Bronchiolitis Flashcards
Bronchiolitis
acute LRTI
most common age 2-6 months
combination of increased mucus, cell debris and oedema produces narrowing and obstruction of small airways
clinical diagnosis based on: breathing difficulties cough decreased feeding irritability apnoeas in the very young wheeze or crepitations on auscultation
causes
usually a viral infection of the bronchioles
respiratory syncytial virus (RSV): is the most common (50-90%)
human metapneumovirus (hMPV): causes a similar spectrum of illness to RSV and is thought to be the 2nd most common cause
adenovirus: occasionally causes a similar syndrome with a more virulent course
epidemiology
peak for RSV infections: november-march
prevalence may be higher in urban areas
60% affected by 1st birthday, 80% by their 2nd
increasing hospital admission over the last 10 years (?increased survival rates for pre-term babies)
environmental and social risk factors
older siblings
nursery attendance
passive smoke (particularly maternal)
overcrowding
breast feeding is considered protective
risk factors for severe disease and/or complications
prematurity (<37 weeks) low birth weight age <12 weeks chronic lung disease eg CF, bronchopulmonary dysplasia CHD neuro disease with hypotonia and pharyngeal dis-coordination epilepsy T1DM immuno-compromise congenital defects of the airways down's syndrome
Sx of bronchiolitis
early Sx match those of a viral URTI:
mild rhinorrhoea, cough, fever (>39 is unusual and may have another cause)
40% will progress to LRTI and Sx will include:
paroxysmal cough and dyspnoea within 1-2 days, wheeze, cyanosis, vomiting, irritability, poor feeding
apnoeas may occur, particularly in young infants
signs
tachypnoea tachycardia fever cyanosis signs of dehydration mild conjunctivitis pharyngitis increased work of breathing widespread inspiratory crackles liver and spleen may be palpable due to hyperinflation of the lungs signs of sepsis are uncommon
DDx
asthma viral induced wheeze bronchitis pulmonary oedema foreign body pneumonia oesophageal reflux aspiration CF Kartagener's (structural and functional defects of cilia)
management
for the most part, self-limiting
usually lasts 7-10 days, 50% asymptomatic by 2 weeks
