Blood Disorders

Question 1

What is the differential count for a newborn?

Answer 1

• polymorphs predominate at birth
• lymphocyte predominance develops after 7 days
• I/T ratio less than 12 percent
• platelets 150- 450 X 109/l

Question 2

Causes of anaemia at birth

Answer 2

• feto maternal bleed
• feto- fetal bleed in mono chorionic twins
• acute bleed- cord or placenta
• haemolytic disease
• antenatal infection eg syphillis

Question 3

Causes of anaemia after birth?

Answer 3

• Immediate clamping of the umbilical cord (iron deficiency anaemia)
• Haemolysis due to RH or ABO incompatibility
• haemorrhagic disease of the newborn
• trauma
• peri ventricular haemorrhage
• acute infection
• anaemia of prematurity
• repeated blood sampling in Ill infants

Question 4

Clinical features of the various causes of anaemia?

Answer 4

Acute blood loss: pallor, tachycardia, shock with poor perfusion, gasping. Evidence of external loss or of internal bleeding

Haemolysis: chronic process with severe anaemia causing cardiac failure and jaundice

Feto- maternal: confirmed by finding fetal RBCs in maternal bleed circulation

Feto- fetal: one twin is pale while the other is plethoric - the latter may need more urgent attention due to fluid overload and resultant heat failure

Late anaemia: reduced rate of erythropoiesis and relatively rapid rate of growth. HB may fall below 10 in preterm infants by 2 months

Question 5

When are indications for blood transfusions?

Answer 5

Acute bleed or late anemia with PCV below 25 percent or a HB below 8

Question 6

At what HB and PCV does the viscosity of blood increase rapidly?

Answer 6

HB: 21
PCV: 65

Question 7

What are the clinical features of polycythemia?

Answer 7

• plethora
• hypoglycaemia
• respiratory distress
• necrotizing enterocolitis
• heart failure
• cns depression, convulsions, cerebral venous thrombosis
• renal or cerebral vein thrombosis

Question 8

What are the causes of polycythemia?

Answer 8

• underweight for gestational age or wasting with chronic fetal hypoxia
• twin to twin transfusion
• infant of a diabetic mother
• trisomy 21

Question 9

What is the treatment of polycythemia?

Answer 9

All infants with clinical signs, other than plethora alone should be treated with a partial normal saline or plasma exchange transfusion (15- 20ml/kg).
Avoid the umbilical vein route if possible
Look for and manage the underlying cause

Question 10

What are normal values for HB, PCV, MCV and WBC in the newborn?

Answer 10

HB: 14.5-21.5 g/do at birth
PCV: 45- 65% at birth. Later drops to 35 in term and 30 in premature infants

MCV: 110-128 fl
WBC: 6-30 X 109/l