Breathing

Respiratory (breathing) problems are the number one cause of illness for people with SMA, and the most common cause of death in children with Type 1 and Type 2. Respiratory care is essential both to survival and to quality of life.

Why is breathing affected?

In SMA, the intercostal muscles that support the chest wall are weak, leaving the diaphragm to do most of the work of breathing. This can lead to:

• an under-developed chest and lungs
• a weak cough, so mucus and secretions are hard to clear
• frequent chest infections
• shallow breathing during sleep

At night, when lying down, the contents of the tummy push against the diaphragm, making deep breaths harder. Oxygen levels may fall and carbon dioxide build up. Morning headaches, daytime sleepiness and poor concentration can be signs of this.

Assessment

A pulmonologist familiar with SMA should evaluate breathing and the ability to cough soon after diagnosis, and regularly afterwards. Children over about five years can do lung function tests — blowing into a tube that measures lung capacity. A sleep study may be suggested to check breathing at night.

Keeping the airways clear

Chest physiotherapy helps to clear secretions. It often uses changes of position, so that gravity drains mucus from each part of the lungs (postural drainage). It can usually be done at home after training from a therapist.

A cough-assist machine (mechanical insufflation–exsufflation) helps people who cannot cough strongly enough to clear their secretions. Suction may also be needed.

Breathing support

BiPAP (bi-level positive airway pressure) is a non-invasive ventilator, worn with a mask, that gives extra breaths of air. It lets the breathing muscles rest, often overnight, and is recommended depending on disease severity.

A pulse oximeter — a small clip on the finger — measures oxygen levels at home. Know your child’s usual oxygen saturation, and ask your doctor which readings should prompt action. Use oxygen only as your doctor advises.

Prevention

• Keep routine immunisations up to date, including the yearly flu vaccine and pneumococcal vaccine.
• Avoid contact with people who have coughs and colds; wash hands often.
• Agree a care plan for illness with your medical team: what to do at home at the first sign of a cold, and when to go to hospital.

When to get urgent help

Go to hospital — and tell them the person has SMA — if there is:

• fast or difficult breathing, or the ribs pulling in with each breath
• blue or grey lips, or low oxygen readings
• unusual sleepiness, confusion or difficulty waking
• inability to clear secretions despite airway clearance

Antibiotics, nebulisation and sometimes hospital care may be needed. Our COVID-19 guidelines include detailed home-care and hospital-admission protocols developed by Indian specialists.