CYSTIC FIBROSIS:

It is an autosomal genetic disorder that is more common in European countries. It is a severe disease and starts in childhood but cases are diagnosed mostly in adults.

CAUSES OF CYSTIC FIBROSIS:

It is caused by a mutation in the gene that codes for the protein  CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR (CFTR) which is located on the long arm of chromosome 7. CFTR is important because it performs the function of absorption, and secretion of sodium, chloride, water, and bicarbonate.

PATHOGENESIS OF CYSTIC FIBROSIS:

Mutation can take place at any part of the gene and it leads to defects according to the location. The most common mutation is ∆F508 and it leads to misfolding of the protein and they are retained inside the endoplasmic reticulum.

This mutation makes epithelial cells impermeable to chloride transport, so the quantity of chloride ions decreases in the airway, and sodium ion absorption increases from the airway into the epithelial cells and with sodium, water also moves toward epithelial cells and it leads to a dehydrated airway.

This causes impairment of ciliary movement and due to this mucus starts getting accumulated in the airway.

CFTR mutation can lead to cystic fibrosis which affects the patient in two ways:

1) The secretions produced are thick and tenacious which blocks the tubes in which these are secreted such as airways and pancreatic ducts.

2) As the transportation of sodium, chloride, and potassium is damaged, the sweat of the patients suffering from cystic fibrosis has abnormally elevated levels of secretion for these electrolytes.

Due to the mutation of this gene, pancreatic insufficiency occurs and absorption of food is hampered especially fat. Fat-soluble vitamins like vitamins A, D, E, and K also are not absorbed properly.

As the pancreas is affected so the islet cell undergo destruction and this can lead to the development of diabetes mellitus.

In the lungs due to decrease mucociliary clearance, the mucus keeps getting accumulated and it leads to obstruction which further progress to tracheobronchial infection and bronchiectasis.

CLINICAL FEATURE:

1) Some babies suffering from cystic fibrosis present with intestinal obstruction with thick meconium which is known as meconium ileus.

2) In childhood pancreatic insufficiency is seen in some children and some present with repeated bronchial infections.

3) Males generally suffer from sterility as both the vas deferens are absent congenitally. In females, the reproductive organs are generally normal but the fertility rate is less in them because of tenacious cervical mucus.

4) Physical examination can reveal clubbing of the fingers, wheezing or rhonchi can be heard on auscultation.

5) Hemoptysis (coughing of blood) can be one of the complications.

HOW TO DIAGNOSE CYSTIC FIBROSIS:

Along with clinical features, some laboratory investigations which can help in diagnosis are:

1) Genetic study to identify if there is a mutation of both CFTR genes.

2) The electrolyte composition of sweat is studied to check for sodium, chloride, and potassium levels. However, in this study, the levels will be high in homozygous carriers of CFTR gene mutation and the heterozygous carrier will have a normal composition of the sweat electrolytes.

3) In-utero genetic study can be done on parents with any family history.

4) Pancreatic enzymes like serum amylase, lipase, and protease should be checked. patient blood glucose should be checked too which includes fasting blood sugar, and postprandial sugar levels.

5) Chest X-ray can show increased broncho vascular marking, tram track appearance similar to bronchiectasis, and obstruction of the small airways.

TREATMENT:

1) Antibiotics are needed to prevent bacterial growth due to the accumulation of bronchial secretion.

2) Bronchodilator medicine is also prescribed by the doctor.

3) Bronchopulmonary drainage can be done.

4) Chest physiotherapy plays a good role in improving the breathing of the patient and also helps in drainage of the secretion.

5) A good nutritive diet is important to increase the strength of respiratory muscle and also improve the immune system to fight against bacterial growth.

6) Ivacaftor which is a newly designed medicine has shown some beneficial effects in improving the overall health conditions of the patient but is not beneficial in all types of CFTR mutation.