Introduction
Cystic fibrosis is a genetic (inherited) disorder that is known to affect a specific protein in the human body, leading to a faulty protein that affects cells, tissues and glands that are responsible for making mucus and sweat. This disorder causes problems with breathing and digestion.
In a normal lung with a healthy bronchus, the airway is completely open with good airflow while in lungs with cystic fibrosis, mucus clogs the airways leading to poor airflow. Airway blockage can lead to frequent infections and difficulty breathing.
The order of inheritance for CF is autosomal recessive manner, meaning that an individual must inherit 2 mutated CFTR genes, each from a biological parent.
CF affects cells that produce mucus, sweat and digestive juices.
Some individuals with CF have few or no symptoms at all, while others can exhibit severe or life-threatening conditions.
CF affects various organs in the body such as lungs and pancreas.
It makes individuals with this disease more likely to develop other medical conditions such as:
Key Facts & Statistics
What are the Key Facts and Statistics surrounding cystic fibrosis?
- Cystic fibrosis affects all races.
- Almost 40,000 persons in the United States and more than 100,000 globally live with cystic fibrosis.
- In the US, children who were born between 2018-2022 and have CF are expected to have a life expectancy of averagely 56 years.
- On the same note, 50% of babies born in 2021 and have CF are expected to live to the age of 65 years or more.
Risk Factors
What are the risk factors for cystic fibrosis?
- Positive family history of CF.
- Race. CF is common in whites from Northern Europe.
- CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene mutation
Causes
What are the causes of cystic fibrosis(CF)?
Genetic mutations to CFTR(Cystic Fibrosis Transmembrane Conductance Regulator) gene cause cystic fibrosis.
CFTR gene makes a protein that works as a chloride ion channel. As chloride ions move out of the cell, they take with them water therefore thinning out mucus and making it become more slippery.
CFTR genetic mutations prevent this normal phenomenon from happening, therefore mucus stays thick and sticky.
Mucus of this kind does not act as a lubricant. Instead, it clogs the tubes, ducts and other passages, especially in the lungs and pancreas.
CF results mainly in chronic respiratory tract infections, pancreatic enzyme insufficiency and other associated complications.
Signs & Symptoms
What are the symptoms of cystic fibrosis?
The following are systemic signs and symptoms of cystic fibrosis:
Gastro-intestinal :
- Loose or oily/greasy faeces(steatorrhea), that are foul-smelling.
- Intestinal blockage in newborns(meconium ileus)
- Severe constipation that can lead to rectal prolapse
- Recurrent abdominal pain
- Abdominal distention
- Jaundice
- GI bleeding
Genito-urinary:
- Amenorrhea
- Delayed secondary sexual development
- Undescended testicles(hydrocele)
Respiratory:
- Wheezing
- Inflamed nasal passages
- Frequent sinus infections(recurrent sinusitis)
- Persistent coughing with thick mucus
- Difficulty breathing(dyspnea on exertion)
- Atypical asthma
- Frequent lung infections such as recurrent pneumonia.
Types
What are types of CF?
There are two types of cystic fibrosis, which are:
- Classic cystic fibrosis
- Atypical cystic fibrosis.
Diagnosis
Diagnosis of cystic fibrosis:
Although the age at which diagnosis can occur varies widely, the median age at diagnosis is 6-8 months old.
Diagnosis involves screening and other tests listed below:
- Screening. Newborns are screened, especially in countries like USA, to check for CF.
- Sweat test. This measures the quantity of chloride ions in sweat. Chloride ion levels are raised in individuals with CF. Although being the most conclusive test, sweat test may show normal chloride levels in people with atypical CF.
- Genetic tests. These check for presence of CFTR gene.
- Pulmonary function tests. They measure how well the lungs are functioning.
- Sputum culture. This test checks for certain bacteria that are mostly found in persons with CF. An example is Pseudomonas bacteria.
- Pancreatic biopsy to check for cysts or injury to pancreas.
- Imaging. For example, chest X-rays, to support diagnosis of CF.
- Intestinal current measurement(ICM). This measures how much chloride is secreted.
Treatment & Management
How is cystic fibrosis treated?
Currently, there is no cure for cystic fibrosis.
But, the disease and its symptoms are manageable.
These include the following:
- Airway clearance techniques
- CFTR modulators for CF
- Surgery
- Diet
Airway clearance techniques:
- Coughing and breathing techniques.
- Positive expiratory pressure (PEP) devices.
- Postural drainage and percussion.
- Airway clearance tests.
CFTR modulators for CF aid in correcting issues with CFTR proteins.
Examples are:
- Ivacaftor
- Ivafactor/lumafactor
Other medications for CF are:
- Antibiotics
- Inhaled bronchodilators
- Inhaled hypertonic saline
- Anti-inflammatory drugs
- Pancreatic enzymes
- Stool softeners for constipation
Surgical procedures:
Lung and liver transplant.
Cystic fibrosis diet:
- Enzyme supplements.
- Higher intake of salt.
- Fatty foods.
- Increased caloric intake.
Complications
What are the complications of CF?
Respiratory complications:
- Bronchiectasis(damaged airways)
- Nasal polyps.
- Chronic lung infections.
- Acute exacerbations
- Respiratory failure, which can lead to death.
- Pneumothorax
- Coughing up blood.
Reproductive system complications:
- Pregnancy complications in women such as preterm delivery
- Infertility in men and people assigned male at birth (Congenital bilateral absence of the epididymis(vas deferens/ sperm duct))
Gastro-intestinal system complications:
- Diabetes
- Liver diseases such as liver cirrhosis, fatty liver disease and jaundice
- Intestinal obstruction
Other complications of CF are:
- Frequent infections
- Osteopenia and osteoporosis
- Dehydration
- Electrolyte imbalance
Prevention
What are the prevention measures for CF?
It seems impossible to prevent CF from manifesting as it is inherited and individuals are born with it.
Screening couples before pregnancy to see if they could have a baby with CF and pregnant mothers during pregnancy to check if they carry a child with CF