Cystic fibrosis

Last reviewed: March 2019

Last updated: September 2018

Summary

Genetic multisystem disease associated with abnormalities in salt and water transport across epithelial surfaces.

Age of onset of symptoms is highly variable; implementation of newborn screening in some countries allows for early detection and treatment.

A sweat test is the most conclusive test for diagnosis. Genetic testing may be required in some cases.

Respiratory disease treatment includes mucus thinners, airway clearance, and antibiotics.

Gastrointestinal disease is treated with supplemental pancreatic enzymes, calories, and fat-soluble vitamins to support growth and nutrition.

Although severely life-shortening, in the past 50 years average survival has increased dramatically to almost 40 years of age.

A range of new drugs are either in development or already approved for use by patients. This includes drugs that restore proper function of the defective protein that causes cystic fibrosis, and drugs that have a direct effect on mucociliary clearance.

Definition

Cystic fibrosis (CF) is a severely life-shortening genetic disease resulting from abnormalities in the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel found in cells lining the lungs, intestines, pancreatic ducts, sweat glands, and reproductive organs. There are over 1500 known disease-causing mutations that interrupt various stages of CFTR synthesis and function. [1] The most common clinical manifestations are pancreatic dysfunction, resulting in calorie malabsorption; and lung disease, resulting from a cycle of mucus retention, infection, and inflammation.

History and exam

Key diagnostic factors

presence of risk factors
positive newborn screen
failure to pass meconium
failure to thrive
voracious appetite
wet-sounding cough
recurrent infection
chronic sinusitis
genital abnormalities in males
haemoptysis

Full details

Other diagnostic factors

malabsorptive stool with steatorrhoea
digital clubbing
gastro-oesophageal reflux
wheeze
increased anteroposterior (AP) diameter of the chest
hx of pancreatitis
hx of acute appendicitis
enlarged liver or spleen

Full details

Risk factors

FHx of CF
known carrier status of both parents
ethnicity

Full details

Diagnostic investigations

1st investigations to order

sweat test
immunoreactive trypsinogen (IRT) test (newborn screening)
genetic testing

Full details

Investigations to consider

sinus x-ray
deep throat swab

Full details

Treatment algorithm

ACUTE

neonates with meconium ileus/partial distal intestinal obstruction

complete intestinal obstruction or peritonitis

acute respiratory infection

asthma exacerbation without infection

ONGOING

respiratory disease

GI disease

Contributors

Authors VIEW ALL 

Samuel B. Goldfarb, MD

Associate Professor of Clinical Pediatrics

The Children's Hospital of Philadelphia

Perelman School of Medicine at the University of Pennsylvania

Philadelphia

Disclosures

SBG declares that he has no competing interests.

Maureen Banfe Josephson, DO

Assistant Professor of Pediatrics

The Children's Hospital of Philadelphia

Perelman School of Medicine at the University of Pennsylvania

Philadelphia

Disclosures

MBJ declares that she has no competing interests.

Acknowledgements

Dr Samuel B. Goldfarb and Dr Maureen Banfe Josephson would like to gratefully acknowledge Dr James L. Kreindler, a previous contributor to this monograph. JLK declares that he has no competing interests.

Peer reviewers VIEW ALL 

Sangeeta M. Bhorade, MD

Associate Professor of Medicine

Medical Director

Lung Transplant Program

University of Chicago Hospitals

Chicago

Disclosures

SMB declares that she has no competing interests.

Alan Smyth, MA, MBBS, MRCP, MD, FRCPCH

Associate Professor & Reader in Child Health

Division of Child Health

University of Nottingham

Queens Medical Centre

Nottingham

Disclosures

AS declares that he has no competing interests.

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Cystic fibrosis

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

neonates with meconium ileus/partial distal intestinal obstruction

complete intestinal obstruction or peritonitis

acute respiratory infection

asthma exacerbation without infection

respiratory disease

GI disease

Contributors

Authors VIEW ALL 

Samuel B. Goldfarb, MD

Disclosures

Maureen Banfe Josephson, DO

Disclosures

Acknowledgements

Peer reviewers VIEW ALL 

Sangeeta M. Bhorade, MD

Disclosures

Alan Smyth, MA, MBBS, MRCP, MD, FRCPCH

Disclosures

Differentials

Guidelines

Patient leaflets

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