Normocytic anaemia

Question 1

Normocytic anaemia : Definition

Answer 1

Normal Mean Corpuscular Volume (MCV):
MCV within the normal range (80-100 fL).

Decreased Red Blood Cell Mass:
* Normocytic anemia is characterized by a* reduction in the total number of red blood cells without significant changes in red blood cell size*.

Question 2

Normocytic anaemia : Causes

Answer 2

There are 3 As and 2 Hs for normocytic anaemia:

1. A – Acute blood loss
2. A – Anaemia of chronic disease
3. A – Aplastic anaemia
4. H – Haemolytic anaemia
5. H – Hypothyroidism

Question 3

Anapaestic anaemia - Definition

Answer 3

1 . Autoimmune destruction of Haematopoeitic stem cells
* Stem cells begin to express foreign antigens

2 . Bone marrow Hypoplasia

• Lymphoid precursor cells —> lymphoblasts —> T cells/B cells/natural killer cells
• Myeloid precursor cells —> erythrocytes / platelets / basophils

3 . Pancytopenia

Question 4

Anapaestic anaemia - Clinical features

Answer 4

• Leukopenia (low WCCs) : high risk of infections
• Thrombocytopenia (low platelets) : excess bleeding
• Anaemia (low RBC) : palpitations, fatigue, pallor

Question 5

Anapaestic anaemia - Causes

Answer 5

1. Inherited : Faconi syndrome
2. Acquired : autoimmune disease e.g. SLE, Drugs, viruses e.g. Epstein Barr, HIV
3. Exposure to toxic chemicals

Question 6

Anapaestic anaemia - Diagnosis

Answer 6

1. Lab results:
   * Low WCC, Low RBC, low platelets - prolonged bleeding down
   * Low reticulocyte count
2. Bone marrow biopsy - no increase in immature blood cells,

Question 7

Autoimmune haemolytic anaemia -Definition

Answer 7

1. Haemolysis of red blood cells due to autoantibody destruction against antigens
2. Attack antigens on the surface of the red blood cells mediated by the immune system

Question 8

Warm AIHA - Pathophysiology

Answer 8

Warm AIHA - most common
1 . Body temperature
* occurs at the optimum temperature

2 . Antibody react with the RBC
* IgG antibodies ‘warm agglutins’ react with Rh antigen on the surface of the RBC membrane
* IgG antibodies bind to the RH antigen

3 . _‘Antibody-dependant cell mediated cell toxicity’_
* Haemolysis of the red blood cells
* Occurs in the Spleen

_Cold AIHA - occurs when people’s blood is exposed to cold temperatures_

Question 9

Warm AIHA -Causes

Answer 9

1. Autoimmune disease - SLE
2. Neoplasia e.g. Lymphoma, chronic lymphocytic leukaemia
3. Drugs e.g. methyldopa

Question 10

Warm AIHA- Diagnosis

Answer 10

1 . _Normocytic anaemia_
2 . Low Haptoglobin -
* Liver produces Haptoglobulin protein
* Binds to free haemoglobin and clears it from the blood - into bile

3 . _High reticulocytes_
* Increase in bone marrow activity -> more immature red blood cells

4 . _LDH_
* Lactate dehydrogenase enzyme breaks down the RBCs
* Resulting in raised LDH levels

5 . _COOMBS test_ - positive direct antiglobulin test
, is a blood test used to detect the presence of antibodies that may be bound to the surface of red blood cells

Question 11

Sickle cell anaemia - Types

Answer 11

1 . Severe sickle cell disease - chronic haemolytic anaemia
* HbSS - homozygous for HbS gene

2 . Mild Sickle cell disease
* HbSC - Hetereozygous for Hb S + abnormal haemoglobin C

3 . Sickle cell trait - carrier
* HbSA - Heterozygous for HbS + Haemoglobin A
* Inherits one copy for normal haemoglobin production

Question 12

Sickle cell anaemia - Pathophysiology

Answer 12

Inherited hemoglobinopathies caused by a mutation of the gene for Beta Globulin protein - producing

1 . Haemoglobin S
Due to mutation of gene

2 . Deformed RBC
* HbS tend to polymerise and deform into a sickle/crescent shape when deoxygenated
* Decreased oxygen carrying capacity
* shorter lifespan due to haemolysis

Triggers for deoxygenation : alcohol, cold, stress

Question 13

Sickle cell anaemia* - Clinical features

Answer 13

1 . Anaemia -
* fatigue, extensional dyspnea, pallor

2 . Hypercoagulability
* Vasoocclusion, tissue ischaemia and infarction
* Spleenic thrombosis leading to hyposplenism increases the risk of infection

Complication : CVS events, Respiratory infection, pain from vaso-occlusive crisis

Question 14

Sickle cell anaemia - Diagnosis

Answer 14

1. Gold standard : Haemoglobin electrophoresis -
   Lab results;
2. Normochromic, Normocytic cells + sickle cells
3. Increased haemolysis of RBC
   * Raised reticulocyte count
   * raised bilirubin, raised LDH and low haptoglobin

Question 15

Sickle cell anaemia* - Management

Answer 15

1. Analgesia
2. Hydroxyurea - can be used as prophylactic management of sickle cell anaemia
   * increases cell deformability, increases Hemaglobin F levels, decreases risk of occlusions

Question 16

Sickle cell crisis

Answer 16

1. Thrombotic crisis
   * Percipitant : infection, dehydration, deoxygenation
   * Painful vaso-occlusion e.g. Avascular necrosis of hip
2. Acute chest syndrome
   * vaso-occlusion within the pulmonary vasculature
   * Dyspnea, Chest pain, pulmonary infiltrates on CXR, low O2
3. Aplastic crisis
   * Infection with parvovirus
   * Sudden fall in haemoglobin
   * Bone marrow suppression - reduced reticulocyte count - immature rbcs.