# Symptoms and stages of cystic fibrosis
Cystic fibrosis does not progress in sharply defined "stages" like some other diseases, but follows a more gradual progressive pattern with periods of stability and acute exacerbations. The course varies greatly from person to person, depending on which genes are affected, how early the diagnosis was made, and how well the lungs and pancreas are maintained. Below I describe the main phases of the disease course as they occur in practice.
Early phase (childhood to young adulthood)
In this period the disease is often discovered through screening of newborns or because parents notice symptoms. The most common complaints are:
- **Chronic cough**: often productive (with mucus), can worsen after exertion or in the mornings
- **Thick, sticky sputum** that is difficult to cough up
- **Recurrent respiratory infections** with rhinovirus, adenovirus or other viruses; these can last for weeks and occur more frequently than in healthy children
- **Growth lag**: often underweight or slower growth than age-matched peers
- **Indigestion and fatty stools** (steatorrhea): sign of pancreatic damage
- **Food intolerance**: children can be tired and hungry without gaining weight well
- **Salt loss in warm weather**: sweat feels salty, can lead to exhaustion in bright sunny weather
**Daily life**: this phase requires intensive care. Parents perform therapy multiple times per day: inhalation of medications, physiotherapy to loosen mucus, taking supplements with food. Children can usually attend school, but are more susceptible to infections and need extra breaks. Nutrition requires much attention.
**Figures for this phase:** children with cystic fibrosis born after 1990 have much longer life expectancies than previous generations. In industrialized countries, the median survival of someone with classical CF is around 50 years (American CF Foundation Registry 2022), but this is a population figure that varies widely by genotype and healthcare. Many children diagnosed at a young age reach adulthood without serious lung damage.
Adolescence and young adulthood (13–25 years)
In this life phase, physical and psychosocial challenges become greater.
**Lung symptoms:**
- **Chronic cough** becomes more intense; many patients cough daily
- **Mucus buildup** increases, especially in the mornings
- **Recurrent lung infections** with bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus and Haemophilus influenzae; these can occur three to four times per year
- **Exacerbations** with larger amounts of sputum, coughing up blood (usually minor, but alarming) and shortness of breath
- **Fatigue** increases, especially after more intense activity
**Pancreas and metabolic complaints:**
- **Cystic fibrosis-related diabetes (CFRD)**: approximately 30–40% of adolescents deal with this; this requires insulin treatment and dietary adjustments
- **Vitamin deficiency**: especially vitamins A, D, E and K can be low despite supplements
- **Chronic pancreatitis**: some patients experience abdominal pain from pancreatic inflammation
**Daily life**: school, work and social contacts are hindered by fatigue, inhalation treatments (two to four times per day), physiotherapy and regular hospital visits. Adolescents struggle with accepting their chronic illness and its visibility (coughing in public, exhaustion). Relationships and sexuality become matters of concern.
**Figures on this stage:** adolescents and young adults with well-managed disease can still bridge many years without serious lung damage, but the time gradually increases. Current registries show that since the introduction of new CFTR-modulators (such as ivacaftor, lumacaftor/ivacaftor and more recently elexacaftor/tezacaftor/ivacaftor) lung function stabilizes or improves in a significant number of patients, especially in certain mutations. However, this does not mean everyone benefits from these advantages.
Adulthood with stable lung function (25–45 years)
Some patients maintain reasonably stable lungs in this stage, especially if they were diagnosed early and are well adherent to therapy.
**Symptoms:**
- **Daily cough** with mucus production; some expectorate less, others more
- **Tired lungs**: exertion causes shortness of breath, but many activities are still possible
- **Infections** continue to occur, but sometimes less frequently than in adolescence
- **Coughing fits** can disrupt night or morning routines
- **Intermittent hemoptysis** in some patients
**Non-lung issues:**
- **CFRD** is usually established in this stage; insulin and nutritional management are routine
- **Bone quality**: osteoporosis or osteopenia (reduced bone density) can occur, especially with long-term use of corticosteroids or vitamin deficiency
- **Kidney stone problems** and other complications occur in fewer patients
- **Sexuality and reproduction**: men with CF usually have reduced fertility (thickened pancreas can block sperm ducts), women can become pregnant but experience greater risks
**Daily life**: many can work and build family life, though treatment (inhalation, physiotherapy, medication) requires two to three hours per day. Regular hospital admissions (once every one to two years) for intensive antibiotic courses are normal. Energy availability is a theme.
**Figures on this stage:** adults in this stage who have been under treatment since youth achieve median survival around 50 years or longer, with increasing variation. Studies from recent years (CF Registry data) show that newer genotype-specific therapies can change the trajectory. However, it remains a population average; individual progression depends heavily on lung damage that has already accumulated earlier.
Advanced lung disease (45+ years and/or FEV1 < 30%)
If lung function declines significantly (measured as FEV1 — the amount of air that can be exhaled in one second) or with very severe lung damage, symptoms and daily life change drastically.
**Lung issues:**
- **Severe chronic cough** with large quantities of thick, yellow or greenish mucus
- **Severe shortness of breath**: even with light work or walking; sometimes also at rest
- **Frequent exacerbations**: infections can last months and require hospitalization
- **Hemoptysis** as a complication of vascular damage in the lungs
- **Sleep apnea** and nocturnal oxygen deficiency can occur
- **Fatigue**: not only physical, but also mental; daily life concentrates on survival
- **Coughing and incontinence**: involuntary urine leakage during severe coughing fits occurs
**Complications that occur more frequently:**
- **Pneumothorax** (collapsed lung)
- **Chronic kidney disease** from age and medications
- **Heart problems**: right heart enlargement due to chronic lung disease (cor pulmonale)
- **Severe malnutrition** despite aggressive supplementation
- **Muscle atrophy** from energy deficit
- **Psychological burden**: depression and anxiety are frequent in this stage
**Daily life**: many patients can no longer work. Hospital admissions are frequent (once every one to two months or more). Home oxygen therapy may be necessary. Labored breathing makes normal activities virtually impossible. Much time goes toward treatment: inhalation, IV antibiotics, physical care, medical appointments.
**Figures about this stage:** patients with CF who reach this stage experience a sharp decline in survival. Studies from 10–15 years ago showed median survival of several years for patients with FEV1 < 20%. With modern therapy and prevention of lung damage, the number of patients in this stage has declined, but those who reach it face serious challenges. The percentage that die in this stage from CF-related causes (mainly lung disease, but also sepsis, heart failure) is high. These are again population figures; individual cases vary.
Terminal stage (end-of-life period)
Some patients reach a stage where curative treatment is no longer feasible and palliation (comfort care) takes priority.
**Symptoms:**
- **Severe shortness of breath** despite oxygen and medications
- **Severe coughing fits** that are exhausting
- **Wasting** and decline in motor function
- **Mental confusion** due to oxygen deprivation
- **Pain**, depending on complications (for example, chest pain in cor pulmonale)
- **Anxiety and existential questions**
**Daily life**: much time is spent in hospitals or hospices. Family is intensively involved. Treatment focuses on comfort and dignity, no longer on prolonging survival.
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When to contact your doctor
Although many CF symptoms are chronic, there are signals that prompt you to contact your pulmonologist or general practitioner faster:
- **Suddenly increasing shortness of breath** at rest, or deterioration in exercise capacity over several days
- **Hemoptysis episodes** — small blood loss can occur, but large amounts require urgent care
- **Severe chest pain** (may indicate pneumothorax or heart problem)
- **High fever** (above 38.5°C) with worsened cough — sign of infection
- **Reduced consciousness** or confusion (may indicate oxygen deprivation)
- **Suddenly flared-up abdominal pain** (pancreatitis or other complications)
Regular appointments with your CF team (pulmonologist, dietitian, physiotherapist, social worker) are crucial to be well supported at each stage and to catch changes early.
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_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._