USMLE preparation and Medical PG Entrance-Hemolytic anemias

I have discussed about Hemolytic anaemia in above video. So listen to and watch above video and start reading about Hemolytic Anaemia from some Standard Textbook of Medicine.

Few Important Points About Hemolytic anaemia are

Introduction:

RBC have a short life span of 120 days

RBCs cannot divide due to lack of intracellular mechanisms needed for cell growth and repair

Erythropoiesis is the process of formation of RBC which takes place in Bone marrow.

Main function of RBCs is to carry oxygen in blood

Hypoxia acts as a stimulus for Erythropoietin

Erythropoietin released from Kidneys acts on bone marrow leading to more RBC production

What is Hemolytic anemia:

It means there occurs premature destruction of RBCs

If BM cannot compensate, hemolytic anemia develops

Mild- Asymptomatic

Severe- Life threatening

Features of Hemolysis:

Increase in unconjugated bilirubin

Increase in LDH level

Increase in reticulocyte count

Increase in urinary urobilinogen

Decrease in Haptoglobin

Decrease in Hemopexin

Increase in urinary hemosiderin

Increase in fecal stercobilinogen

Hemoglboinuria

PBF- Schistocytes, Spherocytes, Bite cells, blister cells

Splenomegaly

Bossing of skull

Etiology:

Congenital

1)Red cell membrane defects– Hereditary spherocytosis

    – Hereditary elliptiocytosis

2) Defect in enzyme pathways

    – Pyruvate kinase deficiency

    – G6PD deficiency

3)Defect in Hemoglobin– Sickle cell anemia

                                           – Thallesaemia

Acquired:

1)Immune disorders

2)Toxic chemicals and drugs

3)Antivirals like Ribivirin

4)Incompatible blood transfusion

Extravascular –

1)Autoimmune hemolytic anemia

2)Hereditary spherocytosis

 Intravascular-

1 ) Prosthetic heart valves

2) TTP,DIC,HUS,Mismatched blood transfusion

3) March hemoglobinuria

4) Thermal burns

Hereditary spherocytosis:

Heterozygous familial disorder

Autosomal dominant pattern of inheritance

Mutations in RBC membrane proteins

Loss of RBC cell membrane leading to instability- Decreases cell membrane surface area

Impaired osmotic fragility

Pathophysiology :

Spectrin deficiency

Spectrin + Ankyrin deficiency

Band 3 deficiency

Protein 4.2 defects

Cytoskeleton abnormality- spherical RBC- Removed from circulation by spleen

Clinical features- Severe cases in infancy- Severe anemia, jaundice

Mild cases- young adults or later

  with jaundice, gall stones, splenomegaly

Lab Abnormality- Increase bilirubin , Increase MCHC, Spherocytes on PBF, Increased osmotic fragility

Treatment- Splenectomy, Folic acid supplementation

Defect in enzyme pathways:

Glycolytic pathway- pyruvate kinase deficiency

Defect in redox metabolism- G6PD enzyme plays an important role in redox metabolism- only source of NADPH, protects against oxidative stress.

Fava beans, Infections, Drugs can cause hemolysis in patients with G6PD deficiency

Drugs- Analgesics- Aspirin, Phenacetin

              – Antimalarials- Primaquine, Quinine

              – Antibiotics- Sulphonamides, 

                Nitrofurantoin , Dapsone

 C/F- Malaise, weakness, lumber pain, jaundice, dark urine due to hemoglobinuria

Anemia- normocytic, normochromic

Hemoglbinaemia, Hemoglobinuria, Increase in Serum LDH level,

Low Haptoglobin level

PBF- Bizarre poikilocytes, Bite cells, Blister cells, Heinz bodies

Acute renal failure

Diagnosis- G6PD level

So you can read this topic and watch the above video and you will be able to solve questions based on this topic of hemolytic anaemia.

Be the first to comment

Leave a Reply

Your email address will not be published.


*