Bronchiolitis in babies: RSV, nebulisers and when to worry

Bronchiolitis is a chest infection of the tiny airways in babies, usually caused by a virus called RSV. Most babies recover at home with careful feeding and a clear nose. Nebulisers, steroids and antibiotics do not help the usual case. What matters is knowing which signs mean your baby needs hospital care.

What is bronchiolitis in babies?

Bronchiolitis is a viral infection of the smallest air tubes in the lungs, the bronchioles. It affects children under 2 years, most often in the first year, and is commonest between 3 and 6 months of age.¹

The virus damages the lining of these tubes. Mucus, dead cells and swelling block airways that are only a millimetre or two wide in a young baby. Air gets trapped in some parts of the lung. That is why you hear crackles or a wheeze, and why the baby breathes fast.

What causes bronchiolitis? Is it RSV?

It is caused by viruses, most often respiratory syncytial virus (RSV).² Other cold viruses can cause the same illness.

RSV spreads through coughs, sneezes and hands. An older child or adult with RSV may have only a cold. A young baby catches the same virus and gets a chest infection, because the airways are so small. In Kolkata Dr Dutta sees bronchiolitis rise through the monsoon and the months after, but cases turn up all year.

What are the symptoms of bronchiolitis?

It usually starts like a cold, with a runny nose for 1 to 3 days, followed by a persistent cough and fast or laboured breathing.¹ Many babies also wheeze or have crackles that a doctor hears with a stethoscope.¹

Other things you may notice:

• Mild fever.
• Feeding less, because the baby is busy breathing.
• The skin between or below the ribs sucking in with each breath (chest recession).

Very young babies, especially those under 6 weeks, may have pauses in breathing (apnoea) without many other signs.¹ This is one reason Dr Dutta takes any cough in a newborn seriously.

How long does bronchiolitis last?

Symptoms usually get worse for the first few days and peak between day 3 and day 5.¹ Then they slowly settle.

The cough lasts much longer. It clears within 3 weeks in 90 percent of babies.¹ So a baby who looks worse on day 4 despite medicines is usually following the normal course, not failing treatment. A cough that lingers for a fortnight is also expected.

Is bronchiolitis the same as pneumonia or asthma?

No. Bronchiolitis is a viral illness of the small airways. Pneumonia is an infection deeper in the lung, and doctors think of it when a child has high fever over 39 degrees C or crackles in one fixed spot.¹

Asthma is a longer term tendency to wheeze. In an older baby who wheezes again and again with colds, doctors may consider viral-induced wheeze or early asthma rather than bronchiolitis.¹ The treatment for those is different, which is why the diagnosis matters.

Does a nebuliser help bronchiolitis?

Usually not. Salbutamol nebulisation does not improve oxygen levels, does not prevent hospital admission and does not shorten the illness in bronchiolitis.³

Salbutamol relaxes tight airway muscle, which is the problem in asthma. In bronchiolitis, the airways are blocked by mucus and swelling instead. A Cochrane review also found side effects such as a racing heart and tremor.³ NICE in the UK advises against salbutamol, adrenaline and ipratropium nebulisers for bronchiolitis.¹

What Dr Dutta wants families to avoid is nebulising every few hours for days because it feels like doing something.

Will steroids help my baby's bronchiolitis?

No. Steroid syrups, injections or inhaled steroids do not reduce hospital admissions or shorten hospital stay in bronchiolitis.⁴

This was tested in 17 trials with about 2600 children.⁴ One large trial hinted that steroids plus adrenaline together might help a little, but the review called that result exploratory.⁴ NICE advises against steroids for bronchiolitis.¹

Does my baby need antibiotics for bronchiolitis?

Usually not. Bronchiolitis is a viral illness, and antibiotics are not recommended unless a doctor suspects a complication such as a bacterial pneumonia.²

Trials comparing antibiotics with placebo found no difference in length of hospital stay or days on oxygen.² NICE also says not to use antibiotics for bronchiolitis.¹ Unneeded antibiotics can cause diarrhoea and rashes, and they help resistant bacteria spread.

Does hypertonic saline nebulisation, steam or chest physiotherapy help?

Steam and chest physiotherapy do not help, and steam can burn. Hypertonic saline may help a little in hospital, but the evidence is weak.

A Cochrane review found that strong salt water (hypertonic saline) nebulisers might shorten hospital stay by under half a day, with low certainty evidence.⁵ NICE does not recommend it.¹ Chest physiotherapy using tapping and vibration made no difference in a separate Cochrane review, and forceful techniques could cause serious harm.⁶ Cough syrups have no role in babies.

How can I help my baby breathe better at home?

Keep the nose clear, keep the baby upright for feeds, and keep the air clean. These simple steps help more than most medicines.

• Put 2 to 3 drops of saline nasal drops in each nostril before feeds.
• If the nose is very blocked and feeding is hard, gently clear only the front of the nostrils with a bulb sucker. NICE suggests suction only when secretions cause breathing or feeding trouble, not routinely.¹
• Hold the baby fairly upright during and after feeds.
• Lay the baby on the back to sleep, as always.
• No smoking at home. Smoke makes bronchiolitis worse.¹ Keep mosquito coils, agarbatti and chulha smoke away too.
• Give paracetamol for fever only if your doctor advises and at the dose given.

How do I feed a baby with bronchiolitis?

Offer smaller feeds more often. A breathless baby tires quickly at the breast or bottle.

Keep breastfeeding. Breast milk is your baby's food and water at the same time. A baby who usually takes 8 feeds a day may need 12 shorter ones. Watch the nappies closely.

Poor feeding is one of the signs doctors watch most closely. NICE suggests a doctor's review if a baby takes only 50 to 75 percent of usual feeds, and urgent help if there has been no wet nappy for 12 hours.¹

Which babies get severe bronchiolitis?

Some babies are more likely to get very sick and need closer watching.¹

• Babies under 3 months old.
• Babies born premature, especially before 32 weeks.
• Babies with chronic lung disease or significant heart disease from birth.
• Babies with nerve and muscle conditions, or a weak immune system.

Doctors take these risk factors into account when deciding whether a baby needs hospital care.¹ If your baby is in one of these groups, Dr Dutta's advice is to see a doctor early in the illness.

When does a baby with bronchiolitis need to be admitted?

NICE advises admission for a baby who has pauses in breathing, takes only 50 to 75 percent of usual feeds, keeps struggling to breathe, or has low oxygen levels in room air.¹ Low means below 90 percent from 6 weeks of age, or below 92 percent under 6 weeks or in a baby with another health condition.¹

Before that stage, NICE says a doctor should consider sending a baby to hospital for breathing faster than 60 a minute, poor feeding, dehydration, or oxygen persistently below 92 percent.¹ Emergency care is needed straight away for any pause in breathing, grunting, marked chest recession, breathing faster than 70 a minute, or blue lips.¹ Count breaths for a full minute while your baby is calm or asleep. Doctors also weigh up how far you live from a hospital and how confident you feel caring for the baby.¹

What treatment will my baby get in hospital?

Hospital care is mainly support: oxygen if needed, help with feeding, and close watching while the airways heal.

For babies aged 6 weeks and over, NICE advises oxygen when the level stays below 90 percent, and below 92 percent for younger babies or those with other health problems.¹ A UK trial found a 90 percent target was as safe and effective as 94 percent.⁷ Babies who cannot feed get milk through a thin tube into the stomach, or fluids into a vein.¹ Some need high-flow oxygen or CPAP (gentle air pressure through the nose). It sounds simple, but it works.

Is there an injection to protect my baby from RSV?

Yes. Antibody injections can protect babies through an RSV season. Palivizumab is given monthly, mainly to high-risk babies, and it reduces RSV hospital admissions.⁸

Nirsevimab is a newer antibody given as a single injection before the RSV season. In a large trial in healthy babies born at 35 weeks or later, it cut RSV chest infections needing medical care by about 75 percent.⁹ Availability and cost in India keep changing, so ask your paediatrician what is available now and whether your baby qualifies.

Is there an RSV vaccine in pregnancy?

Yes, one RSV vaccine is given to mothers late in pregnancy so that antibodies pass to the baby. In a large trial, it reduced severe RSV chest illness needing medical care in the first 90 days of life by about 82 percent.¹⁰

Protection was lower, about 69 percent, by 6 months.¹⁰ No safety concerns were found in mothers or babies in that trial.¹⁰ Whether it is offered in India, and at what cost, is changing. Ask your obstetrician during pregnancy.

Is bronchiolitis contagious, and how do I protect a newborn?

Yes. The viruses that cause it spread easily through coughs, sneezes and hands, so prevention at home matters.

• Wash hands before holding the baby, especially visitors and older siblings.
• Ask anyone with a cold not to kiss the baby's face. It is fine to say this to relatives.
• Keep a young baby away from crowds during the peak season where you can.
• Keep breastfeeding.
• Keep the home smoke-free.¹

When should I take my baby with bronchiolitis to hospital?

Go to an emergency department straight away if your baby has any of these:¹

• Pauses in breathing, or lips or face that look blue or grey.
• Grunting, flaring nostrils, or deep sucking in of the skin between or below the ribs.
• Breathing faster than 70 times a minute.
• Very sleepy, or waking only with a lot of effort.

Go to hospital now, too, if your baby is under 3 months and has a fever of 38 degrees C or more. NICE counts this as high risk and advises a face-to-face check within 2 hours.¹¹

See a doctor the same day if your baby breathes faster than 60 a minute, takes only 50 to 75 percent of usual feeds, or has had no wet nappy for 12 hours.¹ Do the same if your baby was born premature or has a heart or lung condition. And if your baby simply looks worse to you, come in. Parents often notice the change first.