A CHESTY INFANT

This baby has the characteristic clinical features of acute bronchiolitis – a seasonal viral illness occurring from early autumn to spring, principally affecting infants. The commonest causative organism is respiratory syncytial virus (RSV), which is responsible for about 80 per cent of infections. In hospital, a nasopharyngeal aspirate (NPA) may be sent for viral immunofluorescence, polymerase chain reaction (PCR) or culture. This is largely for infection control and epidemiology and does not affect acute management. Around 2–3 per cent of all infants are admitted each year with RSV-positive bronchiolitis but many more are managed at home. Prevention is possible with monoclonal RSV immunoglobulin (Palivizumab) but this is reserved for high-risk infants, e.g. oxygen-dependent survivors of prematurity, as it is extremely expensive. There is no immunization.

Indications for hospital referral

• Apnoeic episodes (commonest in babies 2 months and may be the presenting feature)

• Intake 50 per cent of normal in preceding 24 hours

• Cyanosis

• Severe respiratory distress – grunting, nasal flaring, severe recession, respiratory rate 70/min

• Congenital heart disease, pre-existing lung disease or immunodeficiency • Significant hypotonia, e.g. trisomy 21 – less likely to cope with respiratory compromise

• Survivor of extreme prematurity

• Social factors

Babies usually deteriorate over the first 48–72 hours. Hence there is a low threshold for admitting any baby 2 months of age on day 1–2 of their illness as they may deteriorate and become exhausted and apnoeic. Management is supportive. Investigations are rarely indicated apart from an NPA. A chest X-ray is only needed if the clinical course is unusual and often leads to unnecessary antibiotic prescriptions. Blood tests are only required if there is diagnostic uncertainty, e.g. if the infant has a temperature 39C and a superadded bacterial respiratory infection is suspected. Oxygen saturations should be kept at 92 per cent and the infant should be nasogastrically fed if they cannot maintain 50 per cent of normal intake. Intravenous fluids are used in severe cases. All fluids are restricted to two-thirds of maintenance. Nasal and oral suction is helpful. There is no evidence that bronchodilators, oral or inhaled steroids modify the clinical course or any important outcomes such as the need for ventilation or the length of stay. A capillary blood gas should be checked if the infant is deteriorating. Every season a small proportion of infants need high-dependency or intensive care – most respond well to continuous positive airways pressure (CPAP), avoiding the need for intubation. Babies are discharged when they are well enough to continue recovering at home but many continue to cough and wheeze for weeks and get similar symptoms with subsequent upper respiratory tract infections. Response to conventional asthma treatme variable. Leukotriene antagonists may have a role. Exposure to tobacco smoke must be avoided.

KEY POINTS

• Bronchiolitis is a clinical diagnosis.

• Numerous well-conducted studies have shown no benefit from any drug intervention in the acute phase or in the prevention of long-term sequelae.

• Monoclonal RSV immunoglobulin (Palivizumab) may be given for prevention to highrisk infants, but the costs of widespread