A 19-day-old with weight loss, jaundice and hypoglycaemia
Baby W is a 19-day-old boy, born at 39+2 by spontaneous vaginal delivery after an uncomplicated pregnancy, with a birth weight of 3.42 kg. He is exclusively breastfed. His mother brings him to the after-hours clinic because he is 'too sleepy to feed' and has looked yellow for a week. Today's weight is 2.98 kg - 12.9% below birth weight and 150 g below the weight his midwife recorded four days ago. He has had four wet nappies and no dirty nappy in 48 hours. He is afebrile at 36.9 degrees Celsius, sleepy but rousable, with jaundice extending to the abdomen and dry mucous membranes. Capillary glucose is 2.9 mmol/L. A transcutaneous bilirubin reads 268 micromol/L and a venous sample confirms a total bilirubin of 262 micromol/L with a conjugated fraction of 14 micromol/L. His mother is 29, G2P2, blood group O positive; the baby is O positive with a negative direct Coombs test. There is no hepatosplenomegaly.
1. What is your differential diagnosis for the jaundice and the weight loss, and which do you consider most likely? Justify your reasoning.
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Most likely: inadequate breastfeeding with dehydration, causing both the weight loss and an unconjugated jaundice.
The evidence points one way: a weight 12.9% below birth weight at day 19, when birth weight should have been regained by day 10-14; a further 150 g lost in four days; only four wet nappies; no stool for 48 hours; dry mucous membranes; a sleepy baby who is not waking to feed; and a capillary glucose of 2.9. Poor intake reduces stooling, so bilirubin is deconjugated and reabsorbed through the enterohepatic circulation. The 'too sleepy to feed' and 'not feeding so more jaundiced so more sleepy' cycle is the classic trap.
Other causes to hold in mind
- Breast-milk jaundice: jaundice peaking at days 5-7 and persisting for weeks in a thriving baby. It contributes here but cannot explain a baby who is losing weight.
- Prolonged jaundice beyond 14 days always needs a conjugated fraction and a stool colour check. His conjugated fraction of 14 micromol/L is under 20% of the total and under 25 micromol/L, so this is unconjugated-predominant - but biliary atresia must be actively excluded with a repeat conjugated bilirubin, pale stool history and, if in doubt, urgent referral, because the window for a Kasai procedure is short.
- Infection: a sleepy, poorly feeding neonate needs a urine culture and, if any red flags, a full septic screen. UTI is a classic cause of prolonged jaundice.
- Hypothyroidism: check thyroid function in any prolonged jaundice.
- Haemolysis: blood groups are compatible and the Coombs test is negative, but consider G6PD deficiency, spherocytosis and a cephalohaematoma.
- Metabolic disease such as galactosaemia if there is vomiting, liver dysfunction or reducing substances, and hypernatraemic dehydration, which needs a sodium level tonight.
2. What will you do tonight, and which investigations will you order?
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Disposition
Admit him with his mother to a neonatal or paediatric unit. He is not safe to send home: he has lost more than 10% of birth weight, is dehydrated and hypoglycaemic, and is at day 19 of a jaundice that has not been explained.
Immediate treatment
- Treat the glucose of 2.9 mmol/L: feed him with expressed breast milk or formula if he will take it, and if he is symptomatic or the glucose does not correct, give IV 10% dextrose 2 mL/kg as a bolus followed by an infusion. Recheck within 30 minutes.
- Feeding plan: lactation consultant or midwife review tonight, a structured plan of 8-12 feeds per 24 hours with waking, expressing after feeds and top-ups, and a documented nappy and volume chart. Consider a nasogastric tube if he is too sleepy to feed adequately.
- Rehydration: oral or nasogastric top-ups if he is cardiovascularly stable; slow IV correction if the sodium is high, to avoid cerebral oedema from rapid shifts.
- Phototherapy: check the local (NICE-based) threshold chart. For a well baby of this gestation after 14 days, phototherapy is generally started at around 280 micromol/L, so he sits just below it - but he is not well. Repeat the bilirubin in 4-6 hours and start phototherapy if it is rising, if he remains dehydrated, or if he becomes unwell. Protect the eyes and maintain hydration during treatment.
Investigations
FBC and film, reticulocytes, blood group and direct Coombs, total and conjugated bilirubin, U&E (especially sodium), LFTs, thyroid function, CRP, blood culture, clean-catch urine for culture, G6PD assay, and glucose monitoring. Add ammonia, lactate and urine reducing substances if he deteriorates or the liver function is abnormal.
3. How would you communicate with the family, and what follow-up and safeguarding considerations apply at discharge?
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Communication
Start by acknowledging how frightening this is and by being explicit that she has not failed. Jaundice and slow weight gain are common, treatable problems and she did the right thing bringing him in. Avoid blaming language about breastfeeding - the risk is that she stops altogether. Ask open questions about feeding: pain, latch, frequency, how she is recovering, who is at home to help, sleep, transport, and how she is feeling in herself; screen for postnatal depression with a recognised tool such as the EPDS. Use an interpreter if English is not her first language, and involve whānau if she wishes. Give a written plan: what is wrong, what we are doing, how long it may take, and exactly what she can do at each feed.
Follow-up
- Do not discharge until feeding, weight and bilirubin are demonstrably improving and the glucose is stable.
- Inform the midwife or lead maternity carer, the GP and the Well Child Tamariki Ora provider, and arrange a weight and bilirubin check within 24 hours of discharge and again at 48-72 hours.
- Give clear safety-netting: return immediately if he is floppy, feverish, feeding poorly, has fewer wet nappies, becomes more yellow, or passes pale stools or dark urine.
Safeguarding
This is not automatically a child protection matter, but faltering growth with dehydration requires a documented, shared plan with named responsibilities. Escalate to social work if there are repeated missed appointments, an unexplained further weight drop, maternal mental illness or family violence, or if the family cannot engage with the follow-up. The baby's safety comes first, and it is far better to escalate early and be wrong than to miss a preventable readmission.