Acute Paediatrics: Neuromuscular disorders

Chapter 1 Acute Paediatrics


Neuromuscular disorders



Clinical features


Paediatric neuromuscular (NM) disorders are a diverse group of progressive conditions, characterised by muscle weakness and contractures that include the neck, spine, and jaw.



• Other features of NM disorders:


– spinal deformity, e.g. scoliosis or increased lumbar lordosis

– neck and spine rigidity

– varying degrees of functional limitation

– abnormal gait patterns and/or associated foot postures

– toe walking

– foot drop

– frequent falls

– pes cavus

– developmental delay

– lack of independent mobility

– fatigue

– respiratory involvement

– cardiac problems

– calf hypertrophy, e.g. Duchenne muscular dystrophy (DMD)

– muscle wasting, e.g. type III spinal muscular atrophy (SMA)

– facial weakness

– winging scapulae

– cramp or pain, particularly on exercise.

Children with neuromuscular disorders do not have increased tone, apart from a few who have very rare disorders, or increased tone due to a non-related condition: e.g. an unrelated hemiplegia.


Hypotonic as a term should be avoided, as the terms weak and low tone are frequently used interchangeably; they are not the same.


The conditions vary in many ways, but often the greatest concern for therapists is the rate of progression of symptoms.


An important consideration is the effect of growth; while the underlying condition may be slowly progressive, the increase in height and weight can have a major effect on motor performance and function.


It is important to understand that progressive neuromuscular disorders are frightening for parents and children. The children, especially the weakest ones, will be wary of strangers and may need time before they will co-operate with assessment.



Assessment


This will vary according to age, function, whether an infant, child or teenager is being assessed for the first time or if they are being reviewed.



Subjective assessment




• During the initial assessment, an overview of the onset, progression and major functional difficulties needs to be established.


• Is there any family history of muscle disorders or developmental delay?


• Are the problems getting worse, improving or staying the same?


• If function or power has deteriorated, has this happened gradually or rapidly?


• Is the child experiencing symptoms of nocturnal hypoventilation?


• Weaker children with neuromuscular conditions often suffer from nocturnal hypoventilation, i.e. they under-breathe when asleep.


• To ascertain whether a child may be developing this problem, the following questions should be asked:


– Do they sleep badly (some complain of nightmares)?

– Do they have morning headaches?

– Do they find it difficult to wake or are slow to wake?

– Do they demonstrate morning anorexia (refuse to eat breakfast)?

– Do they experience daytime sleepiness or lack of concentration at school?


Babies and infants




• The following need to be considered when assessing babies or infants:


– Duration of pregnancy; full term?

– Did the baby move appropriately in utero?

– Did they require any respiratory or feeding support in the neonatal period?

– Is the baby making progress in their development?

– Do they have good head control and have they reached their appropriate motor milestones?

– Does the baby interact with parents and their environment?

– Does the baby have good general health or are they prone to chest infections?

– Was the baby born with or have they developed any contractures?


Ambulant children




• When assessing an ambulant child the following need to be considered:


– What age did they walk independently?

– If walking is deteriorating, when did this begin?

– Is walking slower than expected?

– How far can the child walk in terms of time or distance? It may be necessary to specify on a ‘good day’, or when allowed to go at their own pace.

– What limits walking; falls, fatigue, pain?

– What are the major functional difficulties? for example; climbing stairs, getting up from the floor and running.

– Outdoors, can they manage kerbs and slopes?

– Does the child get cramp or pain: and if so where? Are there precipitating factors? Is it most apparent after exercise?

– Have they had previous factures or surgery?

– Are they using any splints or orthotics?

– What exercise and activity do they do?

– Do they swim, ride a bicycle, play football, dance, do gymnastics or participate in any other activities?

– Do they play any musical instruments?

– Do they join in during PE sessions at school?


Non-ambulant children




• When assessing non-ambulant children the following need to be considered:


– Can they sit independently?

– Did they ever walk and if so, when did they lose the ability?

– How do they mobilise?

– Have they any specialist equipment?

– How much are parents carrying or lifting them?

– What are the access issues at home or outside at school or nursery?


Considerations for teenagers




• Onset of disorders in the teenage years can be especially hard – being a teenager is difficult enough!


• There may be conflicting history with parents or playing down of symptoms to feign normality.



Objective assessment


Assessment of infants, children and adolescents will focus on the evaluation of muscle power, joint range and contractures, mobility, posture and function.


In some centres, respiratory function is tested by physiotherapists.


For babies and infants, an assessment of developmental milestones is needed.



Development




• Does the baby have good head control?


• Are they trying to roll?


• Can they get into sitting, or safely lie down once placed in sitting?


• Do they get distressed when placed prone?


• Do they/did they crawl and/or bottom shuffle?


• Can they take weight through their legs when placed in standing?



Muscle power:




• Assessment of muscle power in clinical practice on the whole follows the MRC grading/Oxford scale of 0–5 (MRC 1976).


• Standardised starting positions must be used to ensure reproducibility.


• Pure movements are tested at the neck, trunk, hips, knees and ankles, shoulders, elbows forearms and wrists.


• Rotation movements are not tested, as they are not pure movements. Although strong and often used to compensate for weakness, it is difficult to separate the components of the movement.


• Objective measurement of force using a hand-held dynamometer, also known as myometry, has been shown to be more reliable as a means of measuring muscle power in children (Wadsworth et al 1987) (Figure 1.1).


image

Figure 1.1 Hand-held dynamometer.


With kind permission of Citec, www.citec.nu.



Joint contractures




• Contractures may be present which can influence joint range of motion.


• Caused by shortening of the muscle and other structures around the joint.


• The muscles can be:


– Fibrosed, due to underlying disease

– Shortened, through lack of movement or muscle imbalance

– Shortened, due to repeated poor posture or a reduced repertoire of movement.

• There are children who have joint hypermobility or a combination of hypermobility and contractures.


• Marked hypermobility can be as debilitating as contractures and should be recorded.


• Contractures are more severe and widespread in non-ambulant children.


• They are apparent at birth in many of the congenital muscular dystrophies, but can occur in all of the neuromuscular disorders over time.


• The site of contractures can be related to the underlying pattern of muscle weakness and to the functional level of the child (ambulant or non-ambulant).


• Contractures are important where they interfere with function.


• The most frequently encountered contractures are:


– Hip flexion

– Ankle, loss of dorsiflexion

– Iliotibial band (ITB)

– Elbow

– Long finger flexors

– Loss of supination

– Knee

– Neck and spinal rigidity

– Mid-foot, leading to pes cavus deformity.


Measurement of joint range




• Commonly joint range is measured using goniometry.


• Standardised starting positions and measuring methods need to be defined to ensure repeatability.


• It is also very important to know what constitutes ‘normal’ range when considering the presence of reduced joint range.


• Neck range of movement and spinal mobility are routinely assessed.


• Hamstring range is measured routinely recording the popliteal angle. However tighter hamstrings are a prerequisite for children with pelvic weakness, to ensure the highest level of function.


• Hamstring tightness is not considered to be a problem unless it is associated with collagen disorders, e.g. Ullrich congenital muscular dystrophy (CMD) or Bethlem CMD.



Mobility




• When a child is ambulant, timed tests are used to provide quantitative measures of mobility.


• With the timed 10 metres, the child is instructed to ‘go’ as fast as they can.


• More recently, the 6 minute walk test (6MWT) has been introduced (Li et al 2005). Distance is measured over a course, recommended to be 25 metres long, and continued for 6 minutes with the distance walked being recorded.



Posture




• Descriptions of neck/spine posture in sitting and neck/spine and leg posture in standing are recorded.


• X-rays are taken when necessary.


• The following need to be noted in sitting and standing:


– In sitting, is there a scoliosis, kyphosis, increased lordosis in the spine?

– Is there spinal rotation or rib humps?

– Are the shoulders level?

– Is there winging of the scapulae?

– Is the pelvis level?

– Are waist creases and contours symmetrical?

– Is the head held straight or tilted?

– In standing, is the pelvis level, and does the spinal posture change.

– Is there asymmetry of the legs?

– Does the child have normal foot posture or pes cavus/pes planus?


Function




• Function in neuromuscular disorders is assessed using a functional scale.


• The scales used will depend on the preferences of the centre, the diagnosis and the functional level of the child.


• The main areas that are tested:


– lifting the head

– rolling

– getting to sitting from lying

– crawling

– standing up from the floor

– standing on one leg

– hopping

– jumping

– getting up and down steps/stairs.


Teenagers




• For a teenager reviewed over many years, who has never walked or lost ambulation, assessing power and contractures will provide information that they and their parents/carers will already know, i.e. that they are weaker and more contracted.



Parents and siblings




• It is important to consider whether this is a disorder that may also affect a parent or sibling.


• The following signs may be observed in parents and siblings and may help to give clues to help the formation of a diagnosis:


– Elbow contractures, TA tightness, long finger flexor tightness (Bethlem CMD)

– Facial weakness (fascioscapular-humeral MD)

– Calf hypertrophy (carrier of DMD – females)

– Pes cavus (Charcot–Marie–Tooth).


Summary




• Weakness and contractures are the major barriers to function.


• Many children will have or develop respiratory compromise.


• Many children will have spinal asymmetry that may require corrective surgery.


• It is not appropriate to keep assessing power and contractures in the older, weakest non-ambulant teenagers.


• Progressive disorders are frightening and the fears and anxieties of the parents and children will need to be managed in a sympathetic manner.



Musculoskeletal




• Assessment of a child requires an understanding of normal growth and development of the musculoskeletal system as well as an awareness of potential red flags.


• It is important to involve the whole team, family/carers and the child in all discussions from the outset, so that consequent management aims are realistic, relevant and achievable.


• Whilst both adults and children will attend the initial assessment with an element of anxiety, this tends to predominate in children and it can be harder to reason with them.


– Ensure that the environment and assessment are as non-threatening and friendly as possible.

– Assessment should be undertaken with the parent/carer in close proximity, often with the child on their lap.

– Clear explanations should be given before undertaking any testing procedures.


Subjective assessment



Birth history




• Health of mother and baby during pregnancy including any medication taken


• Gestational age of baby


• Labour and delivery process


• Postnatal problems or care needed.



Development




• Unusual childhood illnesses


• Developmental milestones: e.g. at what age did the infant first roll, sit or walk (Sheridan et al 2008)


• Information regarding school (as appropriate):



Family history




• Number, age and health of siblings


• Similar presentations within family.



Parent/carer concerns




• Take their concerns seriously, as their instincts are often accurate and may help focus your assessment.



Pain




• The manner in which a child expresses pain will depend on their age and may manifest in the following ways:


– Altered sleep patterns and feeding

– Distress on handling or movement of the affected area

– Continuous crying in the presence of severe pain

– Avoidance of moving the affected part or altered function, e.g. limping

• A child may only be able to give a vague description and localisation of pain


• Be aware of underplaying or exaggeration of symptoms in adolescents wanting to either participate in or avoid sports or other activities.


• Various pain assessment tools are available depending on the age and cognitive ability of the child, e.g. pain faces scale (Hicks et al 2001), paediatric pain profile (UCL, ICH, RCNI 2003).



Objective assessment



Baby




• The most rapid period of growth and development occurs in the first 18 months of life.


– By 2 years a child is already approximately half their adult height.

• A fastidious approach is vital as infants tend to be unable to indicate where problems are or to comply with assessment.


• Undress the whole child, irrespective of the referral, to avoid missing any orthopaedic problems or diagnostic clues.



Observation




• Overall size and proportion of child


• Count number, and check separation, of toes (indications of congenital abnormalities)


• Asymmetries (postural deformities are frequent in neonates and may occur as a result of intrauterine pressure or positioning)


• Any baby with asymmetries may have an increased risk of hip dysplasia


• In particular, note any:


– Plagiocephaly (flattening of the skull)

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Nov 5, 2016 | Posted by in MANUAL THERAPIST | Comments Off on Acute Paediatrics: Neuromuscular disorders

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