Cystic Fibrosis

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Cystic Fibrosis by Mind Map: Cystic Fibrosis

1. More than 1000 possible changes can occur in CFTR to cause cystic fibrosis, but approximately 70% of all patients with cystic fibrosis have the same defect: F508.

2. Diagnostic Tests

2.1. All 50 states and the District of Columbia screen babies for CF. This is often done using the immunoreactive trypsinogen (IRT) blood test a few days after birth.

2.2. A “sweat test” is thought to be the most reliable way to tell if someone has CF. It checks the amount of salt in your sweat. People with CF have higher levels of chloride, a compound in salt

2.3. Since cystic fibrosis is caused by a faulty recessive gene that’s passed down from both parents, carrier testing prior to conception can help determine a couple's risk of producing a child with CF.

3. Causative Factors

3.1. CF is an autosomal recessive inherited disorder.

3.2. Approximately 1 in 25 whites carries one copy of an allele that can cause cystic fibrosis.

3.3. Consanguinity, or reproduction between related individuals, can be an increased risk factor for the development of rare recessive diseases like CF.

4. Genetic Details

4.1. The CFTR gene was identified in 1989 and is found at 7q31.2, the long arm (q) of chromosome 7 at position 31.2.

4.1.1. This defect is a deletion of 3 bases that causes the loss of the protein phenylalanine.

4.2. Type I and type II errors in the production of the protein CFTR yield a more classic cystic fibrosis, whereas types III through V errors tend to be less problematic.

5. Pathophysiology

5.1. Cystic fibrosis is the most common lethal recessive disease in white children, occurring in about 1 in every 2500 births.

5.2. The cystic fibrosis gene encodes a protein product that forms chloride channels in the membranes of specialized epithelial cells.

5.2.1. Defective transport of chloride ions leads to a salt imbalance that results in secretions of abnormally thick, dehydrated mucus.

5.3. Defective transport of chloride ions leads to a salt imbalance that results in secretions of abnormally thick, dehydrated mucus.

5.4. Some of the digestive organs, particularly the pancreas, become obstructed, causing malnutrition, and the lungs become clogged with mucus, making them highly susceptible to bacterial infections (especially Pseudomonas).

6. Clinical Findings

6.1. Patients who have a complete loss of the CFTR gene have a clinical phenotype representative of pancreatic disease, severe pulmonary disease, gastrointestinal problems, and infertility (in men) or, sometimes, fertility problems (in women).

6.2. Cystic fibrosis (CF) is a disease of exocrine gland function that involves multiple organ systems but chiefly results in chronic respiratory infections, pancreatic enzyme insufficiency, and associated complications in untreated patients.

6.3. Pulmonary involvement occurs in 90% of patients surviving the neonatal period. End-stage lung disease is the principal cause of death.

6.4. Death from lung disease or heart failure occurs on average by about 40 years of age.

7. Treatment

7.1. Airway clearance techniques (ACTs) loosen thick, sticky mucus so it can be cleared from your lungs by coughing or huffing. Clearing the airways may help decrease lung infections and improve lung function.

7.2. Practitioners may prescribe many medications to help keep the lungs clear, prevent or fight infections and, for some people, help correct the underlying cause of the disease. Medications that people need to fight infections for a long time may require additional devices, such as PICCs and ports.

7.2.1. Click on the Link (arrow) to see the medications commonly used in the treatment of CF

7.3. Many people with cystic fibrosis face the possibility of a lung transplant. Lung transplantation can extend and improve the patient's quality of life, but it involves an extensive evaluation process and a commitment to living the lifestyle required to keep the new lungs healthy.