How does CF affect the body? - CF Buzz

How does CF affect the body?

Cystic fibrosis affects the many body organs, including the respiratory,
gastrointestinal, musculoskeletal, genitourinary and reproductive systems.
The defective gene that causes cystic fibrosis is the Cystic Fibrosis Transmembrane Conductance Regulation (CFTR) gene. The defective gene interferes with the body’s ability to transfer water and salt to and from cells. This turns the normally thin and watery mucus secretions thick and sticky, clogging up organs.

CysticFibrosis areas affected

CF and the respiratory system

Cystic fibrosis affects the way lungs are able to fight off potential disease and infection. Thick mucus builds up and clogs the airways and creates the perfect breeding ground for infections.

Many cells in the human body have microscopic hairs called cilia growing on their surface. They help to move fluids over the cells and also act in a sensory capacity in some cases.


In the respiratory and digestive systems they are called motile, or mobile cilia, and they help remove mucus and other debris like dust and bacteria from the system. The cilia sit in a thin layer of water that covers the epithelial cells (the cells that line many parts of the body). The water helps the cilia move and transport the debris from the body.

The itchy feeling you might get in your nose just before you sneeze is your cilia at work.

In a healthy lung, the layer of water is thick enough to keep the cilia upright and doing their job correctly. They are able to move the debris through the bronchi to a point where it can then be coughed out.

In a CF affected lung, the layer of water is too thin to keep the cilia upright. This is because of the faulty CFTR gene.

This means that in a CF lung, mucus and other debris can’t be moved out of the system effectively and the mucus becomes thick and sticky, clogging up the airways and creating the perfect environment for infections.

In the lungs of someone with CF, inflammation caused by infections can damage the lungs, meaning they are even less capable of dealing with future infections. This is why chest physiotherapy is such a cornerstone of treatment for CF; it works to clear the airways of mucus and relieve inflammation in the lungs.

The lungs aren’t the only part of the respiratory system affected; there are often problems with the upper airways as well, nasal congestion, sinus problems (including polyps), wheezing and asthma-like symptoms are common. People with CF usually develop a chronic cough and periods of shortness of breath may develop as the disease progresses.

CF and the gastrointestinal system

Because the balance of water and salt is affected by the faulty CFTR gene in someone with cystic fibrosis, the gastrointestinal system can become blocked by sticky mucus just like in the lungs. This means food and nutrients can’t be absorbed properly

The gastrointestinal system, or the digestive system, includes the mouth, throat, oesophagus, stomach, small intestine, large intestine, rectum and anus, pancreas, liver and gallbladder. They all work together to digest food and help the body absorb the nutrients.

Just like the respiratory system, the gastrointestinal system contains epithelial cells with cilia (the tiny hairs). They act in a similar way to clear the system of bacteria and mucus, and also help in the process of the breaking down food and absorbing the nutrients.

With CF the two most commonly affected parts of the digestive system are the pancreas and the intestines.



Almost all people with CF develop what is known as pancreatic insufficiency.
The pancreas has two functions: it produces the hormone insulin which regulates glucose in the blood, and it produces digestive enzymes that help breakdown and absorb food. These enzymes are:

  • Protease (for the breakdown of protein)
  • Lipase (for the breakdown of fats)
  • Amylase (for the breakdown of carbohydrates)

They act like scissors, to cut the protein, carbohydrate and fatty acid chains into small enough pieces that the body can use and absorb. The enzymes are passed from the pancreas to the duodenum (first part of the small intestine) via a duct. In people with CF this duct is often blocked with thick sticky mucus.

This means the enzymes can’t reach the small intestines and without them, despite a good appetite, a person with CF will suffer from malnutrition because the body simply cannot absorb what is being eaten.
The results aren’t pleasant and include bloating, abdominal pain and distension, loose foul smelling bowel movements, poor weight gain and malnutrition.

Part of the treatment for cystic fibrosis is enzymes in small granule or capsule forms that are taken with almost all foods. The dosage will be worked out by a CF dietician or doctor. See the Enzymes page for more details.



Mucus build up in the intestines can cause bowel blockages and again makes the absorption of nutrients more difficult. Bowel obstructions are a common complication in CF, and laxatives are a common treatment, but in more serious cases, surgery may be needed to remove the blockage.

Managing the digestive symptoms associated with cystic fibrosis can be tricky. The best thing to remember is to have the right dose of enzymes at the right time with food; too little can cause diarrhoea like symptoms and too many can cause constipation.

Keeping up fluids and salt levels is also essential. Your CF dietician and gastroenterologist are key to managing CF.


Liver and Gallbladder

Sometimes thick secretions can also block the liver and gallbladder. This is rare and only affects about 8 per cent of people with CF. However, if it’s left untreated it can lead to permanent liver damage, and sometimes the removal of the gallbladder is required.


CF and the reproductive system

A build up of mucus can cause blockages and affect the development and function of sexual organs in both males and females. Late onset of puberty and problems with fertility is common in both genders.



Because of the nutrition problems caused by CF, many people with the disease will be underweight. For girls this can mean they will start menstruation later, and their periods may be irregular.

Mucus builds up in the cervix of women with CF and this can lead to difficulties conceiving and carrying a baby. Women are not left infertile, but may need assistance to have a baby.
Click here for more information about female reproduction and CF.



Unfortunately, about 98 per cent of males with CF are infertile. This is because the vas deferens, the tube that carries sperm from the testes to the penis, fails to form properly because of mucus blockages.

However, sperm production still happens, and infertile men with CF can still have their own children. They will just need the assistance of reproductive specialist which can extract the sperm and use IVF therapy to assist in the conception of their baby.

Men with CF can enjoy a normal sex life as the disease doesn’t cause impotence.

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