Haematology

Question 1

what is haemolytic disease of the newborn

Answer 1

breakdown of RBCs in the neonate due to rhesus incompatibility

• rhesus D positive baby born to rhesus D negative mother
• mother makes antibodies to baby’s rhesus D (anti-D antibodies) – these cross placenta and attach to foetal RBCs
• immune réponse causes haemolysis of RBCs – anaemia + high bilirubin – jaundice

Question 2

what test is +ve in haemolytic disease of newborn

Answer 2

Direct Coombs test

Question 3

what is given to babies at birth to prevent haemolytic disease of newborn

Answer 3

IM VIT K

Question 4

when are rhesus -ve mothers offered prophlyactic anti-D

Answer 4

28 + 34 Weeks

15000 units

Question 5

what events during pregnancy would a rhesus -ve mother get anti-D

Answer 5

ectopic pregnancy
amniocentesis
termination of pregnancy
trauma – vaginal bleeding / miscarriage

Question 6

dose of anti-D given after delivery to rhesus -ve mother

Answer 6

500 units

Question 7

when would anti-D not be given after delivery

Answer 7

if Coombs test +ve / infant bilirubin raised

– it is too late

Question 8

inheritance of sickle cell anaemia

Answer 8

autosomal recessive - abnormal gene for beta globin on chromosome 11

• one abnormal copy = sickle cell trait
• two abnormal copies = sickly cell disease

Question 9

management of sickle cell anaemia

Answer 9

avoid dehydration / infective causes of sickle crisis
antibiotic prophylaxis – penicillin V
hydroxyurea – can stimulate HbF (fetal haemoglobin production), has a protective effect

Question 10

what can cause an aplastic crisis in sickle cell anaemia

Answer 10

parvovirus B19

Question 11

what is a splenic sequestration crisis

Answer 11

occurs in sickle cell anaemia

• RBCs block blood flow in the spleen
• causes an enlarged + painful spleen – leads to anaemia + circulatory collapse
• tx: blood transfusions / fluid resuscitation
• splenectomy in recurrent cases

Question 12

what is idiopathic thrombocytopenic purpura (ITP)

Answer 12

Immune mediated low platelet count causing a purpuric rash (non-blanching)

Question 13

what type of reaction is ITP

Answer 13

type 2 hypersensitivity – antibodies destroy platelets

- can be spontaneous or following a viral infection

Question 14

inheritance of Thalassaemia

Answer 14

autosomal recessive

Question 15

what type of anaemia is seen in Thalassaemia

Answer 15

microcytic

Question 16

what are the types of thalassaemia

Answer 16

alpha – defect on chromosome 16

beta – defect on chromosome 11

Question 17

what are the subtypes of Alpha thalassaemia

Answer 17

mild: 1 or 2 alleles affected – microcytic but Hb level normal
moderate: known as HbH disease – microcytic anaemia with splenomegaly
severe: Hydrops fetalis (Barts disease)- all 4 alleles affected, death in utero

Question 18

what are the subtypes of beta thalassaemia

Answer 18

beta thalassaemia trait – one abnormal beta globin gene + one normal. Causes mild microcytic anaemia

beta Thalassaemia intermedia – two abnormal copies. requires occasional blood transfusions for more significant anaemia

beta thalassaemia major – no functioning beta globing genes. severe anaemia + failure to thrive. Requires regular blood transfusions + splenectomy

Question 19

complication of thalassaemias

Answer 19

iron overload

- patens require iron chelation if having repeated transfusions

Question 20

inheritance of hereditary spherocytosis

Answer 20

autosomal dominant

- red blood cells are sphere shaped making them fragile + easily destroyed in spleen

Question 21

presentation of hereditary spherocytosis

Answer 21

jaundice 
anaemia 
gallstones
splenomegaly 
aplastic crisis -- parvovirus infection. no reticulocyte response to haemolysis

Question 22

how is diagnosis of hereditary spherocytosis made

Answer 22

+ve family history
blood film showing spherocytes
raised reticulocytes
raised MCHC (mean corpuscular Hb concentration)

Question 23

management of hereditary spherocytosis

Answer 23

folate supplement + splenectomy

Question 24

inheritance of G6PD deficiency

Answer 24

X linked recessive

- deficiency in G6PD which helps combat oxidative stress

Question 25

symptoms of G6PD deficiency

Answer 25

anaemia
intermittent jaundice
splenomegaly
gallstones

Question 26

what things can trigger jaundice in G6PD deficiency

Answer 26

broad beans
antimalarials
Sulfonylureas
infections

Question 27

what is seen on blood film in G6PD deficiency

Answer 27

Heinz bodies