PassFinals
Respiratory

Cystic Fibrosis

Cystic fibrosis is an autosomal-recessive CFTR disorder in which abnormal epithelial salt and water transport produces dehydrated secretions, chronic suppurative lung disease, pancreatic insufficiency and multisystem complications; modern UK care combines specialist prevention, infection control, nutrition and genotype-directed CFTR modulation.

In a nutshell

Cystic fibrosis is an autosomal-recessive CFTR disorder causing dehydrated secretions, chronic suppurative lung disease, pancreatic insufficiency and salty sweat. Diagnose through newborn-screen follow-up or clinical suspicion with specialist sweat/genetic testing. Core care is multidisciplinary airway clearance, infection surveillance and treatment, nutrition and complication screening, with genotype-directed CFTR modulators for eligible patients.

Classic presentation

A child with a positive newborn screen, recurrent chest symptoms, greasy stools and poor growth has a raised sweat chloride and is referred to a specialist CF centre for confirmation and ongoing multidisciplinary care.

Key points

  • CFTR dysfunction dehydrates airway and pancreatic secretions and reduces chloride reabsorption in sweat ducts.
  • A newborn screen is a risk screen, not the diagnosis; confirm through specialist sweat and genetic assessment.
  • Raised sweat chloride, a suggestive phenotype and/or disease-causing CFTR variants are interpreted together by the CF team.
  • Airway clearance, infection surveillance, nutrition and pancreatic enzyme replacement remain core treatments even when a modulator is prescribed.
  • New Pseudomonas requires prompt specialist eradication treatment; chronic infection and exacerbations need culture-led CF protocols.
  • NICE currently includes IVA–TEZ–ELX options from age 2 and VNZ–TEZ–DIVA options from age 6 for eligible genotypes and NHS arrangements.

First-line investigation

After a positive screen or suggestive phenotype, refer to a specialist CF centre for sweat chloride, CFTR genetic testing and baseline respiratory, nutritional and microbiological assessment.

Management

Refer to the specialist CF pathway

  • Refer suspected, screen-positive, equivocal or genetically suggestive cases to a specialist CF centre and apply cross-infection precautions.1,2

Clear mucus and monitor infection

  • Use a physiotherapist-led airway-clearance plan, regular exercise and culture-guided infection surveillance; new Pseudomonas needs prompt specialist eradication treatment.1,2,7

Protect nutrition and pancreatic function

  • Use pancreatic enzyme replacement when indicated, specialist dietetic support, fat-soluble vitamins and CF-related-diabetes screening; check current SPS and BNF supply and prescribing information.1,9,8

Assess CFTR modulator eligibility

  • Use current NICE technology-appraisal criteria, genotype, age, interactions, monitoring and NHS commissioning arrangements to select a suitable CFTR modulator through the specialist team.5,6,4,8

Treat complications and advanced lung disease

  • Escalate haemoptysis, pneumothorax, distal intestinal obstruction, respiratory failure, diabetes, liver disease, pregnancy or fertility concerns to the relevant specialist service and refer early for transplant assessment when appropriate.1,2

Review the whole-person trajectory

  • Review symptoms, weight, lung function, microbiology, treatment burden, adherence, mental health and extrapulmonary complications at routine and annual CF-centre assessment.1,2

Exam traps

  • A positive newborn screen is not diagnostic; confirm through the specialist sweat/genetic pathway.
  • The sweat is salty because CFTR fails to reabsorb chloride in the sweat duct, not because of dehydration alone.
  • New Pseudomonas is a management turning point requiring eradication, not routine watchful waiting.
  • CF-related pancreatic insufficiency requires enzymes with food and nutritional monitoring.
  • CFTR modulators are genotype- and age-dependent and do not replace airway clearance or infection surveillance.
  • New MRSA, Burkholderia, non-tuberculous mycobacteria, haemoptysis or rapid lung decline needs specialist escalation.

Illustrations

Bronchiectasis in cystic fibrosis on high-resolution CTPaired axial high-resolution chest CT images showing bilateral upper-lobe-predominant bronchiectasis, bronchial-wall thickening and mucus plugging in cystic fibrosis.Opitz M et al., Tomography 2025, CC-BY-4.0 · CC-BY-4.0

Key sources

  1. NICE NG78, Cystic fibrosis: diagnosis and management (Current NICE diagnosis, specialist service, monitoring, airway clearance, infection, nutrition, complication and cross-infection pathway; published 25 October 2017 and last reviewed 19 March 2026)Published 25 Oct 2017
  2. Cystic Fibrosis Trust, Standards for the clinical care of children and adults with cystic fibrosis in the UK (Current UK consensus standards for specialist multidisciplinary care, monitoring, airway clearance, infection prevention, nutrition, medicines, home care and transition; published August 2024)
  3. NHS England, Cystic fibrosis: screening laboratory handbook (Current UK newborn CF screening laboratory protocol covering immunoreactive trypsinogen, CFTR genetic analysis, referral and programme quality; updated 5 January 2026)Published 1 Feb 2014
  4. NHS England, Arrangements for access to CFTR modulators (Current NHS England commissioning statement for licensed and off-label CFTR modulator access and diagnostic-support requirements; published 15 July 2025)Published 15 Jul 2025
  5. NICE TA988, Ivacaftor–tezacaftor–elexacaftor, tezacaftor–ivacaftor and lumacaftor–ivacaftor for treating cystic fibrosis (Current NHS technology appraisal for genotype- and age-appropriate CFTR modulator options, including IVA–TEZ–ELX from age 2 within marketing authorisation; published 24 July 2024)Published 24 Jul 2024
  6. NICE TA1085, Vanzacaftor–tezacaftor–deutivacaftor for cystic fibrosis (Current NHS technology appraisal for VNZ–TEZ–DIVA in eligible people aged 6 and over with at least one F508del mutation, including least-cost suitable-option and commercial-arrangement requirements; published 30 July 2025)Published 30 Jul 2025
  7. NICE QS168, Cystic fibrosis (Current NICE quality standard on specialist treatment of chronic lung infection and inhaled antibiotic pathways)Published 17 May 2018
  8. BNF, cystic-fibrosis medicines and pancreatic enzyme replacement (Current UK prescribing, contraindication, interaction, monitoring and patient-specific dosing reference; access may require subscription or institutional login)
  9. Specialist Pharmacy Service, Pancreatic enzyme replacement therapy supply and prescribing information (UK medicines-supply and prescribing support referenced by NICE during pancreatic enzyme supply disruption; use with the CF team and current BNF)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.