Cystic fibrosis (CF for short) is one of the most common inborn errors of metabolism in the fair-skinned population. Due to a gene mutation, the disease causes the body’s glands to produce viscous mucus that is difficult to drain. This results in typical symptoms such as chronic bronchitis, digestive disorders and deficient pancreatic function. Cystic fibrosis is not curable, but with early consistent therapy, patients born today have a life expectancy of 50 years.
Cystic fibrosis: genetic defect as cause
In cystic fibrosis, there is impaired production of a channel on the cells of the body’s glands because of an altered gene on chromosome 7. As a result, certain salt components (chloride ions) and water cannot be released into the glandular secretions or filtered out. The result is an altered composition of the secretions: the sweat glands produce highly saline sweat, while the mucus in the lungs and intestines and the digestive juices of the pancreas are very viscous. This viscous mucus is particularly difficult for the cells of the bronchial tubes to remove, resulting in difficult breathing and recurrent infections.
Symptoms: Airways particularly affected
Cystic fibrosis is manifested by multifaceted symptoms that can vary in severity depending on the gene mutation. The respiratory tract and lungs are usually particularly severely affected: The viscous mucus produced by the bronchial glands cannot be removed by the cilia of the bronchial tubes, so that it is not coughed up despite chronic coughing. This causes a buildup of secretions, which forms an ideal breeding ground for fungi and bacteria. As a result, recurrent infections such as pneumonia and chronic bronchitis occur. In addition, sinusitis frequently occurs in cystic fibrosis because the drainage of mucus from the sinuses is also impeded. The frequent inflammations cause lung tissue to become damaged and scarred. As a result, lung function increasingly deteriorates. In the advanced stage, patients therefore often suffer from lung weakness and oxygen deficiency.
Malnutrition due to digestive disorders
The digestive system is also usually impaired in cystic fibrosis. The secretion produced by the pancreas is also viscous and clogs the gland’s excretory ducts. This leads, on the one hand, to the digestive enzymes contained in the secretion not being released into the small intestine and, as a result, the food cannot be adequately utilized. Patients with cystic fibrosis therefore often suffer from vitamin deficiencies and growth disorders: Children in particular are usually underweight and significantly too small for their age. In addition, diarrhea, constipation or fatty stools may occur. On the other hand, the congestion of secretions in the pancreas damages glandular cells and replaces them with connective tissue. In the long term, this leads to a loss of function of the pancreas, which can be manifested by a chronic deficiency of digestive enzymes as well as diabetes mellitus. Due to the viscous bile, gallstones and bile stasis can also occur. Possible consequences of this can be inflammation of the liver and, in the further course, cirrhosis of the liver, which may manifest itself as jaundice (icterus).
Infertility in cystic fibrosis.
In addition to the respiratory tract and digestive system, the reproductive organs may also be affected in cystic fibrosis. In 98 percent of men with the disease, the vas deferens are either stuck together or completely absent from birth. Both lead to the affected patients being unable to father children. Although sperm are produced in the testicles, they cannot be ejected during ejaculation. Affected women, on the other hand, usually have only reduced fertility because the mucus in the cervix is more viscous than in healthy individuals, making it more difficult for sperm to penetrate. Nevertheless, patients with cystic fibrosis may be able to conceive children naturally. However, artificial insemination may be an option for both sexes.
Bowel obstruction in babies as first sign
In about 10 to 15 percent of all children with cystic fibrosis, intestinal obstruction (meconium ileus) immediately before or after birth is the first sign of the disease. In this case, undigested amniotic fluid components combined with viscous intestinal mucus cause the intestine to stick together.This is conspicuous by the fact that the newborns vomit and do not pass their first stool (meconium, infantile vomit). In addition, the abdomen is often distended. To correct the intestinal obstruction, an enema with contrast medium is usually first performed under X-ray fluoroscopy. If the bowel obstruction persists afterward or if complications occur, surgery is usually necessary.
Diagnosis of cystic fibrosis
Unlike in many European countries, screening for cystic fibrosis in newborns is not standard in Germany. However, parents have the option of having their child screened at their own expense. The first step is to determine the level of a pancreatic digestive enzyme – known as immunoreactive trypsin – in the blood. If this test is positive twice, a sweat test (pilocarpine iontophoresis) is performed to confirm the diagnosis. This involves measuring the salt content in the sweat. If this is significantly increased, this confirms the diagnosis of cystic fibrosis. However, if the result of the tests is not clear, an additional potential difference measurement can be used. This involves determining the electrical properties of a tissue sample from the nasal mucosa or rectum. If the disease cystic fibrosis is present, the electrical potential at the mucosa is altered due to the disturbed water and salt balance of the cells.
Genetic testing brings certainty
Final certainty is provided by genetic testing of the blood, which detects the gene mutation in the genetic material. This also determines the type of mutation, which can provide more precise information about the severity and expression of the disease. Prenatal diagnosis of cystic fibrosis is only useful if there is already a sick child in a family or if one parent is a healthy carrier. Genetic testing of amniotic fluid (amniocentesis) or a sample of the fetal part of the placenta (chorionic villus sampling) can detect a gene mutation in the child’s genetic material.
Cystic fibrosis: inheritance.
The inheritance of cystic fibrosis follows what is known as autosomal recessive inheritance. This means that a person will only develop cystic fibrosis if he or she inherits a chromosome 7 with a defective gene from both his or her father and mother. People who have one affected and one healthy chromosome in their genome do not develop the disease. However, they can pass on the defective gene to their children and are therefore called healthy carriers of the disease.
Therapies for cystic fibrosis.
There is no cure for cystic fibrosis; however, there are numerous therapies available today to treat the symptoms of each organ system:
- For the respiratory system, mucus-loosening procedures are the primary focus: physical therapy treatments such as tapping massages and learning self-cleaning techniques such as autogenous drainage facilitate the removal of mucus from the lungs. In addition, regular inhalations with mucolytic, antibacterial and bronchodilator medications are useful. Patients with cystic fibrosis should also ensure adequate fluid intake to liquefy mucus.
- Breathing training and special exercises can improve lung function. If lung function is severely compromised, supportive oxygen therapy may be necessary. In some cases, however, the lungs are so severely damaged in the advanced stages of the disease that a lung transplant must be considered.
- To treat and prevent infections, consistent therapy with antibiotics is usually necessary.
- The enzymes of the pancreas can be taken in the form of tablets to support food utilization. Vitamin supplements and other dietary supplements can also counteract malnutrition.
- If the liver is inflamed or the bile ducts are impaired, medications containing ursodeoxycholic acid can be taken to prevent cirrhosis of the liver.
Prognosis: life expectancy has increased significantly
After cystic fibrosis was long considered a mere childhood disease, the life expectancy of patients has increased significantly in recent decades. This is because early diagnosis and careful treatment can now often prevent serious infections and subsequent damage to the organs.Whereas 30 years ago most children with the disease died before the age of ten, newborns with cystic fibrosis now have a good chance of living to 50.
Improve performance with exercise
Sports are not forbidden in cystic fibrosis; on the contrary, physical activity can definitely have a positive effect on the course of the disease. This is because exercise can improve the body’s resilience and strengthen lung function. As a rule, gentle endurance sports such as cycling or walking are suitable. Before starting to exercise, however, it is best for those affected to seek advice from their doctor. Performance in cystic fibrosis varies greatly from individual to individual: time and again, there are reports of patients who run a marathon thanks to consistent therapy and intensive training.
