HAEMATOLOGY PAEDS Flashcards
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)
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
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)
Causes of haemolysis in a neonate
Haemolytic disease of the newborn (ABO/rhesus incompatibility)
Hereditary sperocytosis
G6PD deficiency
Causes of Microcytic anaemia
(TAILS) Thalassaemia Anaemia of chronic disease Iron deficiency anaemia Lead poisoning Siberoblastic anaemia
Causes of Macrocytic anaemia
Megalobastic
- B12/folate deficiency
Normoblastic
- alcohol
- reticulocytosis
- hypothyroidism
- liver disease
- drugs e.g. Azathioprine
Causes of normocytic anaemia
(3 As, 2 Hs) Anaemia of chronic disease Acute blood loss Aplastic anaemia Haemolytic anaemia Hypothyroidism
Generic Symptoms of Anaemia
Tiredness SoB Headaches DIziness Palpitations Worsening of other conditions
Generic signs of anaemia
Pale skin
Conjunctival pallor
Tachycardia
Raised RR
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)
Initial investigations for anaemia
FBC (for Hb and MCV) Blood film Reticulocyte count Ferritin B12 and folate Bilirubin Direct Coombs test Haemoglobin electrophoresis
What does high reticulocytes suggest
Active production to replace rbc - suggests anaemia due to blood loss or haemolysis
Types of leukaemia that affect children
ALL - acute lymphoblastic leukaemia
AML - acute myeloid leukaemia
CML - chronic myeloid leukaemia
Conditions that have a higher risk of leukaemia
Down’s syndrome
Kleinfelter syndrome
Noonan syndrome
Fanconi’s anaemia
Risk factor for leukaemia
Radiation during pregnancy
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
