Cystic Fibrosis

Last Updated: September 21, 2023

Cystic fibrosis (CF) is an inherited condition characterized by thick and sticky mucus that clogs the lungs and leads to breathing problems and lung infections. Cystic fibrosis can affect the lungs, pancreas, liver, intestines, sinuses, and sex organs.

Cystic Fibrosis falls under theLungs & Breathingcategory.

What is cystic fibrosis?

A hallmark of cystic fibrosis is especially thick mucus that is difficult to clear from the lungs and other organ systems, caused by a mutation in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. Mucus is one of the body’s primary forms of defense against pathogens, trapping them as close to entry points (e.g., nose or throat) as possible to more readily clear them out before they can move to vital organs and cause infection. When the body can’t effectively clear mucus that has trapped pathogens, the pathogens can’t be expelled, leaving the entire system susceptible to infection. Cystic fibrosis is a progressive condition that usually shortens lifespan. A lot of time and energy (both on the part of those with CF and their caregivers) is often required to manage the complexities of treating cystic fibrosis.[1]

What are the main signs and symptoms of cystic fibrosis?

The lungs and airway are most frequently affected by cystic fibrosis, but the pancreas, the bowels, and the organs of the reproductive system may also be affected. Although the most prominent issue in CF, and the most likely cause of death due to CF, is lung disease, approximately 96% of individuals with cystic fibrosis also experience manifestations of the disease outside the lungs.[2]

The clinical signs and symptoms of cystic fibrosis include: [3][4]

  • Recurrent respiratory infections with a chronic cough containing mucus
  • Difficulty breathing
  • Chronic sinus or respiratory infections
  • Nasal polyps
  • Cyanosis (blue tint to skin due to lack of oxygen)
  • Finger clubbing
  • Sodium loss
  • Signs of malabsorption or intestinal obstruction
  • Absence of the vas deferens
How is cystic fibrosis diagnosed?

Early detection of the signs and symptoms of cystic fibrosis can be pivotal, since this affords valuable time to manage and mitigate future damage caused by the condition’s progression. Although cystic fibrosis can present at any point in the lifespan, it is commonly identified early in life. Clinical manifestations of cystic fibrosis may be confirmed by a sweat test revealing a high concentration (>60 mEq/L) of sweat chloride.[3][4] Sweat electrolyte levels are raised in the presence of cystic fibrosis, since the condition raises concentrations of sodium and chloride.[2]

Cystic fibrosis can be detected as early as gestation: families that may be genetically predisposed to the condition can undergo amniocentesis (pre-birth genetic testing). After delivery, the presence of bowel obstructions or a positive test on the Guthrie blood spot test (which tests for increased pancreatic immune activity) can both indicate that a newborn may have cystic fibrosis. In infancy and early childhood, recurring respiratory distress with cough, wheezing, and/or pneumonia plus a failure to thrive (due to pancreatic insufficiency, present in 85-90% of cystic fibrosis cases) is another set of clinical warning signs.[2] Through childhood and even adulthood, continuing respiratory symptoms, nasal polyps, sinusitis, and congenital absence of the vas deferens (in males) can also signal the presence of cystic fibrosis.[3][2]

Other tests that might be used in diagnosis include: nasal potential difference testing (with results in alignment with cystic fibrosis) and genetic testing for the presence of pathogenic CFTR variants. Gut malabsorption can indicate that pancreatic function is suffering due to cystic fibrosis; this is tested by measuring fecal elastase. Low levels of fecal elastase suggest pancreatic insufficiency and, likely, malabsorption.[4]

What are some of the main medical treatments for cystic fibrosis?

Once a diagnosis of cystic fibrosis has been confirmed, a primary goal is mitigating future damage, since inflammation and irreversible damage may have already begun. The most important goal is to keep the airway clear, followed by preventing infection. Additionally, maintaining nutritional sufficiency is important since CF’s impact on the pancreas can lead to malabsorption, exacerbating other symptoms for the condition.[2]

Management approaches to CF often depend on the stage of the condition and the time of diagnosis. In the earlier stages, airway clearance techniques (e.g., physiotherapy; mucolytics such as dornase alfa, inhaled mannitol, and hypertonic saline) along with preventative antibiotics and influenza vaccination are often recommended to support lung health.[5][6][7] In the intermediate stages of cystic fibrosis progression, reducing the infection load (through antibiotics and antifungals) and inflammation (via ibuprofen, corticosteroids, etc.) can serve to mitigate the damage done by infection. In the end stages of CF, drainage and even lung and/or heart transplant may be warranted.[8]

There are therapies under exploration focused on correcting the mutations of the CFTR gene. Some of these gene therapies carry mixed results and side effects, though, so careful consideration of this approach, with the support of a trained medical specialist, is imperative. Adjunctive approaches, such as physiotherapy, dietary modifications, insulin, or targeted nutrient/enzyme supplementation, may still be called for with genetic therapies.[4]

Have any supplements been studied for cystic fibrosis?

Because of CF’s multi-system impact on inflammation, lung, and digestive function, a number of supplements have been examined with regards to cystic fibrosis. Some of the longer-studied supplements (fat-soluble vitamins and pancreatic enzymes) are becoming part of routine care.[2] Though pancreatic enzyme replacement supplementation is frequently recommended to improve pancreatic and digestive function in cystic fibrosis patients, there doesn’t appear to be any consensus on the optimal dosage, formulation, duration, or timing of administration.[9] The same goes for several other supplements, including fat-soluble vitamins, omega-3 fatty acids, probiotics, antioxidants, and creatine.[10][11][12][13][14][15]

When it comes to specific fat-soluble supplements, for both vitamin E (to treat deficiency) and omega-3 fatty acids (for inflammation), minor benefits (such as increased serum vitamin E) have been observed, with few to no negative side effects. However, the quality of the evidence for both of these interventions was considered to be low/too weak for clinical recommendations, and further research is needed to determine whether other supplements (such as pancreatic enzymes) should be adjusted or specially formulated/delivered for effects to be seen.[10][11]

N-Acetylcysteine (as a precursor to glutathione) may improve forced expiratory volume when taken for 6 months. However, people with cystic fibrosis are often also on high doses of antibiotics, making it difficult to isolate the effects of antioxidant supplementation alone.[14] While probiotics (specifically, Lactobacillus reuteri) may not consistently improve respiratory difficulties, they have somewhat more consistently produced reductions in fecal markers of intestinal inflammation for both children and adults with cystic fibrosis.[12][13] In one pilot study, creatine supplementation demonstrated consistent improvements in isometric muscle strength; however, no changes in lung function or sweat electrolyte concentrations were seen.[15]

How could diet affect cystic fibrosis?

If the small bowel has been affected by cystic fibrosis (or by common comorbidities such as celiac disease or Crohn's disease), a gluten-free diet, dietary counseling, and other dietary strategies may be helpful in treating associated digestive complications.[2][8]

Oral calorie supplements are another common strategy used in cystic fibrosis to compensate for caloric and nutrient loss due to malabsorption. One review, however, has concluded that oral calorie supplements may be no more effective than dietary guidance or monitoring alone. In light of the current evidence, and considering the high costs of some oral calorie supplements, these may not be considered an essential cystic fibrosis therapy for all when less costly measures are just as effective and readily available.[16]

Vitamin D is connected to lung function, and individuals with lower serum levels (<75 nmol/L) may see an increase in respiratory distress and dysfunction. The mechanism behind this is not yet fully understood, but further exploration of dietary/supplemental vitamin D in cystic fibrosis is warranted.[17]

Are there any other treatments for cystic fibrosis?

Management of cystic fibrosis generally requires a multi-pronged approach, since the condition affects the function of multiple systems. Treatment is improved by the presence of caregivers who can help with routine follow-up and administration of therapies.[4] Psychological care, for both caregivers and people with all stages of cystic fibrosis, can reduce the stress that comes with and compounds a difficult-to-manage condition. However, standard, specific, targeted psychological interventions have yet to be established and validated for people with CF and their caregivers.[1]

Exercise (or exercise combined with other therapies such as breathing techniques) is now more commonly being used to ameliorate the symptoms of cystic fibrosis. At present, the evidence is uncertain and still inconclusive regarding whether exercise can actually replace other therapies, and to what degree it can ameliorate cystic fibrosis (if at all). Exercise does, however, seem to carry little risk of adverse effects, and some people with cystic fibrosis have reported feeling that it has helped them.[5]

What causes cystic fibrosis?

Cystic fibrosis is a genetic recessive disease caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. Mutations in CFTR lead to difficulty with electrolyte movement across the cell membranes of the cells that line our mucosal surfaces.[3] CFTR is primarily expressed in the lungs, but is also expressed in the pancreas, sweat glands, intestine, liver, nasal passages, salivary glands, and reproductive tract.[4] Up to 70% of patients with cystic fibrosis have a specific mutation involving a deletion of phenylalanine at codon 508. There are over 1600 possible (known) mutations of the CFTR gene, which exert a variety of effects, some of which result in milder forms of this disease. Excess pathogenic exposure leaves the respiratory system in a state of chronic, excessive inflammation, which causes irreversible damage, especially to the airway and lungs.[2] [4] Staphylococcus aureus is still the pathogen most frequently found in the lungs of children and adolescents with cystic fibrosis, with some estimates suggesting its occurrence at around 80% of people with the condition.[4]

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Update History
  1. ^Goldbeck L, Fidika A, Herle M, Quittner ALPsychological interventions for individuals with cystic fibrosis and their families.Cochrane Database Syst Rev.(2014-Jun-18)
  2. ^Davies JC, Alton EW, Bush ACystic fibrosis.BMJ.(2007-Dec-15)
  3. ^Braun, C., & Anderson, C.Applied Pathophysiology: A conceptual approach to the mechanisms of disease (3rd ed.)Philadelphia: Wolters Kluwer.(2017)
  4. ^López-Valdez JA, Aguilar-Alonso LA, Gándara-Quezada V, Ruiz-Rico GE, Ávila-Soledad JM, Reyes AA, Pedroza-Jiménez FDCystic fibrosis: current concepts.Bol Med Hosp Infant Mex.(2021)
  5. ^Heinz KD, Walsh A, Southern KW, Johnstone Z, Regan KHExercise versus airway clearance techniques for people with cystic fibrosis.Cochrane Database Syst Rev.(2022-Jun-22)
  6. ^Nevitt SJ, Thornton J, Murray CS, Dwyer TInhaled mannitol for cystic fibrosis.Cochrane Database Syst Rev.(2020-May-01)
  7. ^Yang C, Montgomery MDornase alfa for cystic fibrosis.Cochrane Database Syst Rev.(2021-Mar-18)
  8. ^Onady GM, Stolfi ADrug treatments for managing cystic fibrosis-related diabetes.Cochrane Database Syst Rev.(2020-Oct-19)
  9. ^Somaraju URR, Solis-Moya APancreatic enzyme replacement therapy for people with cystic fibrosis.Cochrane Database Syst Rev.(2020-Aug-05)
  10. ^Okebukola PO, Kansra S, Barrett JVitamin E supplementation in people with cystic fibrosis.Cochrane Database Syst Rev.(2020-Sep-06)
  11. ^Watson H, Stackhouse COmega-3 fatty acid supplementation for cystic fibrosis.Cochrane Database Syst Rev.(2020-Apr-10)
  12. ^Coffey MJ, Garg M, Homaira N, Jaffe A, Ooi CYProbiotics for people with cystic fibrosis.Cochrane Database Syst Rev.(2020-Jan-22)
  13. ^Di Nardo G, Oliva S, Menichella A, Pistelli R, De Biase RV, Patriarchi F, Cucchiara S, Stronati LLactobacillus reuteri ATCC55730 in cystic fibrosisJ Pediatr Gastroenterol Nutr.(2014 Jan)
  14. ^Ciofu O, Smith S, Lykkesfeldt JAntioxidant supplementation for lung disease in cystic fibrosis.Cochrane Database Syst Rev.(2019-Oct-03)
  15. ^Christian P Braegger, Uwe Schlattner, Theo Wallimann, Anna Utiger, Friederike Frank, Beat Schaefer, Claus W Heizmann, Felix H SennhauserEffects of creatine supplementation in cystic fibrosis: results of a pilot studyJ Cyst Fibros.(2003 Dec)
  16. ^Rosalind L Smyth, Oli RaynerOral calorie supplements for cystic fibrosisCochrane Database Syst Rev.(2017 May 4)
  17. ^Iniesta RR, Cook S, Oversby G, Koufaki P, Van der Linden ML, Vlachopoulos D, Williams CA, Urquhart DSSystematic review and meta-analysis: Associations of vitamin D with pulmonary function in children and young people with cystic fibrosis.Clin Nutr ESPEN.(2023-Apr)
  18. ^Gibson-Corley KN, Meyerholz DK, Engelhardt JFPancreatic pathophysiology in cystic fibrosis.J Pathol.(2016-Jan)
Examine Database References
  1. Cystic Fibrosis Symptoms - Christian P Braegger, Uwe Schlattner, Theo Wallimann, Anna Utiger, Friederike Frank, Beat Schaefer, Claus W Heizmann, Felix H SennhauserEffects of creatine supplementation in cystic fibrosis: results of a pilot studyJ Cyst Fibros.(2003 Dec)
  2. Cystic Fibrosis Symptoms - Di Nardo G, Oliva S, Menichella A, Pistelli R, De Biase RV, Patriarchi F, Cucchiara S, Stronati LLactobacillus reuteri ATCC55730 in cystic fibrosisJ Pediatr Gastroenterol Nutr.(2014 Jan)
  3. Forced Expiratory Volume - Ciofu O, Smith S, Lykkesfeldt JAntioxidant supplementation for lung disease in cystic fibrosis.Cochrane Database Syst Rev.(2019-Oct-03)
  4. Bone turnover markers - Wu M, Bhimavarapu A, Alvarez JA, Hunt WR, Tangpricha VChanges in bone turnover after high-dose vitamin D supplementation during acute pulmonary exacerbation in cystic fibrosis.Bone.(2023-Sep)