Clinical problems in Down's syndrome

Patients with Down's syndrome may have undiagnosed problems, warn Dr Christine Jenkins and Dr Jennifer Dennis.

Although many people with Down's syndrome are fit and healthy, it is important that GPs know which medical conditions are over-represented within this population and how to manage them.

Most are readily remedied but cause extra disability if undiagnosed, especially as people with Down's syndrome may not be able to describe symptoms well.

People with Down’s syndrome may struggle to describe their symptoms (Photograph: SPL)

First-year emergencies
The cardiac status of every baby with Down's syndrome must be established in the first six weeks. Between 40 and 60 per cent have congenital heart disease, and 30-40 per cent of those have complete atrioventricular canal defect. Corrective surgery is offered to nearly all of these in the first months of life because irreversible pulmonary hypertension develops more rapidly in children with Down's syndrome than in other children.

Hirschsprung's disease and duodenal atresia or web occur more often than in the general population.

Hirschsprung's disease poses diagnostic problems because constipation is common in children with Down's syndrome.

Growth
For young children with Down's syndrome, the 50th centiles for height and weight are only just above the third centile for the general population. UK Down's-specific growth charts should be used (see box below). These are available in A4 format and are also included in the Down's syndrome personal child health record (PCHR) insert.

Key points
Growth monitoring
  • Appropriate growth monitoring is essential.
  • Down's-specific growth charts, which include BMI charts, must be used.
  • Height or weight below the second centile on the Down's charts may indicate congenital heart disease, other additional pathology, or nutritional deficit, which require investigation or treatment.
  • Being overweight/obese is not inevitable and should be thoroughly assessed.
  • Any child aged 5-18 years who is above the 75th centile for weight should be charted on standard BMI charts. Those above the 98th centile on the BMI charts require further investigation and management.

Children may fail to thrive because of feeding difficulties associated with impaired oral-motor function. Breastfeeding can be slower and more difficult to establish due to poor sucking and low muscle tone.

Appropriate support to breastfeed should be offered and advice on feeding anticipated.

Children and adults with Down's syndrome have an increased tendency to become overweight for their height.

Encouraging healthy nutrition and regular exercise within the family remains important.

Immunisations
Children with Down's syndrome should be immunised according to the universal UK schedule, and additionally given the influenza vaccine. Hepatitis B immunisation should also be considered, especially for those attending day centres or in residential care.

Sensory checks
All newborns should undergo neonatal hearing screening. Hearing loss secondary to glue ear is common. It may develop before 12 months and can then persist well into the school years.

Sensorineural loss may be congenital or may develop later in life. It is important these conditions are recognised early and corrected by hearing aids or grommets. If unrecognised, they confer major additional disability. Hearing should be checked annually until the age of five, and two-yearly thereafter for life.

Around 60-70 per cent of children with Down's syndrome under seven have vision problems. Some have quite high myopia and many have hypermetropia, which may be signalled by the onset of a squint.

Hypermetropia is not picked up by routine screening; refraction by an optician or ophthalmologist is needed. Vision checks are necessary at least once a year up to the age of four, then every two years for life.

Thyroid problems
Thyroid dysfunction, mainly hypothyroidism, is over-represented at all ages. Clinical diagnosis can be difficult because of overlap with normal features of Down's syndrome. Most child development services have local annual or biennial screening protocols in place.

Nevertheless, GPs should have a low threshold for investigation even when previous screening results have been normal.

Two-yearly TFTs should continue in adulthood.

Cervical spine
Atlantoaxial instability due to ligamentous laxity may predispose to dislocation and damage to the spinal cord. Serious sequelae are rare but can be devastating.

There is no effective screening tool to predict those at risk. Cervical spine X-rays can be misleading, suggesting instability in those with no clinical sequelae, while symptomatic dislocation has occurred in those with previously 'normal' X-rays.

Previous DoH guidelines recommending cervical spine X-rays prior to participating in sports have been withdrawn.

Clinical vigilance is vital. Symptoms of spinal cord compression usually precede dislocation and those presenting with torticollis, pain behind the ear, deterioration of manipulative skills, altered gait, or recent onset incontinence should be referred for assessment by a spinal surgeon.

Breathing disorders
Sleep-related breathing disorder is an often unrecognised complication of Down's syndrome at all ages.

A floppy tongue falls back during sleep into a narrow postnasal space, which may be further compromised by adenotonsillar growth.

The condition predisposes to pulmonary hypertension and may seriously affect quality of life. Frequent night-time waking, snoring, lower sternal recession, and daytime sleepiness are clinical indicators. The condition requires specialist appraisal and may be improved by adenotonsillectomy.

Early dementia
Although people with Down's syndrome may remain alert and fit into their sixties or seventies, some develop dementia in their thirties. At any given age, the prevalence is 30 or 40 years earlier than in the general population. But apparent dementia may be due to treatable causes such as depression or hypothyroidism.

Nuisance problems
Nasal congestion, persistent catarrh, sticky eyes, blocked tearducts, dry skin, friable nails, constipation and/or toddler diarrhoea all occur more frequently among patients with Down's syndrome.

With catarrh, a vicious circle of poor postnasal drainage, and repeated secondary infection and exacerbation can occur.

Family support
Throughout childhood, multidisciplinary support is provided in most UK areas by community child health teams working together with social workers and education professionals.

Care is usually co-ordinated by a local community paediatrician. All families should receive the Down's syndrome insert for the PCHR, Early Support information from the DoH - which includes a special booklet on Down's syndrome - and information about the Down's Syndrome Association, local support groups and benefits available.

Unfortunately, such multidisciplinary, co-ordinated, proactive support is rarely available for adults. GPs may therefore need to ensure regular two-yearly checks of hearing, vision and thyroid function, as well as monitoring potential problems.

  • Dr Jenkins is consultant paediatrician in community child health at East and North Hertfordshire NHS Trust, and Dr Dennis is director of information at the Down's Syndrome Medical Interest Group.
  • Information specifically for healthcare professionals is available from the Down's Syndrome Medical Interest Group at www.dsmig.org.uk

Further Reading

Have you registered with us yet?

Register now to enjoy more articles and free email bulletins

Register

Already registered?

Sign in

Before commenting please read our rules for commenting on articles.

If you see a comment you find offensive, you can flag it as inappropriate. In the top right-hand corner of an individual comment, you will see 'flag as inappropriate'. Clicking this prompts us to review the comment. For further information see our rules for commenting on articles.

comments powered by Disqus