Week 1 part 3

Question 1

When hemolysis occurs and leads to a red blood cell imbalance, it is called hemolytic anemia, and there are two types: what are the two types?

Answer 1

Intrinsic and extrinsic (intravascular and extravascular hemolysis)

Question 2

Intrinsic hemolytic anemia

Answer 2

Inherited hemolytic anemia (also called intrinsic hemolytic anemia) is caused by a defect in the red blood cells themselves and result when one or more genes that control red blood cell production don’t function properly. With these conditions, red blood cells are destroyed earlier than normal

Question 3

Extrinsic hemolytic anemia

Answer 3

The spleen destroys healthy red blood cells or they are damaged by an infection, tumors, autoimmune disorders, medication, leukemia, or lymphoma.

Question 4

Consequences of haemolysis

Answer 4

Erythroid hyperplasia (increased bone marrow red cell production)
Excesss red cell breakdown products (e.g. billirubin)

Question 5

COMPENSATED HAEMOLYSIS

Answer 5

Increased red cell destruction compensated by increased red cell production
i.e. Hb Maintained

Question 6

HAEMOLYTIC ANAEMIA

Decompensated haemolysis

Answer 6

Increased rate of red cell destruction exceeding bone marrow capacity for red cell production
i.e. Hb Falls

Question 7

Polychromasia

Answer 7

Polychromasia is the presentation 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.

Question 8

Intravascular & extravascular hemolysis

Answer 8

Intravascular hemolysis occurs when erythrocytes are destroyed in the blood vessel itself, whereas extravascular hemolysis occurs in the hepatic and splenic macrophages within the reticuloendothelial system.

Question 9

Extravascular hemolysis consequences

Answer 9

Hyperplasia in spleen and liver (hepatosplenomegaly)

Release of protoporyphrin (jaundice and gall stones)

Question 10

Intravascular hemolysis consequences

Answer 10

Haemoglobinemia ( due to red cells destroyed in blood vessells and dropping their contents such as HB)

Methaemalbunimea, haemoglobinurea (pink urine), Haemosiderinurea

Question 11

Causes of intravascular hemolysis

Answer 11

Incompatible ABO transfusions
G6PD defiency
severe falciparum malaria

Question 12

Autoimmune hemolytic anemias

Answer 12

Autoimmune hemolytic anemia is caused by autoantibodies that react with red blood cells at temperatures ≥ 37° C (warm antibody hemolytic anemia) or < 37° C (cold agglutinin disease). Hemolysis is usually extravascular. The direct antiglobulin (direct Coombs) test establishes the diagnosis and may suggest the cause

Question 13

Direct Coombs test

Answer 13

Identifies autoantibodies bound to patients own red cells - such as in warm (IgG) and cold (IgM) hemolytic anemias.

Question 14

Alloimmune hemolyis

Answer 14

Alloantibodies - hemolytic transfusion reactions - can be immediate (IgM - mainly intravascular reaction & life-threatening) or delayed reaction (IgG - mainly extravascular & could be due to previous sensitisation)

Question 15

Mechanical hemolytic (acquired) anemias

Answer 15

When mechanical trauma breaks down red blood cells such as through a blood vessel or leaking heart valve.

Question 16

What happens to transferrin levels when iron is high?

Answer 16

transferrin saturation increases

Question 17

What happens to transferrin levels when iron is low?

Answer 17

Transferrin sats decrease

Question 18

What happens to ferritin levels when iron is low?

Answer 18

Ferritin (storage molecule for iron) decreases

Question 19

Sideroblastic anaemia

Answer 19

• excess iron build up in mitochondria (blue granules around nucleus) due to failure to incorporate iron in to haem. Can be hereditary or acquired eg MDS, lead poisoning, alcohol excess

Question 20

Causes of Iron Overload

Answer 20

Primary
•Hereditary haemochromatosis

Secondary
•Transfusional
•Iron loading anaemias

Question 21

Hereditary Haemochromatosis

Answer 21

Commonest form is due to mutations in HFE gene
•Decreases synthesis of hepcidin
•Increased iron absorption
•Results in gradual iron accumulation with risk of end-organ damage

Hereditary hemochromatosis is a disease in which your body has high levels of iron. That means you have too much iron. It’s often called “iron overload.” Your body can’t get rid of the extra iron, and it ends up damaging your tissues and organs.

Question 22

normal Hb in children

Answer 22

6 months to 6 years - 110g/l

6+ years - 120g/l

Question 23

What should we look for in reticulocytosis?

Answer 23

Increased breakdown products like bilirubin may suggest hemolyis is there is a reticuloxytosis.

If bleeding then there is no breakdown products remember.

Splenomegaly due to increased removal of red blood cells may also suggest hemolysis like the increased bilirubin

Question 24

Reticulocyte responses in anemia

Answer 24

Question 25

What is the main underlying pathophysiology of ACD?

Answer 25

Inflammation (malignancy, chronic infection and autoimmunity) leading to decreased erythropoetin release from kidneys. Others mechanism exist too such as reduced Erythropoetin, increased hepciden, reduced red cell survival, increased red cell destruction eg by macrophages,

Question 26

Difference between IDA and ACD in investigations

Answer 26

Very similar results although ferritin is usually low in IDA and normal or increased in ACD. Use ferritin to distinguish the two although remember ACD can also have low ferritin and vice versa sometimes.

Question 27

MCH

Answer 27

The mean corpuscular hemoglobin, or “mean cell hemoglobin”, is the average mass of hemoglobin per red blood cell in a sample of blood

Low = hypochromic
High = hyperchromic

Question 28

MCHC

Answer 28

MCHC checks the average amount of hemoglobin in a group of red blood cells.

The mean corpuscular hemoglobin concentration is a measure of the concentration of hemoglobin in a given volume of packed red blood cells

Question 29

RBC

Answer 29

An RBC count is a blood test that measures how many red blood cells (RBCs) you have. RBCs contain hemoglobin, which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work. Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide.

Question 30

HCT blood test

Answer 30

A hematocrit test measures the proportion of red blood cells in your blood.