Bronchiolitis Flashcards
What is the epidemiology of bronchiolitis?
Most common in babies (3-6m) and children <2yrs – about 1/3 children will be affected in their first year of life
Increases with winter – Oct-March
Can be re-infected twice within the same season
What is the aetiology of bronchiolitis?
Human respiratory syncytial virus (HRSV) (72% of cases)
By 2yrs, almost all will have had HRSV and ½ will have had bronchiolitis
It can survive on a surface for up to 24hrs
Human rhinovirus (26% of cases)
Both spread though coughing/sneezing
What are some risk factors for bronchiolitis?
Chronic lung disease Congenital heart disease Under 3m Prematurity (esp under 32wks) Neuromuscular disorders Immunodeficiency Smokers at home
What is the pathophysiology of bronchiolitis?
LRTI - Inflammation of bronchioles secondary to viral infection – infants more susceptible due to immaturity of lung development
Is a descending infection so may start with coryzal symptoms
What are some symptoms and signs of bronchiolitis?
CAPITALS = CONSIDER ADMISSION
Fever – usually low grade, IF PERSISTENT AT >38+
Wheeze
INCREASED WORK OF BREATHING (WOB) • Subcostal recession • Intercostal recession • Suprasternal recession/tracheal tug • Head bobbing (severe resp. distress) • Grunting (severe resp. distress) • Nasal flaring (severe resp. distress)
INCREASED RR (>70/min)
Cough – dry and persistent – better within 3wks
Coryza
Dehydration
• Dipped fontanelle
• Dry mouth/skin
• Reduced urine output
Difficulty feeding – typically after 3-5 days of illness; IF THEY HAVE TAKEN HALF USUAL AMOUNTS IN LAST 2-3 FEEDS
BRIEF APNOEAS
IRRITABILITY OR DROWSINESS
CYANOSIS
How do you diagnose bronchiolitis?
Usually clinical
As the babies you see in hospital will likely be the worse ones – full septic screen may be indicated
General obs – sats, RR, HR, BP, urine
Admit when
i) Sats <92% on air
Nasal swabs + viral P Bloods – WCC, neutrophils, CRP
No routine bloods + ABG; no CXR (uncless possible ICU) (Can mimic pneumonia and lead to unnecessary Abx)
What is a common differential?
Viral-induced wheeze OR early onset asthma:
If in older infants/young children (these conditions are unusual in children under age 1)
Things to check: Persistent wheeze without crackles,
Recurrent episodic wheeze, interval symptoms, exercise symptoms, diurnal variation, other triggers, Personal/FHx of atopy (hay fever etc)
How do you manage bronchiolitis?
Usually supportive:
Ensure adequate fluids
Paracetamol/ibuprofen only if child is distressed, not as a primary measure to reduce temperature
How do you manage bronchiolitis in hospital?
2-3% of cases will need hospital admission - more common in premature babies or those born with heart/lung conditions
Fluids, oxygen, NG feeding – all considered depending on severity of the infection
i) Give O2 if sats persistently <92% on air (O2 sats will usually drop at night too)
ii) If appear exhausted, are recurrently apnoeic or are failing to maintain sats on oxygen then consider ICU +/- CPAP
Possible need for Abx if blood cultures or urine dip come back positive (concomitant bacterial infection) - Infants are at a greater risk of contracting further bugs – pneumonia - because of their inflamed airways
What is the prognosis for bronchiolitis?
Infection with HSV lasts c. 2wks and will pass without the need for treatment – home treatment, as you would for a cold can be fine
Child can remain infection for up to 3wks – even after symptoms have cleared
Repeated infant bronchiolitis may predispose individuals to developing asthma later in childhood or onwards
How do you reduce the risk of developing bronchiolitis?
Breastfeed more (<2m is an increased risk)
Keep surfaces clean
Keep infected children at home until symptoms improve
Keep newborns away from people with colds/flu
Keep newborns away from sources of smoke/stop smoking
When do you discharge someone with bronchiolitis?
Discharge when
Clinically stable
Taking adequate oral fluids
Maintained O2 sats in air >92% over 4hrs, including a period of sleep
Also consider social setting – ability of parent to spot red flags, quality of supportive treatment, smoking at home
Can be given open access to the ward for 48hrs if deterioration is possible
What is bronchiolitis obliterans and how is it investigated and managed?
RSV is a possible cause (also influenza, HIV, CMV, stevens-johnson syndrome, complications of prematurity, JIA, transplant rejection and toxin exposure etc.)
Inflammation + scarring of airways – severe SOB, wheeze and dry cough with poor FEV1
2-8wks post exposure to causative agent
Dx by CT, PFT, lung biopsy
Irreversible – sometimes requiring lung transplant; managed with corticosteroids, immunosuppressants
What is palivizumab and what is it used for?
Monoclonal antibody
Specific to RSV - targets fusion protein so inhibiting its entry to cells
Only available to RSV+ infants with bronchiolitis who are:
Currently under 9m, ex-prem’s with chronic lung disease/bronchopulmonary dysplasia and who required supplemental O2 for 28+ days postpartum OR
Currently under 6m, ex-prem’s with acyanotic heart disease
Also considered for: under 2yrs with severe combined immunodeficiency syndrome, under 1yr who require long term ventilation, between 1-2yrs with long term ventilation + cardiac disease or pulmonary HTN
Given once monthly IM throughout RSV season - Oct/March
