Anemia

Question 1

What are the broad causes of anaemia?

Answer 1

• Blood loss
• Increased red cell destruction (haemolysis)
• Decreased red cell production

Question 2

What changes occur following acute blood loss?

Answer 2

If the patient survives:

• rapid shift of fluid from interstitial to intravascular compartment (to restore blood volume)
• fluid shift results in haemodilution and lowering of haematocrit
• reduced oxygenation triggers EPO secretion from kidneys
• stimulated erythropoiesis in bone marrow

Question 3

What are the initial vs delayed features in RBCs following acute blood loss?

Answer 3

Initially red cells appear normal (normocytic, normochromic)

As marrow production increases, get reticulocytosis + thrombocytosis.

Question 4

What are the common features of haemolytic anaemias?

Answer 4

1) premature destruction RBCs and shortened RBC lifespan below 120d
2) Elevated EPO and a compensatory increase in erythropoiesis
3) Accumulation of Hb degradation products released by RBC breakdown

Question 5

What is extravascular haemolysis?

Answer 5

Premature destruction of RBCs within phagocytes.

Generally caused by alterations that render the cell less deformable.

Question 6

What are the principal clinical features of extravascular haemolysis?

Answer 6

1) Anemia
2) Splenomegaly
3) Jaundice

Question 7

What are the causes of intravascular haemolysis?

Answer 7

i) Mechanical injury: cardiac valve trauma, repetitive physical trauma.
ii) Complement fixation: Ab bind RBC Ags
iii) Intracellular parasites
iv) Exogenous toxic factors: clostridial sepsis - enzymes digest RBC membrane.

Question 8

What are the clinical features of intravascular haemolysis?

Answer 8

1) Anaemia
2) Haemoglobinemia
3) Haemoglobinuria
4) Haemosiderinuria
5) Jaundice

Question 9

What are the causes of microcytic anaemia?

Answer 9

TAILS

• Iron deficiency
• Thalassemia
• Anemia of chronic disease
• Sideroblastic anaemia
• Lead poisoning

Question 10

What is microcytic anaemia?

Answer 10

MCV

Question 11

What are the causes of megaloblastic macrocytic anaemia?

Answer 11

• B12 deficiency
• Folate deficiency
• Drugs that impair DNA synthesis (methotrexate, sulfa, chemo)

Question 12

What are the causes of non-megaloblastic macrocytic anaemia?

Answer 12

• Liver disease
• Alcoholism
• Reticulocytosis
• Hypothyroidism
• Myelodysplasia

Question 13

What are the causes of normocytic, high reticulocyte anaemia?

Answer 13

High retics indicate increased destruction!

Can be due to haemolysis (inherited or acquired), or bleeding (GI, GU, other).

Question 14

What are the inherited causes of haemolytic anaemia?

Answer 14

• Haemoglobinopathy (sickle cell, thalassemia, unstable Hb)
• Membrane (spherocytic)
• Metabolic (HMP shunt, glycolytic pathway)

Question 15

What are the acquired causes of haemolytic anaemia?

Answer 15

• Immune (Coombs +ve, drug-related, cold agglutinin)
• Infection (malaria)
• Microangiopathic haemolytic anaemias (DIC, TTP, HUS, HELLP)
• Oxidative/drug related

Question 16

What are the clinical features of anaemia on HEENT examination?

Answer 16

Mucous membrane pallor and conjunctiva.
Ocular bruits (Hb

Question 17

What are the clinical features of anaemia on cardiac exam?

Answer 17

• Tachycardia
• Orthostatic hypotension
• systolic flow murmur
• wide pulse pressure
• signs of CHF