Words and definitions related to cystic fibrosis.

CF A to Z

ABPA (Allergic bronchopulmonary aspergillosis)

This is an allergy to the mold Aspergillus fumigatus, often found in the lungs of people with CF. The symptoms of ABPA include increased respiratory symptoms like cough, shortness of breath, increased sputum production and decreased lung function. Diagnosis is made by a blood test and/or skin prick test. Treatment may consist of oral steroids and oral antifungal medication.


A hand-held device that uses vibration and positive expiratory pressure (PEP) to dislodge mucus in the lungs (airway clearance). Patients exhale through the device, which transmits vibrations down into the lungs where mucus is shaken loose from airways. The mucus is then moved toward large airways by huffing or cough maneuvers. These devices are usually used as part of a daily airway clearance regimen.

Airway Clearance

Process of dislodging mucus so that it can be more easily coughed out of the lungs. Typically performed as part of a daily regimen, different methods and devices can be used depending on patient age and preference.


A medication used to treat a bacterial infection. Depending on the specific medication and type of infection, antibiotics can be given either orally (by mouth), by inhalation (using a nebulizer), or intravenously (through an IV).


A class of antibiotics that is used to treat an infection caused by specific bacteria, such as Pseudomonas aeruginosa. Some examples are tobramycin, amikacin and gentamicin.


When the airways into the lungs are blocked, typically by a mucus plug, tiny air sacs called alveoli are unable to fill with air and perform their function of exchanging oxygen and carbon dioxide. The result is atelectasis, a collapse of lung tissue.



Bronchus (pl. Bronchi)

Large airway within the lung. The two airways leading into the right and the left lungs are called mainstem bronchi.


Widening of airways in the lung.


An inhaled medication that causes expansion of the bronchial air passages, helping to clear bronchial secretions. Also used to treat wheezing or cough that is caused by the constriction of air passages in the lungs. Albuterol and levalbuterol are commonly used bronchodilators.


A procedure used to inspect the airways within the lungs and obtain mucus or tissue samples. A long, thin, flexible fiber optic tube (bronchoscope) is advanced through the vocal cords and into the trachea and bronchi (branches) of the lungs. The physician usually uses a camera and video screen to visualize the airways.



Burkholderia cepacia complex

The term Burkholderia cepacia (B. cepacia) complex describes a family of bacteria that are very similar. There are many family members that have slightly different DNA (called a genomovar) and have different names, for example B. multivorans and B. cinocepacia. Members of this family of bacteria can cause chronic infection of the lungs in people with CF.


A single-celled organism that can cause disease when it enters the body, either through the mouth, nose, or skin. In many cases, an antibiotic can be prescribed to help the body either eradicate or reduce the infection caused by the organism. Bacteria are directly or indirectly involved in the lung damage in people with CF.

Central line

An intravenous (IV) catheter that ends in a large (central) vein in the body.

Cystic fibrosis-related diabetes (CFRD)

A type of diabetes found in individuals with CF that results from decreased function of the pancreas due to scarring, which decreases the amount of insulin produced. CFRD is usually diagnosed by measuring the patient’s blood glucose (sugar), which is elevated in those with diabetes. This type of diabetes is slightly different from Type I and Type II diabetes, and usually begins during adolescence or adulthood. Symptoms may include weight loss and muscle wasting, fatigue, decreased ability to respond to infections, respiratory problems, increased thirst and urination, and delayed puberty. Treatment may include insulin injections, nutrition management, and daily measurement of blood glucose levels.   Over half of adults with CF eventually develop CFRD.

CFTR (Cystic fibrosis transmembrane conductance regulator)

The CFTR gene is located on chromosome 7 and encodes a chloride channel of the same name that sits on the surface of specialized cells throughout the body. Mutations in the CFTR gene lead to cystic fibrosis.

CFTR modulator

Medication that improves the function of defective CFTR in people with CF to restore chloride function.


Enlargement and rounding of the nailbeds of the fingers and toes. Clubbing is usually due to chronic respiratory problems, although it can be caused by several other medical conditions. The medical name for clubbing is hypertrophic osteoarthropathy. Although more common in people with CF that have more severe lung disease, people with mild lung disease can also have clubbing. The reason people get clubbing is unknown, but may be due to inflammation in the lungs.

Congenital bilateral absence of the vas deferens (CBAVD)

An absence of the tube (vas deferens) that transports sperm out of the testis leading to infertility in most men with cystic fibrosis.


Medication that improves the transport of defective CFTR in people with CF due to trafficing (class 2) CFTR mutations, for example F508del. Correctors are a type of CFTR modulator.

Distal intestinal obstruction syndrome (DIOS)

A blockage of the intestine due to the accumulation of stool in the large intestine. DIOS is often a sign of intestinal malabsorption. Patients develop progressive symptoms of recurrent, crampy abdominal pain, bloating, nausea, loss of appetite and decreased stooling. About 10-20 percent of people with CF develop this syndrome. The incidence of DIOS tends to increase with age. DIOS is treated with laxatives and enemas. Preventive measures can include staying well hydrated, taking adequate pancreatic enzyme supplementation, increasing dietary fiber, and taking prescribed stool softeners or laxatives.


Substance needed for the proper digestion and absorption of food nutrients. Enzymes are produced mainly by the pancreas.

Epithelial cell

A specialized type of cell that lines the airways, intestines and other organs. A lining of epithelial cells is called an epithelium.


The process of removing mucus or sputum from the lungs by coughing and spitting.

FEV1 (Forced expiratory volume in one second)

A measure of lung function that shows that amount of air a patient can forcefully exhale from the lungs in one second. This measure is compared to a predicted value that is based on a person’s gender, race, age and height.


See Influenza

FVC (Forced vital capacity)

The amount of air that can be exhaled from the lungs after a maximum inspiration. This measure is compared to a predicted value that is based on a person’s gender, race, age and height.

Gastrostomy tube (G-tube)

A small tube inserted through the abdominal wall directly into the stomach. This tube can be used to infuse fluids, medications and supplemental formulas into the stomach, bypassing the mouth and esophagus. A G-tube is typically placed in patients to increase calorie intake to optimize their nutritional status. A gastrostomy tube can be placed through the skin (percutaneously) by a gastroenterologist using an endoscopy (PEG) or by a surgeon during a short operation.

Gastrostomy tube (G-tube)

Gastrostomy tube (G-tube)

Gastroesophageal reflux (GER)

Gastroesophageal reflux is the backward flow of the stomach contents back up into the esophagus. This results from improper functioning of the lower end of the esophagus causing symptoms of heartburn, chest or abdomen discomfort, cough, wheezing, and shortness of breath. Individuals with CF tend to have more gastroesophageal reflux than people without CF, which is associated with decreased lung function. Untreated, GER can also cause pain or difficulty swallowing, damage to the esophagus and esophageal narrowing.

Hemophilus influenzae (H. influenzae)

A type of bacteria that can cause respiratory infections, such as ear or sinus infections, and pneumonia.


The coughing up of blood or sputum mixed with blood. Hemoptysis is often due to an infection in part of the lung that has already been damaged by CF. This can be a serious condition that needs immediate medical evaluation.

Hypertrophic osteoarthropathy

This is the scientific name for clubbing.


A local response to cell injury that is marked by increased blood flow, redness, heat, pain, swelling, and often loss of function. Inflammation serves as the body’s mechanism to attempt to eliminate infection or injury, or to start the healing of damaged tissues.


A highly contagious disease, the “flu” is caused by various strains of the influenza virus. Characterized by sudden onset, fever, severe aches, pains and respiratory symptoms. Each year in late fall/early winter an influenza vaccine, or “flu shot”, is available to prevent infection. Everyone over 6 months old should get an influenza vaccination every year.

Liver disease (CF-related)

Decreased liver function in people with CF is due to the abnormal thickness of fluids (bile) produced by the liver. Many people with CF have abnormal liver function blood tests. About 5 percent of individuals with CF have potentially fatal liver disease that requires liver transplantation, and about 25 percent of those over four years of age have serious issues related to liver function. Severe liver disease is the second most common cause of death in people with CF.


A type of antibiotic, usually given orally, that is prescribed for specific bacterial infections that can cause respiratory problems, including ear and sinus infections, bronchitis and pneumonia. Some people with CF take the macrolide antibiotic azithromycin three times weekly to reduce the level of infection and inflammation in their lungs.


Poor absorption of nutrients from the intestinal tract, which can lead to malnutrition, weight loss, and increased risk of infection. In CF,  this is due to the effect of the disease on the pancreas, which is responsible for making many of the substances needed to effectively break down food and absorb different nutrients in the intestines.

Meconium illeus

Congenital intestinal blockage by thickened meconium (the stool of a newborn infant) in newborn infants. The intestinal obstruction may require surgery to remove the blockage, which is due to the abnormally thick and sticky stool. Approximately 15% of infants with CF have meconium ileus at birth.


A sticky, slippery secretion that is produced by mucous membranes (lining of the mouth, nose, throat and airway) which it moistens and protects. The mucus of people with CF is very thick and accumulates in the intestines and lungs, where it may lead to blockages.


A change in the DNA sequence of a gene which leads to a change in function. Mutations in the CFTR gene lead to cystic fibrosis.

Nasal Polyp

An excessive growth of tissue lining the nose. Nasal polyps are common in people with CF.

Nasal Potential Difference (NPD)

A test of salt transport in the cells lining the nose. Transport of ions such as sodium and chloride creates an electrical potential difference across the epithelium (or lining) of the airway. This nasal potential difference (NPD) can be measured in patients by placing an electrode on the lining of the nose. The NPD can be used as a diagnostic test for CF.


A device used to deliver inhaled medications to a patient. The nebulizer uses pressurized air or oxygen to create an aerosol that can be inhaled into the lungs via a hand-held device or face mask. The nebulizer is attached to a compressor, which generates the air flow to aerosolize medications.

Newborn Screening

Testing for genetic diseases like CF in newborn infants. The goal of newborn screening is to make the diagnosis of CF before the infant has any symptoms so that preventive therapies can be started as early as possible.


A condition which causes reduced bone strength due to decreased calcium in bones, leading to decreased bone density. People with CF are at higher risk for osteopenia due to decreased intestinal absorption of calcium and vitamin D, reduced physical activity, pulmonary disease, and use of steroids. This causes an increased risk of traumatic fractures among people with CF. Osteopenia is common in people with CF at any age, and accelerates during adolescence and early adulthood. Preventive measures include maintaining optimal nutrition and vitamin D levels, encouraging physical activity, and minimizing long-term use of oral steroids. Osteoporosis is a severe form of osteopenia. Bone density can be measured by a non-invasive test called a DEXA scan.


An organ in the digestive system of the body that is responsible for production of many of the enzymes needed for the proper digestion and absorption of food nutrients and also for the production of insulin. In CF, pancreatic insufficiency leads to intestinal malabsorption of fats, proteins, and to a lesser extent, carbohydrates (sugars). This in turn leads to increased unused fat and proteins in the stool, and malnutrition. Most people with CF have pancreatic insufficiency that requires life-long replacement therapy with pancreatic enzyme supplements and fat-soluble vitamins (A, D, E, and K).

Pancreatic insufficiency

Patients with pancreatic insufficiency (which occurs in 85-90 percent of people with CF) need to take medications with every meal and snack that include replacement enzymes for the proper absorption of dietary fats, proteins and carbohydrates. The amount of enzyme replacement taken with each meal is usually based on a patient’s weight and symptoms. Abdominal distension and discomfort, poor weight gain, decreased fat and muscle tissue, and frequent passage of odorous and oily stools can result from lack of enzyme replacement.

PICC (Peripherally Inserted Central Catheter)

An intravenous (IV) catheter placed into a large (central) vein in the body. This type of IV is usually inserted into the patient’s arm by a specially trained nurse. A PICC can stay in place for several weeks.

Pilocarpine Iontophoresis

This is the technical name for a sweat test.


An intravenous (IV) catheter placed permanently under the skin that goes directly into a large vein in the body. The IV catheter is used by medical personnel to administer medications that are given on a frequent basis, or when other IV access is not possible.  Medications are infused through a port, or small receptacle under the skin, by placing a small needle through the skin into the port. This is called “accessing” the port. Once the medications are no longer needed, the needle is withdrawn from the port, which remains under the skin.




Medication that actives defective CFTR that is located on the cell surface. A Potentiator is a type of CFTR modulator.

Pseudomonas aeruginosa

Pseudomonas aeruginosa (P. aeruginosa) is a bacteria that can chronically infect, or colonize, the lungs of people with CF. P. aeruginosa is resistant to many antibiotics and can survive in conditions that few other organisms can tolerate.  The bacteria rarely causes infection in healthy individuals, but in people with CF infection can cause increased cough and sputum production, weight loss, decreased lung function. Nearly 80 percent of people with CF are chronically infected with P. aeruginosa. Antibiotic therapy is usually directed at reducing the amount of chronic infection.

Pulmonary Function Test (PFT)

Evaluation of lung function by measuring the amount of air a patient is able to inhale and exhale. The patient is asked to perform several sequences of maximal inspiration and expiration, and a computer measures the amount of air going into and out of the lungs. The computer can then estimate the capacity and function of the lungs as compared to healthy individuals of the same size.


A type of antibiotic, usually given either orally or through an IV, that is prescribed for specific bacterial infections that can cause respiratory problems, including ear and sinus infections, bronchitis and pneumonia. Quinolone antibiotics are the only oral drugs that are effective against P. aeruginosa. These medications include ciprofloxacin and moxifloxacin and levofloxacin.


Mucus and other matter coughed up from the airways in diseases of the lungs. The word “sputum” comes from the Latin word “sputus,” which means to spit or expectorate.

Sweat test

The standard way of testing for CF. A chemical is placed on the skin that causes sweating. The amount of chloride in the sweat is measured. People with CF have more chloride in their sweat than people without CF. The technical name for a sweat test is pilocarpine iontophoresis


Tobramycin is a aminoglycoside antibiotic. Inhaled tobramycin is effective in decreasing or eliminating respiratory infections due to Pseudomonas aeruginosa. The typical regimen for a person with CF that has chronic lung colonization of P. aeruginosa is to use inhaled tobramycin in alternating cycles of twice daily use for 28 days (on month) alternating with a 28-day cycle without using the drug (off month).


Vitamins are essential in small quantities to our nutrition; they act especially as substances involved in the regulation of metabolic processes but do not actually provide energy by themselves. They are usually present in foods, or are sometimes produced within the body. Since people with CF have a hard time absorbing fats in their diet, they cannot effectively absorb vitamins that are fat-soluble. Therefore, these vitamins (A, D, E, and K) must be given as a separate vitamin supplement on a daily basis. The blood levels of these vitamins should be checked annually.