HAEMATOLOGY PAEDS Flashcards by Amelia Crew

Difference between adult haemoglobin and fetal haemoglobin

HbF has 2 alpha and 2 gamma subunits
HbA has 2 alpha and 2 beta subunits

Affinity to oxygen: HbF > HbA (demonstrated by oxygen dissociation curve)

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Sickle cell disease and HbF

Genetic abnormality in sickle cell = the beta subunit
There is no beta subunit in HbF

Hydroxycarbamide - can be used to increase production of fetal haemoglobin in patients with sickle cell anaemia. Protective against sickle cell crises and acute chest syndrome

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Causes of anaemia in infancy

Physiologic anaemia of infancy (most common)

Other:
Anaemia of prematurity 
Blood loss 
Haemolysis 
Twin-twin transfusion (blood unequally distributed between twins that share placenta)

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Causes of haemolysis in a neonate

Haemolytic disease of the newborn (ABO/rhesus incompatibility)
Hereditary sperocytosis
G6PD deficiency

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Causes of Microcytic anaemia

(TAILS) 
Thalassaemia 
Anaemia of chronic disease 
Iron deficiency anaemia 
Lead poisoning 
Siberoblastic anaemia

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Causes of Macrocytic anaemia

Megalobastic
- B12/folate deficiency

Normoblastic

alcohol
reticulocytosis
hypothyroidism
liver disease
drugs e.g. Azathioprine

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Causes of normocytic anaemia

(3 As, 2 Hs) 
Anaemia of chronic disease 
Acute blood loss 
Aplastic anaemia 
Haemolytic anaemia 
Hypothyroidism

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Generic Symptoms of Anaemia

Tiredness 
SoB
Headaches
DIziness 
Palpitations 
Worsening of other conditions

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Generic signs of anaemia

Pale skin
Conjunctival pallor
Tachycardia
Raised RR

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Specific signs/Sx of iron deficiency anaemia

Pica - dietary craving for abnormal things 
Hair loss / brittle hair and nails 
Koilonychia (spoon shaped nails) 
Angular cheilitis 
Atrophic glossitis (smooth tongue)

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Initial investigations for anaemia

FBC (for Hb and MCV) 
Blood film 
Reticulocyte count 
Ferritin 
B12 and folate 
Bilirubin 
Direct Coombs test 
Haemoglobin electrophoresis

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What does high reticulocytes suggest

Active production to replace rbc - suggests anaemia due to blood loss or haemolysis

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Types of leukaemia that affect children

ALL - acute lymphoblastic leukaemia
AML - acute myeloid leukaemia
CML - chronic myeloid leukaemia

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Conditions that have a higher risk of leukaemia

Down’s syndrome
Kleinfelter syndrome
Noonan syndrome
Fanconi’s anaemia

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Risk factor for leukaemia

Radiation during pregnancy

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Leukaemia presentation

fatigue, pallor
Persistent fever
Failure to thrive 
WEight loss 
Night sweats 
Petechiae and abnormal bruising 
Unexplained bleeding 
Abdo pain 
Generalised lymphadenopathy 
Unexplained or persistent bone/joint pain 
Hepatosplenomegaly

What is Idiopathic thrombocytopenic purpura

Type II hypersensitivity reaction
Antibodies produced that target platelets
Spontaneously or triggered by infection

Idiopathic thrombocytopenic purpura PRESENTATION

Bleeding
Bruising
Petechiae / purpuric rash

Usually presents in children under 10 years. Often Hx of recent viral illness.

Types of non blanching lesions

Petechiae - pin prick spots (<1mm)
Purpura - larger (3-10mm)
Ecchymoses - large area of blood collection under the skin (>10mm)

Idiopathic thrombocytopenic purpura - MANAGEMENT

Urgent full blood count (platelets should be the only abnormality)
Other causes for low platelet excluded - e.g. heparin induced thrombocytopenia, leukaemia
Severity/management depends on how low platelet count is
Usually no treatment is required and patients monitored until platelets return to normal
70% of patients will remit spontaneously

Treatment (if pt actively bleeding or there is severe thrombocytopenia platelets <10)

prednisolone
IV immunoglobulins
blood transfusion
platelet transfusion (only works temporarily)

Idiopathic thrombocytopenic purpura - complications

Chronic ITP
Anaemia
Intracranial and subarachnoid haemorrhage
GI bleeding

Idiopathic thrombocytopenic purpura - ADVICE

Avoid contact sports
Avoid IM injections and procedures such as LP
Avoid NSAIDs, aspirin, blood thinning meds
Advice on managing nose bleeds
Seek help after any injury that may have caused internal bleeding

Sickle cell genetics

Autosomal recessive
Abnormal gene for beta-globin on chromosome 11
One copy —> sickle cell trait (usually asymptomatic)
2 copies —> sickle cell disease

Sickle cell relation to malaria

Having sickle cell trait (1 copy of faulty gene) reduces severity of malaria infection
As a result, areas with malaria - 1 faulty gene is a selective advantage
So there is higher prevalence in these areas (Africa, India, Middle East, Caribbean)

Sickle cell COMPLICATIONS

``` Anaemia Increased risk of infection Stroke Avascular necrosis in large joints such as the hip Pulmonary hypertension Painful and persistent penile erections (priapism) CKD Sickle cell crises Acute chest syndrome ```

Sickle cell GENERAL MANAGEMENT

Avoid dehydration/other triggers of crises Ensure vaccines up to date Antibiotic prophylaxis (usually penicillin V) Hydroxycarbamide - used to stimulate production of HbF Blood transfusion for severe anaemia Bone marrow transplant

Management for sickle cell crises

No specific treatment - manage patients supportively Low threshold for admission to hospital Treat any infection Keep warm Keep well hydrated (IV fluids if needed) Simple analgesia (NSAIDs avoided if renal impairment) Penile aspiration for priapism

Types of sickle cell crises

VASO-OCCLUSIVE - aka “painful crisis” caused by sickle cells blocking capillaries causing distal ischaemia. Associated with dehydration and raised haematocrit. Symptoms: fever and symptoms triggering infection. Can cause priapism = urological emergency SPLENIC SEQUESTRATION - blocking of blood flow within spleen —> enlarged painful spleen. Pooling of blood in the spleen can lead to severe anaemia and circulatory collapse (hypovolaemic shock). EMERGENCY. Management = supportive. Splenectomy prevents these crises and used in the case of recurrent crises. Recurrent crises can lead to splenic infarcts, resulting in susceptibility to infections. APLASTIC CRISIS - temporary loss of creation of new blood cells. Most commonly triggered by infection by parovirus B19. Leads to significant anaemia. Usually resolves spontaneously - blood transfusion may be required. ACUTE CHEST SYNDROME - diagnosis requires 1) fever or respiratory symptoms, with 2) new infiltrates seen on chest X-ray. Can be due to infection (e.g. pneumonia) or non-infective (e.g. pulmonary vaso-occlusion)

Management of ACUTE CHEST SYNDROME

Medical emergency !! High mortality Prompt supportive management and treat underlying cause Antibiotics or antivirals for infections Blood transfusions for anaemia Incentive spirometry Artificial ventilation with NIV or intubation

Thalassaemia signs and symptoms

``` Microcytic anaemia Fatigue Pallor Jaundice Gallstones Splenomegaly Poor growth and development Pronounced forehead and malar eminences ```

Complications of iron overload in Thalassaemia

``` Fatigue Liver cirrhosis Infertility Impotence Heart failure Arthritis Diabetes Osteoporosis and joint pain ```

Management options for Thalassaemia

Blood transfusions Iron chelation Splenectomy Bone marrow transplant

Types of Thalassaemia

Alpha Thalassaemia Beta Thalassaemia - minor - intermedia - major

Hereditary spherocytosis

RBC sphere shaped Most common inherited haemolytic anaemia in Northern Europeans Autosomal dominant

Hereditary spherocytosis presentation

``` Jaundice Anaemia Gallstones Splenomegaly Episodes of haemolytic crises ```

Hereditary spherocytosis: common cause of APLASTIC CRISIS

Parvovirus