CYSTIC FIBROSIS

Introduction

Cystic fibrosis (CF) is a genetic disorder that primarily affects the lungs, digestive system, and other organs of the body. It is a chronic, life-threatening condition that leads to thick, sticky mucus buildup, making it hard to breathe and digest food properly. Despite being a serious condition, advancements in medicine have significantly improved the quality of life and life expectancy for people living with cystic fibrosis.

What is Cystic Fibrosis?

Cystic fibrosis is a hereditary disease that affects the exocrine glands, which produce mucus, sweat, and digestive juices. In healthy individuals, these fluids are thin and slippery. However, in people with cystic fibrosis, a defect in a specific gene causes these fluids to become thick and sticky, leading to blockages in various organs.

These blockages especially affect the:

• Lungs, leading to breathing difficulties and lung infections.
• Pancreas, affecting enzyme release for digestion.
• Liver and intestines, leading to malnutrition and digestive problems.
• Cystic fibrosis is not contagious — it is passed down through families via genes.

Causes

• Cystic fibrosis is caused by a mutation in the CFTR gene (Cystic Fibrosis Transmembrane Conductance Regulator) located on chromosome 7. This gene controls the flow of salt and water in and out of cells.
• When the CFTR gene is defective, it produces a protein that doesn’t function properly, causing mucus and sweat to become thick and sticky.
• Inheritance Pattern
• Cystic fibrosis follows an autosomal recessive inheritance pattern.
• A child must inherit two defective copies of the CFTR gene (one from each parent) to develop the disease.
• If only one defective gene is inherited, the child becomes a carrier but doesn’t show symptoms.

For a baby to be born with cystic fibrosis:

• Both parents must be carriers of the CF gene.
• There is a 25% chance their child will have cystic fibrosis.
• A 50% chance the child will be a carrier.
• A 25% chance the child will be unaffected.

Who is at Risk?

• Cystic fibrosis can occur in any ethnic group, but it is most common among people of European descent.
  Risk factors include:
• Family history of cystic fibrosis.
• Genetic carriers of the CFTR mutation.
• Sibling with cystic fibrosis.

Symptoms

The symptoms of cystic fibrosis can vary depending on the severity of the disease and the organs affected. Some symptoms appear shortly after birth, while others develop later in life.

Respiratory Symptoms

• Chronic coughing with thick mucus.
• Frequent lung infections such as pneumonia or bronchitis.
• Wheezing and shortness of breath.
• Nasal polyps (growths in the nasal passages).
• Sinus infections.

Digestive Symptoms

• Poor weight gain despite normal appetite.
• Greasy, bulky stools due to poor fat absorption.
• Abdominal pain and bloating.
• Constipation or intestinal blockage.
• Malnutrition due to lack of pancreatic enzymes.

Other Symptoms

• Salty-tasting skin (a key identifying sign in newborns).
• Clubbing of fingers and toes (widening or rounding of fingertips).
• Delayed growth and puberty.
• Male infertility due to blockage of the vas deferens.

Complications

Lung Complications

• Chronic infections and inflammation.
• Bronchiectasis (permanent lung damage).
• Respiratory failure in severe cases.

Digestive System Complications

• Diabetes due to pancreatic damage (Cystic Fibrosis-Related Diabetes).
• Liver disease caused by blocked bile ducts.
• Gallstones and intestinal obstructions.

Reproductive Complications

• Infertility in males.
• Reduced fertility in females due to thick cervical mucus.

Diagnosis

1. Newborn Screening

• Most countries include CF testing in routine newborn screening. A blood sample checks for immunoreactive trypsinogen (IRT) levels — high levels may indicate CF.

2. Sweat Test

• The sweat chloride test is the most common diagnostic test for CF. It measures the amount of salt in a person’s sweat.
• Chloride levels above 60 mmol/L usually confirm cystic fibrosis.

3. Genetic Testing

• A DNA test identifies mutations in the CFTR gene. This test can confirm CF or identify carriers.

4. Additional Tests

• Chest X-rays or CT scans to assess lung damage.
• Pulmonary function tests (PFTs) to check lung capacity.
• Stool tests to check digestive enzyme levels.

Treatment

1. Medications

• CFTR Modulators: Target the underlying gene defect (e.g., ivacaftor, lumacaftor, tezacaftor, elexacaftor).
• Antibiotics: Control and prevent lung infections.
• Mucus Thinners: Help clear thick mucus from the lungs (e.g., dornase alfa).
• Bronchodilators: Open airways and make breathing easier.
• Pancreatic Enzyme Supplements: Aid in digestion and nutrient absorption.
• Anti-inflammatory drugs: Reduce lung inflammation.

2. Airway Clearance Techniques (ACTs)

These are daily exercises and physical therapies to help clear mucus from the lungs:

• Chest physiotherapy (CPT): Gentle tapping on the chest to loosen mucus.
• Oscillating vests: Vibrating devices that help break up mucus.
• Breathing exercises: Improve lung function and airway clearance.

3. Nutritional Support

• People with CF need a high-calorie, high-protein diet because they burn more calories fighting infections and struggle with nutrient absorption.
• Vitamin supplements (A, D, E, K) are recommended.
• Digestive enzyme capsules are taken with meals.
• Adequate hydration is important to thin mucus.

4. Oxygen Therapy

• In severe cases, supplemental oxygen may be needed to help with breathing.

5. Lung Transplant

• For patients with severe lung damage and respiratory failure, a lung transplant may be considered as a life-saving option.

Lifestyle and Home Remedies

• Follow daily treatments such as inhaled medications and physiotherapy.
• Avoid smoking and pollutants, as they worsen lung damage.
• Exercise regularly to strengthen lungs and improve stamina.
• Eat nutrient-rich foods to maintain weight and immune function.
• Stay hydrated to prevent mucus from thickening.
• Regular medical checkups for infection control and monitoring.

Prevention

• Cystic fibrosis cannot be prevented, as it is a genetic disorder, but genetic counseling can help families understand their risk.
• Genetic Counseling and Testing
• Couples with a family history of CF should consider carrier testing before having children.
• Prenatal testing can identify whether a baby carries the defective CFTR gene.
• In-vitro fertilization (IVF) with genetic screening can help avoid passing on the mutation.

Living with Cystic Fibrosis

• Thanks to medical advancements, people with cystic fibrosis are living longer and healthier lives than ever before. In the past, most children with CF did not survive into adulthood, but now, with early diagnosis and improved treatments, many live into their 40s, 50s, or beyond.
• Emotional and Social Support
• Managing cystic fibrosis can be emotionally challenging. Patients and families benefit from:
• Support groups and counseling.
• CF care teams that include doctors, dietitians, physiotherapists, and psychologists.
• Online communities for sharing experiences and advice.

Recent Advances in Cystic Fibrosis Research

• Gene therapy aims to correct the faulty CFTR gene.
• CFTR modulators directly improve protein function.
• Stem cell research is being explored to repair lung tissue.
• Personalized medicine focuses on treatments tailored to each patient’s genetic mutation.