A term baby girl, who was born
weighing 3 kg, is admitted to the pediatric
intensive care unit at 14 days of
age. She is breastfeeding reasonably
and has continuous wet nappies. On
examination, she weighs 2.4 kg and
appears dehydrated and unwell. Her
observations reveal systolic blood pressure
of 40 mm Hg. Investigations show the
following values: hemoglobin,
19 g/dl; WBC count, 12 × 109/l;
platelet count, 246 × 109/l;
sodium,
125 mmol/l; potassium, 6.5 mmol/l;
urea, 10.4mmol/l; and plasma creatinine,
250μmol/l.
Abdominal ultrasound shows a provisional diagnosis of
bilateral renal dysplasia and
bilateral pelviureteric junction (PUJ) obstruction.
1 What immediate management would you institute?
2 What other urgent tests are required?
3 When she is better and tolerating enteral feeds, what
further management
might she require?
Discussion
1 Althoughinitiallytermbabiescanloseupto10%of
their birth weight, they
usually regain this by
day 10. However, this baby has lost 20% of her birth
weight at 2 weeks of
age, and clinically this represents severe dehydration.
The immediate management
would be confirmation of hypovolemic
shock looking for
prolonged capillary refill time and other signs of poor
peripheral perfusion.
She required urgent resuscitation with a bolus of
20 ml/kg of crystalloid
(such as 0.9% sodium chloride) and commencement
of intravenous
broad-spectrum antibiotics, ideally after samples of
urine, blood, and cerebrospinal fluid for
culture and sensitivity.
2 Other
urgent tests required are blood gas with tCO2, serum glucose, calcium,
and phosphate.
3 As
she improves, the urinary tract ultrasound should be repeated, as initial
ultrasound when neonates
are dehydrated may not show definitive
pathologies and true
size of dilatation. Long-term prophylactic antibiotics
must also be considered.
Many children with renal dysplasia are obligate
salt losers (with
consistently high urinary sodium levels of60–80mmol/l),
polyuric (even when
dehydrated), and also usually quite acidotic. They
may require large
quantities of both sodium chloride and sodium bicarbonate
to correct these losses,
first intravenously and then enterally. Long term supplementation
with sodium chloride and
sodium bicarbonate will
also be required, but
take care not to overdo it when requirements fall as
the renal function deteriorates.
