Granulocytes: 7 hours
Erythropoiesis
- The formation of red blood cells
- Stages of Red Blood Cell maturation:
- Pluri-potent stem cell
- Uni-potent stem cell (CFU-E)
- Pro-Erythroblast
- Basophilic Erythroblast
- Polychromatic Erythroblast
- Orthochromatuc Erythroblast
- Reticulocyte
- Erythrocyte (Mature RBC)
Granulocytopoiesis | Thrombocytopoiesis
- ------ | --------
- The formation of granulocytes | The formation of platelets
- Pluri-potent stem cell | Pluri-potent stem cell
- CFU-G | CFU-Mega
- Myeloblast | Megakaryoblast
- Pro Myelocyte | Megakaryocyte
- Myelocyte | Platelets
- Granulocyte (PML) |
Normal Ranges (adults)
-
Hemoglobin:
- 13.5 - 17.5 gm/dL (Male)
- 11.5 - 15.5 gm/dL (Female)
-
Haematocrit (PCV): the volume of packed RBCs in 100 ml blood
- 40 - 52% (Male)
- 36 - 48% (Female)
-
RBCs Indices:
-
MCV (Mean Corpuscular volume): 77 - 95 fL
- PCV×10RBCscount/cmm=45×105=90femtolitre.\frac{PCV\times10}{RBCs count /cmm} = \frac{45\times10}{5} = 90 femtolitre.RBCscount/cmmPCV×10=545×10=90femtolitre.
-
MCH (Mean Cell Hb): 27 - 32 pg
- Hb×10RBCscount/cmm=15×105=30Picogram\frac{Hb\times10}{RBCs count /cmm} = \frac{15\times10}{5} = 30 PicogramRBCscount/cmmHb×10=515×10=30Picogram
-
MCHC (Mean Cell Hb Concentration): 32 - 36 gm/dl
- HbPCV×100=15×10045=33gm/dl\frac{Hb}{PCV}\times100 = \frac{15\times100}{45} = 33gm/dlPCVHb×100=4515×100=33gm/dl
-
MCV (Mean Corpuscular volume): 77 - 95 fL
-
RDW (Red Cell Distribution Width): 11.5 - 14.5%
- A measure of the degree of anisocytosis (variation in RBC size)
- Increased: Due to many types of anemia (iron deficiency, pernicious anemia, folate deficiency, thalassemia), liver disease
- A measure of the degree of anisocytosis (variation in RBC size)
- Reticulocytes: 0.5 - 2.5%
- ESR: 2 - 12 mm/1st hour
-
WBC: 4000 - 11000/cmm
- Neutrophils: 50 - 70%
- Lymphocytes: 20 - 45%
- Eosinophils: 1 - 5%
- Monocytes: 3 - 7%
- Basophils: 0 - 1%
- Platelets: 150,000 - 400,000 /cmm
ANEMIAS
- A reduction in one of the following parameters:
- RBCs count
- Hb concentration
- Hematocrite value (packed cell volume)
- Females are usually 1 to 2 gm Hb & about one million RBCs per cmm less than males.
Pathophysiology
- Hyperdynamic circulation -> short circulation time & high cardiac output
- ↑↑↑ Erythropoietin by the kidney -> ↑↑ RBCs
- ↑↑ O2 delivery to the tissue (shift of O2 dissociation curve to the right): This is due to excess production of 2,3 DPG (2,3, diphosphoglycerate) which make the binding between O2 & Hb very weak.
- Redistribution of the blood: blood is shifted to the vital organs e.g.brain
Clinical Picture
- Symptoms*: (depend on the rate of reduction rather than the absolute value of Hb)
- General: Fatigue & lassitude
- CVS: manifestations of low cardiac output inspite of high Cop
- CNS: loss of concentration, headache & dizziness
- Genital: Impotence, menstrual irregularities
Signs
- Pallor
- Hyperdynamic circulation: Tachycardia, ↑S1, gallop, hemic murmur
- Lower limb edema: "due to hyperdynamic circulation, hypoxia & heart failure"
- Papiledema and retinal hemorrhage: due to ↑ permeability
Investigations
-
I.CBC:
- RBCs & HB: ↓↓ with all types
- WBCs & platelets: ↓↓ with Megaloblastic, Aplastic anemia
-
Indices:
- MCV, MCH, MCHC: e.g.- Normal in hemolytic & aplastic anemia.- ↓ in iron deficiency anemia.- ↑ in megaloplastic anemia except MCHC is normal
-
II.Color index: 1 (0.9 - 1.1) except
- Iron deficiency anemia: < 1
- Megaloplastic anemia: > 1
- III.Bone marrow examinations: e.g.Erythroid hyperplasia in iron deficiency, aplasia in aplastic anemia
- IV.Hepatic and renal investigations: e.g.KFTS, LFTs.
Treatment
- Blood transfusion.
- Packed RBCs.
- Treatment of the cause: e.g.- Fe -> in iron deficiency anemia.- Folic acid & vitamin B12 -> Megaloblastic anemia.- Treatment of complications: as HF (and mention)
Classification of Anemias By Pathophysiology
-
I.Decreased production:
- ↓↓ Hb Synthesis: Iron Deficiency anemia, Thalassemia, Anemia of chronic disease.
- ↓↓ DNA Synthesis: Megaloblastic anemia.
- ↓↓ Stem Cell: Aplastic anemia.
- II.Increased destruction: Hemolytic anemia.
- III.Increased RBCs loss: Acute-post-hemorrhagic anemia.
Classification of Anemias by Cell Size:
-
I.Microcytic hypochromic:
- Iron deficiency anemia: defect in haem synthesis
- Thalassemia: defect in globin synthesis.
- Anemia of chronic disease: defect in haem synthesis.
- Sideroblastic anemia: defect in haem synthesis.
-
II.Normocytic normochromic:
- Hemolytic anemia.
- Aplastic anemia.
- Acute-post-hemorrhagic anemia.
- Anemia of chronic disease.
-
III.Macrocytic:
- Vitamin B12 deficiency.
- Folic acid deficiency.
- Myelodysplasia.
- Myxedema.
- Alcohol.
- Chronic liver diseases.
Megaloblastic Anemia
- Hematological disorder characterized by Pancytopenia with 4 criteria:
- Megaloplastic hyperplasia of the bone marrow.
- Evidence of Macrocytosis.
- Good response to vit.B12 & folic acid.
- Neurological & G.I.T manifestations.
Pathophysiology
- Arrest of the division: as vit.B12 & folic acid are essential for DNA synthesis.This will result in big cells (megaloblasts).
- Ineffective erythropoesis: most of megaloblasts undergo intra mdullary hemolysis.
- Evidence of macrocytes: some megaloblasts can escape the bone marrow and appear in the blood as macrocytes.
- Rapid hemolysis: macrocytes are rapidly sequestrated by the spleen
Etiology
-
I.Vitamin B12 deficiency:
- Diminished intake of vitamin B12 which is present in animal products.
- Decreased absorption:
- Pernicious anemia (The most common cause)
- Gasterectomy, chronic gastritis.
- Malabsorption syndrome.
- Ileal resection.
- Chronic liver diseases: Body stores are Sufficient for 3yrs.
- Transcobalamin II deficiency (rare)
-
II.Folic acid deficiency:
- Decreased intake: lack of vegetables & fruits, alcoholism.
- Decreased absorption: malabsorption syndrome.
- Increased requirement: Pregnancy, malignancy.
- Drugs: Methotrexate, phenytoin.
Clinical Picture
- Anemia: see scheme
-
Neurological manifestations (3p): Vit B12 is an important co factor in the formation of myelin sheath.
- Peripheral neuropathy
- Pyramidal tract lesion
- Posterior column -> loss of deep sensations.
-
gastrointestinal manifestations (3 Atrophy):
- Atrophic glossitis.
- Atrophic gastritis.
- Atrophy in the intestine
Investigations
-
I.CBC:
- Pancytopenia: RBCs, Hb, WBCs & platelets: ↓↓
- MCV, MCH, MCHC: ↑ except MCHC is normal.- Anisocytosis (unequal size), Poikilocytosis (abnormal shapes)
- Color index: >1
- II.Bone marrow examinations: Megaloplastic hyperplasia
-
III.Measurement of serum B12 & folic acid:
- serum B12: < 100 pg/mL (N: > 200 pg/ml)
- serum folate: < 4 ng/ml (N: 6-20 ng/ml)
-
IV.Schilling test:
- Giving the patient vit.B12 (100 ug IV) to saturate body stores.
- Giving patient radioactive B12 (lug) orally.
- Collect patient urine /24 h and measure radioactive B12
- If vitamin B12 is absorbed, it will appear in urine.
- Low excretion: Malabsorption.
- Normal after intrinsic factor orally: Pernicious anemia.
- Normal after antibiotic: Bacterial overgrowth.
- Normal after pancreatic enzymes: Pancreatic insufficiency.
- V.Therapeutic test: Giving small dose of vitamin B12 or folic acid -> Reticulocytosis.
- VI.Serological test: Anti parietal cell antibodies & anti intrinsic factor antibodies may be present in pernicious anemia.
-
VII.FIGLU Test: +ve in folic acid deficiency.
- Oral loading with histidine is accompanied by high urinary excretion of Formin Ino GLUtamic acid, an intermediate metabolite in the conversion of L-histidine to L-glutamic acid.(+ve FIGLU test).
Differential Diagnosis
-
Other causes of macrocytic anemias:
- Myelodysplasia
- Myxedema.
- Alcohol.
- Chronic liver diseases.
Treatment
- As scheme plus replacement therapy
-
1.Vitamin B12 deficiency:
- Vitamin B12 (Hydroxycobalamine):
- Intramuscular injections of 1000 ug of vitamin B12: usually given daily for the first week, weekly for the first month, and then monthly for life.
- It is a lifelong disorder, and if patients discontinue their monthly therapy the vitamin deficiency will recur.
- Vitamin B12 (Hydroxycobalamine):
-
2.Folic acid deficiency:
- Folic acid: 5 mg/day orally
- Vitamin B12 is essential for the transformation of folic acid into the active form folinic acid, So large doses of folic acid may aggravate the manifestations of vitamin B12 deficiency especially neurological manifestations.
Conclusion
- The text provided is a detailed summary of hematology diseases.
- It covers normal blood values, the formation of blood cells, the classification of anemias, and specific information on megaloblastic anemia.
- The text includes a wealth of information on the pathophysiology, clinical picture, investigations, and treatments associated with hematology disorders.
- The summary provides a valuable resource for students in medicine or related fields.
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Description
This quiz covers the essential components of blood, including red and white blood cells, platelets, and plasma. It also explores the processes of hemopoiesis, erythropoiesis, granulocytopoiesis, and thrombocytopoiesis, detailing the maturation stages and normal ranges of blood constituents. Test your knowledge on these critical aspects of hematology.
