Mind Map by v.djabatey, updated more than 1 year ago
Created by v.djabatey about 6 years ago


Paediatrics (Haematological disorders) Mind Map on thalassaemias, created by v.djabatey on 03/18/2014.

Resource summary

1 beta-thal
1.1 most often occur in people from
1.1.1 Indian subcontinent
1.1.2 Mediterranean
1.1.3 Middle East
1.2 2 types- both have severe reductn in prodn beta-globin (& so drop in HbA prodn)
1.2.1 disease severity depends on amount of residual HbA & HbF prodn beta-thal major MOST SEVERE FORM can't make HbA (alpha2 beta 2) cos of abnormal beta-globin gene clinical features pallor jaundice bossing of skull & maxillary overgrowth hepatosplenomegaly need for repeated blood transfusions beta-thal intermedia milder form & variable severity beta-globin mutations allow small amount of HbA &/or large amount of HbF to be made
1.3 clinical features
1.3.1 severe anaemia transfusion-dependent from age 3-6 months old + jaundice
1.3.2 failure to thrive/growth failure
1.3.3 extramedullary haemopoiesis prevent by regular blood transfusions if not prevented -> hepatosplenomegaly bone marrow expansion -> classical facies maxillary overgrowth & skull bossing rare in developed countries
1.4 Mx
1.4.1 lifelong monthly RBC transfusions beta thal fatal w/o these aim= keep [Hb] > 10g/dl to reduce growth failure to prevent bone deformation cause chronic Fe overload (cos repeated) ->cardiac failure ->liver cirrhosis ->diabetes ->infertility ->growth failure so Rx w/ ... from 2-3 years old iron chelation e.g. subcut desferrioxamine oral iron chelator drug e.g. deferasirox compliance hard but good comp w/ both -> 90% chance of living til 40s if can't comply, high mortality in early adulthood from overload complications of multiple transfusions iron deposition the most imp complication seen in all pts heart-cardiomyopathy liver-cirrhosis pancreas- diabetes pituitary gland- delayed growth & sexual maturation skin-hyperpigmentation antibody formation (10% of kids) allo-antibodies to transfused RBCs in pts make finding compatible blood hard infection (now uncommon <10% of kids) hepatitis A, B, C HIV malaria prions e.g. new variant CJD venous access common prob often traumatic in young kids may need central venous access device e.g. portacath predispose to infection
1.4.2 bone marrow transplantation the only cure only for kids w/ an HLA-identical sibling cos then 90-95% chance of transfusion independence & long-term cure (success) but 5% chance of transplant-related mortality
1.5 prenatal diag
1.5.1 for parents both heterozyg for beta-thal means 1 in 4 risk of having an affected child
1.5.2 offer DNA analysis of chorionic villus sample + genetic counselling help parents make informed decision re to continue preg
2 beta-thal trait
2.1 heterozygotes usually asymptomatic
2.2 hypochromic & microcytic RBCs
2.2.1 so can be confused w/ mild iron def tell apart by measuring serum ferritin low in iron def NOT beta thal trait measure serum ferritin in pts w/ mild anaemia & microcytosis before starting iron supplements avoid unnecessary Fe therapy
2.3 mild or absent anaemia
2.3.1 + disprop drop in MCH (18-22 fl) & MCV (60-70 fl) so RBC count usually raised (> 5.5 x 10^12/L)
2.4 raised HbA2= most imp diag feature
2.4.1 usually seen in about 5%
2.5 mild elevatn of HbF by 1-3% in 50%
3 alpha-thal
3.1 manifestation depends on no of functional alpha-globin genes
3.1.1 alpha-thal major aka Hb Barts hydrops fetalis cause= deletion of all 4 alpha globin genes so no HbA (alpha2 beta2) can be made occurs in families of S. East Asian origin presents mid-trimester fetal hydrops (oedema & ascites) from fetal anaemia always fatal in utero or within hours of delivery long-term survivors are those who got monthly intrauterine transfusion til delivery + lifelong monthly transfusions after birth diag Hb electrophoresis Hb HPLC (high performance liquid chromatography) only shows Hb Barts
3.1.2 HbH disease 3 of alpha-globin genes deleted px often = mild-moderate anaemia some pts transfusion-dependent
3.1.3 healthy ppl have 4 func alpha-globin genes
3.1.4 alpha-thal trait = deletion of 1 or 2 alpha-globin genes asymptomatic mild/absent anaemia hypochromic & microcytic RBCs so can be confused w/ iron def
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sickle cell disease
normal haemostasis
bone marrow failure syndromes
Anaemia in the newborn
infective endocarditis
Child development
Laryngeal & tracheal infections