How CF Manifests in the Body Over Time

Everybody with cystic fibrosis (CF) experiences progression of CF over time. Progression can occur when the thick mucus building up throughout the body causes inflammation and scarring in many different organs, leading to permanent damage. This damage is often present before it can even be detected by tests, so it's important to stay proactive in conversations with your care team. Since not everyone’s CF progresses in the same way, they can help determine a plan for managing CF that’s right for you or your loved one.

CF in the lungs

Starting from a young age, lung damage may occur before it can even be noticed. There's one thing that remains the same across CF-causing CFTR protein defects—they all cause mucus in different parts of the body to thicken. Even if someone with CF doesn’t feel it, this mucus can cause damage from an early age.

Mucus buildup can lead to infections and inflammation: Thick, sticky mucus is found in the airways of the lungs and may cause symptoms such as wheezing, shortness of breath, and a phlegmy cough. This mucus buildup can’t be cleared from the airways easily. Bacteria can be found in this mucus buildup as well, causing infection, inflammation, and scarring. For someone with CF, a common bacteria in the respiratory tract is called Pseudomonas aeruginosa. If present, this infection should be immediately treated with antibiotics, and it may require continual treatment over time.

Repeated pulmonary exacerbations can lead to permanent lung damage: Beginning early, the buildup of thick, sticky mucus in the lungs results in a cycle of infection, inflammation, and further mucus buildup. Pulmonary exacerbations are often a key part of this cycle. Most people with CF are familiar with pulmonary exacerbations as periods of time when symptoms and/or lung function worsen. These events may require treatment with antibiotics, whether they are by mouth, inhaled, or intravenous (IV), and even a hospital stay. It’s important to have regular check-ins with your care teams so they can monitor respiratory symptoms and lung function, since pulmonary exacerbations may cause permanent lung damage that advances disease progression.

Bronchiectasis causes loss of lung function: It’s important to promptly treat pulmonary exacerbations to prevent and slow the progression of bronchiectasis, a permanent reshaping of the airways that causes them to become loose and scarred. Bronchiectasis eventually affects almost all people with CF and can make it harder to clear mucus from the lungs and move air in and out of the airways. As it worsens, the lungs become more damaged, leading to a permanent loss of lung function.

As adults with CF get older, other pulmonary complications may arise: gradually, over the course of many years, people with CF may develop serious issues such as:

Hemoptysis, coughing up blood
Pneumothorax, a collapsed lung
Advanced lung disease
Respiratory failure

People with CF can have other lung conditions—like asthma. About 20% to 30% of people with CF can also have asthma. Diagnosing asthma in someone with CF can be challenging. If needed, care teams may adjust breathing treatments to treat both conditions.

Getting ahead of lung function decline

It’s never too early to talk to a healthcare provider about potential lung damage. Part of what makes lung function decline so serious is that some people don’t always feel the change. So someone may lose a lot of lung function before they begin to feel like something is wrong. Here are some things to keep in mind when discussing with your CF care team:

In CF, permanent lung damage may occur even before it can be detected by lung function tests
Starting from a young age, people with CF may experience lung function decline of 1% to 3% each year on average
Early management interventions may help slow disease progression and prevent certain complications

Remember, CF is different for everyone. But all cases of CF progress over time. The first step toward managing CF is to take a proactive approach to care.

CF in the digestive system

While CF is often thought of as a problem with the lungs, it also causes significant problems in the digestive system, including the pancreas, liver, and intestines.

Impact on the pancreas

The pancreas does two important jobs. It makes enzymes that help break down food. It also makes hormones, such as insulin, which help regulate blood sugar levels. As CF progresses and thick fluids block the ducts (small tubes) within the pancreas, it can limit the pancreas' ability to do these jobs. This can lead to:

Poor growth and slow weight gain, even if a lot of food is eaten
Frequent, greasy, and bulky stools
Pancreatic insufficiency (PI)
- In people with CF, thick fluids block small tubes in the pancreas called ducts. This blockage makes it harder for the enzymes to reach the small intestine where they help digest food. Not having a sufficient amount of these digestive enzymes in the small intestine leads to PI, which affects 85% to 90% of people with CF even at a young age
Pancreatitis
- Patients that remain pancreatic sufficient may experience a condition called pancreatitis. Pancreatitis is inflammation of the pancreas, and it can result in severe symptoms such as abdominal and back pain, nausea, vomiting, fever, rapid pulse, and weight loss
Cystic fibrosis-related diabetes (CFRD)
- Overtime, scarring in the pancreas caused by thick digestive fluids can damage the cells that produce insulin, and some people with CF can develop CFRD. CFRD is a form of diabetes seen in people with CF that occurs when the pancreas doesn't make enough insulin. When acutely ill, the body also may not properly use the insulin it does produce. As a result, blood sugar levels will increase

According to the American Diabetes Association, annual screening for CFRD should begin by age 10 in all people with CF who do not have CFRD.

~25% of people with CF have CFRD by their 20s

This increases to almost 50%
by the time they reach their 40s

This increases to almost
50% by the time they
reach their 40s

CFRD is a serious condition. Some of the symptoms may be similar to CF. If CFRD is left untreated, CF symptoms can worsen and the effects of chronic high blood sugar can lead to:

Reduced ability to fight infection
Muscle loss
Weight loss
Liver disease
Nerve problems
Complications in the kidneys
Decline in vision

Note that CFRD is different from type 1 and type 2 diabetes and, therefore, is treated differently.

Impact on the liver

The liver is another part of the digestive system affected by CF. Inside the liver are ducts that are meant to drain it of bile. In people with CF, bile is thicker. As a result, the bile ducts can become blocked, leading to irritation or inflammation in the liver. Over time, thick bile can lead to scarring and damage to the liver.

Liver disease is considered to be one of the most serious health risks associated with CF. CF-related liver disease may show up as a buildup of fat in the liver, hepatitis, or a condition called cirrhosis. Keep in mind that cirrhosis occurs in the late stages of CF-related liver disease and not everyone with CF-related liver disease experiences it. Cirrhosis makes it difficult for blood to travel through the liver. It can cause many complications, including:

Low blood counts
Fluid buildup in the abdomen
Bleeding in the esophagus
Difficulty breathing

Care teams regularly monitor liver function in people with CF to check for CF progression in the liver because CF-related liver disease may be present without symptoms.

Impact on the intestines

Thicker digestive fluids can also block the intestines. In most people with CF, blockage of the intestines mainly leads to chronic constipation. It can also lead to acute conditions such as meconium ileus and distal intestinal obstruction syndrome, also known as DIOS. Meconium ileus is a serious form of intestinal blockage that occurs only in newborns, whereas DIOS is an acute problem that can occur at all ages. Both meconium ileus and DIOS may require immediate medical intervention to be treated.

In adults with CF, there is also a greater risk of developing colorectal cancer (especially for people who have received a lung or other solid organ transplant). Most colorectal cancers start as a certain kind of polyp on the inner lining of the colon or rectum called an adenoma. While the cancer doesn’t develop quickly, if left unnoticed it can grow into the wall of the colon or rectum, spread to other parts of the body, and become difficult to treat. It’s important to talk to your care team about getting screened for colorectal cancer, since many people do not experience symptoms until it has spread.

CF in the kidneys

CF does not directly affect the kidneys, however, about 2% of people with CF between the ages of 25 and 35 have chronic kidney disease (CKD). There are 3 risk factors that make adults with CF at risk for CKD:

Treatments with certain necessary medicines
- Treating other CF-related conditions with medicines such as antibiotics for an extended period of time can affect the kidneys
Progressive cystic fibrosis-related diabetes (CFRD)
- High blood sugar in people with CFRD can over time lead to CKD
Kidney stones
- Kidney stones form as a result of an accumulation of minerals inside the body that is caused by how the digestive system of a person with CF absorbs minerals. Kidney stones can cause pain and blood in urine

CF in the sinuses

The sinuses produce mucus, which helps keep them clear by protecting them against dust, dirt, and bacteria. With CF, the sinuses may fill up with thick mucus that is difficult to clear out. If left untreated, the mucus blocks the sinuses, causing pressure and pain, which triggers inflammation that may contribute to nasal polyps (a growth in the nose that is filled with fluid or mucus and blocks where the sinuses drain into the nose). It also allows bacteria to grow, leading to sinus infections or sinusitis.

Up to 19% of children with CF under
the age of 6 have nasal polyps

Up to 19% of children
with CF under the age of 6
have nasal polyps

Up to 45% of adolescents with CF
experience nasal polyps, compared to
4% of the general population

Up to 45% of
adolescents with CF
experience nasal polyps,
compared to 4% of the
general population

CF in the ears

Although CF does not directly impact hearing, medications and treatments that are extremely important for people with CF can damage hearing over time. Hearing loss is common in people with CF who have been exposed to certain medications such as aminoglycosides for an extended period of time. People with CF who receive certain necessary antibiotics may experience a ~20% loss in hearing.

It’s important to discuss the progression of hearing loss with the care team so they can help.

CF in the bones

For people with CF, different factors contribute to low bone density, a condition where bones become less dense and are not as strong as they should be. Up to 26% of adults with CF may have low bone density. Low bone density is sometimes referred to as osteopenia, and, when severe, osteoporosis.

Bone health may be affected because people with CF often have trouble absorbing enough vitamin D. Another factor contributing to low bone density is the increased inflammation throughout the body that is made worse by frequent lung infections. This may cause bones to be weak and less dense. Therefore, they can fracture more easily. These factors can contribute to both osteopenia and osteoporosis.

Care teams begin screening people with CF for bone health at an early age and may suggest using vitamin D supplementation.

There is still research being done on how CF progresses in the body and all the organs it impacts. Now that some people with CF are beginning to reach an older age, they may have questions about health events and complications beyond those mentioned here. It’s important to work with your CF care team to continue getting the appropriate screenings and to meet with the right specialists for your specific needs.

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