Cystic Fibrosis (CF)

 

Cystic Fibrosis (CF) is a genetic disorder caused by an autosomal recessive mutation in the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene. This mutation results in defective chloride ion transport, leading to thicker, more viscous body secretions and elevated chloride levels in sweat.

Key Clinical Features

i. Salty Skin: Due to high chloride concentration, parents often notice a salty taste when kissing their child.

Respiratory Symptoms

i. Thick mucus accumulation in the lungs leads to airway blockages, creating an environment for recurrent bacterial infections.
ii. Symptoms include frequent coughing, wheezing, and recurrent chest infections like pneumonia or sinusitis.
iii. Long-term respiratory complications may include bronchiectasis (dilated airways prone to mucus build-up) and respiratory failure.

Gastrointestinal Involvement
i. Pancreatic Insufficiency: Thick secretions block the pancreatic ducts, preventing enzyme release. This leads to poor fat and protein absorption, resulting in malnutrition, weight loss, and failure to thrive.
ii. Steatorrhea: Fat malabsorption causes bulky, greasy, and foul-smelling stools.
Over time, the pancreas can become damaged, leading to CF-related diabetes mellitus (CFRD).
iii. Reproductive Issues:
In males, congenital absence of the vas deferens often leads to infertility.
iv. Newborn Presentation:
Meconium ileus can occur due to thickened meconium obstructing the intestines, a potential early indicator of CF.
v. Other Common Signs:
Finger clubbing
Big appetite but poor weight gain
Progressive respiratory difficulties

Complications of Cystic Fibrosis
i. Diabetes Mellitus: Due to long-term pancreatic damage.
ii. Cirrhosis: As a result of thick secretions affecting the bile ducts.
iii. Bronchiectasis: Chronic lung changes leading to frequent infections.
iv. Respiratory Failure: The most common cause of death in CF.

Diagnosis

i. Newborn Screening:
In the UK, the Guthrie test (heel-prick test) is performed at 7–10 days old to screen for CF.
If positive, diagnosis is confirmed with a sweat test (measuring chloride levels) and genetic testing for CFTR mutations.
ii. Older Individuals:
For those presenting with symptoms later, a sweat test or genetic testing confirms the diagnosis.

Treatment and Management

i. No Cure: Treatment focuses on symptom management and preventing complications.
ii. Respiratory Care:
iii. Antibiotics: Used to treat and prevent lung infections; azithromycin may be prescribed long-term.
iv. Inhaled Treatments: Hypertonic saline and bronchodilators (e.g., salbutamol) help clear mucus.
v. Airway Clearance Techniques: Chest physiotherapy aids in mucus clearance but may have unclear long-term benefits.
vi. Lung Transplantation: Considered in advanced cases when lung function declines significantly.

Gastrointestinal Management

i. Pancreatic Enzyme Replacement Therapy (PERT): Helps with fat and protein absorption.
ii. Vitamin Supplementation: Particularly fat-soluble vitamins (A, D, E, and K) are essential.