Neonatal Jaundice Flashcards
Where does haemopoesis occur in the foetus vs post natally?
- Fetal life Main site is liver
* Post natal Bone marrow
Describe phases of Haemoglobin production in fetus and newborn
Embryonic phase
• Embryonic Hb (produced between 4-8 weeks gestation)
Fetal phase
• Hb F main Hb in fetal life • α2 γ2
• Higher affinity for oxygen
At birth
• HbF, Hb A and HbA2
• gradually replaced by HbA & HBA2 by end of yr 1.
At 1 year of age, fetal Hb should be low. What is the significance of increased HbF?
Increased HbF is an indicator of inherited Hb disorders
How do Hb levels change at birth?
At birth Hb is high (14-21.5g/dl)
falls over the first few weeks, nadir around 2-3 months of age
(~10g/dl)
Preterm infants may have a steeper falls at an earlier age
6.5 - 9g/dL at 4-8 weeks of age
Why do pre-term infants require vitamin supplementation?
- The stores of iron, folic acid and vitamin B12 adequate at birth
- However they are inadequate in pre term birth and have to be replenished.
- Stores of iron, folic acid & vitamin B12 are adequate but may get depleted at early age in preterms
Cause of anaemia can be categorised by which three categories?
Impaired red cell production: Red cell aplasia, Ineffective erythropoiesis (Iron deficiency, chronic inflammation)
Increased red cell destruction: auto-immune haemolysis, haemoglobinopathies, red cell membranes diseases
Blood loss: Fetomaternal bleeding, Haemorrhage, Bleeding disorders
Presentation in iron deficiency anaemia in infants
- Tire easily, feed slowly
- History of blood loss or malabsorption
- May appear pale
- May have ‘pica’ - Inappropriate eating of non food materials
Differential for microcytic hypo chromic anaemia in children
Iron deficiency anaemia
Β or α thalassemia trait
Anaemia of chronic disorders
Iron deficiency anaemia - management
• Dietary advice
• Supplement with oral iron
Sytron (sodium iron edetate) or Nifirex (polysaccharide iron) Until Hb is normal and then 3 months to replenish stores
If non responsive, investigate for other causes (e.g. coeliac)
Iron deficiency anaemia - dietary advice
- High in iron: Red meat, liver, kidney, Oily fish
- Average iron: Pulses, beans, Fortified cereals, Dark green vegetables – broccoli, spinach, Dried fruits, nuts seeds
- Foods to avoid in excess: Cow’s milk, Tea, High fibre foods
Diagnostic clues for haemolytic anaemias
- Anaemia, hepatosplenomegaly
- Raised reticulocyte count (polychromasia on blood film)
- Unconjugated bilirubinaemia and increased urobilinogen
- Abnormal red cells on blood film
- Increased red cell precursors in bone marrow
Intrinsic abnormalities of the red cells
- Red cell membrane – hereditary spherocytosis
- Red cell enzyme disorders - G6PD
- Haemoglobinopathies – sickle cell, thalassemias
Clinical features of Hereditary spherocytosis
- Jaundice: Intermittent in childhood or Severe haemolytic jaundice in neonatal period
- Anaemia
- Splenomegaly
- Aplastic crisis
- Gallstones
Manage of Hereditary spherocytosis
- Oral folic acid
* Splenectomy in select patients after 7 years
Clinical features of Glucose –6-phosphate dehydrogenase (G6PD) deficiency
- Neonatal jaundice: May need exchange transfusion
- Acute haemolysis: Triggered by infections, fava beans, drugs, naphthalene balls
- Fever, malaise and passing dark urine (haemoglobin and urobilinogen)
Diagnosis of of Glucose –6-phosphate dehydrogenase (G6PD) deficiency
- Between episodes normal blood picture
- G6PD activity in red cells
- Management – advice
Pathophysiology of sickle cell disease
• Commonest genetic disorder in Uk; Autosomal recessive
• HbS – point mutation in codon 6 of B-globin gene leading to
change in amino acid encoded from glutamine to valine
• HbS polymerises in RBCs deforming red cells into a sickle shape
• Reduced red cell lifespan
• RBC trapped in microcirculation leading to vaso-occlusion and organ ischaemia
three main forms of of sickle cell disease
- Sickle cell anaemia (HbSS) • HbSC disease (HbSC)
* Sickle β-thalassemia
Clinical manifestations of sickle cell
Infections: encapsulated organisms, Osteomyelitis due to salmonella, Due to hyposplenism and microinfarction of spleen
Painful crises
Haemolytic or sequestration crisis
Priapism
Long-term issues: pubertal delay, stroke, gall stones, HF
Sickle cell triggers
Precipitated by cold, dehydration, stress, hypoxia, infections
Management of sickle cell
- Prophylaxis against encapsulated organisms: Fully immunised including pneumococcal infections. Daily oral penicillin
- Folic acid daily oral: increased demand by chronic haemolytic anaemia
- Crises minimised: Avoidance of triggers, Practical measures; dress warmly, Extra drinks before exercise, Keep children warm after swimming or playing outside
Management of sickle cell crisis
- Oral or intravenous analgesia
- Good hydration – oral or intravenous
- Prompt treatment of infections with antibiotics
- Oxygen if saturations reduced
- Exchange transfusion
Prognosis of sickle cell
- Prognosis
- Premature death
- 50% of severe patients die before 40 years
- 3% mortality in childhood
- Prenatal diagnosis and screening
- Part of neonatal screening test • Early penicillin prophylaxis
Clinical features of Beta-thalassemia
- Severe anaemia – transfusion dependant from 3-6 months of age • Failure to thrive
- Extramedullary haemopoiesis
- Prevented by regular transfusions
