Paediatric clinic - cystic fibrosis
Dr Sarah Mayell, consultant in paediatric respiratory medicine, continues our series on uncommon but serious presentations with a case of cystic fibrosis
An 11-year-old girl presents to her GP with a long history of cough, which is productive of green sputum. She is breathless on exertion. On questioning, her parents report that the cough has been present since early infancy. When she was five years old, she was diagnosed with asthma but had a poor response to treatment. She has received several courses of antibiotics in primary care but these only give temporary improvement. She also has a poor appetite and frequent abdominal pain.
She is referred to the respiratory paediatric clinic. Her height and weight are both on the 25th centile. She has early clubbing, a wet cough and scattered bilateral crackles. Pulmonary function testing shows FEV1 40% and FVC 54% of predicted values. Systemic examination is otherwise unremarkable. Chest radiograph shows bilateral bronchial wall thickening and dilatation with multiple areas of atelectasis. A sweat test confirms cystic fibrosis. She is pancreatic sufficient with no fat on faecal microscopy and normal faecal elastase.
She has four siblings, and one is subsequently diagnosed with cystic fibrosis. Her other siblings have normal sweat tests and are offered genetic counselling on their potential carrier status.
Cystic fibrosis is one of the most common inherited diseases in the UK, and one in 25 of the UK population is a carrier.
Decreased chloride secretion results in increased viscosity of mucus and sticky secretions in the respiratory tract, gastro-intestinal tract and pancreas. The spectrum of disease severity varies widely – median predicted survival is currently about 41 years.1
Newborn screening for cystic fibrosis in the UK has been available since 2007. But this will not detect all cases because:
- older children and adults may not have been screened
- screening only detects 96% of cases
- screening may be declined.
Meconium ileus is a presenting feature in 10–15% of newborns with cystic fibrosis.
Without newborn screening, presenting features include faltering growth, recurrent respiratory tract infections, rectal prolapse, nasal polyps and infertility.
Screening protocols use measurement of immunoreactive trypsinogen and DNA analysis. Diagnosis is confirmed by a sweat test, measuring sweat chloride or conductance, in conjunction with genetic testing. The median age of diagnosis without screening is four months, but the range is from birth to over 60 years.2 Antenatal diagnosis is possible.
- Regular review by a multidisciplinary cystic fibrosis team, including a physiotherapist, dietician, physician, nurse specialist, psychologist and social worker.
- Prevention of cross-infection between patients.
- Management of pancreatic insufficiency with pancreatic enzyme and fat-soluble vitamin supplementation, managing the high energy demands of chronic infection and inflammation, and sodium chloride supplementation.
- Physiotherapy, including airway clearance and exercise.
- Antibiotics – prophylactic and in response to pulmonary exacerbations (nebulised, oral and intravenous).
- Seasonal influenza vaccination in addition to the routine immunisation schedule.
- Mucolytics – nebulised DNase and hypertonic saline.
- Management of complications, such as allergic bronchopulmonary aspergillosis, cystic fibrosis-related diabetes, cystic fibrosis-related liver disease, bone disease and infertility.
- Management of advanced disease with long-term oxygen therapy, non-invasive ventilation and possibly lung transplantation.
Dr Sarah Mayell is a consultant in paediatric respiratory medicine at Alder Hey Children’s Hospital, Liverpool
Alder Hey is one of Europe’s biggest children’s hospitals providing care for over 275,000 children and young people each year. Alder Hey has a broad range of hospital and community services for direct referral from primary care. It is the designated national centre for head and face surgery and a Centre of Excellence for children with cancer, spinal and brain disease. Alder Hey has been chosen to be a national centre for heart surgery, a respiratory ECMO surgery centre and one of just four specialist centres to provide surgery for drug-resistant epilepsy. More information can be found at alderhey.nhs.uk.
1 UK Cystic Fibrosis Registry. Cystic Fibrosis Trust annual data report 2010. December 14 2011.
2 McCormick J, Green MW, Mehta G et al. Demographics of the UK cystic fibrosis population: implications for neonatal screening. Eur J Hum Gen 2002; 10: 583–90
- Cystic Fibrosis Trust. cftrust.org.uk
- UK Newborn Screening Programme Centre. newbornbloodspot.screening.nhs.uk