What are the effects and signs?
Effects and signs of cystic fibrosis relate to the effects of abnormal mucus production and the effects this has on organs over time. The main effects are on the lung but other organs are often affected as well. This section of the guidance describes each organ system separately; in every case the lungs will be affected, for some this will be the only or most significant problem. Most children will have lung and gut related problems and some will have more than this. Older children because they have had the condition for longer are more likely to have severe disabling effects related to their condition than younger children.
Lungs and respiratory system
The lungs are the main organ affected in every case. The state of the lungs will determine how well the child can function and usually be the main contributor to care or mobility problems. In the past children would be tested for and diagnosed with cystic fibrosis in their first years, usually already having developed the chronic respiratory symptoms associated with the condition:
- Cough in an infant under 4 weeks of age
- Wheezing as a baby or toddler
- Recurrent respiratory or chest infections
- Chest infections with unusual organisms
- Breathlessness
UK wide screening has been introduced for new born babies. Affected babies will now receive prophylactic treatment from birth. Lung damage that would have occurred in the past, prior to diagnosis, hopefully can be minimised by early interventions to clear mucus and prevent repeated chest infections. Such treatment may delay colonisation with organisms such as pseudomonas that are associated with lung damage.
Over time, despite treatment, repeated chest infections occur and the lungs are damaged by repeated cycles of infection and inflammation. Bronchiectasis (abnormal dilated airways with pooling of mucus) occurs. At some point mucus becomes chronically colonised with bacterial organisms the most common of which is called Pseudomonas aeruginosa. Once this occurs lung function tends to deteriorate more rapidly. Many of the treatments in the treatment section are designed to postpone this event for as long as possible.
The following symptoms are likely:
- Chronic cough, may produce a lot of sputum even when well
- Repeated chest infections
- Repeated chest infections with pseudomonas
- Wheezing
- Reduced exercise tolerance
- Loss of appetite and weight loss
Children with cystic fibrosis will have their lung function monitored regularly. Some children may remain relatively well with near normal exercise tolerance whilst others deteriorate, having frequent chest infections, admissions to hospital and progressive lung damage. Once enough lung function is lost oxygen demands of the body cannot be met. At first this may mean the child cannot run about, it may progress to getting out of breath walking slowly, to being unable to walk at all and getting breathless from the oxygen demands of getting dressed or eating a meal. Once a child has reached this point they may be referred to in the medical evidence as having ‘end stage lung disease’ or ‘respiratory failure’, such children are likely to be on home oxygen and may be on a waiting list for lung transplant.
Nose
The normal nose produces mucus which works to keep the nose clean and healthy. In cystic fibrosis the mucus is abnormally thick and sticky just like it is elsewhere in the body. Recurrent and chronic sinusitis is common. Nasal polyps commonly occur probably as a result of repeated infections and may need to be removed surgically. The main reasons for surgical removal are the polyps can become very large, affecting growth and development of the face or blocking the nose. Very rarely nasal polyps may erode through the sinus wall.
Gut and digestive organs
Mucus and other secretions are produced throughout the normal digestive tract by the intestines and the digestive organs. These secretions enable enzymatic digestion of food and absorption of nutrients from the diet. Cystic fibrosis has the following effects on each organ:
Intestines
The intestines normally secrete a lot of fluid in the upper end and this aids passage of intestinal contents on their journey. At the lower end the gut reabsorbs most of this fluid. In cystic fibrosis fluid secretion is much reduced and gut contents may remain relatively solid, sometimes blocking the bowel completely. When this occurs in newborns it is called ‘meconium ileus’, it is one of the ways cystic fibrosis was diagnosed at birth in the past (up to 10% affected). Meconium is the medical term for the contents of the bowel at birth which is normally evacuated within a few hours of being born. In meconium ileus the bowels are not evacuated and the baby is ill with signs of bowel obstruction. Treatment is given in hospital either in the form of enemas or surgery, there are usually no long term disabling effects.
Recurrent incomplete blockages due to abnormally solid bowel contents may occur for the same reasons later in life and may be called ‘distal intestinal obstruction syndrome’ or ‘meconium equivalent syndrome’. The symptoms are colicky abdominal pain, abdominal bloating and vomiting and failure to open the bowels. It can often be prevented from recurring by attention to the diet and treated by the use of hypertonic enemas when it occurs. Children with thick intestinal contents prone to sludging and blocking the bowel are more prone to developing acute bowel obstruction due to any cause and may require emergency surgical management. Complications of cystic fibrosis due to blockage of the intestines are likely to require hospital care and may require long term medical treatment in the form of laxatives and mucolytic agents.
Pancreas
The pancreas is a gland that secretes acid-neutralising bicarbonate and enzymes in to the upper end of the small intestine as acidic stomach contents arrive. The pancreatic digestive enzymes cannot work in an acidic environment. Unfortunately in cystic fibrosis bicarbonate secretion is reduced and enzymes work less efficiently. Thick mucus may block pancreatic ducts leading to inflammation and pancreatitis damaging the enzyme producing capacity of the pancreas. This leads to the characteristic cystic and fibrosed (scarred) appearance of the pancreas seen in cystic fibrosis that gave the condition its name. In most it is severe and pancreatic insufficiency occurs. This is a clinical syndrome of inadequate production of digestive enzymes and inadequate absorption of calories and nutrients from the diet that causes growth retardation and vitamin deficiencies even though the diet is adequate. The symptoms of this are:
- Poor weight gain (failure to thrive)
- Frequent greasy offensive stools (steatorrhoea)
- Flatulence
- Colicky abdominal pain after feeding
- Vitamin deficiencies – especially fat soluble vitamins A, D, E and K
This complication may be managed by pancreatic enzyme supplements taken by mouth and may require medication to reduce the acidity of intestinal contents. In severe cases particularly when the appetite is reduced through chronic illness artificial feeding may be required.
Cystic Fibrosis Related Diabetes
The pancreas is also an endocrine gland that produces insulin. This function of the pancreas can fail. The loss of insulin producing capacity is usually very gradual in cystic fibrosis and this type of diabetes is called Cystic Fibrosis Related Diabetes (CFRD). There is a long period during which insulin continues to be produced but levels are not quite enough to prevent hyperglycaemia after meals. Affected children are often screened for diabetes with an oral glucose tolerance test yearly once they are 12. About 50% of people with cystic fibrosis will become diabetic by the age of 30. Some children may require an insulin injection just to cover meals; others will require a more standard regimen because they produce no insulin. Blood sugar management may be complicated by artificial feeding, for example overnight gastrostomy feeding. The principles of managing blood sugar are the same in children with cystic fibrosis as they are for children with type 1 diabetes. However dietary advice given to children with CF will differ from that given to children with type I diabetes in view of the need for a high calorie diet in CF.
Liver
The liver has an important role in digestion through the production of secretions in to the upper part of the small bowel and it is affected by cystic fibrosis. These secretions are called bile, bile carries breakdown products for excretion and helps to neutralise stomach acid along with pancreatic secretions. The effect is that small bile ducts in the liver that secrete bile may become blocked by thick secretions; this can lead to cirrhosis of the liver. Cirrhosis tends not to cause symptoms until it is at an advanced stage and the liver is failing. Cirrhosis has serious complications including portal hypertension (high blood pressure in the veins draining the gut) and oesophageal varices (dilated veins at the lower end of the oesophagus that can bleed profusely). Symptoms of advanced cirrhosis are those of bleeding from the gut and liver failure and include lethargy, jaundice, ascites and confusion.
Because the bile is thicker than normal, gallstones are more common and occur at a younger age in cystic fibrosis. Gallstones can usually be removed surgically.
