Paeds hematology Flashcards
pathophysiology ITP
Antibodies are directed against the glycoprotein IIb/IIIa or Ib-V-IX complex. It is an example of a type II hypersensitivity reaction.
when is management indicated for ITP? what are options?
If the platelet count is very low (e.g. < 10 * 109/L) or there is significant bleeding.
- oral/IV corticosteroid eg prednisolone
- IV immunoglobulins
- platelet transfusions can be used in an emergency (e.g. active bleeding) but are only a temporary measure as they are soon destroyed by the circulating antibodies
Philadelphia chromosome t(9;22)
chronic myeloid leukemia
65+
Most common leukemia in children? triad?
Acute lymphoblastic leukemia
anaemia, thrombocytopenia, neutropenia
Genetics and inheritance sickle cell
autosomal recessive
abnormal variant called haemoglobin S (HbS)
abnormal gene for beta-globin on chromosome 11
Definitive diagnosis sickle cell disease
haemoglobin electrophoresis
Management sickle cell
General:
- avoid dehydration and triggers
- vaccines inc pneumococcal polysaccharide vaccine every 5 years
- abx prophylaxis eg penicillin V
- hydroxycarbamide (stimulate fetal HbF)
- blood transfusion
- bone marrow transplant can be curative
vaso-occlusive pripism:
- aspiration of blood
splenic sequestration:
- blood transfusion and fluid resus
aplastic:
- blood transfusion
acute chest:
- abx and antivirals
- blood trans
- ventilation
reticulocyte count sickle cell anaemia?
high (needing to constantly make new rbc)
may be low in aplastic crisis
normal is 0.45–1.8 percent
cause of aplastic crisis sickle cell
parovirus B19
reticulocytes may be low
gold standard investigations sickle cell
Haemaglobin electrophoresis
blood film sickle cell
A blood film shows target cells and Howell-Jolly bodies.
Blood reuslts rickets
Low calcium, low phosphate, high ALP and high PTH
Inheritance of thalassemia?
autosomal recessive
What does FBC show thalassemia?
microcytic anaemia
Investigations thalassmeia
Full blood count shows a microcytic anaemia.
Haemoglobin electrophoresis is used to diagnose globin abnormalities.
DNA testing can be used to look for the genetic abnormality
Pregnant women in the UK are offered a screening test for thalassemia at booking.
On what chromosome is defect that causes alpha thalassemia?
chromosome 16
On what chromosome is defect that causes beta thalassemia?
chromosome 11
beta thalassemia minor pathophysiology, presentaiton and management
Patients with beta thalassaemia minor are carriers of an abnormally functioning beta globin gene. They have one abnormal and one normal gene.
Thalassaemia minor causes a mild microcytic anaemia and usually patients only require monitoring and no active treatment.
Thalasssemia intermedia - pathophysiology, presentation, management
Patients with beta thalassaemia intermedia have two abnormal copies of the beta-globin gene. This can be either two defective genes or one defective gene and one deletion gene.
Thalassaemia intermedica causes a more significant microcytic anaemia and patients require monitoring and occasional blood transfusions. If they need more transfusions they may require iron chelation to prevent iron overload.
Thalassemia major - pathophysiology, presentation, manageement
Patients with beta thalassaemia major are homozygous for the deletion genes. They have no functioning beta-globin genes at all. This is the most severe form and usually presents with severe anaemia and failure to thrive in early childhood.
Thalassaemia major causes:
Severe microcytic anaemia
Splenomegaly
Bone deformities
Management involves regular transfusions, iron chelation and splenectomy. Bone marrow transplant can potentially be curative.
