1b Anaemia and Transfusion Flashcards
How do we interpret an increase in unconjugated bilirubin?
Unconjugated hyperbilirubinemia is caused byproblems with red blood cell stability and survival or by defects in the bilirubin-conjugating enzyme, UGT.
How do we interpret an increase in conjugated bilirubin?
In contrast, disorders that result in conjugated hyperbilirubinemia are usually caused by intrinsic liver dysfunction
What is seen on a blood film in a patient with raised unconjugated bilirubin?
Round cells that lack central pallor = spherocytes
polychromatic MACROCYTES
high reticulocyte count
What causes hereditary spherocytosis?
Disruption of vertical linkages in the membrane, usually due to ankyrin/spectrin
What causes high reticulocytes?
Reticulocytosis can be a key indicator that the bone marrow is responding to a need for increased red blood cell production. Causes include anaemia,compensated blood loss or hemolysis and hypoxia
How does the bone marrow respond to haemolytic anaemia?
Reticulocytosis - immature red blood cells enter into circulation which then form reticulocytes, and can lead to polychromasia
What is polychromasia?
Polychromasia is thepresentation of multicolored red blood cells in a blood smear test. It’s an indication of red blood cells being released prematurely from bone marrow during formation.
Why is there colour seen on the red blood cells in polychromasia?
ribosomes still left on the immature blood cells, which are not found on mature red blood cells. These cells still contain a nucleus with genetic material as well due to the early release, which is not needed in mature blood cells because their only function is to carry oxygen in the blood.
What is haemolytic anaemia?
Increased destruction with shortened RBC survival and resultant anaemia = haemolysis which leads to a reduction in Hb
What is the treatment for haemolytic anaemia?
Folic Acid (because of the increased need)
Splenectomy (to increase the life span of the red blood cells
Vb12
What is the major consequence of haemolytic anaemia?
Gallstones
What are the symptoms of gallstones which might present in a patient with haemolytic anaemia?
Upper abdominal pain
Tenderness
Jaundice - due to elevated conjugated bilirubin
The gallstones cause obstructive jaundice
Liver is still able to conjugate the bilirubin but it isnt passing from the bile ducts and gall bladder into the duodenum
What type of stones do patients with haemolytic anaemia get?
Pigment stones
What are the two possible causes of anaemia?
RBC failure of production
RBC excess loss / destruction
What are some of the effects of SLE?
Autoimmune
- Polyarthritis
- Renal impairment
- Facial skin rashes
- Hepatitis
- Tiredness
What are some of the changes seen to the blood cells when a patient has SLE?
Low HB = anaemia
High MCV = macrocytic
What is DAT?
Direct anti-globulin test = antibodies that bind to antigens on the erythrocyte membrane in a patient who has developed an auto-antibody
What is DAT used to do?
Confirm the presence of autoimmune haemolytic anaemia
What is AIHA?
Auto-immune haemolytic anaemia
What is AIHA associated with?
Disorders of the immune system = SLE and lymphoma
Outline 4 laboratory evidence of haemolysis?
LDH raised
Unconjugated bilirubin
Reduced haptoglobin
Reticulocytosis
Why is raised LDH a sign of hameolysis?
LDH is present in red cells and hemolysis causes release into the plasma.
Why is reduced haptoglobin a sign of haemolysis?
Haptoglobin is primarily produced in the liver and is functionally important for binding free hemoglobin from lysed red cells in vivo, preventing its toxic effects. Because haptoglobin levelsbecome depleted inthe presence of large amounts of free hemoglobin, decreased haptoglobin is a marker of hemolysis.
What are the 2 categories of haemolytic anaemia?
- Inherited(RBC defect)
- Acquired (RBC environment defect/plasma/vasculature)
Which two conditions are spherocytes present in and what test is used to differentiate between them?
Hereditary spherocytosis
Acquired auto-immune haemolysic anaemia
DAT test = positive in AIHA
What environmental factors can cause non-immune haemolysis?
Microangiopathic
Malaria
Snake venom
Drugs
What pathway provides energy for the cell?
Glycolytic pathway
Which shuttle protects the glycolytic pathway from oxidant damage?
Pentose shunt
What enzyme is key in the pentose shunt?
G6PD
What is G6PD
Glucose-6-phosphate deficiency
What is the HMP shunt tightly coupled to?
The metabolism of glutathione - protects from oxidant damage
Why is G6PD deficiency a problem?
Makes the red cells susceptible to oxidant damage= resulting in haemolysis