cystic fibrosis

The cystic fibrosis - A serious and potentially fatal genetic disorder, characterized by a tendency to develop chronic lung infections combined with an inability to absorb fats and other nutrients from food. The main characteristic feature of cystic fibrosis (CF) is the secretion of sticky, viscous mucus in the nose, throat, airways, and intestines.

CAUSES:
CF is caused by an inherited defect in a gene. The defect is recessive, which means that one faulty gene must be inherited from each parent before any abnormality appears. People with only one defective gene have no symptoms but are “carriers” and can pass the gene on to their children. 209

The defective gene causes a biochemical abnormality in which the faulty movement of ions across cell membranes affects mucus formation. As a result, the mucus-forming glands in several organs do not function properly. Most seriously, the glands in the lining of the bronchial tubes produce thick mucus, which predisposes the person to chronic lung infections.

Another serious malfunction is poor or absent secretion of pancreatic enzymes, which are involved in the breakdown and absorption of fats in the intestine. The sweat glands are also affected and excrete excessive amounts of salt.

SYMPTOMS AND COMPLICATIONS:
The course and severity of CF vary. Typically, a child passes unformed, pale, oily, foul-smelling faeces and may fail to thrive. Often, growth is stunted and the child has recurrent respiratory infections. Without prompt treatment, pneumonia, bronchitis, and bronchiectasis may develop, causing lung damage. Most males and some females are infertile. Excessive salt loss from sweating may lead to heatstroke and collapse.

DIAGNOSIS AND TREATMENT:
Early diagnosis, confirmed by simple sweat and blood tests, improves the outlook for children with CF. Prompt treatment with intensive physiotherapy and antibiotics helps to reduce the severity and frequency of lung infections.

In addition, lung function may be improved by treatment with dornase alfa, a genetically engineered version of a human enzyme, which is administered by nebulizer. Pancreatin and a diet rich in proteins and calories are given to bring about weight gain and encourage more normal faeces. Supervision of the treatment is best carried out from a special centre that is staffed by paediatricians, nurses, and physiotherapists who have particular knowledge of the disease.

OUTLOOK:
The highly specialized treatment now available for people with CF maximizes their chances of a reasonable quality of life. About 9 in 10 children survive into their teens; many live well into their 40s. Progressive respiratory failure is the usual cause of death, but in some cases a heart-lung transplant may be considered.