Cystic Fibrosis
What is a single gene disorder?
- Genes carry the information that determines the formation of proteins and traits in the body.Genetic disorders that can be caused by a change in one gene are known as single gene disorders.
- Change in single gene CFTRleads to a genetic condition known as cystic fibrosis.
Cystic fibrosis and symptoms?
It is a genetic condition which primarily affects lungs and digestive system but can affect other parts of the body too. When the cells in these parts of the body do not function properly, fluids or liquids produced by them becomes thicker than normal.
Symptoms starts developing from early childhood and it may vary from child to child. The condition progresses slowly causing increased damage to lungs and digestive system. Occasionally, other organ systems are can be involved too.
- Respiratory system: It mainly affects lungs. The thick liquid or fluid cause difficulty in breathing and increases the risk of recurrent chest infections like pneumonia.persistent cough, shortness of breath and damage to airways are some of the common symptoms.
- Digestive system:Thick secretions block the organ called as pancreas which results in poor release of enzymes. This causes problems in digestion of the food. oily/pasty stools, constipation, poor growth and weight gain, yellowing of skin and eyes (jaundice) and bowel obstruction in new born babies are commonly seen symptoms. Some individuals can also get diabetes. It also causesincrease in liver size, liver cirrhosis and elevated liver enzyme levels.
- Fertility:95% males are infertile. Fertility is not affected in females.
How is cystic fibrosis diagnosed?
New born screening by immunoreactive trypsinogen (IRT) test can be performed at day 3 of life. If it comes positive then genetic test can be performed to confirm the diagnosis. Another test named sweat-chloride test may be ordered by your doctor if they suspect cystic fibrosis. Lastly, a genetic testcan be performed to confirm the diagnosis of cystic fibrosis.
What is the outcome of the condition?
Cystic fibrosis is a lifelong condition. Symptomatic and supportive therapies for cystic fibrosis have improved a lot over the past few decades. Even with improved care and treatment, cystic fibrosis is one of the life-limiting conditions(variable life expectancy)
How is cystic fibrosis inherited?
- It is an autosomal recessive genetic condition which means two copies of an affected gene will cause cystic fibrosis in your child. A person will one affected copy of gene will not manifest the condition. They are asymptomatic carriers.
- There will be 25% chance in every subsequent pregnancy for a baby to be affected, if both the parents are carriers. This can be diagnosed prenatally at 11-13 weeks of gestation by a procedure called chorionic villus sampling.
MANAGEMENT & TREATMENT
Treatment and management of the symptoms make the condition easier to live with.Multidisciplinary team and a care plan are required based on a person’s needs.
- Respiratory (Consultation with a pulmonologist)
- Medicines to make secretions thinner in the lungs.
- Antibiotics to prevent and treat chest infections.
- Other complications can be treated as required.
- If the genetic testing has been performed then personalized therapy can be given:
- Ivacaftor for individuals age ≥2 years who are heterozygousfor p.Gly551Asp and other specific pathogenic variants
- Ivacaftor/lumacaftor combined therapy for individuals age ≥12 years who are homozygousfor p.Phe508del
- Lung or lung/heart transplant in case of severe condition.
Surveillance and care:
- Newborns to be examined every month till 1 year of age.
- 1 year or older- should be examined every 4 months.
- Culture respiratory tract secretions at least four times yearly.
- Pulmonary function studies, chest radiographic examination, and at least annual blood tests for electrolytes, fat soluble vitamin levels, and IgE levels are appropriate.
- Bronchoscopy and chest CT examination are indicated for individuals with symptoms and signs of lung disease who fail to respond to intervention.
- Consult a physiotherapist for learning appropriate exercises.
- All routine immunizations should be given at the recommended times.
- Influenza vaccine should be administered annually in infants age six months and older.
- Physical activity such as running, swimming or football, exercise, and conditioning help maintain bone health and improve airway clearance
- Exocrine pancreatic insufficiency (Consultation with a dietician and an endocrinologist)
Thickening of fluids/liquids makes it difficult for our body to digest food and absorb nutrients. Therefore, it is very important for people with cystic fibrosis to eat properly.
- Oral pancreatic enzyme replacement with meals (consult an endocrinologist)
- Nutritional therapy that may include breast milk, special infant formulas, supplemental feeding, salt supplementation, fat-soluble vitamin supplements, and zinc. (consult a dietician)
- High-calorie, high-fat nutritional supplements.
- Extra salt and water for hydration and salt losses in hot, dry climates.
- Management of CF-related diabetes mellitus with endocrinology consultation and (if required) glucose monitoring and insulin therapy
Surveillance:
- Weight gain and calorie intake to be monitored every month till 6 months of age.
- Fecal elastase to be repeated, if required
- Measure oral glucose tolerance annually after age ten years.
- Evaluate bone mineral density in adolescence.
- Liver disease
- Liver transplant, if indicated.
- Oral ursodiol
- Annual: Liver function test and liver ultrasound
- Fertility
- Assisted reproductive techniques
- AGENTS/CIRCUMSTANCES TO AVOID
- Respiratory irritants (Ex: smoke, dust etc).
- Contact with individuals with respiratory infections.
- Avoid dehydration. Add extra salt and water to diet in hot, dry climates because of perspiration-related salt losses.