Cystic Fibrosis (Adult)
CF High-yield Verified · Sep 2026Cystic fibrosis is an autosomal recessive genetic disorder caused by mutations in the CFTR gene on chromosome 7; the faulty chloride channel makes secretions thick and sticky, mainly affecting the lungs, digestive system and reproductive system.
One faulty channel, many organs. The adult with CF clears mucus every day, takes enzymes with food, may take a CFTR modulator that needs liver tests, keeps 6 feet from other people with CF, and needs to know when a change in breathing or blood in the sputum means call the doctor — and when it means call 9-1-1.
What’s going wrong in the body
The normal physiology, where it fails, and why the body’s compensation backfires.
01 A faulty chloride channel dries out secretions
StatPearls: "Cystic fibrosis is caused by a genetic mutation in a gene on chromosome 7 that codes for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. This protein functions as a transmembrane cAMP-activated chloride channel." NHLBI: "More than 2,000 mutations of the CFTR gene can cause cystic fibrosis."
Salt and water. NHLBI: "Normally, the CFTR protein controls how salt and water move in and out of cells. In people who have cystic fibrosis, the CFTR protein does not work properly. The faulty CFTR protein causes mucus to become thick and sticky, because it contains less water. Also, the sweat glands make extra-salty sweat."
Most common mutation. "The most common mutation is [delta]F508 in exon 11, found in 70% of White patients in the United States with cystic fibrosis and two-thirds of all cases worldwide" (StatPearls). NHLBI: "The mutation makes a CFTR protein that can’t stay in the correct shape."
Inheritance. NHLBI: "People who inherit two copies of a mutated CFTR gene (one copy from each biological parent) will have cystic fibrosis." When both parents are carriers, each child has a "25% (1 in 4) chance of inheriting two normal CFTR genes," a "50% (1 in 2) chance of being a cystic fibrosis carrier, because they inherit one normal gene and one mutated gene," and a "25% (1 in 4) chance of inheriting two genes with mutations and having cystic fibrosis." "Carriers are generally healthy, but they may have some mild symptoms of cystic fibrosis."
02 Lungs — obstruction, infection, inflammation
StatPearls: "Notably, the lungs of a cystic fibrosis patient are normal in utero, at birth, and after birth. Disease results as a cascade effect following infection and the subsequent inflammatory process. Mucus plugging in the bronchioles results in a clinical picture of obstructive lung disease. As a result of obstruction, an environment optimal for bacterial growth is created within the airways. Bronchiectasis and further thick purulent sputum production occur."
"Poorly managed pulmonary manifestations are the primary cause of death in patients with cystic fibrosis" (StatPearls). Adults may have "chronic bronchitis, abnormal pulmonary function tests, bronchiectasis, atypical asthma, allergic bronchopulmonary aspergillosis, and colonization with P aeruginosa."
Exacerbation. StatPearls: "A pulmonary exacerbation is the worsening of lung function due to an infection. Often, this is characterized by shortness of breath, fatigue, productive cough, and fever." "P aeruginosa is the typical infectious etiologic agent."
03 Pancreas, intestine, liver
Pancreas. "Pancreatic manifestations of cystic fibrosis are primarily due to pancreatic ductular obstruction by thickened secretions." "As a result, intestinal chyme is not enzymatically processed, resulting in pathognomonic greasy stools, colicky abdominal pain, and malabsorption of nutrients from ingested foods. In particular, fat-soluble vitamins A, D, E, and K are notably deficient" (StatPearls).
CF-related diabetes. "Cystic fibrosis-related diabetes results from abnormal glucose metabolism primarily characterized by insulin deficiency and intermittent insulin resistance." Prevalence rises with age: "It is present in 2% of children, 19% of adolescents, and up to 50% of individuals 30 years of age and older." "Ketoacidosis, a common finding in type I diabetes, is uncommon in CFRD due to the residual insulin production present" (StatPearls, CFRD).
DIOS. StatPearls, citing ECFS: "Distal intestinal obstruction syndrome (DIOS) in cystic fibrosis is caused by thickened fecal material in the terminal ileum and colon, commonly in patients with pancreatic insufficiency and a history of meconium ileus or prior DIOS episodes. Symptoms include abdominal pain, distension, and vomiting, diagnosed by x-ray."
Liver. "The biliary ductules may be plugged with secretions. Obstructive cirrhosis and posthepatic hyperbilirubinemia can occur"; "up to 15% of patients with cystic fibrosis have gallstones" (StatPearls).
Sweat. Failure to reabsorb chloride causes "the pathognomonic salty skin of cystic fibrosis. In prolonged or warm environments or more severe cases, sodium and fluid loss may lead to hyponatremic dehydration" (StatPearls).
04 Diagnosis — screening, then sweat chloride
Newborn screening. NHLBI: "All newborns in the United States are tested for cystic fibrosis. Newborn screening identifies more than half of cystic fibrosis cases. However, many people born before 2010 have not been screened." "Screening tests for CFTR mutations sometimes miss cases of cystic fibrosis in babies who have Asian or African ancestry."
Sweat test. "The sweat test is the standard test for diagnosing cystic fibrosis." "A chloride level of 60 millimoles per liter (mmol/L) or greater indicates cystic fibrosis. A chloride level of 30 to 59 mmol/L indicates that a diagnosis of cystic fibrosis is unclear, and that further testing is needed. A chloride level of less than 30 mmol/L indicates that a diagnosis of cystic fibrosis is unlikely" (NHLBI).
Genes. StatPearls: "However, the finding of 2 cystic fibrosis-related mutations confirms the diagnosis." NHLBI: genetic testing also shows whether CFTR modulator therapy is likely to work.
05 When breathing changes: call the doctor or call 9-1-1
NHLBI: "Cystic fibrosis may have serious complications. Call your doctor right away if you believe you have any of the following:" a pulmonary exacerbation ("more coughing or wheezing, chest congestion, and a change in mucus color. You may also have weight loss, a poor appetite, or fever"); "Coughing or spitting up blood may be a sign that an artery has broken and is bleeding into the airway"; "Sudden shortness of breath or chest pain may be a sign of a pneumothorax, or collapsed lung."
NHLBI: "Call 9-1-1 for help if you suddenly have trouble breathing or talking, you feel confused, or your family or caregivers notice a bluish color on your skin or lips. These are signs of respiratory failure." "Also call 9-1-1 or go to the hospital if you start coughing up a lot of blood. If you are coughing up a small amount of blood, call your doctor."
Causes & risk factors
Modifiable factors are teaching targets — the patient can act on them.
Signs & symptoms
Each finding tied to the mechanism that produces it — and the triage it calls for.
Diagnostics
Complications
Medications for this condition
Why each class is prescribed here — every card links to its full pharmacology page.
Inhaled tobramycin (TOBI) for Pseudomonas. TOBI label: "TOBI is indicated for the management of cystic fibrosis in adults and pediatric patients 6 years of age and older with Pseudomonas aeruginosa." "TOBI is administered twice daily in alternating periods of 28 days. After 28 days of therapy, patients should stop TOBI therapy for the next 28 days." Warnings: bronchospasm; "Tinnitus and hearing loss have been reported in patients receiving TOBI" — "Tinnitus may be a sentinel symptom of ototoxicity"; nephrotoxicity; worsening muscle weakness; "Aminoglycosides can cause fetal harm." "TOBI should not be diluted or mixed with dornase alfa or other medications in the nebulizer."
Open the airways. NHLBI: "Bronchodilators relax and open airways. These treatments are taken by inhaling them." StatPearls: "Inhaled bronchodilators, including albuterol and ipratropium bromide, should support ventilation and oxygenation."
CF-related diabetes. StatPearls (CFRD): "Insulin is the preferred treatment for individuals with cystic fibrosis-related diabetes. Insulin therapy has been associated with better glycemic control, improved weight gain, and improved pulmonary function in CFRD." StatPearls, citing ISPAD: "There is currently insufficient data to recommend non-insulin injectables or oral hypoglycemic agents in CFRD. Prescribing these medications should not take place in this population outside of clinical trials."
Beyond medications
- Airway clearance every day (NHLBI) — "Removing mucus improves breathing and lowers the chance of infections." Techniques: breathing and coughing methods "such as active cycle of breathing (ACBT) and autogenic drainage"; "Devices used by mouth, called positive expiratory pressure (PEP) devices."; "Manual chest physical therapy."; "Therapy vests, also called high-frequency chest wall oscillation." In chest physical therapy another person "claps or shakes the chest wall. It can also be done using a percussion device. Lying in certain positions during therapy helps the mucus drain out of the lungs."
- Mucus thinners — StatPearls: "agents, such as inhaled dornase alfa or inhaled hypertonic saline (7%), are prescribed to promote airway secretion clearance in conjunction with chest physiotherapy."
- Exacerbations — StatPearls: managed with "2 primary goals: treating the infection and improving oxygenation." "antibiotic therapy should have spectrum coverage against this pathogen" (P aeruginosa). NHLBI: antibiotics may be "oral, inhaled, or intravenous (IV)."
- CFTR modulators (NHLBI) — "CFTR modulators make faulty CFTR proteins work better." They "only work for certain CFTR gene mutations." "People who are Asian, Black, or Hispanic are more likely to have mutations that will not respond to available CFTR modulators." If they will not work: "talk with your healthcare team about mental health support and other treatment options for you."
- TRIKAFTA administration (label) — "Administer TRIKAFTA tablets (swallow the tablets whole) or oral granules orally with fat-containing food, in the morning and in the evening approximately 12 hours apart." Strong CYP3A inducers such as rifampin and St. John's wort reduce its effect — "concomitant use is not recommended." Cataracts: "Baseline and follow-up examinations are recommended in pediatric patients initiating TRIKAFTA treatment."
- Pancreatic enzymes (StatPearls, Pancrelipase) — "The drug is administered with a meal or immediately before it with sufficient fluids." "Patients should swallow the capsules whole." "If the patient cannot swallow, the enteric-coated micro-spherules can be removed from the capsule, mixed with a small amount of acidic food, and administered." "High doses of pancreatic enzyme replacement therapy are associated with the risk of fibrosing colonopathy."
- Nutrition — StatPearls: "Individuals with cystic fibrosis are encouraged to consume a high-fat diet with supplemental fat-soluble vitamins to compensate for malabsorption" and "a high-calorie diet to maintain a healthy weight." "Those living in hot climates or participating in activities that cause sweating are encouraged to consume additional sodium." Tube feeding if intake falls short; "Parenteral nutrition has been linked to increased risk for sepsis events and should be used sparingly."
- DIOS — StatPearls, citing ECFS: "Treatment involves rehydration, polyethylene glycol, and sometimes aggressive interventions." "Preventive measures include optimizing enzyme therapy, hydration, and maintenance laxatives."
- Stay apart; wash hands (NHLBI) — "People with cystic fibrosis can spread infections to others who have the disease. To protect each other, people with cystic fibrosis should stay 6 feet apart. This advice does not apply to people in the same household." Wash hands often, especially "Before eating, beginning a cystic fibrosis treatment, or brushing their teeth" and "After using the bathroom, touching pets or other animals, or playing outside."
- Vaccines (NHLBI) — "Vaccines are important for preventing complications among people with cystic fibrosis." The list: "Annual influenza (flu) shots"; "COVID-19 vaccine and booster shots at the recommended times"; "Pertussis (whooping cough) vaccine"; "Pneumonia vaccine when appropriate, based on your age or risk factors." "Family members and other close contacts should also get vaccinated to help protect you." After a lung or liver transplant some vaccines can be dangerous.
- Exercise and rehab — "Chronic, supportive therapy for patients with cystic fibrosis includes regular physical exercise" (StatPearls). "Pulmonary rehabilitation is a supervised medical program that helps people with lung diseases live and breathe better" (NHLBI).
Nursing considerations
The RN-specific layer — each action paired with the reason it matters.
How a real nurse thinks
The clinical-judgment loop, worked for a typical presentation — reasoning, not reference.
- 1 Recognize cues
More cough, change in mucus color, fever, poor appetite, weight loss and lower oxygen saturation — a pulmonary exacerbation. Glucose is running high. No trouble talking, no confusion, no blue lips, no hemoptysis.
- 2 Analyze cues
An exacerbation is "the worsening of lung function due to an infection"; P aeruginosa is the usual organism. Acute illness raises insulin needs in CFRD. There are no 9-1-1 signs now.
- 3 Prioritize
Airway clearance and oxygenation, sputum culture then antibiotics covering Pseudomonas, glucose control during the illness, and nutrition.
- 4 Generate solutions
Sputum culture; antibiotics as ordered; airway clearance sessions with mucus thinners; oxygen as ordered; bedside glucose checks with insulin adjustment; enzymes with meals; TRIKAFTA with fat-containing food; keep her away from other patients with CF.
- 5 Take action
The nurse sends the sputum culture, starts the ordered antibiotics, coordinates chest physical therapy, checks glucose before meals and reports rising readings, and gives enzymes and TRIKAFTA with her meals.
- 6 Evaluate
Over several days her fever resolves, sputum lightens, oxygen saturation improves and her insulin needs fall back toward baseline — the nurse watches for low glucose as the illness resolves.
Scenario — you’re the nurse
Work each question before revealing the answer. Rationales explain the wrong options too.
A 24-year-old with cystic fibrosis takes TRIKAFTA and has CF-related diabetes on insulin. For 4 days she has had more cough, greener mucus, fever and poor appetite.
Q1 Multiple choice A sweat chloride result is 45 mmol/L. How does the nurse explain it? - A. It confirms cystic fibrosis
- B. It means the diagnosis is unclear and further testing is needed
- C. It rules out cystic fibrosis
- D. It shows the person is a carrier
Reveal answer & rationale
Q2 Select all that apply Which findings should a person with CF treat as a reason to call 9-1-1? Select all that apply. - A. Sudden trouble breathing or talking
- B. Feeling confused
- C. Bluish color of the lips or skin
- D. Coughing up a lot of blood
- E. A change in mucus color with more coughing
Reveal answer & rationale
Q3 Multiple choice How should the nurse give pancreatic enzyme capsules? - A. Crush the capsules and mix them into milk
- B. Give them with the meal or immediately before it, swallowed whole with enough fluid
- C. Give them at bedtime on an empty stomach
- D. Give them only on days with greasy stools
Reveal answer & rationale
Q4 Select all that apply The patient takes TRIKAFTA. Which nursing actions match the label? Select all that apply. - A. Give it with fat-containing food
- B. Follow the liver function test schedule
- C. Ask about new anxiety, depression or suicidal thoughts
- D. Give it with rifampin to boost its effect
- E. Report signs of liver injury such as abnormal liver tests
Reveal answer & rationale
Q5 Multiple choice Two patients with cystic fibrosis are admitted at the same time. What is the best room plan? - A. Room them together so they can support each other
- B. Keep them in separate rooms and at least 6 feet apart
- C. Room them together if both grow Pseudomonas
- D. No special plan is needed because CF is not contagious
Reveal answer & rationale
Common questions
What causes cystic fibrosis (adult)?
If both parents are carriers, what are the chances for each child?
Why do people with CF need to stay 6 feet apart?
Is CF-related diabetes treated like type 2 diabetes?
Does everyone with CF qualify for a CFTR modulator?
How long do people with CF live?
Sources
- Cystic Fibrosis — StatPearls — StatPearls (NCBI Bookshelf)
- Cystic Fibrosis — Causes (NHLBI) — National Heart, Lung, and Blood Institute
- Cystic Fibrosis — Symptoms (NHLBI) — National Heart, Lung, and Blood Institute
- Cystic Fibrosis — Diagnosis (NHLBI) — National Heart, Lung, and Blood Institute
- Cystic Fibrosis — Living With (NHLBI) — National Heart, Lung, and Blood Institute
- Cystic Fibrosis–Related Diabetes — StatPearls — StatPearls (NCBI Bookshelf)
- Cystic Fibrosis — Treatment (NHLBI) — National Heart, Lung, and Blood Institute
- TRIKAFTA (elexacaftor, tezacaftor, ivacaftor) — FDA label — U.S. FDA / NLM DailyMed
- TOBI (tobramycin inhalation solution) — FDA label — U.S. FDA / NLM DailyMed
- Pancrelipase Therapy — StatPearls — StatPearls (NCBI Bookshelf)
Reviewed by Hae Suk Lee, RN
Educational summary for nursing students. Scenarios are fictional teaching cases. Always verify against current guidelines and your institution's protocols before acting in practice. Not medical advice.