Beta-thalassaemia, haemolytic newborn, Fanconi Flashcards Preview

Paeds - Haematology + Oncology > Beta-thalassaemia, haemolytic newborn, Fanconi > Flashcards

Flashcards in Beta-thalassaemia, haemolytic newborn, Fanconi Deck (10)
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1
Q

Beta-thalassaemia Ex and PPx:

A

Ex:
- Autosomal recessive condition
- Little or no Beta chain production resulting in excess alpha chains.
- These alpha chains combine with whatever gamma or delta chains produced - increased HbA2 (delta) and HbF (gamma)
- Common in India, middle eastern and mediterranean
PPx:
- Defects are normally as a result of point mutations - resulting in highly unstable Beta global chains that cannot be utilised.
- In heterozygous beta-thalassaemia - asymptomatic microcytosis with or without mild anaemia.
- Can be divided into 3 - B-thalassaemia minor, intermedia, major.

2
Q

Clinical presentation of B-thalassaemia minor?

A
  • Carriers (trait)
  • Heterozygous beta-thalassaemia
  • Asymptomatic
  • Anaemia is mild or absent
  • Confused with iron deficiency - but can be distinguished since serum ferritin and the iron states are normal.
  • Hb electrophoresis shows increased HbA2 and often HbF
3
Q

Clinical presentation of B-thalassaemia intermedia?

A
  • Includes those who are symptomatic with moderate anaemia but do not require regular blood transfusions
  • Splenomegaly, bone deformities, infections, recurrent leg ulcers, gallstones.
4
Q

Clinical presentation of B-thalassaemia major?

A

Presents in children with homozygous beta-thalassaemia in FIRST YEAR of life with:

1) Failure to thrive
2) Recurrent infections
3) SEVERE anaemia in 3m-6m when switch from gamma to beta-chain production should occur
4) Extramedullary haumatopoeisis (ineffective RBC production OUTSIDE the marrow) - resulting in hepatospleonomegaly (due to to haemolysis) and BONE EXPANSION - giving rise to classic thalassaemic facies
5) Lifelong transfusion dependant
6) Hypertrophy of ineffective bone marrow leads to bone abnormalities

5
Q

Diagnosis of B-thalassaemia?

A

In homozygous disease:

  • Blood count and film: Hypochroic microcytic anaemia, raised reticulocyte count, nucleated RBC in peripheral circulation.
  • Haemoglobin elecrophoresis - RAISED HbF (gamma), absent or less HbA
  • Prenatal diagnosis: For parents who are both heterozygous - 1 in 4 risk of having affected child, DNA analysis of a chorionic villous sample should be offered and genetic counselling to help parents decide whether or not to continue pregnancy.
6
Q

Treatment of B-thalassaemia?

A

1) Regular, lifelong transfusions to keep Hb above 90g/L and to suppress extra medullary haumatopoeisis and to allow normal growth.
2) Iron chelating agents to prevent iron overload - Desfersirox - (iron overload can cause cardiac failure, liver cirrhosis, diabetes, infertility and growth failure)
3) Splenectomy if hypersplenism persists with increasing transfusion requirements - do after childhood to reduce infection risks
4) BONE MARROW TRANSPLANT - only cure
5) Long term folic acid

7
Q

Complications with blood transfusions?

A

1) Iron overload
2) Deposited in liver and spleen - fibrosis and cirrhosis
3) Also deposited in heart and endocrine glands - cardiac failure, diabetes, infertility, growth failure, hypothyroidism, hypocalcaemia, premature death

8
Q

Haemolytic disease of the newborn PPx:

A
  • Mother has Rhesus negative blood (RhD negative)
  • Newborn has Rhesus positive blood (RhD positive)
  • Mothers blood is exposed to babies blood during pregnancy - immune system recognised babies rhesus positive blood and produces antibodies against it.
  • First baby is unaffected - takes time for antibodies to be produced - mother sensitised to RhD positive blood.
  • However if mothers second baby also has RhD positive - antibodies will be produced immediately.
  • Antibodies are able to cross to newborn via placenta and being destroying babies RBC’s - resulting in haemolysis in newborn resulting in ANAEMIA and JAUNDICE.

Dx: Coombs test (positive direct anti-globulin test)

Tx: Following positive Coombs test - ANTI D IMMUNOGLOBULIN can be given throughout pregnancy. Anti-D neutralises babies blood cell antigens before they are recognised by mother’s immune system hence NO antibodies produced.

9
Q

Fanconi Anaemia Ex and PPx:

A
  • Type of inherited aplastic anaemia - results in pancytopenia (reduction in all major cell lines - RBC, WBC, platelets) with hypocellularity (aplasia) of the bone marrow.
  • Typical presentation of aplastic anaemia:
    1) Anaemia due to decreased RBC numbers
    2) Infection due to reduced white cells (leucopenia)
    3) Bruising and bleeding due to thrombocytopenia
  • Most common form of inherited aplastic anaemia - AUTOSOMAL RECESSIVE.
  • Defective stem cell repair and chromosome fragility leads to progressive bone marrow failure and aplastic anaemia.
10
Q

Clinical presentation, Dx, Tx of Fanconi Anaemia?

A

1) Congenital abnormalities - short stature, abnormal radius, thumb hypoplasia renal malformations and pigmented skin lesions.
2) Signs of bone marrow failure - becomes apparent at 5 or 6 yrs.
- HIGH RISK OF DEATH DUE TO BONE MARROW FAILURE/ transformation to ACUTE LEUKAEMIA

Dx:
- Neonates usually have normal blood count - diagnosed by demonstrating increased chromosomal breakage of peripheral blood lymphcytes.

Tx:
- Bone marrow transplant only cure