Microcytic Anaemia Flashcards
Haematology : RBC production
1. Erythropoetin
* a hormone produced by the kidneys in response to cellular hypoxia
2. Bone marrow
* Erythropoetin bind on the erythropoietin receptors on the immature blood cells causes them to mature
* Immature (Proerythroblast) —-> mature (Erythrocytes)
Haematology : Components of Erythrocyte
1 . Haem molecule x 4
Components;
* Protoporphyrin
* Iron
2 . Globin (polypeptide)
Made up two main types of globin molecules;
* Alpha Globin x2
* Beta Globin x2
Haemoglobin - components
4x haem groups in a single haemoglobin molecule
Each Haem group Consist of;
1. Iron (Fe2+) - site of O2 molecule binding
2. Porphyrin ring (Bound to Iron)
-
Globin chains - protein subunits that make up the backbone of the haemoglobin molecule
* HbA (Adult Haemoglobin)
* 2x Alpha Globin
* 2x Beta Globin chain
structural integrity of hemoglobin and contribute to its ability to undergo conformational changes during oxygen binding
Microcytic anaemia : Causes
microcytic anaemia is “TAILS”:
* T – Thalassaemia
* A – Anaemia of chronic disease
* I – IRon deficiency anaemia
* L – Lead poisoning
* S – Sideroblastic anaemia
Iron deficiency anaemia : Pathophysiology
- Reduced Iron stores
-
Impaired Haem synthesis
* Iron is a critical component of the heme group,
* insufficient iron availability impairs the synthesis of heme.
3 . Decreased Hemoglobin Production:
shortage of heme results in decreased hemoglobin production within the developing red blood cells.
4 . Microcytic Red Blood Cells:
* Inadequate haem results in microcytic RBC in bone marrow
* hypochromic - reduced hemoglobin content.
5 . Decreased Oxygen-Carrying Capacity:
Iron deficiency anaemia : Causes
- Decrease in RBC due to insufficient iron stores
Causes of IDE
1. Inadequate Iron Intake
2. Impaired Iron Absorption
3. Chronic Blood Loss:
Iron deficiency anaemia - Clinical features
- Decreases oxygen to tissues : Pallor, Fatigue, palpitations, tachypnea
- PICA : craving for non food substances
- Glossitis - smooth beefy red tongue
- Koilonychia - spoon shaped, concave nails
Iron deficiency anaemia - Diagnosis
Lab results :
* Low MCV, low haemoglobin
% saturation low : % of iron occupying Transferrin
2 . TIBC increases :
* Measure of the maximum amount of iron that can be bound to transferrin - ability to bind and transport Iron
3 . Serum ferritin
* Reduction : Low iron stores
* Increase : Iron overload / Inflammation
(less iron, less iron occupying transferrin), low Ferritin, TIBC increases (to compensate for the low iron)
Iron deficiency anaemia - Mx
1 . Medication - PO iron supplement
2 . Increase dietary iron
* Vitamin C increases absorption of iron, avoid calcium can decrease iron absorption
3 . Avoid transfusion except in acute cases
* Lack of iron, unable to maintain Hb levels
Anaemia of Chronic disease- Pathophysiology
1 . Hepcidin - protein produced by Liver
* Blocks absorption of iron in duodenum
* Reduces Iron levels in the blood
2 . Inflammation - increases Hepicidin level
* Avoids Iron used for bacterial nutrient
3 . Reduced iron levels
* Chronic inflammation reduces serum iron levels
Anaemia of Chronic disease- Diagnosis
Lab results:
1 . Low serum Iron
2 . Low transferrin saturation %
3 . Low total iron binding capacity -
* decreases production of transferrin to reduce iron in the blood stream
4 . High Ferritin
* increases storage of iron
Anaemia of Chronic disease - Mx
Anaemia of chronic disease often occurs with;
* Chronic kidney disease due to reduced production of erythropoietin by the kidneys
* the hormone responsible for stimulating red blood cell production. Treatment is with erythropoietin.
Haemoglobin - Globin chain component
Haemoglobin - Globin chain component
Hemoglobin consists of four globin chains: two alpha (α) and two beta (β) chains in adults.
* Alpha globin chains are encoded by four genes (two on each chromosome 16),
* Beta globin chains are encoded by two genes (one on each chromosome 11).
Alpha thalassaemia : Definition
Deletion or Mutation of Alpha Globin Genes:
1. Alpha thalassemia results from the deletion or mutation of one or more alpha globin genes.
2. The severity of the condition depends on the number of affected genes.
Alpha thalassemia : Types
1 . Silent Carrier:
* One alpha globin gene is affected (usually due to deletion)
* no clinical symptoms.
2 . Alpha Thalassemia Trait:
2. Two alpha globin genes are affected,
* Clinical symptoms : Mild anemia.
Individuals are usually asymptomatic or have minimal symptoms.
3 .Hemoglobin H Disease:
1. Three alpha globin genes are affected
* Clinical symptoms : moderate to severe anemia.
* Hemoglobin H (HbH) is formed, which is less stable and leads to red blood cell damage
4 .Hydrops Fetalis:
1. All four alpha globin genes are affected - complete absence of alpha globin chains
* Clinical symptoms : This condition is incompatible with life, and affected fetuses may not survive to term.
