Haematology Flashcards
(27 cards)
what is haemolytic disease of the newborn
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
what test is +ve in haemolytic disease of newborn
Direct Coombs test
what is given to babies at birth to prevent haemolytic disease of newborn
IM VIT K
when are rhesus -ve mothers offered prophlyactic anti-D
28 + 34 Weeks
15000 units
what events during pregnancy would a rhesus -ve mother get anti-D
ectopic pregnancy
amniocentesis
termination of pregnancy
trauma – vaginal bleeding / miscarriage
dose of anti-D given after delivery to rhesus -ve mother
500 units
when would anti-D not be given after delivery
if Coombs test +ve / infant bilirubin raised
– it is too late
inheritance of sickle cell anaemia
autosomal recessive - abnormal gene for beta globin on chromosome 11
- one abnormal copy = sickle cell trait
- two abnormal copies = sickly cell disease
management of sickle cell anaemia
avoid dehydration / infective causes of sickle crisis
antibiotic prophylaxis – penicillin V
hydroxyurea – can stimulate HbF (fetal haemoglobin production), has a protective effect
what can cause an aplastic crisis in sickle cell anaemia
parvovirus B19
what is a splenic sequestration crisis
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
what is idiopathic thrombocytopenic purpura (ITP)
Immune mediated low platelet count causing a purpuric rash (non-blanching)
what type of reaction is ITP
type 2 hypersensitivity – antibodies destroy platelets
- can be spontaneous or following a viral infection
inheritance of Thalassaemia
autosomal recessive
what type of anaemia is seen in Thalassaemia
microcytic
what are the types of thalassaemia
alpha – defect on chromosome 16
beta – defect on chromosome 11
what are the subtypes of Alpha thalassaemia
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
what are the subtypes of beta thalassaemia
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
complication of thalassaemias
iron overload
- patens require iron chelation if having repeated transfusions
inheritance of hereditary spherocytosis
autosomal dominant
- red blood cells are sphere shaped making them fragile + easily destroyed in spleen
presentation of hereditary spherocytosis
jaundice anaemia gallstones splenomegaly aplastic crisis -- parvovirus infection. no reticulocyte response to haemolysis
how is diagnosis of hereditary spherocytosis made
+ve family history
blood film showing spherocytes
raised reticulocytes
raised MCHC (mean corpuscular Hb concentration)
management of hereditary spherocytosis
folate supplement + splenectomy
inheritance of G6PD deficiency
X linked recessive
- deficiency in G6PD which helps combat oxidative stress
