Haemolytic Anaemias

Question 1

congenital causes of haemolytic anaemia

Answer 1

• hereditary spherocytosis
• hereditary ellipocytosis
• G6PD deficiency
• PK deficiency
• thalassemia
• sickle anaemia

Question 2

acquired causes of haemolytic anaemia

Answer 2

• autoimmune haemolytic anaemia
• microangiopathic haemolytic anaemia
• malaria
• wilson’s disease
• zieve’s syndrome
• mechanical haemolysis

Question 3

clinical features of haemolytic anaemia

Answer 3

• pallor
• fluctuating jaundice
• dark urine
• splenomegaly
• gallstones
• folate deficiency

Question 4

lab results of haemolytic anaemia

Answer 4

• increased unconjugated bilirubin
• increased urine bilinogen
• low haptoblobins
• reticulocytosis
• marrow erythroid hyperplasia

Question 5

what happens when there is intravascular haemolysis?

Answer 5

• erythrocytes destroyed directly in circulation
• Free Hb released rapidly and saturates plasma haptoglobins
• Free excess Hb filtered by glomeruli
• Appears as haemoglobinuria
• Acute renal failure
• Laboratory features: haemoglobinuria, haemosidinuria

Question 6

what is hereditary spherocytosis?

Answer 6

• autosomal dominant

- defect in spectrin

Question 7

differential diagnosis for hereditary spherocytosis

Answer 7

autoimmune haemlysis (warm) - distinguish by Coombs test

Question 8

investigations of hereditary spherocytosis

Answer 8

• blood film
• radiolabelled studies
• spectrin assays
• osmotic fragibility tests
• autohaemolysis test

Question 9

treatment of hereditary spherocytosis

Answer 9

• splenectomy

- folate supplements

Question 10

what does Coombs test do?

Answer 10

detects the antibody that causes autoimmune haemolysis

Question 11

expected results from HS

Answer 11

• high bilirubin
• reticulocyte count
• splenomegaly

Question 12

what are the different grades of severity?

Answer 12

• mild: compensates well

- severe: neonatal jaundice

Question 13

what is G6PD deficiency?

Answer 13

• glucose-6-phosphase dehydrogenase deficiency
• X-linked
• rapid intravascular haemolysis precipitated by oxidative stress
• precipitants include infection, drugs, fava beans
• Hb is normal between crisis

Question 14

how do you diagnose G6PD?

Answer 14

• blood film with bite cells and Heinz bodies

- G6PD assay

Question 15

what is paraoxysmal noctural haemoglobinuria?

Answer 15

• rare acquired clonal effect
• red cell membrane unduely sensitive to complement mediated lysis
• chronic intravascular haemolysis
• recurrent thrombosis

Question 16

how do you diagnose paraoxysmal noctural haemoglobinuria?

Answer 16

• flow cytometry (CD55 and CD59)

- Ham’s test

Question 17

management of PNH?

Answer 17

• leucodepleted blood products
• long term anticoagulation
• eculuzumab
• BMT

Question 18

what are the types of autoimmune HA?

Answer 18

• warm autoantibodies (IgG)

- cold autoantibodies (IgM)

Question 19

causes of autoimmune HA

Answer 19

• idiopathic
• viral infections
• mycoplasma
• lymphoma
• systemic autoimmune diseaes
• exposure to certain drugs

Question 20

lab features of autoimmune HA

Answer 20

• spherocytic cells

- bits of the red cell removed

Question 21

investigations for autoimmune HA

Answer 21

• blood film

- DCT positive

Question 22

management of autoimmune HA

Answer 22

• avoid transfusion
• immunesuppression
• splenectomy
• folate supplements

Question 23

what is thalassemia?

Answer 23

failure to produce a globin chain

- autosomal recessive

Question 24

which types of haemoglobin molecules are affected by alpha thalassemia?

Answer 24

HbA, HbF, HbA2

Question 25

what happens if there is a globin chain imbalance?

Answer 25

the protein gets denatured

Question 26

what type of anaemia does thalassemia give you?

Answer 26

microcytic hypochromic

Question 27

expected lab results for b-thalassemia

Answer 27

- normal Hb - MCV, MCH reduced - RBC normal or raised - raised HbA2

Question 28

features that a thalassemia major patient has

Answer 28

- severe anaemia (transfusion-dependent) - hyperplasia of bone marrow - hepatosplenomegaly - iron overload - endocrine deficiencies - osteoporosis

Question 29

management of thalassemia major

Answer 29

- transfusion every month - iron chelation (to prevent iron overload - done orally) - splenectomy - hormone replacement - bisphosphonates - folate supplementation - bone marrow transplant

Question 30

what is thalassemia intermedia?

Answer 30

condition which is intermediate in severity between the major and the minor

Question 31

another name for thalassemia intermedia in alpha-globin deficiency

Answer 31

HbH disease

Question 32

which amino acid substitution is in sickle cell anaemia

Answer 32

valine for glutamic acid

Question 33

heretability of sickle cell anaemia

Answer 33

autosomal recessive

Question 34

trigger for a sickle crisis

Answer 34

- infection - dehydration - cold - hypoxia

Question 35

presentation of sickle cell anaemia

Answer 35

- jaundice - gallstones - anaemia - asplenic (multiple infarctions) - organ failure (multiple infarctions) - leg ulcers - recurrent infections - aseptic necrosis of bone - chronic renal disease - retinopathy

Question 36

when does sickle cell anaemia present?

Answer 36

6 months of age

Question 37

management of a sickle cell crisis

Answer 37

- oxygen (for hypoxia) - IV fluids - antibiotics - analgesia - exchange transfusion

Question 38

management of a sickle cell patient

Answer 38

- hydroxyurea to increase HbF - folate supplements - penicillin, vaccines - bone marrow transplant