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Cystic Fibrosis

CF

Cystic fibrosis (mucoviscidosis) is an autosomal recessive genetic disorder of the exocrine glands. It is characterized by the production of abnormally viscous mucus by the affected glands. Cystic fibrosis is usually recognized in infancy or early childhood.

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Presentation

The clinical manifestations of cystic fibrosis are typically categorized as pulmonary and non-pulmonary.

Pulmonary manifestations

The pulmonary manifestations of cystic fibrosis are encountered in the majority of the cases. They are often the presenting complaints of the patient.

  • Recurrent pulmonary infections are very characteristic of cystic fibrosis. The most common pathogen responsible for pulmonary infection in cystic fibrosis is Staphylococcus aureus. Other pathogens commonly encountered in this disease include Pseudomonas aeruginosa, Hemophilus influenza and Burkholderia cepacia.
  • The patient also suffers from persistent (or recurrent) productive cough. In addition, dyspnea and wheezing are also present.
  • With time, the damage resulting from these recurrent infections and coughing accumulates and leads to progressive bronchiectasis. There is also scarring of the airways which may result in airflow obstruction.

Other manifestations

The non-pulmonary manifestations of cystic fibrosis cover several organ systems and are summarized below.

  • General physical manifestations: A number of findings will be seen in the advanced cases of cystic fibrosis upon general physical examination. Clubbing of the fingernails is often present. The anteroposterior diameter of the chest is also increased and upon percussion, the chest is found to be hyper-resonant.
  • Upper respiratory tract manifestations: The patients of cystic fibrosis often suffer from sinusitis. The upper respiratory tract may produce purulent secretions in large amount. Nasal polyps also occur frequently in cases of cystic fibrosis.
  • Gastrointestinal tract manifestations: In newborns, the distal gastrointestinal tract can become filled with thick, sticky intestinal secretions, causing meconium ileus and obstruction of the small intestine. The meconium also contains a higher amount of carbohydrates and proteins [5]. Although much less pronounced in adults, advanced cases can present with similar findings.
  • Pancreatic insufficiency: Both the exocrine and endocrine functions of the pancreas can be affected. Dysfunction of the exocrine part can cause some degree of indigestion. This mostly comes to notice as steatorrhea due to the high undigested lipid content in the stool. Pancreatic insufficiency also leads to decreased levels of insulin. As a result, insulin dependent diabetes mellitus can occur.
  • Reproductive system manifestations: Almost all the male patients suffering from cystic fibrosis are infertile. This is due to the inability of the vas deferens to develop on both sides.
Infertility
  • Case 1 patient is a 39-year-old infertile man presenting with congenital unilateral absence of the vas deferens and recurrent episodes of epigastric pain.[ncbi.nlm.nih.gov]
  • The abnormal CFTR genotypes in these patients with pancreatitis resemble those associated with male infertility.[ncbi.nlm.nih.gov]
  • Important comorbidities caused by epithelial cell dysfunction occur in the pancreas (malabsorption), liver (biliary cirrhosis), sweat glands (heat shock), and vas deferens (infertility).[ncbi.nlm.nih.gov]
  • Thirteen married men with CF who were referred for infertility. History, physical examination, semen analysis, transrectal and renal ultrasonography, CF mutation analysis, and microsurgical sperm aspiration coupled with ICSI.[ncbi.nlm.nih.gov]
  • Other complications include: Bowel problems, such as gallstones, intestinal blockage, and rectal prolapse Coughing up blood Chronic respiratory failure Diabetes Infertility Liver disease or liver failure, pancreatitis, biliary cirrhosis Malnutrition Nasal[nlm.nih.gov]
Malnutrition
  • Diet-induced protein calorie malnutrition in C57BL/6J mice resulted in impaired pulmonary clearance of P. aeruginosa.[ncbi.nlm.nih.gov]
  • These results indicate that malnutrition impairs pulmonary clearance of P. aeruginosa . Table 1.[doi.org]
  • Patients with cystic fibrosis are at great risk of infection by nontuberculous mycobacteria from the environment because of certain predisposing factors such as bronchiectasis, malnutrition, and diabetes.[ncbi.nlm.nih.gov]
  • She had been diagnosed with CF 8 years previously after being treated for recurrent Pseudomonas aeruginosa pneumonia and malnutrition based on sweat chloride concentrations and the CFTR protein gene mutation test.[ncbi.nlm.nih.gov]
  • INTRODUCTION: Patients with CF present numerous pathological conditions such as malnutrition, depletion of fat-free mass, metabolic disturbances (abnormal glucose metabolism, increased insulin resistance, chronic energy deficit, local and chronic inflammation[ncbi.nlm.nih.gov]
Weight Loss
  • An oral glucose tolerance test is recommended annually for patients or 10 years of age and for any patients presenting unexplained weight loss or symptoms of diabetes. Patients hospitalized with severe diseases should also be screened.[ncbi.nlm.nih.gov]
  • loss Symptoms related to the lungs and sinuses may include: Coughing or increased mucus in the sinuses or lungs Fatigue Nasal congestion caused by nasal polyps Repeated episodes of pneumonia (symptoms of pneumonia in someone with cystic fibrosis include[nlm.nih.gov]
  • loss or failure to gain weight despite increased appetite Salty tasting sweat Infertility (men) and decreased fertility (women) DIAGNOSING CYSTIC FIBROSIS If a doctor suspects a patient has CF, a ‘sweat test’ may be administered.[cysticfibrosis.ca]
  • Problems with digestion can lead to diarrhea, malnutrition, poor growth, and weight loss. In adolescence or adulthood, a shortage of insulin can cause a form of diabetes known as cystic fibrosis -related diabetes mellitus (CFRDM).[ghr.nlm.nih.gov]
Anemia
  • Female sex and chronic anemia were independent predictors of readmission. The most common causes of readmission were pulmonary exacerbation (31%), lung transplant complications (5.2%), and septicemia (3.4%).[ncbi.nlm.nih.gov]
  • Additional resources: American Sickle Cell Anemia Association Genetics Home Reference: Sickle Cell Anemia MEDLINEplus: Sickle Cell Anemia UK : NHS Sickle Cell & Thalassaemia Screening Programme Haemophilia Haemophilia is a hereditary bleeding disorder[who.int]
  • Other complications include osteopenia/osteoporosis, depression and anxiety, chronic pain, obstructive sleep apnea, renal stones, dialysis-dependent chronic kidney disease (possibly related to treatments as well as to CF), iron deficiency anemia, and[merckmanuals.com]
  • Induction of HbF production in subjects with sickle cell anemia by oral sodium phenylbutyrate. Blood. 1994; 84 :339. [ PubMed ] [ Google Scholar ] 148. Perrine SP.[ncbi.nlm.nih.gov]
Recurrent Respiratory Infections
  • respiratory infection is a major presenting feature 85% of CF patients have pancreatic insufficiency 10% of CF newborns suffer meconium ileus patients are also prone to hepatic cirrhosis and male infertility There are many different mutations responsible[gpnotebook.co.uk]
  • People with CF have difficulty clearing mucous from their lungs and have recurrent respiratory infections, which can result in lung damage over time.[betterhealth.vic.gov.au]
  • Infancy and childhood Recurrent respiratory infections. Diarrhoea. Failure to thrive (thriving does not exclude diagnosis). Rectal prolapse. Nasal polyps (in children, nearly always due to CF). Acute pancreatitis.[patient.info]
  • CF is characterized by the clinical phenotype of recurrent respiratory infection, pancreatic insufficiency, and elevated sweat chloride.[ncbi.nlm.nih.gov]
Cough
  • This makes it easier to cough the mucus out of the lungs.[nlm.nih.gov]
  • To determine the effectiveness and acceptability of chest physiotherapy compared to no treatment or spontaneous cough alone to improve mucus clearance in cystic fibrosis.[ncbi.nlm.nih.gov]
  • Some common types of medications for CF lung disease are: Mucolytics – to loosen lung mucus so it can be coughed up more easily Bronchodilators – to expand the airways; usually taken before physiotherapy to allow mucus to be coughed up more easily Steroids[web.archive.org]
  • Cough was the most common side effect in the mannitol alone arm but there was no occurrence of cough in the dornase alfa alone arm and the most commonly reported reason of withdrawal from the mannitol plus dornase alfa arm was pulmonary exacerbations.In[ncbi.nlm.nih.gov]
Hemoptysis
  • Abstract Massive hemoptysis occurs in a minority of patients with cystic fibrosis, with an annual incidence of 1%. Although rare, massive hemoptysis can be a severe and potentially fatal complication of this disease.[ncbi.nlm.nih.gov]
  • KEYWORDS: bronchial artery embolization; bronchial circulation; cystic fibrosis; hemoptysis[ncbi.nlm.nih.gov]
  • Hemoptysis and pneumothorax are complications commonly reported in patients with cystic fibrosis. Objectives : This document presents the CF Foundation's Pulmonary Therapies Committee recommendations for the treatment of hemoptysis and pneumothorax.[dx.doi.org]
  • Later in the disease, larger volume hemoptysis, which may be life-threatening, as well as pneumothoraces become more common 2 .[radiopaedia.org]
Chronic Cough
  • Respiratory organs The viscous mucus causes chronic coughing and regular infections of the respiratory organs with germs such as staphylococcus aureus and pseudomonas aeruginosa.[aoporphan.com]
  • These infections cause chronic coughing, wheezing, and inflammation. Over time, mucus buildup and infections result in permanent lung damage, including the formation of scar tissue (fibrosis) and cysts in the lungs.[ghr.nlm.nih.gov]
  • Chronic cough, recurrent pneumonia , and the progressive loss of lung function are the major manifestations of lung disease, which is the most common cause of death of persons with cystic fibrosis.[britannica.com]
  • Bladder : Chronic coughing weakens the bladder muscles. Almost 65% of women with CF have what’s called “ stress incontinence .” This means that you leak urine when you cough , sneeze , laugh, or lift something.[webmd.com]
  • Chronic coughing weakens the bladder muscles. Almost 65% of women with CF have stress incontinence. This means that you leak urine when you cough, sneeze, laugh, or lift something. Though more common in women, men can have it, too. Kidneys.[webmd.com]
Sputum Production
  • Acute or subacute clinical deterioration (cough, wheeze, exercise intolerance, exercise-induced asthma, change in pulmonary function, or increased sputum production) not attributable to another etiology. 2.[doi.org]
  • Periods in which the lung infections worsen are called exacerbations, which are associated with more coughing and sputum production, and may require treatment with the use of intravenous antibiotics.[healthychildren.org]
  • Presentation As normal digestive function is possible with The most common presentation is with respiratory problems - usually recurrent lower respiratory tract infection (LRTI) with chronic sputum production.[patient.info]
  • Sputum production No trials looked at sputum production. 4. Exercise tolerance One short‐term trial (n 8) looked at exercise tolerance ( Young 2008 ).[doi.org]
  • Patients diagnosed later in childhood or in adulthood are more likely to have pancreatic sufficiency and often present with chronic cough and sputum production.[emedicine.medscape.com]
Dyspnea
  • The patient was admitted to our department with fever, cough, and dyspnea at rest unresponsive to antibiotics CONCLUSIONS: Late diagnosis of cystic fibrosis in uncommon.[ncbi.nlm.nih.gov]
  • In addition, dyspnea and wheezing are also present. With time, the damage resulting from these recurrent infections and coughing accumulates and leads to progressive bronchiectasis.[symptoma.com]
  • Dyspnea on exertion, history of chest pain, recurrent sinusitis, nasal polyps, and hemoptysis may also occur. Urogenital tract manifestations Undescended testicles or hydrocele may be present in boys.[emedicine.medscape.com]
  • Strong recommendation, very low-quality evidence For patients with cystic fibrosis who have both mild chronic hypoxemia and dyspnea on exertion, we suggest that home oxygen therapy be prescribed.[doi.org]
  • Failure to thrive (despite adequate appetite) Flatulence or foul-smelling flatus, steatorrhea Recurrent abdominal pain Jaundice GI bleeding Respiratory symptoms may include the following: Cough Recurrent wheezing Recurrent pneumonia Atypical asthma Dyspnea[emedicine.medscape.com]
Diarrhea
  • Both adaptations would avoid severe diarrhea attacks following lactose ingestion.[doi.org]
  • […] the very high frequency of cystic fibrosis (CF) mutations in most populations of European descent, it has been proposed that CF heterozygotes have a survival advantage when infected with Vibrio cholerae or Escherichia coli, the toxins of which induce diarrhea[ncbi.nlm.nih.gov]
  • This leads to problems with digestion (e.g. diarrhea, fatty stools) and to malnutrition. Children do not grow properly and do not gain sufficient weight. In rare cases, newborns may be afflicted by intestinal blockage (meconium ileus).[aoporphan.com]
  • Proposed diseases that the CF carrier state may protect against include diarrhea from cholera or lactose intolerance, typhoid fever, high blood pressure and tuberculosis.[nationaljewish.org]
Constipation
  • However, gastrointestinal problems such as constipation and distal intestinal obstruction syndrome (DIOS) are also important and well-recognised complications in CF.[ncbi.nlm.nih.gov]
  • The most common form of cystic fibrosis is associated with respiratory symptoms, digestive problems (steatorrhea and/or constipation) and staturoponderal growth anomalies. Mortality and morbidity depend on the extent of bronchopulmonary involvement.[orpha.net]
  • Symptoms in newborns may include: Delayed growth Failure to gain weight normally during childhood No bowel movements in first 24 to 48 hours of life Salty-tasting skin Symptoms related to bowel function may include: Belly pain from severe constipation[nlm.nih.gov]
  • Symptoms of cystic fibrosis depend on the severity of the disease, but may include: Shortness of breath Frequent lung infections Persistent coughing Wheezing Fatigue Nasal congestion Stomach pain Weight loss Abnormal and foul-smelling stools Constipation[radiologyinfo.org]
Abdominal Pain
  • Here we report the case of an adolescent who suffered acute chest pain in September after an history of acute abdominal pain and fever.[ncbi.nlm.nih.gov]
  • They share similar symptoms e.g. bloating, abdominal pain, but are distinct conditions.[ncbi.nlm.nih.gov]
  • Forest plot of comparison: 2 ECM versus ECT, outcome: 2.3 Abdominal pain [% days].[doi.org]
  • Serious adverse reactions that occurred more frequently with ivacaftor included abdominal pain, increased liver enzymes, and low blood sugar (hypoglycemia).[investors.vrtx.com]
  • pain, mean difference -7.96% (95% confidence interval -12.97 to -2.94; P 0.002); and fecal fat excretion, mean difference -11.79 g (95% confidence interval -17.42 to -6.15; P 0.0001).[ncbi.nlm.nih.gov]
Vomiting
  • Cough, haemoptysis, bronchospasm, pharyngolaryngeal pain and post-tussive vomiting were the most commonly reported side effects in both treatment groups.[ncbi.nlm.nih.gov]
  • There was insufficient evidence reported across the trials to determine the rate of different adverse events such as cough, chest tightness, tonsillitis and vomiting (very low-quality evidence).[ncbi.nlm.nih.gov]
  • These small, hard mineral deposits can cause nausea, vomiting , and pain . If ignored, they can lead to a kidney infection . Reproductive organs: Excess mucus affects fertility in men and women.[webmd.com]
  • These small, hard mineral deposits can cause nausea, vomiting, and pain. If ignored, they can lead to a kidney infection. Reproductive organs. Excess mucus affects fertility in men and women.[webmd.com]
  • Cough is the most troublesome complaint, often accompanied by sputum, gagging, vomiting, and disturbed sleep.[merckmanuals.com]
Failure to Thrive
  • We present the case of an exclusively breastfed, 2-month-old boy with known cystic fibrosis admitted with failure to thrive and erosive dermatitis.[ncbi.nlm.nih.gov]
  • Children with CF have the following symptoms: Failure to thrive (inability to gain weight despite having good appetite and taking in enough calories) Loose stools or oily stools Trouble breathing Recurrent wheezing Frequent lung infections (recurrent[my.clevelandclinic.org]
  • Children who have CF have the following symptoms: Failure to thrive (inability to gain weight despite having a good appetite and taking in enough calories) Loose or oily stools Trouble breathing Recurrent wheezing Frequent lung infections (recurrent pneumonia[my.clevelandclinic.org]
  • GI tract presentation in early infancy may be in the form of steatorrhea, failure to thrive, or both.[emedicine.medscape.com]
Chest Pain
  • KEYWORDS: Bornholm; chest pain; cystic fibrosis; enterovirus; myositis[ncbi.nlm.nih.gov]
  • At Children’s, we treat kids and teens who have a range of respiratory problems, including: Asthma Bronchiolitis Bronchopulmonary dysplasia Chest pain Chronic cough Chronic respiratory failure and ventilator dependence Congenital abnormalities of the[choa.org]
  • Patients may experience the following when using Pulmozyme: change in or loss of their voice, discomfort in the throat, rash, chest pain, red watery eyes, runny nose, lowering of lung function, fever, indigestion, and shortness of breath.[pulmozyme.com]
  • Pneumothorax can cause chest pain and breathlessness. Respiratory failure. Over time, cystic fibrosis can damage lung tissue so badly that it no longer works. Lung function usually worsens gradually, and it eventually can become life-threatening.[mayoclinic.org]
  • Dyspnea on exertion, history of chest pain, recurrent sinusitis, nasal polyps, and hemoptysis may also occur. Urogenital tract manifestations Undescended testicles or hydrocele may be present in boys.[emedicine.medscape.com]
Cyanosis
  • 用 語 対 訳 cutaneous 皮膚の【形】 cutdown カットダウン、動(静)脈切開法 cutis laxa 弛緩性皮膚 cut-off method カットオフ法 CVP (central venous pressure) 中心静脈圧 CVR (coronary vascular resistance) 冠[状]血管抵抗 CVVH (continuous veno-venous hemofiltration) 持続的静脈静脈血液濾過[法] cyanosis チアノーゼ、紫色症 cyanotic[j-circ.or.jp]
  • […] polyps Findings related to the pulmonary system may include the following: Tachypnea Respiratory distress with retractions Wheeze or crackles Cough (dry or productive of mucoid or purulent sputum) Increased anteroposterior diameter of chest Clubbing Cyanosis[emedicine.medscape.com]
  • Intercostal retractions, use of accessory muscles of respiration, a barrel-chest deformity, digital clubbing, cyanosis, and a declining tolerance for exercise occur with disease progression.[merckmanuals.com]
  • […] of disease, as follows: Nose – Rhinitis, nasal polyps Pulmonary system – Tachypnea, respiratory distress with retractions, wheeze or crackles, cough (dry or productive of mucoid or purulent sputum), increased anteroposterior chest diameter, clubbing, cyanosis[emedicine.medscape.com]
Amenorrhea
  • Amenorrhea may occur in females with severe nutritional or pulmonary involvement.[emedicine.medscape.com]
  • Amenorrhea may occur in females with severe nutritional or pulmonary involvement. Physical Examination Physical signs depend on the degree of involvement of various organs and the progression of disease.[emedicine.medscape.com]

Workup

Diagnosis of cystic fibrosis can easily be made on clinical grounds but a number of examinations are still very useful for confirming the diagnosis. Investigations can also be performed routinely in patients with an affected first degree relative. The following investigations are of diagnostic importance in cystic fibrosis.

Sweat sodium or chloride concentration

The amount of salt in the sweat is increased in the patients suffering from cystic fibrosis. Values of sweat sodium or chloride greater than 60 mmol/L are diagnostic of cystic fibrosis.

DNA analysis

The patient’s DNA can be analyzed in order to locate defects in the gene corresponding to this disease.
Pulmonary function tests: Pulmonary function tests may indicate an obstructive and/or restrictive disease pattern. There may be hypoxemia and in advanced stages, respiratory acidosis.

Imaging

Features of cystic fibrosis can be identified on imaging. Common findings in cystic fibrosis include hyperinflation of the lungs, peribronchial cuffing, mucus plugging, bronchiectasis and peripheral opacities.

Atelectasis
  • Postoperative complications, management, and outcomes of bronchiectasis Complications after surgical resection for lung abscess are infrequent and include atelectasis, bronchopleural fistula, and wound infection.[web.archive.org]
  • Lungs had atelectasis (black arrow), hyperinflation (asterisk) and pneumonia (white arrows, left panel, scale bar, 5 cm).[ncbi.nlm.nih.gov]
  • Lungs showed mucopurulent airway obstruction (arrow) and adjacent atelectasis (asterisks). Bar 757 μm. G.[ncbi.nlm.nih.gov]
  • Subsequent changes include areas of infiltrate, atelectasis, and hilar adenopathy. With advanced disease, segmental or lobar atelectasis, cyst formation, bronchiectasis, and pulmonary artery and right ventricular hypertrophy occur.[merckmanuals.com]
  • Axial CT image of a 16-year-old adolescent with group A streptococcal mediastinitis, demonstrating rim-enhancing fluid collections in the mediastinum, bilateral pleural fluid collections, pericardial fluid collections, and bilateral atelectasis.[emedicine.medscape.com]
Pulmonary Infiltrate
  • Allergic bronchopulmonary aspergillosis (ABPA) is an allergic disease characterized clinically by wheezing, pulmonary infiltrates, bronchiectasis, and fibrosis that affects patients with asthma and cystic fibrosis (CF).[ncbi.nlm.nih.gov]
  • However, when A. fumigatus does cause clinical symptoms they are most often along the spectrum of ABPA, which is characterized clinically by wheezing, pulmonary infiltrates, bronchiectasis, and pulmonary fibrosis.[doi.org]
Bilateral Atelectasis
  • Axial CT image of a 16-year-old adolescent with group A streptococcal mediastinitis, demonstrating rim-enhancing fluid collections in the mediastinum, bilateral pleural fluid collections, pericardial fluid collections, and bilateral atelectasis.[web.archive.org]
Left Pleural Effusion
  • CT scan of the thorax of a sixteen-year-old with Lemierre's syndrome and anterior mediastinitis revealing pneumomediastinum posterior to and to the left of the trachea, free fluid surrounding the trachea, and left pleural effusion.[web.archive.org]
Hypercapnia
  • Patients with FEV1 30% predicted had a higher risk of death only when their Pa(CO2) was or 50 mm Hg (HR, 7.0; 95% CI, 1.5-32), while the increased risk of death with FEV1 or 30% was not further influenced by the presence of hypercapnia.[ncbi.nlm.nih.gov]
  • Patients with FEV 1 30% predicted had a higher risk of death only when their Pa CO 2 was 50 mm Hg (HR, 7.0; 95% CI, 1.5–32), while the increased risk of death with FEV 1 30% was not further influenced by the presence of hypercapnia.[dx.doi.org]
  • There is also some evidence that the use of oxygen therapy may be at the expense of worsening hypercapnia ( Gozal 1997 ; Milross 2001 ).[doi.org]
  • […] and hypercapnia ( 109 ).[doi.org]
Hyponatremia
  • Laboratory analysis on admission showed hyponatremia (115-133 mmol/L, mean 122.4 mmol/L), high plasma renin activity (229-500 pg/ml, mean 324 pg/ml) and metabolic alkalosis (pH 7.5-7.6, mean 7.56) in all the patients, and in four of them high blood level[ncbi.nlm.nih.gov]
Pseudomonas
  • Respiratory tract infection with Pseudomonas aeruginosa occurs in most people with cystic fibrosis.[ncbi.nlm.nih.gov]
  • Pseudomonas putida was grown from the left and right hands of the same member of staff. All other staff hand samples were negative for growth of Pseudomonas species.[doi.org]
  • Chronic Pseudomonas aeruginosa infection is associated with increased morbidity and mortality in patients with cystic fibrosis (CF).[ncbi.nlm.nih.gov]
  • RESULTS: New respiratory pathogens prompting investigation included: Mycobacterium abscessus(2), Stenotrophomonas maltophilia(3), Pseudomonas aeruginosa(3), Pseudomonas fluorescens(1), Nocardia spp.(1), and Achromobacter xylosoxidans(1).[ncbi.nlm.nih.gov]
  • Cross-infection with Pseudomonas aeruginosa and Pseudomonas cepacia has been shown sometimes to occur between cystic fibrosis (CF) patients in some CF centres, in some summer camps and during some social contacts between CF patients.[ncbi.nlm.nih.gov]
Staphylococcus Aureus in the Sputum
  • aureus Haemophilus influenzae Sputum rheology (stickiness, as measured by a validated method) Mucociliary clearance of the airway (as measured by a validated method) Airway potential difference measurements (measuring salt transport) Baseline potential[doi.org]

Treatment

Treatment of cystic fibrosis focuses on the removal of respiratory tract infections, reduction of secretions and reversal of bronchoconstriction coupled with interventions to combat pancreatic and nutritional insufficiency.

  • In cases of respiratory tract infections, the sputum should be cultured and appropriate antibiotics are then administered. Short term antibiotics are used against the infections caused by Staphylococcus aureus, Hemophilus influenza, Burkholderia cepacia and Stenotrophomonas maltophilia. Long term antibiotics are required against Pseudomonas aeruginosa [6].
  • Inhaled bronchodilators are effective in reducing respiratory symptoms in most patients.
  • Mucolytics are given to reduce the viscosity of the secretions.
    Pancreatic enzyme supplements are given in order to make up for pancreatic insufficiency.
  • Nutritional supplements and multivitamins are required.
  • A new oral drug named ivacaftor has recently become available for 5% of the cystic fibrosis patients with G551D mutation. This drug reverses the dysfunction of the chloride membrane channel [7]. This treatment is therefore referred to as CFTR corrector therapy.
  • Lung transplantation is the most definite treatment in severe respiratory disease [8].
  • Adopting an exercise regimen can improve the quality of life of the patient [9].

Prognosis

In the past few decades, the prognosis of patients with cystic fibrosis has significantly improved. The life expectancy of these patients averages 40 years [10].

Modern treatment strategies enable more than 80% of the cystic fibrosis patients to reach adulthood. Deaths in these patients usually result from complications related to the lungs.

Etiology

Cystic fibrosis is primarily a genetic disease and is inherited in an autosomal recessive pattern. The underlying genetic defects involve only a single gene on chromosome 7.

Currently, a total of 1965 different mutations have been identified in the aforementioned gene and up to 230 genes have been proven to cause clinical manifestations of cystic fibrosis [3].

The most common mutation in cystic fibrosis is ΔF508. It is characterized by a deletion of three nucleotides that code for the amino acid phenylalanine at position 508. It is present in over 65% of the clinical cases of cystic fibrosis worldwide [4].

Other common mutations of clinical significance include G542X, G551D, N1303K and W1282X.

Epidemiology

Cystic fibrosis seems to be a rare disease on paper but practically, it is the most common fatal disease in the white population [1]. As expected from this statement, the disease is much more common in the western world, particularly in Europe; and much less common in the Asian and African countries.

In the United States, the prevalence of the disease varies among various races. The highest prevalence (one case per 3200 population) is present in the population of European descent. On the other hand, the lowest prevalence (one case per 31,000 population) is present in the Asian Americans. Hispanics and African Americans (at one case per 9200 and 15000 population, respectively) lie between these two extremes.

Ireland has the highest worldwide incidence of this disease with 1 new case per 1353 individuals per year [2].

Sex distribution
Age distribution

Pathophysiology

The defective gene in this disease encodes a membrane chloride channel and regulatory protein known as Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). This membrane chloride channel is normally found in the apical epithelia of several organs of the body including the lungs, pancreas, stomach, intestines, endocrinal and reproductive organs.

Cystic Fibrosis Transmembrane Conductance Regulator encoded from the mutated gene has several functional defects. There is an abnormal transport of chloride ions and water molecules across the apical surface of the epithelia in the respective organs. The transport of sodium, bicarbonate and other ions may also be affected in some mutations.

As a result, the mucus produced at these epithelial surfaces is unusually thick, viscous and sticky causing clinical manifestations. In the respiratory tract, this viscid sputum prevents the adequate hydration of the mucociliary epithelium and also predispose the epithelium to recurrent infections. The surface epithelium starts acquiring damage and chronic inflammation results. Sloughing of the epithelium into the mucus causes the production of viscid sputum.

In endocrinal organs, the thick, sticky mucus gathers in the duct and causes obstruction. Similar pathologies occur in the gastrointestinal tract and reproductive organs. The salt content in sweat is also increased due to defects in Cystic Fibrosis Transmembrane Conductance Regulator.

Prevention

There are no guidelines for prevention of cystic fibrosis.

Summary

Cystic fibrosis is an autosomal recessive disease resulting from mutations in the gene encoding a membrane chloride channel called Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) that is present in the epithelia of various tissues of the body, including the lungs, pancreas, stomach, intestines, endocrinal and reproductive organs.

Dysfunction of this channel causes the production of abnormal secretions in these organs, which ultimately leads to a multitude of pulmonary and extra-pulmonary manifestations.

With proper management, the life expectancy of most patients exceeds 40 years.

Patient Information

Cystic fibrosis results from a genetic defect that causes a malfunction in a protein present in tissues in many organs of the body including the lungs, pancreas, stomach, intestines, endocrinal and reproductive organs.

This causes the production of abnormal secretions and symptoms related to these organs result.

The management of cystic fibrosis has improved in recent years and the prognosis is fairly good.

References

Article

  1. Davis PB DM, Konstan MW. Cystic fibrosis. Am J Respir Crit Care Med. Nov 1996;154(5):1229-1256.
  2. Farrell P JS, Foley L, Canny GJ, Mayne P, Rosenberg M. Diagnosis of cystic fibrosis in the Republic of Ireland: epidemiology and costs. Ir Med J. Sep 2007;100(8):557–560.
  3. Consortium CFGA. Cystic fibrosis mutation database. CFMDB Statistics http://www.genet.sickkids.on.ca/cftr/StatisticsPage.html. Accessed Feb 21, 2014.
  4. Mitchell K, Robbins, Abbas, Fausto, Nelson. Robbins Basic Pathology. Saunders/Elsevier; 2007.
  5. Green MN CJ. Studies in cystic fibrosis of the pancreas; protein pattern in meconium ileus. Pediatrics.21(4):635-641.
  6. Hansen CR PT, Koch C, Høiby N. Long-term azitromycin treatment of cystic fibrosis patients with chronic Pseudomonas aeruginosa infection; an observational cohort study. J. Cyst. Fibros. Mar 2005;4(1):35-40.
  7. Ramsey BW DJ, McElvaney NG. A CFTR potentiator in patients with cystic fibrosis and the G551D mutation. N Engl J Med. Nov 3 2011;365(18):1663-1672.
  8. Yankaskas JR MGJ. Lung transplantation in cystic fibrosis: consensus conference statement. Chest. January 1998;113(1):217-226.
  9. Moorcroft AJ DM, Webb AK. Exercise limitations and training for patients with cystic fibrosis. Disabil Rehabil.20(6-7):247-253.
  10. Elborn JS SD, Britton JR. Cystic fibrosis: current survival and population estimates to the year 2000. Thorax. Dec 1991;46(12):881-885.

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Last updated: 2018-06-22 09:45