Cystic Fibrosis

Cystic fibrosis is the most common fatal and inherited disease in Caucasian populations, caused by the acquisition of two recessive genes from carriers who are typically not affected themselves. The abnormality affects the so-called exocrine glands and the most obvious and troublesome feature is the development of chronic infections of the respiratory tract. Many organ systems are affected by the glandular abnormalities but it is the eventual failure of the respiratory system which is the most common cause of death.

Increased thickness of the mucus produced by the body is the main abnormality caused by the lack of the normal genes, increasing the likelihood of infection by bacteria. Respiratory tract secretions are more viscid and so difficult to expectorate but also affected are the sweat glands, digestive tract, liver and pancreas. The lungs are normal at birth but the start of a cycle of infections and inflammatory reactions occurs leading to the routine presence of bacteria in the lungs. Respiratory failure can ensue as the membranes of the lungs thicken and gas exchange becomes less efficient.

A reduction in the efficiency of nutrient absorption and the possibility of bowel obstruction can occur from thickened mucus secretions blocking the gut, poor nutrition showing in a baby failing to thrive which means they do not grow as normally expected. Adhesions in the gut can progress to obstruction and require bowel surgery to remove a length which reduced further the area for absorption. Pancreatic enzymes work with a reduced efficiency and if pancreatic insufficiency occurs then poor absorption of fat soluble vitamins such as D, E, A and K is likely.

The incidence of cystic fibrosis makes it the most frequently occurring lethal genetic condition, inherited via a recessive gene trait. In populations of white European origin the typical frequency is one in 3200 births while in populations in Asia this may be one in 90,000 only. 37 years is the typical age of survival with male patients living for a significantly longer period than female patients. Progression of the lung abnormalities goes from bronchitis to bronchiectasis and then on to heart failure with end stage disease of the lungs. The disease is very variable in how it progresses, the age of the patient at presentation, the severity of the symptoms and the manner of disease progression.

Gallbladder inflammatory changes and the presence of gallstones have a higher incidence in patients with cystic fibrosis. Secondary sexual characteristics and the onset of puberty are typically delayed and males are infertile due to absence of a vas deferens, while female patients may have reduced fertility to some degree. Progression of lung disease is worse in patients who come from the lower socioeconomic levels. Overall the severity of lung symptoms is less in male patients than in female patients, with females suffering worse lung prognosis and a lower life expectancy.

The diagnosis and management of cystic fibrosis is a complex matter with involvement of a large number of body systems so a multidisciplinary team is necessary for full evaluation, preferably in a centre which specialises in these conditions. Once the diagnosis and investigations have been taken care of, the plan of treatment involves many aspects of disease management. Patient and/or parent education is crucial as the length of life and the quality of life is strongly affected by the patient’s adherence to the treatment regimen. Coping with a disabling and lifelong condition can require counselling and airway clearance techniques and the use of nebulisers and inhalers should be taught by a physiotherapist.

The complications of respiratory disease may need surgical management to treat such conditions such as collapsed lung or considerable coughing up of blood. Gastrointestinal complications and obstruction may also need to be managed surgically. End stage lung disease can be managed by lung transplant or heart-lung transplant, but transplants may not increase life expectancy although quality of life may be improved. The diet can be essentially normal with an increased energy and fat intake recommended with supplementation of vitamins and minerals. Malabsorption of nutrients and the increased nutrient demand of having chronic inflammation require nutritional supplementation.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapists, physiotherapy, Bristol Physiotherapy, back pain, orthopaedic conditions, neck pain and injury management. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.