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Flashcards in Haematology Deck (60):
1

What are the types of causes of anaemia in children?

reduced rbc production
increased haemolysis
blood loss

2

Give examples of causes of reduced rbc production

ineffective erythropoiesis:
- iron deficiency
- B12/folate deficiency
- JIA
- chronic renal failure
- lead poisoning
rbc aplasia:
- parvovirus b19
- diamond blackfan
- transient erythroblastopenia of childhood

3

Give examples of causes of increased rbc haemolysis

haemolytic disease of the newborn
autoimune haemolytic anaemia
haemoglobinopathies: thalassaemia, sickle cell
rbc enzyme - G6PD deficiency
roc membrane - spherocytosis

4

What can cause blood loss leading to anaemia?

meckels diverticulum
VW disease

5

what are causes of iron deficiency anaemia?

inadequate intake
malabsorption
blood loss

6

what are the clinical features of iron deficiency anaemia?

asymptomatic until <6-7g/dl
tire easily
slower feeding
pica
pale?

7

What are diagnostic clues of iron deficiency anaemia?

low MCV and MCH - microcytic, hypochromic
low serum ferritin

8

give causes of microcytic anaemia

• Iron deficiency
• Beta-thalassaemia trait
• Alpha thalassaemia
• Anaemia of chronic disease

9

What is the management of iron deficiency anaemia?

1. Change diet
2. Oral iron supplements - Sytron (sodium iron edetate), Niferex
Continue supplementation until Hb is normal and then for a minimum of 3 months

10

why should children w iron deficiency w normal hb still be treated?

iron is essential for normal brain development and IDA is associated w behavioural and intellectual deficiencies

11

What are the 3 main causes of red cell aplasia?

congenital red cell hyperplasia
transient erythroblastopenia of childhood
parvovirus b19

12

What are the diagnostic clues of red cell aplasia

low reticulocyte count despite low hb
normal bilirubin
negative direct Coombs
absent red cell precursors on bone marrow examination

13

what are some congenital abnormalities found in diamond blackfan anaemia?

short stature
abnormal thumbs

14

What is the rx of diamond blackfan anaemia?

oral steroids
monthly rbc transfusions if steroid unresponsive

15

What is the difference between diamond blackfan and transient erythroblastopenia of childhood?

same haematological features but TEC always recovers

16

What are the effects of haemolytic from increased roc breakdown?

anaemia
hepatosplenomegaly
increased blood levels of unconjugated bilirubin
XS urinary urobilinogen

17

What are the diagnostic clues of haemolytic anaemia?

o Reticulocyte count (lilac on blood film)
o Unconjugated bilirubinaemia (present in the blood) and urinary urobilinogen
o Abnormal appearance of rbc’s on blood film e.g. Sickle cell, spherocytes, v hypochromic)
o +ve coombs
o rbc precursors in the bone marrow

18

wat is the genetic inheritance of hereditary spherocytosis?

autosomal dominant

19

how does spherocytosis lead to haemolysis?>

reduction in surface to volume ratio causes them to become spheroidal, they’re less deformable than normal rbc’s and are destroyed in the microvasculature of the spleen

20

what are the clinical features of hereditary spherocytosis?

Highly variable
Can be asymptomatic
i. Jaundice
ii. Anaemia
iii. Splenomegaly - depending on rate of haemolysis
iv. Aplastic crisis - caused by parvovirus B19 infection
v. Gallstones - due to bilirubin excretion

21

how is a diagnosis of hereditary spherocytosis made?

blood film- spherocytes
direct ab test if no FH of HS

22

what is the management of mild spherocytosis

oral folic acid

23

what is the management of severe spherocytosis?

splenectomy if poor growth and severe signs for >7y.o due to risk of sepsis

24

what is the management of aplastic crises?

½ blood transfusions over 3-4 weeks when no rbcs are produced

25

what is the inheritance of G6PD deficiency?

x-linked

26

what is G6-PD

GLUCOSE 6 phosphate dehydrogenase
rate limiting enzyme
prevents oxidative damage to rbcs

27

What are the clinical features of G6PD deficiency?

neonatal jaundice (first 3 days of life)
fever
malaise
passage of dark urine (as contains Hb and urobilinogen)

28

what precipitates acute haemolytic in G6PD deficiency?

infection
drugs
broad beans

29

why can G6PD b difficult to diagnosis?

between episodes the person has a normal blood picture and no jaundice or anaemia

30

what is the management of G6PD deficiency ?

make aware of signs of acute haemolytic (jaundice, pallor, dark urine)
avoid certain drugs:
1. antimalarial - primaquine, quinine, chloroquine
2. abs - sulphonamides, quinolone, nitrofurantoin
3. aspirin

31

What are the different types of haemoglobinopathies that are associated with haemolytic anaemia?

• Sickle cell disease
• HbSC disease
• Sickle cell trait
• - and ß-thalassaemia

32

when do clinical manifestations of haemoglobinopathies appear and why?

around 6 months as most f the HbF present at birth has been replaced by adult HbA

33

What is a trigger of spherocytosis that can cause transient severe anaemia?

parvovirus b19

34

what is the pathophysiology in sickle cell disease?

HbS polymerises w/in rbc's forming rigid tubular spiral bodies -> sickle shape
They have reduced life span and may be trapped in microcirculation causing vast-occlusion and ischaemia in an organ or bone

35

What exacerbates sx of sickle cell disease?E

low oxygen tension
dehydration
cold

36

what is the most severe form of sickle cell anaemia?

HbSS

37

Why are infections more common in sickle cell anaemia?

hyposplenism secondary to chronic sickling and micro infarction of spleen in infancy

38

what organisms are more likely to cause infection In sickle cell?

encapsulated - pneumococci, h.influenzae

39

What is a painful crisis?

vaso-occlusion in sickle cell

40

wat is the common mode of presentation of painful crises?

hand-foot syndrome - dactylitis w swelling and pain in fingers and feet

41

what is acute chest syndrome?

severe hypoxia w need ofr mechanical ventilation and emergency transfusion

42

What precipitates acute vast-occlusive crises?

cold
dehydration
XS stress or exercise
hypoxia
infection

43

What can cause acute anaemia in sickle cell?

haemolytic crises
aplastic crises - parvovirus cause complete, temporary cessation of rbc production
sequestration crises - sudden splenic or hepatic enlargement, abdo pain and circulatory collapse from accumulation of sickled cells in spleen

44

what are long term problems of sickle cell?

short stature, delayed puberty
stroke
adenotonsillar hypertrophy
cardiac enlargement
HF
renal dysfunction

45

What is the general management of sickle cell?

1. prophylaxis - immunisation from pneumococcal, HiB and meningococcus inf. give daily oral penicillin throughout childhood
2. OD oral folic acid due to increased demand caused by chronic haemolytic anaemia
3. avoid exacerbations of vast-occlusive crises

46

What is rx of acute crises of sickle cell?

1. Oral/IV analgesia
2. Hydration
3. Treat infection w abx
4. Give oxygen if sats
5. Exchange transfusion for: acute chest syndrome, stroke and priapism

47

What is the treatment of chronic problems in sickle cell?

→ Bone marrow transplant - for most severely affected children w strokes or don’t respond to hypoxyurea - cure rate of 90%

48

What are potential complications of sickle cell disease?

proliferative retinopathy in adolescence
prone to osteonecrosis of hips and shoulders

49

what is thalassaemia?

disorder of global chains

50

What are the types of thalassaemia?

alpha and beta

51

what type of genetic inheritance is thalassaemia?

autosomal recessive

52

what populations is thalassaemia more common in?

Mediterranean, india, south east asian

53

what are the features of beta-thalassaemia trait?

usually asymptomatic
mild hypochromic, microcytic anaemia

54

What are the features of

failure to thrive and hepatosplenomegaly
microcytic anaemia
HbA2 and HbF raised
HbA absent

55

What chromosome is the genetic deformity of beta thalassaemia major found?

11

56

what is the pathophysiology of beta thalassaemia major?

little or no beta chain production, resulting in excess alpha chains, increased HbA2 and HbF

57

what is the feature of beta thalassaemia major found on head xr?

hair on end appearance of the skull

58

what does alpha thalassaemia severity depend on?

dependent on whether 1,2,3 or all 4 genes are deleted for alpha globin

59

What is the management of

repeated transfusions

60

What chromosomes are the genes for alpha chains?

16