Cystic Fibrosis and Bronchiectasis

Basic Cystic Fibrosis Info

• Cystic Fibrosis is an inherited disease occurring in about 1 in 2500 white births in the US.
• It used to be thought of as only a disease of childhood because no one really lived much past the age of 20.
  • However, good news is that about 1/3 of patients with Cystic Fibrosis now live into their 30s.
• There are several diagnostic criteria for Cystic Fibrosis. The defining test is a positive sweat test (Cl- >60mEq/L). This, plus one of the following is enough to diagnose an individual with Cystic Fibrosis.
  • Chronic airway obstruction.
  • Exocrine pancreatic insufficiency (the lipases, proteases, and amylases, not insulin or glucagon)
  • Family history of Cystic Fibrosis
• Cystic Fibrosis is almost always a pulmonary disease but it can manifest in several other ways as well.
  • Pancreatic insufficiency is seen in nearly all patients (Cystic Fibrosis patients tend to be very thin).
  • Nasal polyps and GI problems are fairly common.
  • Glycosuria, cirrhosis, and heat prostration are rarer problems.

• The basic defect in cystic fibrosis is a mutated gene on the long arm of chromosome 7.
  • This gene codes for a chloride transporter found in the lungs. When it’s dysfunctional, the osmotic gradient is lowered and less water moves out of the body and into pulmonary secretions.
  • This thicker mucus is difficult to clear and the mucociliary apparatus does not function properly.
  • Cystic Fibrosis patients are predisposed to infections and pneumothoraces.

Bronchiectasis

• Bronchiectasis is defined as dilatation and destruction of bronchial walls associated with chronic infection and inflammation of the airways.
• It is often associated with cystic fibrosis or ciliary dyskinesis syndrome.
  • I had no idea what the second one was, but it’s in the draft chapter. Apparently, it’s a mutation that creates dysfunctional cilia in your bronchial lining leading to a failure of the mucociliary apparatus.
• There are two types of bronchiectasis.
  • Tubular bronchiectasis is reversible and associated with acute pneumonia.
  • Saccular bronciectasis is irreversible. Round blind sacs are formed within the lung and really, this isn’t good.
• Signs and symptoms of bronciectasis include
  • Chronic cough with purulent sputum
  • Digital clubbing (not having a dance party in a chat room)
  • Hemoptysis and associated anemia
  • Fever
  • Chronic sinusitis
  • Rhonchi and wheezes
• To diagnose bronchiectasis in a patient
  • A chest x-ray will demonstrate dilated airways, but a high resolution CT scan is now more commonly used as a definitive diagnostic.
  • Bronchiography, or inhalation of radio-opaque materials to image the lung is almost never done anymore.
  • PFTs are useful to show obstruction in airflow.
  • Sputum cultures will often show S. pneumoniae or H. influenza.
    • The stagnant mucus is a perfect breeding ground for bacteria.

Back to the Respiratory System Index