Neurodevelopmental medicine

Associations

Some of the problems associated with ID are related to the underlying causes, but others are seen independent of whether any cause is identified. The following are more common in individuals with ID:

• epilepsy (approximately 30 times more likely)

• constipation (approximately 11 times more likely)

• visual impairment (approximately 8 times more likely)

• obesity

• mental health disorder, particularly depression and anxiety

• hearing loss

• reflux and heartburn

• some forms of dementia

Investigations

Investigations must be tailored to the individual child and clinical judgement used as to which, if any, are required. Investigations to consider would aim to identify any underlying pathology and would include:

• genetic analysis

• metabolic screen

• MRI imaging

• EEG

• skeletal survey

• congenital infection screen

Treatment and management

For some with ID, there are specific management issues related to an underlying diagnosis. The majority with ID will not need long-term paediatric care unless there are allied medical concerns that require management in their own right. For most children and young people with ID, management is based around some guiding principles:

Classification

Cerebral palsy can be classified in a number of different ways:

Type of movement disorder:

• spastic (motor cortex damage)

• dyskinetic (basal ganglia damage—resulting in additional involuntary movements)

• ataxic (cerebellar damage affects proprioception)

• mixed pattern (damage to a combination of areas)

Distribution of the effects on the limbs:

• bilateral (diplegia or quadriplegia)

• unilateral (hemiplegia or monoplegia)

Severity of impact on functional abilities:

• clinical scales have developed to describe levels of motor skills, communication and functional capacity

Use of the appropriate terminology not only facilitates communication between professionals but can also help discuss a child’s broad prognosis and potential comorbidities.

Cerebral palsy may present with:

• tonal abnormalities (a stiff irritable baby)

• asymmetry of movements (early hand preference)

• atypical or late motor development (delayed walking, persistent toe walking)

In the mildly affected child, issues may not become apparent until the child is independently mobile and starts to show more subtle differences such as toe walking. Clinical signs will depend on the nature and severity of the cerebral palsy but will include abnormalities of muscle tone, posture and reflexes, together with any developmental impact these may have.

Alternative diagnoses

Many other disorders may have an initial presentation similar to cerebral palsy and include:

• inborn errors of metabolism—citrullinaemia and biotinidase deficiency

• mitochondrial disorders—Leigh’s disease (though these features progress)

• genetic dystonias, hereditary spastic paraparesis—children may have a family history of ‘cerebral palsy’

Associations

• gastro-oesophageal reflux

• sialorrhoea (drooling) due to bulbar dysfunction and poor oro-motor control

• bowel and bladder dysfunction

• epilepsy

• sleep disorders due to pain and musculoskeletal discomfort

• respiratory illnesses from aspiration of food or gastric contents and inadequate cough

• postural issues can cause restrictive respiratory difficulties

Investigations

All children with a clinical picture of cerebral palsy should have neuroimaging (preferably MRI) performed. This will often confirm underlying aetiological changes such as periventricular leukomalacia or a large middle cerebral artery infarct

Treatment and management

A coordinated multiagency approach is essential. Growing knowledge and understanding of the developing brain supports the need for early targeted intervention coordinated by a paediatrician who can make appropriate assessment and involve the appropriate members of the multidisciplinary team.

• physiotherapy— to support and promote development of motor skills, maintain ranges of movement and minimise deformities and other complications of tonal and postural abnormalities

• occupational therapy —to support development in play and self-care skills and participation needs in school/nursery

• orthotics —provide a range of aids such as splints and gaiters to support a child’s posture and development

• speech and language therapy —to address communication, feeding and swallowing difficulties

• visual impairment —70% of children with cerebral palsy are thought to have some degree of strabismus, visual field loss, difficulties with eye movements, reduced visual acuity or cerebral visual impairment in which the eye has good visual acuity but the brain is not able to process the images seen

• hearing impairment— an estimated 10% to 20% of children with cerebral palsy have some degree of hearing impairment

• intellectual disability— affects around 50% of people with cerebral palsy and is moderate or severe in around 20%. Involvement of the early-years education team (Portage) may be appropriate depending on likely cognitive level or developmental trajectory.

Relevant pharmacological agents used

Medication may be required to manage hypertonia or symptoms of associated issues including gastro-oesophageal reflux disease, constipation, neuropathic bladder, drooling and epilepsy ( Table 27.2 ).

Botulinum toxin A is a treatment for focal hypertonia (spasticity or dystonia) and the toxin is injected directly into the muscles needing treatment. The effect lasts around 4–6 months. It is contraindicated in patients receiving aminoglycoside treatment due to potentiation of the action of the toxin.

Two main surgical treatments are available for spasticity associated with cerebral palsy.

Intrathecal baclofen pumps provide a continuous low dose of baclofen directly into the intrathecal space. This produces a global effect on an individual’s hypertonia and, since much lower doses are required than when used orally, the risk of adverse drug-related effects is much lower. The reservoir of drug within the pump system needs refilling every 3 months.

Selective dorsal rhizotomy is a procedure in which a proportion of the sensory nerve roots at one or more spinal levels are cut, reducing the sensory feedback within the spinal reflex and thus reducing the spasticity. The current availability on the NHS is limited to a specific group of children who are already walking with a degree of independence and who have particular changes on their MRI brain scan.

Complications and sequelae

Hip subluxation , which may progress to complete dislocation, is a common complication. Approaches to control or reduce the progression of subluxation include a postural management programme, use of botulinum toxin A, oral medication and tendon lengthening surgery.

Scoliosis is frequently, but not exclusively, related to pelvic obliquity or hip subluxation. The availability of ‘growing rods’ (implanted rods that can be extended as the child grows) allows earlier surgical intervention for those in whom progression of the curvature is rapid or is causing other issues such as respiratory difficulties.

Down syndrome

Relevant features that may impact on development:

• hypotonia and hypermobility

• intellectual disability common (usually mild–moderate)

• respiratory and ENT infections—glue ear common giving hearing problems

• obstructive sleep apnoea

• hypothyroidism

• coeliac disease—increased risk

• diabetes mellitus type 1—increased risk

• leukaemia—increased risk of acute myeloid and lymphoid leukaemia