Tell Me About Primary Ciliary Dyskinesia
This web page will tell you about lung anatomy and what Primary Ciliary Dyskinesia is, as well as what the common symptoms are.
What is Primary Ciliary Dyskinesia?
Cilia are tiny hair-like structures on the surface of the lining of the respiratory tract. Unlike hair, cilia can move, and the body uses cilia primarily to transport mucous out of the respiratory tract. Primary Ciliary Dyskinesia (or Kartagener's Syndrome) is a chronic lung disease which occurs when the cilia are unable to move at all, or fail to beat properly. This causes mucous to become stuck in various parts of the respiratory tract, leading to symptoms.
Primary Ciliary Dyskinesia is a very rare syndrome, with an incidence of about 1 in 30,000 persons. Because it is so rare, large studies on this condition have not been performed. Much of the treatment of Primary Ciliary Dyskinesia is based on the treatment of Cystic Fibrosis, which is commoner (1 in 2,000 persons) and has some similar features.
A Tale of Many Names
Primary Ciliary Dyskinesia has this name because it involves cilia, and dyskinesia means "abnormal movement.” This disease used to be called Immotile Cilia Syndrome, because we used to believe that in this condition the cilia in the body are unable to move at all. We now know that in some forms of Immotile Cilia Syndrome, cilia can move, but are unable to beat effectively. Because of this, that the name has been changed to Primary Ciliary Dyskinesia (dyskinesia means "abnormal movement"). In about 1/2 of patients with Primary Ciliary Dyskinesia, the heart and other organs are located on the right side, rather than the left. When patients with Primary Ciliary Dyskinesia have the heart on the right side, they are said to have Kartagener's Syndrome.
It is important to realize that Primary Ciliary Dyskinesia and Kartagener's Syndrome all refer to exactly the same condition, with the same symptoms and needing the same treatments (except that all patients with Kartagener's Syndrome also have the heart on the right side). Incidentally, having the heart on the right side is known as dextrocardia. Having all the organs on the opposite side from the usual (for example, having the liver on the left side and the stomach on the right side of the body) is known as situs inversus.
A Little Anatomy
The lungs consist of airways (also known as bronchial tubes, or bronchi), and air sacs (also known as alveoli). The purpose of the airways is to allow fresh air to travel into the air sacs, and to allow spent air to travel out of the lungs. Blood vessels move blood close to the alveoli, so that fresh oxygen inhaled from the atmosphere can move into the blood. In addition, waste gas (or carbon dioxide) travels from the blood into the alveoli, to be later exhaled into the atmosphere. Other blood vessels move the blood, newly-loaded with oxygen and relatively-free of waste gas away from the alveoli, to travel to the rest of the body.
The bronchial tubes have tiny bands of muscle, which encircle them. When air containing noxious gases or fumes (such as cigarette smoke or polluted air) is inhaled, these bands of muscle can constrict, narrowing the airways and reducing the amount of irritating gas entering the lungs. This is known as bronchospasm. When irritating gases enter the lungs, the inner lining of the bronchial tubes produce mucous, to trap any irritating particles. In addition, the inner lining of the bronchial tubes contains special cells, called inflammatory cells, which release chemicals after exposure to irritants.
Inflammation is the body's way of dealing with physical injuries, such as injury to the lining of the bronchial tubes caused by harmful gases. Inflammation is produced when inflammatory cells in the area release special chemicals, known as inflammatory chemicals. These chemicals:
- cause swelling of the tissues;
- promote mucous secretion (in airways);
- help destroy any bacteria which have entered the tissues (the chemicals which destroy bacteria can also cause further tissue damage in the area);
- tell the body to send more inflammatory cells into the area;
- promote healing of the damaged area.
Everyday examples of inflammation which everyone's familiar with include the redness, pain, and swelling which occur after a minor burn, and when a splinter is not removed promptly.
Small amounts of mucous are normally produced in the bronchial tubes to trap soot, bacteria, and other small particles we all breathe in every day, and larger amounts of mucous are produced when the bronchial tubes are inflammed (for example, after smoke or polluted air exposure, or during a respiratory infection). The cells lining the bronchial tubes are covered by tiny, moving hairs called cilia, which beat in the direction of the mouth.
The beating of these cilia moves mucous up the bronchial tubes and windpipe up to the mouth, where the mucous is either swallowed or, occasionally, coughed out.
The passages of the nose, sinuses, and Eustachian tube (the tube connecting the middle ear with the inside of the throat) are lined by tissues which are very similar to the tissues of the bronchial tubes, and the cells lining these passages are also covered by cilia.
- Out of the sinuses and into the nose;
- Out of the nose and into the throat; and
- Out of the Eustachian Tube(s) and into the throat.
The Structure of Cilia
Cilia can just barely be seen with the strongest regular microscopes. To see the parts that make up individual cilia, an electron microscope, providing magnification of 60,000X or greater, is needed.
Cilia are made up of even tinier tubes, called microtubules. All cilia contain 9 outer pairs of microtubules, and 2 central single tubules. From each outer pair of microtubules, a pair of dynein "arms" reach towards the next pair of microtubules. The dynein arms actually grab the adjacent pair of microtubules in a specific order, which causes the cilia to bend. Radial spokes extend from each outer pair of microtubules towards the inner central tubules. Nexin links also join each outer pair of microtubules with the adjacent outer pair. Radial spokes and nexin links help stabilize the cilia's structure.
Tell Me More About Primary Ciliary Dyskinesia