Dr Claire Strauss and Dr Leigh Dyet
A midwife calls you to review a baby who has just been born. She is concerned that they have some unusual facial features. When you arrive, the mother is holding the baby and asks “Do you think they have Down syndrome?”
How do you approach this?
- Examine the baby. Features may be subtle and particularly unclear if you are examining the baby very soon after birth when they may be slightly distorted.
Don’t forget to think about the possibility of other trisomies which may explain any other unusual features e.g. overlapping digits, rocker-bottom feet
- Review the antenatal notes:
Was there screening for trisomies? This usually happens around 11-14 weeks of pregnancy with the first ultrasound. Combined screening uses the nuchal translucency, maternal age and bloods for Pregnancy Associated Plasma Protein-A (PAPP-A) and free beta-human Chorionic Gonadotropin (b-hCG) to calculate the likelihood of trisomy 13, 18 or 21 (Down syndrome). If this is not possible, the quadruple test may be performed for trisomies.
What was the calculated likelihood?
Was invasive testing performed if there was a high likelihood?
Were there any anomalies on antenatal scans, such as cardiac defects or growth concerns?
What discussions were had with the parents about these tests and findings?
- Get a senior review before going further with diagnosis and management. You may feel under pressure to state whether the baby has Down Syndrome but you certainly need senior input before anything else happens.
Your consultant reviews the baby and feels that they are likely to have trisomy 21.
What do you say to the parents?
- Be honest about your concerns
- Be careful about the language you use, and try not to frame the conversation negatively – they have a lovely baby and should be congratulated.
- Give the parents time to ask questions and to assimilate the information
- Do not overwhelm them with details
What do they know about Down Syndrome? What information are they ready for?
Some of this may be more appropriate once a diagnosis is confirmed.
- Our genetic material is organised into chromosomes and we usually have 46, pairs numbered 1-22 and the sex chromosomes XX or XY.
- Down syndrome occurs when a person has an extra chromosome 21. This is not usually inherited.
- There are some common characteristics, although each person with Down syndrome may have them to a different extent. These include a characteristic appearance and a degree of learning difficulties. There can be important conditions associated with Down syndrome which will need to be monitored for. These include heart and bowel problems.
- Whether or not the baby has Down Syndrome will be confirmed by genetic testing.
- For now they should enjoy their baby as they would any new baby. You will need to do some blood tests and care will need to be taken to monitor feeding.
Can the baby stay with mum on the postnatal ward?
Probably, unless there is a specific reason! There is no reason all babies with (suspected) T21 would need admission to NICU. Some reasons might be:
- Poor feeding (secondary to hypotonia and a large tongue)
- Severe polycythaemia or jaundice
- Associated cardiac defects with features of heart failure.
- Suspected gastrointestinal problems causing bowel obstruction
What investigations are needed immediately?
- Rapid karyotype
- Full blood count (FBC) and blood film
What are the potential complications in the neonatal period and what needs doing?
Feeding will need to be closely observed whether on the postnatal ward or NICU
Parents and babies may need extra feeding support (whether breast or bottle feeding)
If there are significant concerns, a speech and language therapy assessment may be helpful and a nasogastric tube (NGT) might be needed to help with top ups (or possibly for all feeds). Depending on your unit this may mean an admission to NICU.
Transient Abnormal Myelopoesis (TAM)
Send an FBC and blood film early on due to the possibility of Transient Abnormal Myelopoesis (TAM) (also known as Transient Leukaemia of Down Syndrome or Transient Myeloproliferative Disorder). 5-30% of children with T21 are born with TAM. TAM is usually benign and resolved by 3 months but severe symptoms can be life-threatening. 20% of survivors later develop Acute Myeloid Leukaemia, so follow up is required.
Clinical features suggestive of TAM include organomegaly, cholestasis and hepatopathy, skin rash, pericardial, pleural effusions and hydrops.
If there are concerns that TAM is likely (clinical features and/or blasts >10%) consider investigations for life threatening features:
- Multi-organ failure
- White cell count >100 x 109/L
- Hepatopathy (conjugated bilirubin > 83 mmol/l)
- Pleural or pericardial effusion
- Renal failure
- DIC and bleeding.
Discuss any baby with suspected TAM urgently with paediatric oncology and send a blood sample for GATA1 mutation and analysis. These patients may be suitable for cytarabine treatment 15.
Polycythaemia occurs in approximately 65% of newborn babies with Down syndrome. In some babies, the elevation in the number of red blood cells can be associated with some types of congenital heart defects Typically the polycythaemia will resolve within the first few months of life and not require any intervention. Occasionally a dilutional exchange transfusion may be required.
Macrocytosis, transient thrombocytopenia and leukopoenia are also common occurrences.
40-60% of babies with T21 will have a cardiac anomaly. The most common type (30-40%) of anomaly is complete atrioventricular septal defects (AVSD). This puts them at risk of early pulmonary vascular disease and they may require early surgery to prevent this.
The baby must be examined but this alone is not enough. They should have blood pressures, four limb O2 saturations and an ECG. An echocardiogram (echo) should be performed for all babies by 6 weeks. If they have abnormal clinical findings or an abnormal ECG (particularly a superior QRS axis) they are considered by DSMIG to have a high risk of developing pulmonary vascular disease and should have an echo within 2 weeks.
The Down Syndrome Medical Interest Group (DSMIG) recommends that an echo is done even if a fetal echo has been performed.
One third of babies with duodenal atresia have Down syndrome. This may be detected antenatally and causes bowel obstruction. Any bilious vomiting (or sometimes recurrent non-bilious vomiting) requires the baby to be made nil by mouth with an NGT on free drainage and intravenous fluids. It will need urgent investigation for bowel obstruction including abdominal X-Ray and a surgical review. The classic X-Ray finding is the ‘double bubble’ appearance.
Hirschsprung’s disease is when there is a section of aganglionic distal bowel preventing easy passage of stool which can cause dilatation of the bowel in front of the affected segment. Make sure the baby has passed meconium before they are discharged. If there’s a delay in passing meconium, a surgical assessment will be needed.
Congenital cataracts, infantile glaucoma
Congenital cataracts are ten times more common in children with T21 than the general population.
Congenital eye abnormalities should be looked for in the routine Newborn and Infant Physical Examination (NIPE) and referred to ophthalmology.
Cataracts may be seen as clouding of the lens and are often picked up when checking for the red reflexes.
Primary Congenital Glaucoma / infantile glaucoma
Symptoms may include; one or both eyes seeming large or protuberant, eye watering and light sensitivity. They also have an increased risk of developing glaucoma later in life.
Narrow ear canals predispose to buildup of wax which may affect hearing and impedance testing. Infants should have the routine newborn hearing screen and later have a targeted hearing assessment at 6-10 months.
What else is needed before the baby goes home?
- Referral to community team for developmental follow up. There may be a specific service or contact for children with trisomy 21.
- The routine hearing screen should be conducted and the screeners should be made aware of the (suspected) diagnosis. A formal audiology referral should also be made.
- If an echocardiogram has not been done already, it should be booked within the next few weeks. Be sure to safety-net parents about features which might indicate heart failure, in which case they would need to come to hospital immediately.
- Give parents written information about trisomy 21. The Down Syndrome Association have a new parents pack with lots of useful information.
- The community midwife and GP should be informed of the (suspected) diagnosis.
- Has the baby passed meconium? If there is a delay, consider the possibility of Hirschsprung’s disease. If you’re concerned about Hirschprung’s, an urgent referral to a paediatric surgical team should be made.
Many hospitals have policies of checking thyroid function tests within the first 7 days however the DSMIG recommend that no additional thyroid testing is done beyond the routine newborn blood spot.
There is an additional section which can be inserted into the Personal Child Health Record (red book) . This contains details on adjusted developmental milestone timelines and the Down Syndrome specific growth charts.
The parents should be signposted to sources of support such as the Down Syndrome Association.
Dr Claire Strauss and Dr Leigh Dyet