3: Haematology - Haemaglobinopathies in Children Flashcards
What is thalassemia
Defect in genes encoding globing chains - causing defect globing chains
What is a-thalassemia
Defect in one or more genes encoding a-globin genes
In which two ethnicities is a-thalassemia more common
Asian
African
what is the inheritance pattern of a-thalassemia
Autosomal recessive
explain aetiology of a-thalassemia
Deletion of at least one of four-alleles which encode two a-globin chains on chromosome 16
what chromosome is impacted in a-thalassemia
Chromosome 16
what is a thalassemia minima
a-/aa
Deletion one gene
how will a thalassemia minima present
Silent carrier
what defect is present in a thalasemia minor
a-/a- or aa/–
what deletion in a-thalasemia minor is more common in Africans
Trans (a-/a-)
what deletion in a-thalasemia minor is more common in Asians
Cis (aa/–)
what is trans
Deletion on different chromosomes
what is cis
Deletion on same chromosome
how does a-thalassemia minor present
Mild haemolytic anaemia
RBC and RDW in normal range
what is HbH Disease
a-/–
how dies HbH disease present
Jaundice
Anaemia
Hepatosplenomegaly
what is Hb-Barts hydrops fatalis
Deletion all 4 alpha-alleles of a-globin chains
what is hydrops fatalis
Collection of fluid in two or more compartments
what does Hb-Barts hydrops fatalis cause
In-utero death
how will a-thalasemia present on FBC
Microcytic Hypochromic Anaemia
how can thalasemia be differentiated from IDA
Normal RDW
What can be seen on peripheral blood smear in thalassemia
Teardrop cells
What is confirmatory-test for thalasemia
Hb electrophoresis
How is a-thalasemia minima treated
No Rx
How is a-thalasemia minor treated
Iron
Folate
How is HbH treated
Iron, Folate
Transfusion
Allogenic stem cell transplant - curative
What is B thalasemia
Defect in genes encoding B-globin chains
How many genes encode B-globin chains
Two
How many variations of B-thalasemia are there
Two Diseases
What ethnicity is B-thalasemia more common in
Medeteranian
What is the inheritance pattern of B-thalasemia
Autosomal recessive
When will b-thalasemia symptoms manifest and why
6-months
Initially a foetus is born with foetal Hb (2-alpha and 2-gamma chains). This gradually decreases and adult Hb is produced (2-alpha, 2-beta)
What is B thalassemia minor
B/-
How does B thalassemia present
Mild anaemia
Asymptomatic
What is B thalassemia major
-/-
How does B-thalasemia major present
- Severe anaemia
- Secondary growth dysfunction
- Extramedullary enlargement
How will FBC present in thalasemia
Microcytic hypochromic anaemia
How can anaemia in thalasemia be differentiated from IDA
RDW will be normal
What is a sign of haemolysis in thalasemia
Low haptoglobin
High LDH
High reticulocytes
What can be seen on blood smear in thalassemia
Teardrop cells
What is confirmatory test for thalasemia
Hb Electrophoresis
How is B-thalassemia major treated
Regular blood-transfusions every 3-4W
What is risk of frequent blood transfusions
Iron overload
What is the only definitive management of B-thalasemia
Allogenic bone marrow transplant
What does ITP stand for
Idiopathic (Immune) thrombocytopenia purpura
What are the three types of ITP
- Acute
- Chronic
- Evans
When is acute ITP seen
Young children following viral infection. It resolves in 1-2W
When is chronic ITP seen
Middle-age adults: presents as a relapsing and remitting course
What is Evan’s syndrome
ITP and autoimmune haemolytic anaemia
What age does acute ITP occur
2-5 years
What causes ITP
Autoantibodies to glycoprotein IIa and IIb
What precedes ITP
Viral Infection
How does ITP present clinically
- Petechiae
- Bleeding: gums, melena, haematuria
- Easy bruising
Explain pathophysiology of ITP
IgG antibodies bind to glycoprotein IIa and IIb on platelets - which causes spleen to remove platelets
What will be seen on FBC in ITP
Thrombocytopenia
What will be seen on coagulation screen in ITP
Increased bleeding time
What is used to control moderate bleeding in ITP
Tranexamic acid
What is used to control severe bleeding in ITP
Glucocorticoids and IVIg
