Primary ciliary dyskinesia
Cilia are tiny, hairlike organelles in the human body that have many important roles. The main role of the involuntarily moving organelles is to brush bacteria and mucus away from the lungs, but they also have other functions. If the cilia are not moving correctly, the entire body is negatively affected. Primary ciliary dyskinesia occurs when the cilia in the respiratory tract, ears, and reproductive organs are not functioning correctly.
Definition & Facts
Cilia are supposed to move 7 to 22 times per second, but in patients with primary ciliary dyskinesia, the hairs often do not move at all. In cases where the cilia are still moving, they move in an unsynchronized way that cannot properly fulfill the function of cilia.
Symptoms & Complaints
The cilia are not capable of clearing mucus, dirt, dust, and bacteria from the lungs, so patients tend to have recurring respiratory infections. As early as childhood, patients tend to repeatedly have bronchitis and pneumonia.
The recurring lung infections can lead to a buildup of scar tissue that causes severely damaged lungs later in life. Malfunctioning cilia in the nose can also cause a mucus and bacteria buildup in the sinus that results in sinusitis. Some patients also report a lack of smell due to this nasal mucus buildup.
Trouble with cilia in the ears can lead to a progressive hearing loss. Male patients with primary ciliary dyskinesia often suffer from infertility because their sperm are immotile. Women with this condition also suffer from fertility issues because the cilia normally help to move eggs from the ovaries to the uterus. Therefore, they suffer from a higher risk of ectopic pregnancies which occur when a fertilized egg implants outside of the uterus.
Primary ciliary dyskinesia is a genetic condition that is inherited from parents. It is a recessive condition, so patients will only develop primary ciliary dyskinesia if both their parents passed on a gene for the disorder.
However, there is not one specific genetic mutation that can cause the cilia to not work. Cilia are very complicated organelles with an inner and outer arm, radial spokes, and other structures. If any of the genes needed to correctly create functioning cilia is absent, the cilia may not be able to work.
Cilia may also have difficulty coordinating movements when a mutation makes them lean at the incorrect angle. This causes cilia to sweep in a "D" shape instead of a circle, and they cannot effectively move mucus and other particles along.
One particular set of genetic mutations also causes Kartagener syndrome, which is why so many primary ciliary dyskinesia patients also have inverted organs. So far, all of the precise mutations that can cause primary ciliary dyskinesia have not been identified. There are 32 genes that are associated with primary ciliary dyskinesia.
Diagnosis & Tests
It can take quite a while for primary ciliary dyskinesia to be diagnosed because it does not have any obvious symptoms. However, it is very important to get a diagnosis as soon as possible so that permanent lung damage can be avoided. Primary ciliary dyskinesia normally is not suspected until a patient complains of frequent sinusitis or has had several bouts of respiratory infections. If this happens, doctors can screen patients for the condition.
The typical method of doing this is a measure of nasal nitric oxide levels. A tube is inserted into the patient's nose and then they hold their breath while nitric oxide is tested. People with primary ciliary dyskinesia will have very low levels of nitric oxide.
If a patient seems to have primary ciliary dyskinesia, then a biopsy will be needed to confirm the diagnosis. A small piece of tissue will be removed from the sinuses or lungs and examined under a microscope. The defects in cilia will be evident when examined at a cellular level.
Genetic testing can also be done to examine a portion of the patient's DNA to see if it is associated with one of the known mutations that causes primary ciliary dyskinesia. However, a patient can still be diagnosed with the condition even if none of the known genetic mutations are present.
Treatment & Therapy
There is no way to cure this condition and make cilia move normally. However, the proper medical care can make it possible for patients to have a normal lifespan without significant impairment. If the primary ciliary dyskinesia has not caused any permanent damage yet, treatments will mostly be preventative.
Patients may need to regularly take mucus thinning medications, and they will need to routinely suction out mucus from the sinuses and ears. Bronchodilators can be used to ease breathing and make it easier for patients to cough up mucus instead of inhaling it. Regular antibiotic doses can help to prevent infections and inflammation in the airways.
If a patient has suffered from severe lung damage, they may eventually develop respiratory failure. This condition can only be treated with a lung transplant. For patients struggling with infertility due to primary ciliary dyskinesia, there are many potential treatments. With in vitro fertilization, it is possible for people with primary ciliary dyskinesia to have children.
Prevention & Prophylaxis
Couples who might carry the genes for primary ciliary dyskinesia can benefit from genetic counseling or family planning therapy to learn about their risk of having children with primary ciliary dyskinesia.