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PCD Glossary

We know that sometimes medical letters have complicated terms that you may not have heard before. This page has been created to help you understand these words and phrases so that you can better understand the information given by your PCD teams.

If this glossary does not help answer your questions, please get in touch with your PCD teams, and send us a message through our Contact Us page so that we can update this information.

 

Diagnostics Terms Explained:

The diagnosis of PCD can be complicated and take some time, so if you would like more information on how the diagnosis of PCD is done, head over to our Diagnostics page.

Air liquid interface (ALI) culture: A method of growing cilia in an incubator so they can be analysed free from bugs and mucus. If successful this means another brushing will not be needed. Occasionally, if infection is present, it doesn’t work and a repeat nasal brushing may be necessary. 

Cilia: Microscopic, hair like structures that line the airways in the chest, nose and ears. Cilia beat in a coordinated way to clear the airways of mucus and debris. This process is known as mucociliary clearance (MCC). In PCD, MCC is absent or ineffective. 

Ciliary beat frequency (CBF): The speed at which cilia beat. 

Ciliary beat pattern (CPB): The way in which the cilia move.  Normally cilia move together in a coordinated pattern, in PCD they move erratically or not at all.

Consanguineous: Descended from the same ancestor e.g. family members, related by blood.

Dynein arms: Microscopic (tiny) structures within cilia that enable them to beat.  If they are absent or not constructed properly the cilia will usually be static (not moving) or twitching. 

Dyskinetic: Not moving in a coordinated fashion.

High speed video microscopy (HSVM): The method used to examine the ciliary beat pattern and frequency from the cilia sampled during a nasal brushing. Video recordings are taken through a microscope and are slowed down to aid analysis. 

Hz: Hertz, a unit used to measure the speed or frequency of the beating cilia (CBF)

Immunofluorescence (IF): A microscope method to look at proteins within the cilia using coloured labels. Absence of a protein may help diagnose PCD.

Microscopic: Anything that is so tiny that it invisible to the naked eye and can only be seen with special microscopes. 

Microtubule: Microscopic structures within the cilia which have a role in helping them beat properly and coordinate with one another. 

Mucociliary clearance (MCC): Often compared to an escalator, MCC is the process of the cilia moving mucus and debris to the back of the throat where it can be swallowed. This does not happen effectively in PCD.

Nasal brushing biopsy: The process of inserting a small brush into the nostril to take a sample of cilia. These samples are then observed using various microscopes and techniques and can be re-grown in ALI culture. 

Nasal nitric oxide (nNO) test: A simple breathing test to measure the level of nitric oxide in the nose and sinuses. In PCD, nNO tends to be lower than in the general population, but not always. 

ppb: Parts per billion, a unit used to measure nNO levels. This is sometimes converted to nanolitres per min (nL/min). 

Rotating: Moving round in circles. Rotating cilia do not effectively move mucus causing PCD. 

Static: Not moving

Tomography: A three-dimensional (3D) examination of cells at high magnification to examine the internal structure and identify defects within the cilia’s ultrastructure. This is usually only used to look for very specific defects within the cilia when a defect cannot be seen using traditional TEM. 

Transmission electron microscopy (TEM): A two-dimensional (2D) examination of cells at high magnification to examine the internal structure and identify defects within the cilia’s ultrastructure which is carried out routinely for all patients who have PCD testing. Around 15% people with PCD have normal TEM results. 

Ultrastructure: The fine structure within the cilia, made up of microtubules, dynein arms and other microscopic structures. 

 

Genetics Terms Explained:

PCD is a disorder caused by changes, called mutations, in your genes. If you want to know more  about PCD genetics, we suggest you head on over to our dedicated PCD Genetics page.

DNA: The genetic code that determines all the characteristics of a living things. It is like an ‘instruction book‘ to determine what we look like and how we function. ‘Spelling mistakes’ (known as ‘mutations’, see below) within the code can cause PCD.

Gene: A unit of DNA that controls the development of one or more characteristics such as eye/ hair colour or how our cilia work.

Genetics: The study of genes and how they are inherited. In relation to PCD, genetics is usually describing the test or result which finds the gene responsible for causing PCD. We only know about approximately two thirds of PCD causing genes which means a negative result does not mean you don’t have PCD, although does make this less likely. 

Heterozygous: Having 2 different versions of the same instructions within a gene e.g. one PCD mutation and one healthy copy, therefore not causing PCD. This is also sometimes described as you being a ‘carrier’ for a PCD mutation.

Compound heterozygous: Having 2 different mutations or ‘spelling mistakes’ within the same PCD gene. If both of these ‘spelling mistakes’ are ‘pathogenic’ (see below) then this will be the cause of you having PCD 

Homozygous: The inheritance of 2 of the same mutations or ‘spelling mistakes’ within the same gene. If pathogenic, these ‘spelling mistakes’ would cause PCD. 

Mutation: If we think of our DNA as an instruction book, a mutation within a gene is like a ‘spelling mistake’. Some of these mutations cause no issues whilst others can cause genetic conditions such as PCD. You normally need to inherit a mutation from both parents to have PCD. 

Pathogenic: Disease causing. In this case a pathogenic mutation or ‘spelling mistake’ which is known to cause PCD. 

Phenotype: Characteristics seen in an individual with a genetic cause. This can be clinical characteristics e.g. wet cough or microscopic characteristics e.g. static cilia

RNA sequencing: A special test occasionally undertaken when a genetic result is uncertain. It is used as a research tool to help understand whether a mutation, which is not fully understood, causes a problem. If you or your child needs this, further explanation will be given by your team.  This is not a standard diagnostic test and is only carried out through research funding when available.

Variant of unknown significance (VUS): A mutation or ‘spelling mistake’ which can be seen but it is unknown whether it causes a problem. Some patients may have one pathogenic mutation and one VUS which would mean we wouldn’t know for sure they had PCD without other test results to confirm a diagnosis. 

Whole exome sequencing: A special test occasionally undertaken when a genetic cause is unknown. This is not a standard diagnostic test and is normally only carried out through research funding when available.

Whole genome sequencing: Some patients have taken part of the100k genome project which looked at their whole genome (their whole genetic ‘instruction manual’). Most PCD genetic testing looks at specifically at known PCD causing genes. Whole genome testing looks more widely and may identify further PCD genes in the future. The project is closed to new recruits, but it is still a term you may see, and may be available on a research basis in some centres.  

 

PCD Management Terms Explained:

PCD is managed in a number of different way, and with a number of different types of doctors and nurses. Here we have explained some of technical wording you may come across, but if you'd like more information about the management of PCD, why not head to our PCD Management page?

Cardiac: Term referring to the heart.

Cardiovascular: Your heart and many blood vessels in your body make up your cardiovascular system

Congenital: Present from birth

Dextrocardia: Heart situated on the right side of the chest

Heterotaxy: Birth defect that involves heart and other organs. ‘Hetero’ means ‘different’ and ‘taxy’ means ‘arrangement’. Heterotaxy therefore means ‘different or unusual placement’ (of the organs). There are different forms of heterotaxy which can involve the formation and placement the heart, stomach, intestines, liver, spleen and lungs.

Levocardia: Heart situated on the left side of the chest, the normal side for most people. 

Situs inversus (totalis): Complete mirror image placement of the heart and other organs.

Sitis solitis: Normal organs arrangement.

Abdominal ultrasound: Similar to the ultrasound/ antenatal scans undertaken in pregnancy but to look at the organs within the abdomen (tummy area). Jelly is placed on the tummy and a probe looks at the placement of the internal organs. This test is painless and is normally only undertaken once.  

Audiology: Hearing test. There are different ways to assess hearing depending on age. Testing is painless. The frequency of your hearing tests will be different depending on age and previous issues. 

Blood pressure (BP): A measurement of the force used to pump blood around your body. Usually, a ‘cuff’ is placed around the top of the arm. This cuff is inflated and tightens briefly around the arm, before slowly deflating.

Bronchoscopy: ‘Broncho’ refers to the tubes you breathe through in your lungs – bronchi, ‘scopy’ means to look using a ‘scope’. A bronchoscopy is usually performed while you are under sedation/anaesthetic. A small camera is fed into your lungs so the doctor can look for any inflation (swelling), or unusual arrangement of the breathing tubes. The doctor can also take samples of sputum during this investigation.

Cough swab: A sample taken by holding a swab near the back of the throat and coughing on to it. This is to normally done for those who can’t cough up sputum to see if any bugs are growing in the chest. 

CPET: Cardiopulmonary exercise testing. A type of exercise test to assess performance of the heart and lungs during effort of exercise.

CT Scan/HRCT: High resolution computed tomography. This is a type of scan to help see the lungs/sinuses in greater detail than can be seen on x-ray.

Culture: Grow or multiply. Used in PCD diagnostics regarding the growing of new cilia to analyse – ALI culture. Also in relation to sputum samples/ microbiology where the laboratory examine bugs grown from cough swab or sputum. 

Endoscopy: Like bronchoscopy, this involves a scope (small camera) being used to look inside the body. An endoscopy usually looks at the stomach or bowel.

Immune system: The parts of the body that fight off infection and other disease.

Immunology: The study of the immune system. Immunology bloods look at markers in the blood related to the immune system.

Microbiology: The study of small organisms (bugs) such as bacteria, viruses, fungi etc. Sometimes used in the clinic to refer to the results of cough swab/ sputum culture or the laboratory who run the tests.

Oral flora: Sometimes called normal flora. This refers to the normal bugs we grow in our mouths that don’t cause us a problem.

Pathogenic: Causing or capable of causing disease. Respiratory pathogens refer to bugs that grow within the lungs or nose/sinuses, that might cause people to be unwell. You may also see this term in the genetic diagnosis of PCD, referring to mutations/spelling mistakes within the gene that might cause PCD.

Oxygen saturations/sats/SPO2: Oxygen saturations are measured by placing a probe on the fingers or toes to measure the percentage of oxygen within the blood. This is a painless test. Normal oxygen saturations may vary from person to person (especially for those with heart issues) so check with your clinical team what is normal for you/your child. 

Rhinoscopy: ‘Rhino’ refers to nose, ‘Scopy’ refers to looking using a scope (small camera). In a rhinoscopy, an ENT (ear, nose, and throat) doctor will use a scope to look inside the nose.

Sputum sample: This is a sample of mucus coughed up from the chest that can be sent to the laboratory to test for bugs that might grow there. Sputum, mucus and phlegm are often used to mean the same thing. 

Tympanogram: A type of hearing test that looks at how much the ear drum moves, looking for the presence of fluid in the ear, often called glue ear. 

X-ray: Images/pictures of the inside of the body.  

Consolidation:  When the air that usually fills the small airways in your lungs is replaced with something else.  Often mucus which makes it hard to breathe.

Hyperinflation: Too much air in the lungs which limits the amount of new air you can take in. 

Peri bronchial thickening: Thickening of the walls of the airways or tubes within the lungs.

Shadowing: Description of an abnormal appearance that can be seen on a chest X-ray.

ECG: Electrocardiogram is a test done by placing leads on the chest to check the heart rhythm and electrical activity.

Echo/Echocardiogram: Similar to the ultrasound/ antenatal scans undertaken in pregnancy but to look at the structure of the heart, blood vessels nearby and blood flow. Jelly is placed on the chest and a probe is moved across it to look at the heart.

Lung Function Test: These are a range of tests that look at how well your lungs are working to help you breathe.  

Spirometry: A test that we use to look at how much air you can breathe in and out.  Children will normally play games on the computer, like blowing out candles or bowling to make it easier for them.  It is important that you/your child blow as hard as you can for this test.

Nuvoair:  This is a piece of equipment that you use at home to perform spirometry testing.  The device is black and connects to an app on a phone.

Spirobank: This is a piece of equipment that you use at home to perform spirometry testing.  The device is orange and connects to an app on a phone.

FEV1/ Forced expiratory volume in 1 second: This is the amount of air that you can blow out in the first second during your spirometry test.

FVC/ forced vital capacity: This is the total amount of air that you can breathe out in one blow during your spirometry test.

LCI/ lung clearance index: This is a test where you breathe normally and we see how long it takes for your lungs to blow out all of a certain gas, this normally takes a few minutes each time.

Auscultation: Listening to sounds of the heart and lungs with a stethoscope.

Apnoea: Temporary pause in breathing

Asymptomatic: Not showing any symptoms.

Bibasal: Crackles at the base of left and right lungs.

Bronchiectasis: Condition where the airways of lungs become wider.  This causes a build-up of mucus in the lungs that can cause infection.

Clubbed: Enlargement of fingertips.

Crackles: The sound of the small airways in the lungs snapping open.  Maybe due to fluid in the lungs and/ or the airways not inflating/opening properly.

Crepitations: Abnormal breath sound in the base of the lungs.  Due to infection, inflammation, or fluid in air sacs.

Chronic: Lasting a long time. PCD is a chronic condition as you have it from birth.

Colonised: In PCD, we say colonised when referring to a bacteria that grows in the lungs all the time, without causing any infection.

Cyanosis: Blueish colour to the skin, usually around the mouth and on the face.  This is a sign of low oxygen levels in the blood.

Eradication: To remove or destroy something. In PCD, eradication often describes the treatment of an infection in the nose or lungs. 

Exacerbation: Increase in the severity of a disease or its signs and symptoms.

Somnolence: A state of drowsiness or strong desire to fall asleep.

Tachypnoea: Rapid breathing.  A breathing rate that is faster than the usual respiratory rate.

Trachea: The tube that connects the throat to the lungs. It is also called a “windpipe”.

Wheeze: A high pitched whistling sound in the chest.  Caused by inflammation or obstruction of the airways.

Coryzal: A head cold with symptoms of a runny nose  

Glue ear: A chronic condition marked by a collection of thickened fluid in the middle ear, due to obstruction of the Eustachian tube (tubes that connect the ear to the throat). 

Otorrhea: Fluid or discharge draining from the ear. 

Otitis media: An infection in the middle part of the ear.  Sometimes this can be chronic leading to glue ear 

Nasal polyp: A growth or swelling of the mucous membrane inside the nose 

Paranasal sinuses: Spaces between the bones of the skull and face that are filled with air. 

Polypectomy: The surgical removal of polyps.  

Rhinitis: Inflammation of the mucous lining of the nose causing a runny nose, and congestion  

Sinusitis: Inflammation of the sinuses, airspaces within the bones of the face typically caused by infection.   

Antibiotics: A drug used to treat infections caused by bacteria rather than viruses. 

Cannula: A thin tube inserted into a vein to give medication such as IV antibiotics. A cannula normally only works for a few days so a longer line may be inserted for a longer course of treatment.

DNase (Dornase Alfpha):  A type of enzyme that breaks down the DNA and therefore reduces the thickness of the mucus making it easier to clear. This is delivered as a nebuliser.  

Hypertonic saline: Special salty water nebuliser prescribed before or during physiotherapy

Intramuscular (IM): Medication given into the muscle e.g. flu jab/ vaccine

Intranasal: Medication given into the nose e.g. flu vaccine given at school

Intravenous (IV): Medication given into the veins mostly in hospital e.g., fluids or antibiotics 

Nasal rinse/douche: Washing salty water solution into the nose and sinuses to clear them of mucus, sometimes referred to as sinus rinse/douche.

Nebuliser/nebs: A fine mist of medication that is inhaled into the lungs.

PICC line: Peripherally Inserted Central Catheter, it is a long tube, more durable than a cannula which can be inserted into a vein for a longer course of treatment. Can last up to 3 months but is often inserted for 2 week courses of IV antibiotics in preference to repeated cannulas. 

Port/portacath: a small device that is placed under the skin on the chest. It is attached to a rubbery tube that sits in one of the large veins leading to the heart. A port is often inserted in people who need many courses of IV antibiotics to protect the veins and prevent the need for lots of cannulas or PICC lines. 

Prophylactic: Medication taken to help prevent illness. 

Medication abbreviations:

OD: Once a day

BD: twice a day

TDS: three times a day

QDS: four times a day

PRN: as needed

Nocte: at night

Acute: Increased intensity of symptoms and increased range of symptoms.

Annual Review: Yearly review of PCD health.  Looking back over the year for interventions required, changes that have been made or occurred.

Bilateral: affecting both sides.

Chronic: A constant state of health or constantly recurring symptoms.

Congenital: A disease or abnormality from birth.

Consanguineous: Descendent from the same family ancestor. Related by blood.

DLA: Disability Living Allowance is an allowance which can be applied for and given to a parent/ carer who delivers care of 1 hour a day or more for the child’s PCD which is anything over and above as would be standard for non PCD children of the same age.

Gestation: Number of weeks of pregnancy at time of birth.

NICU: Neonatal Intensive Care Unit.  Premature babies who are acutely unwell will be cared for in hospital.  Highly specialised medical and nursing care can be delivered in NICU.

NIV: Non- Invasive ventilation.  Pressure is delivered from a ventilator via a mask to support breathing.

PICU: Paediatric Intensive Care Unit Children who are acutely unwell will be cared for in hospital.  Highly specialised medical and nursing care can be delivered in PICU.

PIP: Personal independence payment.  Personal payment that can be applied for by anyone over the age of 16. You must have a physical or mental health condition or disability where you:

        i.          have had difficulties with daily living or getting around (or both) for three months, and

       ii.          expect these difficulties to continue for at least nine months

Ready Steady Go (RSG): A programme used to assist and support the young people to develop confidence and awareness in preparation to moving from children to adult health services.

Research: PCD is a rare disease.  Research is carried out to acquire new knowledge about health and disease.  You will be invited to take part in research.  Taking part is voluntary.  Before agreeing to take part, read the information sheet and discuss and ask questions with your health care professionals.  The standard of care you/ your child receives, will not be affected by your decision.  

SCBU: Special Care Baby Unit.  Hospital ward that cares for unwell or premature babies when they are first born.

Transition: The process of moving from children to adult healthcare services, when young people are taught to be more independent in their care and learn more about their condition. 

Acapella: Airway clearance device used for physiotherapy (oscillating PEP)

Aerobika: Airway clearance device used for physiotherapy (oscillating PEP)

Autogenic drainage: Breathing technique for airway clearance physiotherapy.

Bubble Pep: Airway clearance device used for physiotherapy (blowing bubbles in a bottle of water) 

Nebuliser/Compressor: The box that powers a nebuliser.

Expectorate: To cough out sputum / mucus.

Forced expiratory technique (FET):  Short sharp or long deep “huff” or breath out like you are trying to steam up a mirror.

Huff: Short sharp or long deep breath out like you are trying to steam up a mirror.

Manometer: Pressure gauge, used in a PEP mask circuit to see if the correct breath out is being achieved.

Oscillating PEP: A PEP device which also vibrates.

PEP/PEP device: Positive expiratory pressure. Something making it harder to breath out. A device which provides resistance as you breath out through it.

 

Dietary Terms:

Eating healthily is important whether or not you have PCD. We've included some of the terms that dieticians use here, but we have a whole page dedicated to keeping up with a health lifestyle here: Healthy Lifestyle and PCD.

Allergy: A reaction involving the immune system; these can either be immediate or delayed allergies.

Anthropometry: The taking of measurements of the human body. 

Body composition: The anatomical make-up of the body in terms of bone, muscle, water, and fat. 

Body Mass Index (BMI): A calculation which takes into account your height and weight, is used to determine whether a person is of a healthy weight. 

DEXA (dual-energy X-ray absorptiometry) scan: A method of measuring bone density based on the proportion of a beam of photons that passes through the bone. 

Dietary fibre: A part of plants eaten in foods which is not digested in the small intestine, but rather the large intestine. 

Dietary Reference Values: A series of estimates of the amount of energy and nutrients needed by different groups of healthy people in the UK population. There are three types of estimates: Reference Nutrient Intakes, Estimated Average Requirements and Lower Reference nutrient Intakes.

Enteral feeding: A method of ensuring adequate nutrition in patients who have a functioning gastrointestinal tract but are unable to maintain an adequate or safe oral intake.

Faltering growth: A slow rate of weight gain in childhood than expected for age and sex. 

Food aversion: These are behaviours seen in infants, children, young people and sometimes adults indicating a persistent unwillingness to eat. These can include signs of distress when presented with food, spitting of food and avoidance behaviour. 

Food fortification: A process involving the addition of vitamins and minerals to foods as part of manufacture or processing. 

Gastrostomy tube: The creation of an artificial passage between the stomach and the abdominal surface and is commonly used for long-term enteral feeding support. 

Growth centiles (children): These centile lines are based on measurements taken from many children and they show how one child compares with other children of the same age and sex. 

Intolerance: A reaction to a food or substance that does not involve the immune system. A wide range of symptoms present and are individual. They can also be immediate or delayed. 

Macronutrients: These are nutrients we need in larger quantities that provide us with energy such as fats, protein, and carbohydrates. 

Malnutrition: A condition that happens when a person does not get a correct amount of nutrients from the diet. 

Micronutrients: These are nutrients in the body needed in very small amounts. The play essential roles and deficiencies should be avoided. 

Milk intolerance: A milk intolerance is better known as a lactose intolerance, where a person has no or too little lactase (enzyme) to break down lactose in dairy products. 

Nasogastric tube/ Naso jejunal tube: For short-term nutritional support by feeding directly into the stomach or jejunum (small intestine). 

Nutrient: A substance that must be consumed as part of the diet to provide a source of energy, material for growth or substances to regulate growth. Nutrients include carbohydrates, fats, proteins, minerals and vitamins. 

Nutrition: The study of food in relation to the physiological processes that depend on its absorption by the body (growth, energy production, repair of tissues etc). The science of nutrition includes the study of diets and of deficiency diseases. 

Nutritional assessment: The systematic process of collecting and interpreting information in order to make decisions about the nature and cause of nutrition-related issues that affect the individual. 

Nutritional status: The health and wellbeing of individuals and populations as influenced by their intake and utilisation of nutrients. 

Nutrient-dense foods: Those foods rich in vitamins, minerals and other nutrients important for health without too much saturated fat, sugars or sodium. 

Nutritionist: Providers of information about food and healthy eating. They are not protected by law and do not require registration in order to work. 

Obesity: A medical condition described as excess body weight in the form of fat, where the accumulation of fat can lead to health impairments. Obesity is descried as a BMI of 30-39.9 kgm^2. 

Oral liquid nutrition supplement: A high-energy liquid feed designed for enteral use, usually selected and prescribed after specialist advice from a paediatric dietitian/adult dietitian. 

Oral Nutrition Support (ONS): A collective term to describe the nutritional options available via the oral route to manage those with malnutrition or at risk of malnutrition. 

Overweight: A term to describe a person whose BMI is 25-29.9 kgm^2. 

Prebiotics: Food that the good bacteria in your gut eat. Prebiotics encourage the growth of good bacteria in your gut. 

Probiotics: Good bacteria found naturally in food products or supplements. Probiotics improve the balance of gut bacteria. 

Registered Dietitian: A qualified and regulated health professional that assesses, diagnoses and treats dietary and nutritional problems at an individual and wider public-health level. Dietitians are regulated by law. 

Sensory feeding difficulty: These occur when a child or adult has a sensory aversion to certain types of foods, usually based on their texture, taste, smell or look of the food. 

Stadiometer: A device for measuring height which consists of a vertical ruler with a sliding horizontal rod which rests on the top of the head. 

Supplements: Thickeners- thickening agents added to normal fluids to make them more viscous, and therefore easier for people to swallow. 

Undernutrition: This occurs when a person’s nutrition is not sufficient. A person with undernutrition may be abnormally thin, may weigh less than expected for their length or height and if prolonger, may lead to stunting in the early years. 

Underweight: A term to describe a person whose BMI is less than 18.5 kgm^2. 

Weight management: The process of adopting long-term lifestyle modifications to maintain a healthy body weight on the basis of a person’s age, sex and height. Methods of weight management include eating a healthy diet and increasing physical activity levels.