haem Flashcards
what two mechanism can cause decreased RBC production in babies
ineffective erythropoesis (increased destruction, shorter survival) red cell aplasia (no RBC production)
mx IDA
advice: leafy veg and fortified bread
supplement with oral ferrous sulphate (continue 3 months after corrected to replenish iron stores)
monitor regularly to ensure compliance
advice for IDA
S/E of iron - GI irritation, diarrhoea, constipation, impaction, nausea
take iron w/ food or reduce frequency of dose
monitoring for IDA
check FBC after 2-4 weeks, then check at 2-4 months
LIKELY TO BE COMPLIANCE IF NOT RISING
3 causes of red cell aplasia
Congenital - diamond blackfan
transient erythroblastopaenia - can’t make precursors post viral infection (looks like Diamond blackfan but ALWAYS RECOVER)
Parvovirus B19 - only cause problems in kids w/ haemolytic anaemias
Ix in red cell aplasia
low reticulocytes despite low Hb
normal bili
absent RBC precursors in bone marrow
What is a specific test for hereditary spherocytosis
osmotic fragility
mx of hereditary spherocytosis
neonates:
supportive transfusion
folate
phototherapy if jaundiced
infants: transfusions folate splenectomy (but then Abx prophylaxis against encapsulated organsims - h.influenzae, strep pneumonia) query cholecystectomy
triggers for haemolysis in G6PD
INFECTION antimalarials Abx - sulphonamide (cotrimoxazole), chloroquinolones (ciprofloxacin, nitrofurantoin aspirin in high doses toxins - naphthalene, fava beans
why could you get misleadingly elevated G6PD during infections
reticulocytes have higher G6PD
Where is sickle cell mutation
Chr 11
recessive mutation on codon 6 of beta globin gene (valine for glutamine)
What are the 4 types of sickle cell
Sickle cell disease
2 HbS
no HbA (as both beta globin genes are broken)
some HbF
HbSC disease
1 HbS 1 HbC (different point mutation on beta globin gene)
no HbA - both beta globin genes broken
sickle beta thalassemia trait
1 HbS 1 beta thalassemia trait
no HbA
sickle trait
1 HbS
Complications of sickle cell disease
anaemia
infection (increased risk of capsulated organisms and salmonella osteomyelitis - both due to hyposplenism)
vaso-occlusive crises - acute chest syndrome, hand + foot syndrome
acute anaemia - aplastic crsies, SEQUESTRATION CRISES, haemolytic crises
Long term:
STROKE
mx SCD prophylaxis
immunisations against encapsulated organisms
daily penicillin
daily folate
discourage excessive exercise, cold, encourage hydration
mx acute crisis
IV analgesia
rehydrate
infection tx w/ Abx
do exchange transfusion for stroke, acute chest syndrome and priapism
mx chronic
> 3 admissions per year - hydroxycarbamide (encourage HbF) but monitor for low WCC
splenectomy
BM transplant if severe
types of beta thalassemia
Have 2 beta globin genes
Beta thalassemia major - severe anaemia, can’t make HbA
beta thalassemia intermedia - mild anaemia, can make some HbA and HbF
beta thalassemia minor - asymptomatic
features of beta thalassemia
severe anaemia (can be transfusion dependent)
faltering growth)
Jaundice (haemolysis)
extramedullary haematopoeisis leading to hepatosplenomegaly
bone marrow expansion leading to frontal bossing + maxillary overgrowth
mx beta thalassemia
if beta thalassemia major you’re transfusion dependent
complication of iron overlod: heart failure, liver cirrhosis, diabetes, infertility
only cure is bone marrow transplant
if beta thalassemia trait:
GENETIC COUNSELLING
can do prenatal screen by CVS
how do you diagnose beta thalassemia trait
mild hypochromic microcytic anaemia
normal ferritin (unlike IDA which will have low ferritin)
MOST IMPORTANT - RAISED HBA2
types of alpha thalassemia
alpha thalassemia major (Barts)
deletion of all 4 genes
death in utero - foetal anaemia, foetal hydrops
HbH -
deletion of 3
mild - moderate anaemia
some transfusion dependent
a thalassemia trait
deletion of 1 or 2 genes
asymptomatic
causes for anaemia in newborn
Failure of production
red cell aplasia (Parvovirus or Diamond-blackfan)
Destruction of RBC maternal Ab Membrane problems enzyme problems heamoglobinopathies
Blood loss
foeto-maternal haemorrhage (foetus bleeds into mum)
TTTS
late - term blood loss - placental abruption
anaemia of prematurity
due to low EPO
short RBC lifespan
iron/folate def
what Ab are involved in Haemoytic disease of newborn
Anti-D
ABO incompatibility Ab
anti-Kell
what are the features of Fanconi
recessive don't present w/ bone marrow failure til 5-6 years short stature pigmented skin short thumbs renal problems
Dx fanconi
increased chromosomal breakage of peripheral lymphocytes
How does haemophilia present
recurrent + spontaneous bleeding
typically get intracerebral bleeds
bleeding after circumcision and heel prick
bleeding into joints when they start walking
mx of haemophilia
recombinant factor 8 or 9
(can give desmopressin for haemophilia A as it stimulates release of vWF and factor 8)
acute bleeds - recombinant factors and anti-fibrinolytics (tranexamic acid)
What to avoid in kids w/ haemophilia
NSAIDs
aspirin
IM injections
complications of haemophilia mx
develop Ab against recombinant factors
transfusion infections
what are the 2 roles of vWF
provide bridge between PLT and endothelial wall for adhesion
carrier for f8 (vWF def = f8 def)
features of vWD
bruising
excessive bleeding post surgery
mucosal bleeding (epistaxis)
menorrhagia
unlike haemophilia soft tissue bleeding is uncommon
Mx of vWD
type 1 can be treated w/ desmopressin (but be careful if 1
what are the main causes of acquired diseases of coagulation
haemorrhagic disease of newborn (due to low vit K)
immune thrombocytopaenia
DIC
liver disease
clinical picture of vit k def
increased prothrombin time
increased bleeding time
causes of vit K def
warfarin
malabsorption (coeliac)
malnutrition
pathophysiology of ITP
IgG Ab destroy PLT
ITP presentation
1-2 weeks after viral infection
bruising and petechiae
diagnosis of exclusion (rule out bernard soulier)
look out for anaemia and neutropenia (leukaemia and aplastic anaemia)
mx of ITP
resolves in 6-8 weeks most people can be managed at home
treat if major bleed
CHECK BONE MARROW BEFORE GIVING STEROIDS (do not want to miss diagnosis of ALL)
if major bleed: IVIg, steroid, PLT transfusion
give immunomodulators if its really chronic
causes of DIC
sepsis (meningococcal esp.)
tissue trauma + burns
mx DIC
treat cause
replacement - transfuse PLT, FFP (coagulation factors), cryoprecipitate
chronic DIC - heparin, tranexamic acid
causes of thrombosis in children
congenital:
protein C+S def (both AD)
factor V leiden (factor V resistant to protein C degradation
antithrombin def
acquired: SLE + antiphospholipid DIC polycythaemia malignancy
