The upper respiratory tract—nose, nasal passages or sinuses, and the pharynx—filters and warms the air. Several abnormalities, such as nasal polyps and excess tissue growth in the nasal cavity, may affect people with CF. Chronic or recurrent sinusitis occurs when secretions become infected and cause inflammation. As in the lungs, mucus in the sinuses is abnormally thick and cannot be cleared easily; promoting accumulation of bacteria and inflammation that stimulates more mucus production. Often, the sinuses are infected with bacteria similar to those found in the lungs. Recurrent or chronic sinusitis is typically treated with antibiotics and saline irrigation. In some cases endoscopic surgery is preformed to remove polyps and promote mucus drainage.

A CT scan of a child with CF shows that the right maxillary sinus is completely filled with mucus.

The structure of the lung allows rapid uptake of oxygen from the air and diffusion into the bloodstream. Air is warmed and moistened in the mouth and nose, which makes it less irritating to the airways, while nose hairs trap particles such as dust, pollen, and bacteria. The filtered air then moves through branching airways that are lined with mucus to collect any particles that get through. The air travels through smaller and smaller airway branches until reaching tiny air sacs called alveoli, where oxygen and carbon dioxide are exchanged.

In CF, faulty transport of electrolytes across airway tissues leads to abnormal mucus production along the respiratory tract. This mucus is easily dehydrated and difficult to clear. Eventually, the mucus obstructs the airway, impairing the alveoli, and prevents foreign particles from being cleared, resulting in chronic lung infections.

Chronic Lung Disease

Cystic fibrosis airways are obstructed by thick mucus that make it difficult to clear infection-causing bacteria like Pseudomonas aeruginosa, Staphylococcus aureus, Hemophilus influenzae and Burkholderia cepacia. Over time, chronic bacterial infections lead to inflammation and damage to the airway walls and bronchiectasis, an abnormal stretching of the respiratory passages.

Several tests determine the extent of infection, inflammation, bronchiectasis and mucus plugging in the lungs. Spirometry (pulmonary function testing or PFT) measures the respiratory cycle as an individual breathes in and out of a mouthpiece. Changes in the rate of airflow will detect the progression of lung disease and response to therapy. More extensive pulmonary imaging procedures such as chest X-rays and chest CT scans are also used to determine the extent of CF lung disease.

Pulmonary Exacerbation

Cystic fibrosis is characterized by recurrent pulmonary problems like shortness of breath, increased cough and sputum production, fatigue and occasionally hemoptysis, or coughing up of blood. Exacerbations are caused by bacterial or viral infections in the bronchi and bronchioles leading to inflammation. Some pulmonary exacerbations can be treated at home with antibiotics, aggressive airway clearance and breathing treatments. If symptoms persist or worsen, hospitalization will likely be necessary for intravenous antibiotics and other interventions

The pancreas, located behind the stomach in the center of the abdomen, extends into the left side of the abdomen. The pancreas is connected to the first part of the intestine, the duodenum. The pancreas secretes enzymes that aid food digestion and help to regulate blood sugar.

Abnormal Function in CF

In CF, the altered transport of electrolytes across pancreatic tissues leads to abnormal production of digestive enzymes. Decreased production of sodium bicarbonate makes pancreatic secretions dehydrated and thickened, blocking the pancreatic ducts. Despite these blockages, the pancreas continues to make more enzymes required for food digestion. The abundant enzymes damage the pancreatic tissue, eventually leading to fibrosis of the pancreas until it is no longer able to produce enough enzymes to properly digest food. The lack of bicarbonate secretion also prevents stomach acid from being neutralized when it enters the small intestine.

Pancreatic Insufficiency

Pancreatic insufficiency occurs when the pancreas loses about 90 percent of its ability to secrete digestive enzymes. People with pancreatic insufficiency are unable to digest food properly, which leads to the malabsorption of nutrients, or even malnutrition. Fat-soluble vitamins, such as A, D, E, and K, and fats, are the most important nutrients that are not absorbed. The impaired absorption of fats causes diarrhea, weight loss, and malnutrition, but supplemental pancreatic enzymes can help with digestion. Approximately 80 percent of people with CF develop pancreatic insufficiency.

Large Intestine

The large intestine is involved in the reabsorption of water from the gastrointestinal tract and is also the site of feces formation and excretion. The large intestine spans the perimeter of the abdomen. The large intestine does not function normally in CF. Incompletely digested proteins, sugars, and fats, decreased electrolytes and water content make the feces very thick.

Distal Intestinal Obstruction Syndrome

Individuals with CF are prone to intestinal impaction and obstruction. Symptoms include decreased stool output, abdominal pain and distention, nausea, and vomiting. Previously known as meconium ileus equivalent, the newer terminology is distal intestinal obstruction syndrome, or DIOS. About 10 to 20 percent of people with CF will have DIOS at least once, and up to approximately 5 percent of people will have recurrences. Prompt recognition is essential for proper treatment. Physical examination and X-rays of the abdomen can diagnose this blockage. Treatment varies based upon the severity of the symptoms and degree of intestinal obstruction. Laxatives and enemas are typical therapies.

Recal Prolapse

In this condition, the lower part of the colon, called the rectum, falls out of its usual position and can be seen outside the body. Rectal prolapse can be a presenting symptom for some children with CF.

Colon Cancer

Compared with the general population, individuals with CF have a similar overall risk of cancer. But when it comes to colon cancer and other intestinal cancers, studies show, people with CF have an increased risk. The CF Foundation recommends routine colon cancer screening for adults with CFTR. The best screening test is a colonoscopy.

Individuals with pancreatic insufficiency often develop CF-related diabetes (CFRD) because pancreatic duct blockages and digestive enzyme damage lead to chronic inflammation and fibrosis or scarring of the pancreas. This scarring impairs the endocrine functions of the pancreas, such as regulating insulin secretion. Impaired production of insulin results in diabetes mellitus. Diabetes or impaired glucose regulation occurs in over 40 percent of people with CF over the age of 35. Cystic fibrosis-related diabetes (CFRD) has features of both Type I and Type II diabetes. Once diagnosed, strict blood glucose control is required using frequent monitoring and insulin injections. A decline in pulmonary function may be related to uncontrolled diabetes. Other complications, including: kidney, neurological and eye disease can also occur.

Male Reproductive System

Cystic fibrosis affects the male reproductive system leading to bilateral absence of the vas deferens in most people. Recent medical advances have made this a potentially treatable problem. In vitro fertilization (IVF) can be used with a technique called intracytoplasmic sperm injection (ICSI). Microepididymal Sperm Aspiration (MESA) is a procedure performed for men who have bilateral absence of the vas deferens. This procedure is either done as a scheduled procedure or is coordinated with their female partner’s egg retrieval. MESA is performed in the operating room with general anesthesia utilizing the operating microscope. People usually cryopreserve sperm during this procedure for future IVF/ICSI. MESA allows for an extensive collection of sperm as compared to aspiration techniques, and is the preferred method of retrieval for men with bilateral absence of the vas deferens.

In males with CF with chronic lung disease and malnutrition, puberty is often delayed because of impaired production of sexual development hormones, follicle-stimulating hormone (FSH) and luteinizing hormones (LH). Despite this delayed onset, over 90 percent of individuals CF with adequate nutrition achieve normal height. For males with CF, there is a four-fold increase in the incidence of fluid accumulation around the testes, known as hydrocele. There is a fifteen-fold increase in the risk of having an undescended testicle.

Female Reproductive System

Women with CF can have functional reproductive abnormalities, such as absence of menstruation, related to malnutrition and chronic disease. Although there are no structural reproductive abnormalities, the quality and quantity of the cervical mucus essential to implantation of the fertilized egg can be altered. However, a woman’s overall heath will determine her fertility. With good nutrition and lung function, fertility rates approach that of the general population. However, even women with severe disease can become pregnant.

Muscle

Muscle weakness, particularly in the arms, legs and diaphragm, is common in individuals with CF. Malnutrition contributes greatly to muscle dysfunction. Chronic illness leads to reduction in muscle mass and strength, and impaired regulation of electrolytes, the hallmark of CF, also contributes to muscle weakness. Medications used to treat CF complications, like steroids, may worsen underlying muscle weakness. Proper nutrition and regular exercise help maintain conditioning and retain muscle mass.

Bone

Adults with CF are at a high risk for reduced bone density, known as osteoporosis. Over 70 percent of adults with CF will develop the condition. Thinning of the bones makes them more prone to fractures that may occur even without trauma. Low levels of vitamin D—due to malabsorption—impair bone formation. Individuals with CF are further prone to low vitamin D levels because they may not receive adequate sunlight exposure required for converting vitamin D into its active form. Recommendations for vitamin D supplementation are available.

This accelerated bone breakdown increases with inactivity, chronic lung disease, and steroid use. Also, inflammation from chronic lung disease may increase bone breakdown. Lung transplant recipients using immunosuppressive drugs like corticosteroids also have an accelerated rate of bone loss. Low levels of sex hormones important to bone development and delayed onset of puberty limit the time for adult bone formation, more often in men. Cystic fibrosis-related diabetes, alcohol use and cigarette smoking may also hasten the onset of osteoporosis.

Adults with CF should be screened every 1-5 years with a DEXA (Dual-energy radiograph absorptiometry) scan. Using two separate X-rays, it measures bone density at the spine, femur, and other sites. Patients should also have serum vitamin D levels checked annually along with diabetes screening. Prevention of osteoporosis involves implementation of a health plan that emphasizes diet and weight-bearing exercise.