Frequently Asked Questions

This chapter translates the questions most often raised in primary care and general paediatrics into clinical decisions.

In which child should I check creatine kinase?

In any boy with unexplained motor delay, toe walking, frequent falls or raised transaminases. Toe walking is a common complaint and is usually idiopathic, but creatine kinase should be checked before it is accepted as such.

Which test should I request first in a hypotonic infant?

First make the central-peripheral distinction. If a peripheral cause is suspected, check creatine kinase. In a hypotonic, areflexic infant with tongue fasciculations, SMN1 deletion analysis comes first and is urgent. If cardiomyopathy is present, add dried blood spot acid alpha-glucosidase for Pompe disease.

Should I request electromyography?

It is not required in a typical SMA or typical Duchenne presentation, where genetic testing is requested directly. It is valuable in suspected junction disorders, in distinguishing acquired neuropathy, in separating demyelinating from axonal neuropathy, and in uncertain presentations where genetic testing has been unrevealing.

Genetic testing was negative — what next?

First question whether the method was appropriate: repeat expansions and large deletions or duplications are not detected by standard sequencing. If the method was appropriate, widen the panel or move to exome sequencing. In undiagnosed cases, reanalysis of the data every few years is advisable because variant interpretation changes over time.

Which patients should I refer, and when?

• A hypotonic, areflexic infant — without delay.
• Loss of a previously acquired motor skill — without delay.
• Markedly raised creatine kinase.
• A Gowers manoeuvre, pseudohypertrophy, a waddling gait.
• Fatigable ptosis or diplopia.
• A positive newborn screen for SMA — within days.
• Unexplained recurrent apnoeic episodes.
• Rapidly progressive weakness — as an emergency.

What should be considered before anaesthesia?

Suxamethonium is not used; total intravenous anaesthesia is preferred over inhalational agents; respiratory and cardiac assessment is carried out beforehand; and stress dosing is planned for patients on corticosteroids. Every neuromuscular patient should be given a portable information card summarising the diagnosis, anaesthetic risks and what to do in an emergency.

Families ask about treatments still under investigation — how should I respond?

Explain clearly that licensed disease-modifying treatments and approaches still under investigation are separate categories. Delay to a licensed treatment or to a standard of care causes concrete loss, and this opportunity cost should be discussed. Explain the difference between participation in a registered clinical trial (ethics committee approval, predefined follow-up, data collection) and interventions outside a research protocol. Record that the discussion took place and what was explained. Follow-up continues whatever the family decides.

What should I record at follow-up visits?

At every visit: the functional scale (with date, scale name and assessor), weight and height, examination of contractures and spine, enquiry about respiratory symptoms, review of the cardiac surveillance schedule, drug adverse effects, and school and psychosocial status. Where possible, video of gait and rising from the floor; this is the most valuable record for comparison over time.