Synopsis
Recognise cystic fibrosis and non-CF bronchiectasis from chronic wet cough, growth and infection patterns, confirm CF with specialist sweat and genetic testing and bronchiectasis with thin-section CT, investigate treatable causes, and coordinate airway clearance, culture-directed antibiotics, nutrition and CFTR-modulator care.
- Cystic fibrosis is an autosomal-recessive CFTR disorder causing dehydrated secretions in lung, pancreas, gut, biliary and reproductive tracts. Bronchiectasis is irreversible bronchial dilatation from repeated infection and inflammation and has many causes.
- Think CF with chronic wet cough, recurrent infection, poor weight gain, steatorrhoea, meconium ileus, rectal prolapse, salt-loss episodes, nasal polyps or affected sibling.
- Newborn screening uses immunoreactive trypsin with mutation testing, but it is screening rather than diagnosis. Symptomatic children still require a specialist CF pathway.
- Reference diagnostic test: sweat chloride using pilocarpine iontophoresis in an accredited service. At least 60 mmol/L supports CF, 30–59 is intermediate and below 30 makes CF less likely; interpret with phenotype and CFTR genotype.
- Confirm bronchiectasis with specialist thin-section chest CT showing airway dilatation relative to accompanying artery, failure to taper and peripheral visibility. Do not use chest radiography to exclude it.
- Investigate non-CF bronchiectasis for immune deficiency, primary ciliary dyskinesia, aspiration, airway foreign body, post-infectious damage and structural disease; test CF when phenotype or cause remains compatible.
- First-line daily care is individually taught airway-clearance physiotherapy plus exercise. Increase frequency during exacerbations and review technique as the child grows.
- Obtain sputum or cough-swab culture at routine review and before antibiotics when possible. Treat exacerbations promptly with culture-directed oral or intravenous antibiotics, commonly for about 14 days in bronchiectasis, with specialist adjustment.
- New Pseudomonas in CF usually triggers an eradication protocol; chronic infection may require inhaled antibiotic. Regimens are organism-, age- and centre-specific and must use the CF team's current protocol.
- CF mucolytic treatment may include dornase alfa first, hypertonic saline or mannitol according to age, response and NICE guidance; bronchodilator is used for demonstrable benefit or before hypertonic therapy.
- Pancreatic-insufficient CF requires pancreatic enzyme replacement with every fat- or protein-containing meal and snack, high-energy nutrition, salt advice and fat-soluble vitamins guided by a CF dietitian.
- CFTR modulators are disease-modifying and mutation/age specific. The CF centre checks genotype eligibility, interactions, liver tests, eye monitoring where applicable, adherence and pregnancy implications.
Key red flags
Chronic daily wet cough is pathological; clubbing, crackles, poor growth or recurrent pneumonia requires respiratory investigation.
Meconium ileus, prolonged neonatal jaundice, salty-tasting skin, rectal prolapse or pancreatic malabsorption suggests cystic fibrosis even after newborn screening.
Haemoptysis, pleuritic pain, sudden breathlessness or unilateral absent air entry suggests major bleeding or pneumothorax.
Increasing cough, sputum, breathlessness, fatigue, reduced appetite, weight loss or lung-function fall signals a pulmonary exacerbation.
Persistent Pseudomonas, MRSA, non-tuberculous mycobacteria or repeated intravenous antibiotics requires specialist infection-control and eradication planning.
A negative newborn CF screen does not exclude disease in a symptomatic child; refer for diagnostic testing.
Investigation priorities
Demonstrate CFTR dysfunction after positive screening or compatible symptoms.
Management branches
Multisystem CF features or an affected sibling is present.
- Refer to a specialist CF centre and obtain accredited sweat testing.
- Use CFTR genetics and functional interpretation when sweat is intermediate or discordant.
- Begin nutrition and infection assessment without waiting for advanced lung disease.