Primary ciliary dyskinesia (PCD) is a very rare disorder which can be inherited from parents and even be passed down to children. This disorder mainly affects the cilia, which are microscopic, “hair-like” projections which line various organs in the body. 

The most important organs which are affected by PCD are the lungs because the cilia that line them play a very important function in keeping the lungs clear for proper breathing. How this disorder affects cilia and how it can cause respiratory and other problems in the body will be discussed later in this article.

Understanding primary ciliary dyskinesia

This is a very rare disorder that only affects about 1 in every 10,000 to 30,000 people.¹ It is inherited in an autosomal recessive manner which means that you have to inherit a mutated gene from each parent in order to show symptoms of this disease. In this case, the parents are usually just carriers of the disease and do not show symptoms themselves. 

The hair-like projections that line various organs in the body are known as cilia and they are affected in this disorder. The function of the cilia is to move in a coordinated direction in order to keep mucus moving through the lungs, towards the throat where they can be sneezed or coughed out of the body. When the mucus is cleared from the lungs, other unwanted substances which we breathe in are cleared with it, such as bacteria, dust and other particles. This helps to keep the lungs clear which in turn, keeps breathing regular.

In PCD, the cilia do not move at all or they only move a little in a discoordinated manner, which renders them ineffective. Thus, mucus, bacteria and particles cannot be cleared from the lungs and they accumulate in the lungs leading to inflammation and respiratory infections. PCD also affects cilia in other parts of the body, such as the ears and when they cannot effectively clear the ears, it leads to repeated ear and sinus infections. 

Clinical presentation 

The lungs are one of the main organs affected so respiratory symptoms are the main symptoms which are seen. These symptoms can start from birth but many children can remain undiagnosed until they reach a school-going age. Symptoms are caused by inflammation and infection in the lungs, ears and nose and can include:² 

• Constant runny or blocked nose
• A constant cough which is wet (a cough which brings up mucus)
• Shortness of breath, trouble breathing and wheezing 
• Repeated bouts of pneumonia 
• Clubbing (swelling at the ends of fingers due to chronically low levels of oxygen)

Some people with severe PCD may also go on to develop a serious lung disease known as bronchiectasis. The most common symptom of this disease is constant cough which produces a large amount of mucus. There might also be wheezing, coughing up blood and chest pain. 

Since cilia is present in other organs of the body, other symptoms can also be present such as: 

• Recurrent ear infections, hearing problems and glued ear 
• PCD can also lead to infertility if left untreated.³ In males affected with PCD, their sperm motility is impaired which can lead to possible infertility. In females, the cilia which line the fallopian tubes in the reproductive system is impaired which leads to infertility.
• Some people affected with PCD are also afflicted with a condition known as heterotaxy syndrome. In this, the organs in the chest and abdomen such as the liver, heart and spleen, are positioned wrong or can sometimes even be missing altogether. 
• Some people affected with PCD also have a mirror-image reversal of their internal organs which means that their organs are on the opposite side of which they are supposed to be. This condition is known as situs inversus totalis.
• In a very rare phenomenon, PCD can affect the cilia in a person's brain and lead to the accumulation of fluid in the brain (hydrocephalus). 

Diagnosis of PCD

Since the symptoms associated with this disorder are not unique and can occur quite commonly, especially in children, PCD is tricky to diagnose. Generally, your doctor might refer your child for testing if they show symptoms such as a persistent runny nose, wet cough or repeated ear and respiratory infections. 

Your healthcare provider may start by ordering some blood and sputum samples, breathing tests or a chest X-ray. This can help them rule out other disorders. After this, you might be referred to an Ear Nose and Throat (ENT) specialist or a pulmonologist. Some tests which they might suggest include:⁴

• Genetic testing to test for the faulty gene which causes PCD
• A quick and accurate test to check the levels of nitrous oxide (NO). This test is conducted if your child is over 8. They will be asked to blow through their nose into a small machine which can detect NO levels. These levels are markedly reduced in PCD
• If your child is under 8 or their NO test is abnormal, they will be referred to a specialist centre. A very small brush will be rubbed inside your child's nose to obtain a sample of their cilia and then this is observed under a microscope to check for the abnormalities associated with PCD. 

Management and treatment approaches 

Unfortunately, there is no known cure for PCD and your healthcare provider will most likely focus on treating the symptoms and limiting the progression of the disease.¹

If there is an ear, lung or sinus infection, antibiotics might be prescribed. In fact, life-long antibiotics might be required to prevent lung damage. You will require regular checkups with your healthcare providers who will take sputum samples in order to determine whether your antibiotics need to be altered. At times, if the infection is very severe you might require a hospital stay with antibiotics given via an intravenous (IV) drip.

Other medications commonly used to manage PCD are bronchodilators. These are medications which you can inhale and they help to relax the muscles surrounding the airway and keep it open. Anti-inflammatory medications can also be taken to treat any inflammation which may be present. Mucolytics may also be useful for PCD; they help to break up the mucus in your lungs and make it easier to cough out. 

Chest physical therapy is also an important component of managing PCD, along with breathing and coughing techniques.⁵ Usually, chest physical therapy involves using your hand or an instrument to bang on your chest and back repeatedly in order to loosen the mucus in your lungs and airways and allow it to be coughed up. 

At times, oxygen therapy might be required especially during exercise. If PCD is particularly severe breathing assist devices might be needed or even a lung transplantation (when the damaged lung is removed and replaced by a healthy donor lung). 

If there are also problems with the ears, such as repeated infections and hearing problems, your doctor might suggest a tympanostomy. This is a simple procedure in which a small tube is inserted inside the eardrums to help drain the mucus from the ears. 

In addition, it is also very important to take care of your overall health in PCD. Staying hydrated can help to soften the excess mucus to some extent. It is also important to maintain a healthy diet and obtain regular exercise. 

Outlook

It can be quite stressful being diagnosed with a lifelong condition, both for the child and their parents. Luckily, there is a lot of help available in the UK for patients who suffer from PCD. Any child who has PCD is registered with a specialist service in order to have access to specialist teams who can properly provide care. This includes doctors, nurses, physiotherapists and even psychologists. If at any point you are worried about your child’s well-being you can easily contact the specialist team and get the help you need. 

There is also lots of help available online in the UK, to help manage PCD and more information can be found here and here. 

 Since it is a long-term condition, PCD will significantly impact your life but that does not mean that you cannot go on to live a relatively normal and long life. Some people may only experience bouts of sickness between healthy periods. On the other hand, if you had severe symptoms and were diagnosed at birth, you might be quite ill throughout your life. 

Conclusion 

PCD is a very rare genetic disorder which can affect anyone. Usually, the parents are carriers of the disease and they pass it down to their children. Some children are diagnosed immediately after birth as they begin to exhibit symptoms, but some children are not diagnosed till later on in their childhood. Since the symptoms associated with this disorder are very common symptoms, it can be slightly difficult to diagnose. However, if suspected, there are a series of specific tests which can confirm its diagnosis. 

Unfortunately, there is no cure for this disorder but there are several things that can be used to manage the disease and slow down or halt its progression. Antibiotics, oxygen therapy and physical therapy are the mainstay in the management of PCD. 

PCD is a life-long disorder which might need life-long treatment and regular doctor visits. However, it is completely possible to go on and live a full life despite having this disorder.