Haemolytic Anemias

Question 1

Give a succinct definition of haemolytic anemia

Answer 1

Decompensated ⬆️ destruction of RBC.

Lifespan of 120days fails to 15days.
Bone marrows erythropoiesis can no longer compensate

Question 2

Hb molecule is a ❓ of ❓ polypeptide chains

Answer 2

A tetramer of 4 ppc, 2alpha (141 aa) and 2beta (146 aa)

Question 3

List the different ways haemolytic anemia can be classified

Answer 3

Based on:
•Site of defect
•Site of destruction
•Inherited or acquired

Question 4

Classify haemolytic anemia based on the site of defect

Answer 4

•Intrinsic/Intracorpuscular
I: Membranopathy e.g spherocytosis, elliptocytosis, pyropoikilocytosis

Enzymopathy e.g G-6-PD deficiency, pyruvate kinase deficiency

Hemoglobinopathy e.g SCD, thalassemias

A: PNH

•Extrinsic/Extracorpuscular
Immune (Allo/Auto) hemolytic deficiency

Drugs

Infections eg malaria, clostridium perfingens

Microangiopathic processes eg
DIC-Disseminated intravascular coagulations
TTP-thrombotic thrombocytopenia purpura
HUS-hemolytic uremic syndrome

Splenic sequestration/hypersplenism

Question 5

Typically, inherited disorders are caused by intrinsic defects and acquired disorders are caused by extrinsic defects

True or false
Mention an exception

Answer 5

True

Paroxysmal Noctural Haemoglobinuria

Question 6

Briefly describe the extravascular degradation of hemoglobin

Answer 6

Hemoglobin 
⬇️
Heme+Globin➡️a.a pool
⬇️
Biliverdin+CO➡️lungs+Fe➡️Transferrin
⬇️
Bilirubin 
⬇️
Bilirubin-Albumin
⬇️
Bilirubin diglucuronide 
⬇️
Urobilirubin

Question 7

Briefly describe the intravascular degradation of hemoglobin

Answer 7

Destruction of RBC
⬇️
Free Hb in blood
⬇️
Hb+haptoglobin*➡️liver
⬇️Hb in excess
Methemoglobin 
⬇️
Heme(Fe+++)+Globin➡️a.a pool
⬇️
Heme-hemopexin
⬇️Hb in excess
Methemalbumin

*a and b dimers-Urine hemoglobin and urine hemosiderin

Question 8

Clinical features of hemolytic anemia❓

Answer 8

Jaundice
Pallor
Splenomegaly
Expansion of marrow cavities in congenital HA

Question 9

List some laboratory evidences of hemolytic anemia

Answer 9

⬆️Destruction of RBCs:

Hyperbilirubinaemia 
⬇️Serum haptoglobin
⬇️Haemopexin levels
Haemoglobineamia
Haemoglobinuria
Haemosiderinuria 
Methaemalbuminaemia

⬆️LDH

⬆️Production of RBCs:
In blood:
Polychromasia/Reticulocytosis
Erythroblastaemia

Bone marrow:
Erythroid hyperplasia
⬇️Myeloid/erythroid ratio

Question 10

What is the normal retin count?

Answer 10

Retin %- 0.5-3.0%

Absolute count- 20-130*10^9/L

Question 11

_____ of RBC weight is made of Hb

Answer 11

1/3 of a RBC weight

Question 12

Each red cell has ____ molecules of Hb

Answer 12

640 million molecules

Question 13

1. Which membranopathy is the common❓
2. What is the incident rate❓
3. Inheritance is ❓
4. What is the molecular defect❓
5. What are the clinical features❓

Answer 13

1. Heredity spherocytosis
2. 1 in 5000
3. Autosomal dominant/ recessive

4i. Spectrin deficiency-loss of erythrocyte surface area
ii. Defect in ankyrin

5. Usually asymptomatic
   Spenomegaly
   Increased RBC osmotic fragility

Question 14

1. Which enzymopathy is the common❓
2. What is the incident rate❓
3. Inheritance is ❓
4. What is the pathophysiology❓
5. What are the lab features❓

Answer 14

1. G6PD deficiency
2. 1% of worlds population
3. X-linked recessive

4. 
No G6PD
⬇️
No Hexose Monophosphate Pathway 
⬇️
No NAPDH
⬇️
Glutathione cannot be reduced 
⬇️
RBC isn’t protected from oxidative damage

5. Anisocytes
   Heinz bodies
   Bite cells

Question 15

Speak briefly on autoimmune HA

Answer 15

1. Warm autoimmune HA:
   
   • Idiopathic
   -Secondary to:
   Lymphoproliferative disorders
   Autoimmune diseases
2. Cold autoimmune HA:
   -Cold Agglutinin syndrome
   •Idiopathic
   •Secondary to mycoplasma, infectious mono, LPD-Paroxysmal cold hemoglobinuria
   •Idiopathic
   •Secondary to measles, mumps or syphilis
3. Drug-induced IHA