Haematology Flashcards
(84 cards)
1
Q
Haemoglobin types by age
A
Newborn: HbF predominant, with HbA and HbA2
Children >1y: HbA prominent with HbA2 (2%)
High Hbf within first year means some children are asymptomatic of disease .e.g. sickle cells
2
Q
Haematological values at birth and infancy
A
Hb at birth 140-215g/L Hb 2m: 100g/L Preterm 4-8w: 65-90g/L Blood volume term infant 80ml/Kg Preterm blood volume 100ml/Kg Folic acid, iron and vit B12 stores depleted by 2-4m in preterm infants WCC neonates: 10-25 x 10^9/L Platelet count at birth 150-400 x 10^9/L
3
Q
Definition of anaemia
A
Neonate: Hb<140g/L
1m-12m: Hb<100g/L
1y-12y: Hb <110g/L
4
Q
Mechanisms of anaemia
A
Reduced red cell production -Red Cell aplasia -Ineffective erythropoiesis Increased red cell destruction -Red cell membrane disorder -Red cell enzyme disorder -Haemaglobinopathies -Immune Blood loss (uncommon in children) -Feto-maternal bleeding -Chronic GI blood loss -Inherited bleeding disorder
5
Q
Causes Red cell Aplasia
A
Parvovirus B19 infection (only in children with Dx haemolytic anaemia) Diamond Backfan Anaemia Transient eryhtoblastopenia of childhood Fanconi anaemia Aplastic anaemia Leukaemia
6
Q
Causes Ineffective erythropoiesis
A
Iron deficiency Folic acid deficiency Chronic renal failure Chronic inflammation Myelodysplasia Lead poisoning
7
Q
Causes increase haemolysis
A
RBC membrane disorder: Hereditory spherocytosis
RBC enzyme deficiency: G6PD deficiency
Haemoglobinopathy: thalassaemia, sickle cell
Immune: haemolytic disease of the newborn, autoimmune haemolytic anaemia
8
Q
Diagnosis Ineffective erythropoeisis
A
Normal reticulocyte count
Abnormal MCV
-Low in iron deficiency
-Raised in folic acid deficiency
9
Q
Causes iron deficiency
A
Inadequate iron intake (common in infants)
Malabsoprtion
Blood loss
10
Q
Iron intake requirements
A
1y: 8mg/day
Adult female: 15mg/day
Adult male: 9mg/day
11
Q
Iron sources in childhood
A
Breast milk (low content highly available) Infant formula (supplemented iron) Cows milk (high content poor absorption) Dietary: solids introduced at weaning -cereals supplemented (poor absorption)
12
Q
Diagnostic features on blood film
A
Spherocytes: hereditory spherocytosis
Sickle cells/target cells: sickle cell disease
Hypochromic/microcytic red cells: thalassaemia, iron deficiency, anaemia of chronic disease
13
Q
Hb HPLC diagnostic features
A
Sickle cell: HbS and no HbA
Beta thalassaemia major: only HbF present
Beta thalassaemia trait: Increase HbA2
Alpha thalassaemia trait: HPLC normal
14
Q
Inhibition of iron absorption
A
Tanin in tea
Phytates in high fibre food
15
Q
Clinical features iron deficiency anaemia
A
Typically asymptomatic until 60g/L
Tire easily
Feed slowly
Pale- conjunctivae, tongue, palmar creases
Pica: inappropriate eating non-food materials
Behaviour and intellectual decline
16
Q
Diagnosis iron deficiency
A
Microcytic hypochromic anaemia
-low MCV, low MCH
Low serum ferritin
17
Q
Mx Iron deficiency
A
Dietary advice Supplementation with oral iron -Syntron (sodium iron edetate) -Nifarex (polysccharide iron complex) -Continues until Hb normal + 3m Normal Hb rise with supplements ~ 10g/L/week
18
Q
Diagnosis of Red cell aplasia
A
Low reticulocyte count Low Hb Normal bilirubin Negative Coombs test Absent red cell precursors on bone marrow
19
Q
Features Diamond-Backfan anaemia
A
Rare Family history (20%) Present at 2-3m or birth Symptoms of anaemia Associated with congenital abnormality .e.g. short stature, abnormal thumbs
20
Q
Mx Diamond Backfan anaemia
A
Oral steroids
Monthly rbc transfusions (steroid unresponsive)
Stem cell transplantation
21
Q
Features transient erythroblastopenia of childhood
A
Similar features to Diamond Backfan anaemia
Always recovers
Usually within several weeks
22
Q
Features of increased haemolysis
A
Anaemia Hepatomegaly Splenomegaly Increased unconjugate bilirubin Excess urinary urobilinogen
23
Q
Diagnosis haemolysis
A
Raised reticulocyte count Polychromasia on blood film (lilac colour on stained film) unconjugated bilirubinaemia Increased urinary urobilinogen Abnormal rbc appearance on film Positive direct antiglobulin test increased rbc precursors in bone marrow
24
Q
Features hereditory spherocytosis
A
Jaundice
Anaemia
Mild-moderate splenomegaly
Aplstic crisis: transient 2-4w with parvovirus B19
Gallstones: associated with increased bilirubin
25
Diagnosis hereditory spherocytosis
Blood film usually diagnostic
Specific tests: dye binding assay, osmotic fragility
dDx spherocytes on film: autoimmune haemolytic anaemia (excluded by antibody test)
26
Genetics hereditory spherocytosis
Mutation in rbc membrane proteins
-spectrin, ankyrin, band 3
Loss of membrane on passage through spleen
Reduction in SA:V
Spheroidal cells destroyed in microvasculature of spleen
27
Mx hereditory spherocytosis
Oral folic acid (raised requirement)
Splenectomy (poor growth or symptomatic anaemia)
-HiB, Men C and Strep immunisations
Lifelong oral daily penicillin prophylaxis
Cholecystectomy if symptomatic gallstones
28
Mx Aplastic crisis
1-2 blood transfusions over 3-4w period
29
Features G6PD
```
Neonatal jaundice (within 3d)
Acute haemolysis
-infection
-medications
-fava/braod beans
-naphthalene in mothballs
```
30
Drugs to avoid in G6PD
Antimalarias .e.g. primaquine, quinine, chloroquine
Anitbiotics .e.g. sulphonamides, quinolones, nitrofurantoin
Analgaesics .e.g. aspirin
31
Pathology G6PD
Rate limiting enzyme in pentose phophate pathway
Essential for preventing oxidative damage
RBC susceptible to oxidant-induced hymolysis
X linked
32
Presentation of haemolysis in G6PD
```
Fever
Malaise
Abdo pain
Passage of dark urine (Hb and urobilinogen)
Rapid Hb drop (<50g/L within 24-48h)
```
33
Diagnosis of G6PD
G6PD activity in RBS
May be misleadingly elevated during haemolytic crisis due to reticulocyte conc.
Repeat assay required after haemolytic episode
34
Mx G6PD
Safety net parents re recognition of haemolysis
Avoidance of precipitants
Transfusion rarely required
35
Features of sickle cell
Anaemia
Infection (associated with hyposplenism): Hib, penomoccoci, salmonella osteomyelitis
Painful crisis: vaso-occlusive, typically limbs and spine
-precipitated by excercise, stress, infection, cold, dehydration, hypoxia
Acute anaemia
Priapism
Splenomegaly
36
Sickle cell painful crisis types
Hand-foot syndrome: dactylitis
Acute chest syndrome
Avascular necrosis of femoral head
37
Long term Cx sickle cell
```
Short stature
Delayed puberty
Stroke and cognitive problems
Adenotonsillar hypertrophy (sleep apnoea)
Cardiac enlargement
Heart failure
Renal dysfunction
Pigment gallstones (increased bile production)
Leg ulcers
Psychosocial problems
```
38
Features sequestration crises
Sudden splenic or hepatic enlargement
Abdominal pain
Circulatory collapse
Accumulated sickle cells in spleen
39
Types of sickle cell disease
Sickle cell anaemia: homozygous HbS
HbSc disease: no HbA and no normal beta globulin
Sickle beta thalassaemia: no HbA or beta globulin
Sickle cell carriers: 40% HbS haemoglobin
40
Pathogenesis sickle cell
HbS polymerises with rbc forming rigid tubularspiral bodies
Deformation of rbc into sickle shape
Reduced cell lifespan
trapped in microvasculature causing occusion and ischaemia
41
Mx Sickle cell
```
Infection prophylaxis
-immunisation
-daily oral penicillin
Daily folic acid
Reduce precipitates of crisis
Hdroxycaramide (increased HbF production)
Bone marrow transplant
```
42
Mx acute sickle cell crisis
```
Oral or IV analgaesia
Good hydration
Abx if infection
Oxygen if reduced sats
Exchange transfusion for acute chest syndrome, stroke, and priapism
```
43
Prognosis sickle cell
Premature death ~ 40y
| Mortality rate in children 3% due to infection
44
Features Haemoglobin SC disease
Nearly normal Hb
Fewer painful crises
Proliferative Retinopathy in adolescence (periodically checked)
Osteonecrosis of hips and shoulders
45
Sickle cell trait
Assyptomatic
| Risk with general anaesthetic (sickling possible in low oxygen tension)
46
Types beta thalassaemia
Major: HbA cannot be produced
Intermedia: small amount of HbA and large amount of HbF
Trait: assymptomatic
47
Features beta thalassaemia
```
Severe anaemia
Jaundice
Faltering growth/growth failure
Extramedullary haemoppoiesis (without transfusion)
-hepatosplenomegaly
-bone marrow expansion
-maxiallry overgrowth and skull bossing
```
48
Mx Beta thalassaemia
Transfusion dependant by 3-6m
-lifelong monthly transfusion
Iron cehlation .e.g. subcut desferrioxamine, oral deferasirox from 2-3y
Bone marrow transplantation
49
Complications regular transfusions
```
Iron deposition
-cardiomyopathy
-liver cirrosis
-diabetes
-impaired growth and sexual maturation
-hyperpigmentation of skin
Antibody formation
Infection
Venous access difficulty requiring portacath
```
50
Alpha thalassaemia types
Major (Hb barts hydrops fetalis): midtrimester fetal hydrops fatal in utero/hours postnatally
-possibility of monthly intrauterine tranfusion
HbH disease: 3 genes effected, mild/moderate anaemia
Trait: assymptomatic
51
Causes of anaemia in the newborn
Congenital B19 parovirus infection
Congenital red cell aplasia
Haemolytic anaemias
Blood loss
52
Causes of anaemia of prematuriry
Inadequate erythropoeitin production
Reduced rbc lifespan
Frequent blood sampling
Iron/folic acid deficiency (2-3m)
53
Causes blood loss in newborn
Feto-maternal haemorrhage
Twin-twin transfusion
Blood loss during delivery .e.g. abruption
54
Features Fanconi anaemia
Aplastic anaemia
AR mutation in FANC gene
Associated congenital abnormality .e.g. short stature, abnormal radii and thumbs, renal malformation, micropthalmia, pigmented skin lesions
Bone marrow failure apparent 5-6y
55
Ix Fanconi Anaemia
Normal blood count
| Chromosomal breakage of peripheral blood lymphocytes
56
Cx Fanconi anaemia
Bone marrow failure
| Transformation to acute leukaemia
57
Features Schwachman Diamond Syndrome
```
AR SBDS gene mutation
Bone marrow failure
Pancreatic exocrine failure
Skeletal abnormality
Isolate neutropenia
Mild pancytopenia
Risk of transformation to acute leukaemia
```
58
Screening tests in coagulopathy
FBC and blood film
Prothrombin time (Factors II, V, VII, X)
APTT (Factors II, V, VIII, IX, X, XI, XII)
50:50 mix with plasma in prolonged APTT and PT distinguishes factor deficiency or inhibitor prescence
Thrombin time (fibrinogen)
Quantative fibrinogen assay
D-dimers (fibrinogen degradation products)
Biochemical screen, renal and liver function tests
59
Features haemophilia
Recurrent spontaneous bleeding into joints and muscles
Present when starting to walk or crawl
Neonatal intracranial haemorrhage
Bleeding postcircumscision
Prolonged oozing from heel stick and venepuncture sites
60
Severity and factor VIII
<1% - spontaneous
1-5%- bleeds on minor trauma
>5-40% - bleeds after surgery
61
Mx Haemophilia
```
Factor VIII haemophilia A
-Desmopressin A in mild haemophilia A
Factor IX haemophilia B
Circulating level to 30%
Major surgery/big bleeds:
-100% circulating level
-maintenance 30-50% for 2w
Avoid: IM injections, aspirin and NSAIDs
```
62
Cx treatments for haemophilia
Inhibitors: reduce or inhibit effect of treatment, may be amenable to immune tolerance induction
Transfusion transmitted infections
Vascular access difficulty
63
Features von Willebrand disease
Bruising
Excessive prolonged bleeding following surgery
Mucosal bleeding .e.g. epistaxis, menorrhagia
64
Mx von Willbrand disease
Desmopressin in type 1
-caution in <1y associated hyponatraemia and seizures
Plasma derived FVIII
65
Acquired disorders of coagulation
Haemorrhagic disease of the newborn (Vit K deficiency)
Liver disease
ITP
DIC
66
Causes of vitamin K deficiency
Inadequate intake
Malabsorption .e.g. coeliac, cystic fibrosis, obstructive jaundic
Antagonists .e.g. warfarin
67
Platelet counts and bleeding
Platelet count <150 x 10^9/L
Severe (spontaneous bleeding) <20
Moderate (bleeding in trauma or surgery) 20-50
Mild (major op or severe trauma ) 50-150
68
Presentation thrombocytopenia
```
Mild:
-Bruising
-Petechiae
-Purpura
-Mucosal bleeding
Severe:
-GI haemorrgae
-Haematuria
-Intracranial bleeding
```
69
Causes of purpura
Increased platelet destruction .e.g. SLE, ITP, HUS, DIC
Impaired platelet production .e.g. Fanconi anaemia, Wiskott-Aldrich, aplastic anaemia, marrow infiltration
Platelet dysfunction .e.g. uraemia
Vascular disoders .e.g. scurvy, meningitis, vasculitis
70
Features ITP
```
Antiplatlet IgG autoantibodies
Megakaryocyte increase in bone marrow
2-10y
1-2w post viral infection
Petechiae
Purpura
Superficial brusing
epistaxis
```
71
Mx ITP
```
Self limiting within 6-8w
Often no therapy required
Treat if major bleeding
-oral prednisolone
-IV anti-D
-IV immunoglobulin
Transfusion in life threatening haemorrhage
Avoid trauma and contact sports
```
72
Features chronic ITP
Platelet count low 6m after diagnosis (20%)
73
Mx Chronic ITP
```
Mainly supportive
Rituximab: B lymphocyte monoclonal antibody
Thrombopoietic growth factors
Splenectomy (if drug failure)
SLE screening
```
74
Features DIC
Due to severe sepsis or shock and circulatory collapse
Bruising
Purpura
Haemorrhage
75
Ix DIC
```
Thrombocytopneia
Low fibrinogen
Prolonged PT and APTT
Raise fibrinogen degradation productions and D-dimers
Microangiopathic haemolytic anaemia
Reduction in protein C,S and antithombin
```
76
Mx DIC
Underlying cause
FFP, cryoprecipitate and platelets
Antithrombin and protein C concentrates
77
Pathology DIC
Coagulation pathway activation leading to diffuse fibrin deposition
Consumption of coagulation factors and platelets
Initiated through tissue factor pathways
78
Acquired disorders thrombosis
```
Catheter related thrombosis
DIC
Hypernatraemia
Polycythaemia
Malignancy
SLE
Persistent antiphospholipid antibody syndrome
```
79
Congenital prothrombotic disorders
```
Protein C deficiency
Protein S deficiency
Antithrombin deficiency
Factor V leiden (resistant to protein C degradation)
Prothrombin gene G20210A mutation
```
80
Indication for thrombosis screening
Unanticipated or extensive venous thrombosis
Ischaemic skin lesions
Neonatal purpura fulminans (or +ve fHx of)
81
Screening thrombophilia
```
Protein S Assay
Protein C Assay
Antithrombin Assay
PCR factor V leiden
Prothrombin gene mutation PCR
```
82
Features HSP purpura
lesiosn confined to buttocks, legs, arms
Swollen painful knees and ankles
Abdominal paid
Haematuria
83
Features septic purpura
Meningococcal or viral
Fever
Speticaemia
+ve glass test
84
Features leukaemia thrombocytopenia
```
Malaise
infection
pallor
hepatosplenomegaly
lymphadenopathy
low Hb blasts on film
```
