Haematology Flashcards
Anaemia in newborn
<140g/L
Anaemia 1-12 months
<100g/L
Anaemia 1-12 years
<110g/L
Hb types at 4-8 weeks gestation
Hb Gower 1, 2
Hb Portland
Where does foetal haematopoeisis occur?
Liver
Sites of post natal haematopoeisis
Bone marrow
Globin chains in HbF
2 alpha 2 gamma
Globin chains in HbA
2 alpha 2 beta
Globin chains in HbA2
2 alpha 2 delta
What is an increased proportion of HbF after one year indicative of?
Some inherited disorder of Hb production
Three broad causes of anaemia
Haemolysis (membrane, enzyme, autoimmune)
Reduced red cell production (reduced erythropoeisis, red cell aplasia)
Blood loss
Two causes of red cell aplasia
Parvovirus B19
Diamong-Blackfan anaemia
In whom does parvovirus B19 cause red cell aplasia?
Those with inherited haemolytic anaemias
Blood features of red cell aplasia
Low reticulocyte count, normal BR
Features of Diamond-Blackfan anaemia
Presents 2-3 months
Profound anaemia
Short stature
Abnormal thumbs
IDA biochem
Low Hb
Low MCV
Hypochromic
Low serum ferritin
IDA Mx
Explore underlying cause
Dietary advice - iron rich foods: dark green leafy veg, iron-fortified bread, meat, apricots, prunes. Dietician r/f
Oral iron supps
- Ferrous sulphate 200mg BD/TDS
(Continued for 3 months after resolution to replenish stores)
What should be checked in patients with IDA not responding to treatment
Malabsorption e.g. coeliac
How long after resolution of IDA should oral iron be continued for?
3 months - replenish stores
How quickly should Hb increase on iron therapy
1g/dL / week
Adverse effects of iron treatment
Constipation / diarrhoea
Faecal impaction
GI irritation
Nausea
Four categories of haemolytic anaemias
Membrane (sphero/elliptocytosis)
Enzyme (G6PD)
Haemoglobinopathies (SCD/b-thal)
Autoimmune
Symptoms haemolytic anaemias
Anaemia
Raised BR (UC)
Hepatosplenomegaly (extramedullary haematopoeisisi)
Biochem haemolytic anaemias
Low Hb High retics Raised BR (UC) Abnormal cells on film Increased red cell precursors \+ DAT if autoimmune
When does haemolysis become an anaemia?
When BM erythropoeisis cannot compensate for the haemolysis
Where does extravascular haemolysis take place?
Liver, spleen
Two examples membrane disorders leading to haemolysis
Hereditary spherocytosis
Hereditary elliptocytosis
Presentation of hereditary spherocytosis
Anaemia
Jaundice
Mild splenomegaly
Gallstones
Investigations for hereditary spherocytosis
Film - spherocytes
Osmotic fragility test
DAT -ve
Mx hereditary spherocytosis
Neonates: supportive, folic acid. Phototherapy if significant jaundice
Non-neonate: Supportive care +/- transfusion. Folic acid Splenectomy + vaccine (encapsulated) Cholecystectomy
Mode of inheritance hereditary spherocytosis
AD
What is the defect in hereditary spherocytosis
Spectrin gene - membrane molecule
What type of bacteria ae vaccinated against if splenectomy?
Encapsulated
Example of enzyme disorder causing haemolysis
G6PD
Which kind of haemolysis does G6PD result in?
Intravascular
Populations with high prevalence G6PD
Central Africa, Med, Middle East
Inheritance pattern G6PD
X linked
Presentation of G6PD
Neonatal jaundice <3 days
Jaundice, pallor, malaise, dark urine (Hb)
Triggers for acute haemolysis in G6PD
Infection
Drugs (e.g. quinines and quinolones)
Fava beans
Naphthalene
Ix G6PD
Measure G6PD levels during STEADY STATE (levels can rise during acute haemolysis)
Mx G6PD
Advise parents to look out for acute haemolysis (pallor, jaundice, dark urine)
Avoid triggers
Supportive care + folic acid in acute haemolysis
Blood transfusion
Renal support
When do clinical manifestations of disorders of the B globin chain occur? Why?
Approx 6 months - HbF being replaced by HbA
What is the mutation in sickle cell?
Chr 6 B globin gene
Mutation substituting glutamine for valine
= dehydration, polymerisation and sickling
What is the prognosis for patients with sickle cell?
40% die before 50 years
Common populations with sickle cell
Africa
Caribbean
Prophylactic management SCD
Immunisations against encapsulated bacteria
Penicillin OD
Folic acid
Avoid triggers
Acute crises management SCD
IV analgesia O2 Warming IV abx Hydration Exchange transfusion (acute chest, priapism, stroke)
Chronic management SCD
Hydroxycarbamide for children with recurrent crises/admission
(Monitor for WCC suppression)
Consider BM transplant
which drugs induce HbF production?
Hydroxycarbamide
What should be monitored for patients on hydroxycarbamide?
White cell counts (causes suppression)
Inheritance pattern of sickle cell
AR
Beta thal populations
Indian sub continent
Med
Middle east
Two types beta thal
Major
Trait
(+intermedia)
Beta thal presentation
Approx 3-6 months (when HbF being replaced by HbA)
Profound anaemia
Jaundice
FTT/growth failure
Hepatosplenomegaly
Extramedullary haematopoeisis
Mx beta thal
Blood transfusions (aim to keep above 100g/L) Iron chelation - desferrioxamine
Bone marrow transplant - curative, but only performed with HLA identical sibling
When is a bone marrow transplant appropriate in beta thal?
If HLA identical sibling
Complications of constant blood transfusions in beta thal
Iron overload - cardiac failure, cirrhosis, infertility, growth failure
Treatment for iron overload
Iron chelation - desferrioxamine
Test for antibody mediated haemolytic anaemias
DAT/Coombs
Inheritance pattern haemophilia
XR
Comonest haemophilia
A (factor 8)
Three grades of haemophilia
Mild
Mod
Severe
Features of haemophilia
Spontaneous, recurrent bleeding into joints/muscles
–> joint damage
When does haemophilia typically present?
40% neonates - intracranial haemorrhage, prolonged bleeding from venepuncture, etc.
When babies start to crawl/walk
Acute mx of bleeding in haemophilia
Recombinant factor 8/9
Antifibrinolytics (TXA)
PROMPT IV INFUSION
Analgesia
Ortho r/v
Prophylactic management haemophilia
Prophylactic factor 8 in severe haemophilia A to reduce the risk of joint damage
How is the risk of chronic joint damage in haemophilia reduced?
Prophylactic recombinant factor (8)
What should be avoided in patients with haemophilia
IM injection
Aspirin
NSAIDs
Mx mild haemophilia
DDAVP - stimulates factor 8 and vWF
Which drug stimulates factor 8 and vWF?
DDAVP desmopressin
Features of VWD
Mucosal bleeding - epistaxis, menorrhagia
Bruising
Prolonged, excessive bleeding
Mx VWD (mild/severe)
Mild: DDAVP (stimlulated F8 and vWF production) - caution <1 years as can cause hyponatraemia –> seizures
Severe: F8 concentrate
What should be avoided in VWD
IM injections
Aspirin
NSAIDs
What should be avoided in bleeding disorders?
IM injections
Aspirin
NSAIDs
What caution should be taken prescribing DDAVP for <1 year old
Hyponatraemia –> seizures
Commonest cause thrombocytopenia in childhood
ITP
Pathophysiology of ITP
Destruction of platelets by circulating anti-platelet IgG antibodies
What might be seen in the bone marrow of a child with ITP
Increased megakaryocytes
Age of presentation ITP
2-10years (1-2 weeks after viral infection)
Presentation of ITP
Petechiae
Bruising
Purpura
ITP diagnosis
Diagnosis of exclusion
Leukaemia
Aplastic anaemia
SLE
No abnormality in blood other than a low platelet count
Mx ITP
80% of children - acute, benign, self limiting in 6-8 weeks (home management)
Treatment indicated if evidence of major bleeding:
- IVIG
- Corticosteroid
- Platelet transfusion
- Antifibrinolytics (TXA)
When is active treatment indicated in ITP
Major bleeding
- otherwise 80% resolve spontaneously at home
Petechiae/purpura DDx
HSP ITP Leukaemia Sepsis (DIC) NAI
DIC mx
TREAT UNDERLYING CAUSE (e.g. sepsis)
Supportive care
Replace platelets, cryo, FFP
Protein C concentrates
