Children’s Health – The unconscious baby

Guidance and Resources – The unconscious baby

In case Children’s Health – The unconscious baby

Guidance

In this case we aim to continue the theme of the child with a reduced conscious level exploring this in the context of a neonate. We will explore the history, examination findings, differential diagnosis and the investigations required to reach a definitive diagnosis.

eBooks

Illustrated Textbook of Paediatrics 4th edition. Lissauer (Mosby Elsevier)

Web Links

British Inherited Metabolic Diseases Group (BIMDG)

Expanded Newborn Screening

National Newborn Screening Program (NNSP)

The management of children and young people with an acute decrease in conscious level [2015] – (RCPCH)

CASE COMPONENT

Case Introduction – The unconscious baby

In case Children’s Health – The unconscious baby

You are the FY1 in paediatrics and 7 day old Adam has been sent up to the assessment unit by his GP because for the past 24 hours he has not been waking for feeds and fluctuates from being irritable to being very sleepy.

Adam was born at 39+4 weeks after a normal pregnancy with normal antenatal scans. His birth weight was 3 Kg. There was no prolonged rupture of membranes. Prior to the past 24 hours he was waking for bottle feeds every 3-4 hours and taking 2-3 oz of SMA each time. He was passing regular urine and had his bowels open 2-3 times per day. In the past 24 hours he has only had 1 wet nappy.

Adam is the third child of first cousin, Pakistani parents. He has 2 healthy female siblings aged 5 and 3 years. Adam’s mother’s sister had a baby boy who died at 7 days of age in Pakistan but she does not know the cause of death. Adam’s dad’s brother died at 2 days of age, again in Pakistan, but he does not know any details as the family do not like to talk about it.

Adam’s Family Tree: Click on the hotspots for more information:

On examination Adam weighs 3 Kg. He is not jaundiced, is warm centrally but his hands and feet are cool. His heart sounds are normal with palpable femoral pulses. He has nasal flaring with occasional grunting but his chest is clear. His fontanelle is soft and normotensive. He is sleepy and when he wakes he does so with an irritable cry. He has reduced tone and his reflexes are easy to elicit but not brisk.

·       Further Case Information – The unconscious baby

·       In case Children’s Health – The unconscious baby

·       The results return and are as follows:

·       FBC, liver function, coagulation, C-reactive protein, glucose, urine dip and microscopy and lumbar puncture are normal.

·       U&E: Na 140 mmol/L, K 3.5 mmol/L, urea 2.3 mmol/L, Cl 110 mmol/L

·       Capillary gas: pH 7.1, pCO2 2.1, BXS -10, Bic 12, lactate 5, glucose 4.5 mmol/L

·       Ammonia: 543 micromols/L (normal range <100 micromols/L in neonates, <50 micromols/L in children)

·       Background Science – The unconscious baby

·       In case Children’s Health – The unconscious baby

·   Watch this presentation on ‘inborn errors of metabolism’ by Dr Andrew Morris:

·   Video Player http://www.taibahumbbs.com/wp-content/uploads/2017/09/edited_morris_dvd.mp4?_=1

CASE COMPONENT

Case Conclusion – The unconscious baby

In case Children’s Health – The unconscious baby

Adam was transferred to the regional metabolic centre. Specialist investigations of acylcarnitines and urine organic acids resulted in a diagnosis of methylmalonic acidaemia. This is a rare autosomal recessive disorder that classically presents in the first 5-7 days of life as described in this case. It is highly likely Adam’s cousin and uncle had died from this condition. Adam was treated with ammonia scavenging medications (sodium benzoate and sodium phenylbutyrate) and his metabolic acidosis was corrected with intravenous sodium bicarbonate. A CT scan showed mild cerebral oedema which is a common finding in hyperammonaemia and in some patients will lead to seizures. Once biochemically stable he was commenced on a specialist low protein diet. He was discharged home 10 days after admission and will remain on life-long follow-up by the specialist metabolic medicine team.

Take home messages

· While this case involved a consanguineous family metabolic disease it is important to remember that genetic disease can occur in non-consanguineous families.

· Inborn errors of metabolism are individually rare but collectively common and must be considered in the differential of many childhood presentations, e.g. acute illness, developmental delay, cyclical vomiting, seizures, dysmorphism, organomeglay, hypoglycaemia

· Inborn errors of metabolism are only diagnosed on specialist testing so discussion with the local regional metabolic centre is essential.

It is important to always calculate the anion gap in cases of metabolic acidosis in both children and adults.

Formative Assessment – The unconscious baby

Newborn screening(NBS) is performed on day 5 of life. Unfortunately the organic acidaemias are not one of the 6 inborn errors of metabolism screened for.