Paediatrics - haematology Flashcards
(151 cards)
1
Q
What are the types of haemoglobin present in a healthy adult (2)?
A
- HbA
- HbA2 (low levels)
2
Q
What is HbA made up of?
A
2 alpha, 2 beta chains
3
Q
What is HbA2 made up of?
A
2 alpha, 2 delta chains
4
Q
What is the main Hb present in a foetus?
A
HbF
5
Q
What is HbF made up of?
A
2 alpha, 2 gamma chains
6
Q
What is the main difference between HbF and HbA in terms of its function?
A
HbF has a higher affinity to oxygen due to the relatively hypoxic environment of the foetus
7
Q
What age does HbF usually disappear by?
A
1 year of age
8
Q
What happens to the levels of haemoglobin from birth throughout childhood?
A
Hb at birth is high to compensate for the hypoxic foetal environment (140+), Hb decreases over the first few months/ year of life due to transition to adult Hb (shouldn’t go below 100), Hb increases from that point on up to 130/120
9
Q
What are 3 categories for the causes of anaemia?
A
- Haemolysis
- Impaired red blood cell production
- Blood loss
10
Q
What are the two categories of impaired red cell production in children?
A
- Red cell aplasia (no RBC production)
- Ineffective erythropoiesis
11
Q
What causes red cell aplasia (3)?
A
- Fanconi anaemia
- Parvovirus B19 infection (only in children already with inherited haemolytic anaemias)
- Congenital red cell aplasia
12
Q
What causes haemolytic anaemia in children (6)?
A
- Haemaglobinopathies (sickle cell, thalassaemia)
- Hereditary spherocytosis/ eliptocytosis
- G6PD deficiency
- Auto/ allo immune haemolytic
- Infections e.g. malaria
- Mechanical e.g. HUS, TTP (due to turbulent blood flow damaging RBCs)
13
Q
What are some general features of anaemia in children (4)?
A
- Failure to thrive
- Pallor
- Fatigue
- Tachycardia/ tachypnoea
14
Q
What would haemolytic anaemias cause an increase of in the blood?
A
Bilirubin
15
Q
What are some features of haemolytic anaemias (3)?
A
- Jaundice
- Splenomegaly
- Gallstones (due to increased bilirubin excretion)
16
Q
What causes microcytic anaemia in children (5)?
A
- Thalassaemia
- Anaemia of chronic disease
- Iron deficiency
- Lead poisoning
- Sideroblastic
17
Q
What causes normocytic anaemia (5)?
A
- Aplastic anaemia
- Anaemia of chronic disease
- Acute blood loss
- Haemolytic anaemia
- Hypothyroidism
18
Q
What are the two categories of macrocytic anaemia?
A
- Normoblastic
- Megaloblastic
19
Q
What causes normoblastic macrocytic anaemia (3)?
A
- Alcohol
- Hypothyroidism
- Liver disease
20
Q
What causes megaloblastic mactrocytic anaemia (2)?
A
- B12 deficiency
- Folate deficiency
21
Q
What is the most common cause of anaemia in children?
A
IDA
22
Q
What causes IDA in children (3)?
A
- Poor intake (not breast fed?)
- Malabsorption
- Blood loss (e.g. ringworm in developing countries)
23
Q
What is a specific symptom of IDA in children?
A
PICA (eating non food items)
24
Q
What is fanconi anaemia?
A
Inherited impaired response to DNA damage in the bone marrow
25
How is fanconi syndrome inherited?
Autosomal recessive
26
What is a complication of fanconi syndrome?
Cancer (esp. AML)
27
How is hereditary spherocytosis inherited?
Autosomal dominant
28
What is the pathophysiology of hereditary spherocytosis?
Mutations in the proteins coding for RBC membrane e.g. spectrin
29
Why does hereditary spherocytosis cause haemolysis?
Spherical shape of RBCs --> destruction in the spleen
30
What is a complication of hereditary spherocytosis?
Aplastic crisis caused by parvovirus infection
31
How is hereditary spheocytosis managed (2)?
* Folic acid supplements (due to higher RBC production)
* Splenectomy after age 7
32
How is hereditary spherocytosis diagnosed?
Blood film (direct Coombs test can exclude AHA)
33
How does G6PDD cause haemolysis?
Allows ROS to damage and break down RBCs
34
What can precipitate anaemia in those with G6PDD (2)?
* Certain medications
* Fava (broad) beans
35
What is sickle cell disease and how is it inherited?
Autosomal recessive condition caused by a mutation in the beta chain on Hb, causing 2 alpha and two mutated beta chains = HbS
36
How is sickle cell often diagnosed?
In the newborn spot blood test
37
How does sickle cell disease cause anaemia?
RBCs become sickle shaped especially when stressed --> stuck in blood vessels --> haemolysis
38
What are some complications of sickle cell disease (6)?
* Sickle cell crises
* Increased infection risk
* Gallstones
* Avascular necrosis
* Stroke
* Priapism (painful erection)
39
What are the types of sickle cell crises (4)?
* Vaso-occlusive crisis
* Splenic sequestration crisis
* Aplastic crisis
* Acute chest syndrome
40
What are the symptoms of a Vaso-occlusive crisis in sickle cell disease (2)?
Swollen + painful hand/ foot (or whichever body part is affected)
*can be associated with fever*
41
What is splenic sequestration crisis?
RBCs block blood flow in the spleen
42
What are the signs/ symptoms of splenic sequestration (3)?
* Enlarged painful spleen
* Severe anaemia
* Hypovolaemia (due to blood pooling)
43
What causes aplastic anaemia in those with sickle cell?
Parvovirus B19
44
What is acute chest syndrome?
Vessels supplying lungs become clogged with RBCs
45
What are the signs/ symptoms of acute chest syndrome?
* Fever
* SOB
* Chest pain
* Cough
* Hypoxia
46
How are sickle cell crises managed?
Supportive management, no specific treatments
*analgesia + oxygen usually - can give Abx/ fluids*
47
How is sickle cell disease managed with medications (2)?
* Hydroxycarbamide (increases production of HbF)
* Crizanlizumab (monoclonal antibody against p-selectin, prevents RBCs from sticking to walls)
48
What is given as prophylaxis for those with sickle cell?
Penicillin V (stop infections)
49
Other than pharmacologically, how else is sickle cell managed (4)?
* Blood transfusions
* Vaccinations
* Avoid crises (e.g. prevent dehydration)
* Bone marrow transplant (potentially curative)
50
How is Thalassaemia inherited?
Autosomal recessive
51
What is thalassaemia?
Defects in either the alpha or beta Hb chains
52
What are the different types of alpha thalassaemia?
Ranging in severity from 1 to 4
53
How does alpha thalassameia compensate for defective Hb?
Produces more HbH (4 beta chains)
54
What are the different types of beta thalassaemia (3)?
* Thalassaemia minor (1 deleted/ abnormal beta gene)
* Thalassaemia intermedia (2 abnormal/ 1 abnormal 1 deleted beta gene)
* Thalassaemia major (2 deleted beta genes)
55
What are the signs/ symptoms of thalassaemia?
* Pronounced forehead + malar eminences (chipmunk facies - due to growth of bone marrow)
* Hepatosplenomegally
56
When is thalassaemia screened for in the UK?
Pregnancy (upon booking appointment)
57
How is thalassaemia managed (3)?
* Transfusions
* Bone marrow transplant
* Splenectomy
58
What is a complication of frequent blood transfusions?
Iron overload
59
How is iron overload treated?
Iron chelation
60
What age do haemaglobinopathies tend to present?
6 months - 2 years (once HbF decreases in prevalence)
61
What causes anaemia in the newborn (6)?
* Blood loss
* Anaemia of prematurity
* Haemolytic anaemias
* Reduced red cell production
* Twin-twin transfusion (unequal distribution of blood between twins that share a placenta)
* Normal physiological dip in Hb
62
What are some signs/ symptoms of anaemia in newborns (2)?
* Pallor
* Poor feeding
63
What are the two main causes of reduced red blood cell production?
* Congenital parvovirus B19 infection
* Congenital red cell aplasia (Diamond-blackfan anaemia)
*both quite rare*
64
What would the bloods look like for those with reduced blood cell production (3)?
* Low Hb
* Low reticulocytes
* Normal bilirubin
65
What are the main causes of blood loss in a newborn (4)?
* Foeto-maternal haemorrhage (blood loss into mother)
* Blood loss around time of delivery (e.g. placental abruption)
* Recurrent blood sampling
* Haemorrhagic disease of the newborn
66
What causes haemorrhagic disease of the newborn?
Low vitamin K (most babies are born low in vitamin K)
*IM vitamin K can be given*
67
What would blood tests show on newborns with anaemia due to blood loss (3)?
* Low Hb
* High reticulocytes
* Normal bilirubin
68
What are the causes of anaemia of prematurity (3)?
* Less time receiving iron in-utero
* Reduced EPO levels (due to negative feedback)
* Frequent blood sampling
69
What causes haemolytic anaemias in newborns (3)?
* Haemolytic disease of the newborn
* Hereditary spherocytosis
* G6PD deficiency
70
What is a sign of haemolytic anaemias in newborns?
Jaundice
71
What is haemolytic disease of the newborn?
Blood group incompatibility between the foetus and mother leading to maternal antibodies that cross the placenta and attack the foetal RBCs
72
What is the most common cause of haemolytic diseases of the newborn?
Rhesus D incompatibility
73
What must the blood group of the mother and the foetus be for HDN to occur?
* Mother = rhesus-D negative
* Foetus = rhesus-D positive
74
What must happen before a foetus would be able to develop HDN?
A sensitisation event must have occurred in the mother
75
What are some possible sensitisation events that may expose a mother to RhD antigens (3)?
* Blood transfusions
* Miscarriage
* Previous pregnancy
76
Which immunoglobulin is responsible for HDN and can cross the placenta?
IgG
77
What gestational age does a sensitisation event become possible after a miscarriage?
12 weeks
78
How is haemolytic disease of the newborn prevented?
Anti-D antibodies are given to the mother if she has been exposed to a possible sensitisation event
79
How is HDN managed during pregnancy (2)?
* Plasmapheresis - to remove the Igs responsible
* Intrauterine transfusion
80
How is HDN managed once the foetus has been delivered (2)?
* Exchange transfusions
* Phototherapy (brevet bilirubin buildup)
81
How is HDN diagnosed?
Direct Coombs test (tests for antibodies attached to RBCs)
82
What is a complication of anaemia in a foetus?
**Hydrops foetalis** - fluid accumulation in multiple areas due to the heart having to pump harder
83
What are some bleeding disorders that are common in children (3)?
* Haemophilias
* Von Willebrands disease
* Acquired disorders of coagulation
84
What are the types of acquired coagulation disorders in children (5)?
* Haemorrhagic disease of the newborn (vit K deficiency)
* Disseminated intravascular coagulation
* Immune Thrombocytopenic Purpura
* Thrombotic Thrombocytopenic Purpura
* HUS
85
What clotting factors is vitamin K involved with producing?
10,9,7,2
86
How is haemophilia inherited?
X-linked recessive
87
What are the two types of haemophilia?
A and B
88
What clotting factors are affected in haemophilia?
* A = factor VIII
* B = factor IX
89
When does haemophilia typically present?
Towards the **end of the first year** of life (when they start to walk) or during the **neonatal** period
90
How might haemophilia present in the neonatal period (2)?
* Intracranial haemorrhage
* Bleeding (post circumcision, blood tests or heel prick test)
91
What are the signs/ symptoms of haemophilia in children (3)?
BLEEDING
* Haematoma
* Epistaxis
* Bleeding (in or out of body)
92
Where is a common site for children with haemophilia to bleed into?
Joints --> severe arthritis
93
What can bleeding into muscles cause?
Compartment syndrome
94
How is haemophilia diagnosed (3)?
* Blood coagulation times/ tests
* Clotting factor assays
* Genetic testing
95
Which blood coagulation time is increased in haemophilia?
aPTT
96
How is haemophilia managed?
Factor 8/ 9 can be given
97
Why does the treatment of haemophilia with recombinant factor 8/9 stop working over time?
Formation of antibodies agains factor 8/9 (town as inhibitors) destroy the factors
98
What treatment can sometimes be given to those with mild haemophilia A?
Desmopressin (stimulates factor VIII and vWF)
99
What is von Willebrand disease?
Reduced function/ deficiency of vWF of varying severities
100
What is the function of vWF (2)?
* Facilitates platelet adhesion to endothelium
* Acts as carrier protein for factor 8
101
How are most cases of vWD inherited?
Autosomal dominant
102
What age is vWD usually diagnosed?
Varies depending on the severity between birth and adulthood
103
What are the signs/ symptoms of vWD (2)?
* Bruising (spontaneous bleeding like seen in haemophilia is rare)
* Easy bleeding
104
How is vWD managed (4)?
* Daily management not usually necessary
* Desmopressin
* Transexamic acid
* vWF + factor VIII
105
What is important to consider in younger children with thrombocytopenia?
Inherited/ congenital cause
106
What is the most common cause of thrombocytopenia in children?
Immune thrombocytopenia purpura
107
What is immune thrombocytopenia purpura?
Autoimmune destruction of platelets (type 2 hypersensitivity)
108
What are the signs/ symptoms of ITP (3)?
* **Non blanching purpuric rash**
* Bleeding
* Bruising
*no thrombotic features*
109
What age does ITP usually present?
2-10 years
110
What often precedes ITP?
Viral infection 1-2 weeks ago
111
How is ITP diagnosed?
Diagnosis of exclusion
112
What is the prognosis for ITP?
Most cases (70%) remit spontaneously without treatment within 3 months
113
How is ITP managed?
* Steroids (prednisolone)
* IVIgs
* Platelet transfusions (for life threatening bleeding)
114
What should be investigated in children with ITP before beginning them on steroids?
Bone marrow biopsy to rule out malignant causes of thrombocytopenia
115
What should children be advised to avoid doing who have ITP (2)?
* Avoid contact sports
* Avoid NSAIDs/ blood thinners
116
What are some complications of ITP (2)?
* Chronic ITP
* Intracranial/ GI bleed
117
What is disseminated intravascular coagulopathy?
Coagulation pathway activation leading to micro thrombi formation and consumption of coagulation factors and platelets
118
What is the main cause of DIC?
Severe infection (sepsis)
119
How is DIC diagnosed?
No specific test, just blood results that indicate DIC
120
How is DIC managed (2)?
* Treat underlying cause (usually infection)
* Supportive care (fresh frozen plasma)
121
What is thrombotic thrombocytopenia purpura?
Formation of microthrombi thought the body leading to depletion of platelets
*similar to DIC but with a different underlying cause*
122
What is the underlying cause of TTP?
Deficiency in ADAMTS13 enzyme (this prevents blood clots forming)
123
How is TTP managed (2)?
* Plasma exchange
* Steroids
124
How is HUS different to TTP?
HUS usually proceeds a gastroenteritis infection and the microthrombi are caused by the shiga toxin
125
What thrombocytopenias would a prolonged clotting time (PT/aPTT) be expected in?
DIC
*the others do not use up clotting factors*
126
What thrombocytopenias would schistocytes be expected in?
DIC, TTP, HUS
*not ITP as thrombi do not form therefore RBCs are not damaged*
127
What is the difference between bleeding time and clotting time?
* Bleeding time is dependant on clotting factors and function/number of platelets
* Clotting time is dependant only on the clotting factors
128
What are thrombophilias?
Conditions that predispose patients to having blood clots
129
What thrombophilias are most common in children ()?
* Factor V leiden
* Protein C/S deficiency
* Prothrombin gene mutation
130
What is factor 5 Leiden?
Clotting factor 5 is resistant to inactivation by protein C
131
What do protein C and S do?
Inactivate various clotting factors
132
How are most thrombophilias inherited?
Autosomal dominant
133
What thrombophilia occurs more often in adults and often presents with multiple miscarriages?
Antiphospholipid syndrome
134
What are the most common vasculitis in children?
* Henoch-Schonlein purpura
* Kawasaki disease
* Takayasu arteritis
135
What is henoch schonlein purpura?
Small vessel IgA vasculitis associated with IgA immune complex deposition
136
What age does Henoch schonlein purpura usually affect?
Under 10
137
What are the signs/ symptoms of Henoch schonlein purpura (4)?
* Purpura
* Joint pain
* Abdo pain (bowel involvement)
* Renal involvement
138
How is Henoch schonlein purpura managed (2)?
* Supportive care
* Steroids (effectiveness debated - started by specialist)
139
What is important to monitor in HSP (2)?
* Urine dip (for renal involvement)
* BP (for hypertension)
140
What is Kawasaki disease?
Medium vessel vasculitis with an unknown cause
141
What often precedes Kawasaki disease?
Infections
142
What are the signs/ symptoms of Kawasaki disease (7)?
* Persistently high fever > 5 days
* Widespread erythematous maculopapular rash
* Desquamation (peeling of skin) on hands and feet
* Bilateral conjunctivitis
* Strawberry tongue
* Cracked lips
* Cervical lymphadenopathy
143
What age is typically affected by Kawasaki disease?
Under 5 years
144
What is the course of the disease (3)?
* **Acute phase**: 1-2 weeks - systemically unwell
* **Subacute phase**: 2-4 weeks symptoms begin to settle - risk of coronary artery aneurysms
* **Convalescent stage**: 2-4 weeks - symptoms + aneurysms improve
145
What is a significant complication of Kawasaki disease?
Coronary artery aneurysm
146
How is Kawasaki disease investigated (3)?
* FBC, LFT, CRP
* Urinalysis
* Echo (for coronary aneurysms)
147
How is Kawasaki disease managed (2)?
* High dose aspirin
* IV Igs
148
What is aspirin not usually given to children?
Reyes syndrome
149
What is reyes syndrome?
Very rare, rapidly worsening brain + liver disease in children given aspirin
150
What is takayasu arteritis?
Rare disease causing inflammation of the aorta and its branches
151
What are the symptoms of takayasu arteritis?
Symptoms of reduced blood supply to the arms
