From a runny nose to intensive care - the many faces of bronchiolitis

Each year in the UK, around 20,000 babies and young children are admitted to hospital with severe bronchiolitis. Some develop life-threatening complications, yet there is no specific treatment. Researchers hope detailed studies of the disease process will reveal why these children become so desperately ill, a vital step in the strive towards improved treatment.

What's the problem and who does it affect?

Children with severe bronchiolitis need hospital care

The first symptoms of bronchiolitis seem harmless enough - the infection starts out as little more than a cough and cold. But, within just one or two days, some children become so desperately ill they must be rushed to hospital, struggling for breath.

Most are just babies, of less than six months old. They suffer distressing symptoms, such as, extreme difficulties breathing and feeding, fever, lethargy and a blue tinge to their skin.

There can be few more terrifying experiences for a parent than the sight of their tiny baby struggling for breath.

Current treatments can't target infection

There are no specific treatments that can help sick children in their battle against infection and no vaccine. So, doctors help as best they can by relieving symptoms -for example, they give intravenous fluids to counter dehydration and oxygen to help with breathing. Around 2 or 3 percent of hospitalised children have to go on a ventilator. 1

Parents face an anxious wait while the disease takes its course. The vast majority of children do get better, though many have a lingering cough and, sadly, some can even die, though this is rare.

What is the project trying to achieve?

Why do symptoms vary so much?

Bronchiolitis is caused by a viral infection, most commonly by a virus called respiratory syncytial virus (RSV). Nearly all children are infected with this virus before their second birthday.

For most children, infection causes only the mild symptoms of a cold. Other children go on to develop bronchiolitis - they get a fever, begin wheezing and their breathing becomes fast and shallow. A vulnerable minority of youngsters - more than 1 in 50 of all infants - develops more severe bronchiolitis and must be admitted to hospital. 2

No-one knows why some children become so severely ill, whereas others escape with mild symptoms. So these researchers aim to get a better understanding of the disease processes that lead to severe bronchiolitis. They will look in particular at the role of a certain type of white blood cell, called a neutrophil. They will study the cells' function and behaviour, and how this differs in children with and without bronchiolitis.

What are the researchers' credentials?

The research team is uniquely positioned to investigate the disease processes involved in RSV bronchiolitis. The Royal Liverpool Children's Hospital NHS Trust is the largest children's hospital in Western Europe. Each year, the hospital admits around 300 to 400 children with RSV bronchiolitis - more than any other centre in the UK. The Paediatric Intensive Care Unit cares for about 30-40 babies with severe RSV disease each winter.

Professor Smyth has led a programme of research into bronchiolitis at the Royal Liverpool Children's Hospital for over 10 years. The importance of her work is recognised internationally. Her team has made a number of important discoveries, which have led to exciting new insights into this disease.

Who stands to benefit from this research and how?

Striving for treatments that target the disease process

Researchers hope to reveal important information about the disease processes involved when viral infection leads to severe bronchiolitis. They hope to reveal why a vulnerable minority of children become so desperately ill they end up on a ventilator in intensive care, whereas others escape with only mild symptoms.

The researcher's ultimate goal is to use their findings to help develop new treatments for children with bronchiolitis, treatments that target the disease process rather than just alleviating symptoms. The 20,000 children who are hospitalised each year stand to benefit the most.

Wider benefits during epidemics

Even more children stand to benefit indirectly. During the winter months and early spring, when epidemics occur, large numbers of children can be admitted to hospital with bronchiolitis. This disrupts other work within hospitals - some operations have to be cancelled, for example. What's more, since the illness is highly infectious, there is also a risk of cross-infection to other very sick children in the hospital.

So, better treatment could help other children who are being treated in hospital as well as those with bronchiolitis.

Footnotes

1.Allport TD, Davies EG, Wells C, Sharland M. Ribavirin and bronchiolitis: variation in use in the UK. Arch Dis Child 1997;76:385.
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2. Simoes EA, Carbonell-Estrany X. Impact of severe disease caused by respiratory syncytial virus in children living in developed countries. Pediatr Infect Dis 2003 February; 22(2 Suppl):S13-S18.
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