sickle cell anaemia Flashcards
what is sickle cell anaemia
autosomal recessive condition that results from synthesis of abnormal haemoglobin chain termed HbS
more common in people of african descent
genetic component of sickle cell disease
autosomal recessive affecting the gene for beta-globin on chromosome 11
screening for sickle cell anaemia
tested for on the newborn blood spot screening test
pregnant women at high risk are offered testing
definitive diagnosis by haemoglobin electrophoresis
types of sickle cell crises
thrombotic, vaso-occlusive, painful crises
acute chest syndrome
anaemia
- aplastic
- sequestration
infection
precipitating factors for thrombotic crises in sickle cell anaemia
infection
dehydration
deoxygenation
presentation of thrombotic crises
pain and swelling in hands or feet but can also affect chest, back, lungs, spleen and brain
can be associated with fever
can also cause priapism
what is acute chest syndrome
vaso-occlusion within the pulmonary microvasculature - > infarction in the lung parenchyma
presentation of acute chest syndrome
dyspnoea
chest pain
pulmonary infiltrates on cxr
low pO2
management of acute chest syndrome
pain relief
respiratory support: oxygen
antibiotics
transfusion
what is aplastic crisis
caused by infection with parvovirus
sudden fall in Hb
bone marrow suppression causes a reduced reticulocyte count
what is sequestration crisis
sickling within organs such as the spleen or lungs causes pooling of blood with worsening of the anaemia
associated with increased reticulocyte count
indications for blood transfusion in sickle cell crises management
severe or symptomatic anaemia
pregnancy
pre-operative
indications for exchange transfusion in sickle cell crises
acute vaso-occlusive crisis (stroke, acute chest syndrome, multiorgan failure, splenic sequestration crisis)
rapidly reduce the percentage of HbS containing cells
long term management of sickle cell anaemia
hydroxyurea
pneumococcal polysaccharide vaccine every 5 years
