Glossary of common terms in renal medicine


abdomen - the part of the body that lies below the rib cage and above the pelvis, more commomly known as the tummy or belly.

access - in order to perform dialysis on a patient, a means or way must be found to gain entry to the patient’s blood vessels for haemodialysis of the abdomen for peritoneal dialysis. This is known as ‘access’. See also: vascular access; fistula; permacath; Tenckhoff

Acute Renal Failure (ARF) - sudden onset of kidney failure. May be reversible

Acute Tubular Necrosis (ATN) – the name given to the condition when, after transplant, the donor kidney appears to be ‘asleep’ and not working. A biopsy of the kidney shows no sign of rejection.

Albumin - a protein found in the blood that helps to carry other materials in the bloodstream. See the leaflet 'Understanding Your Blood Results'

Alport’s Syndrome – an inherited renal disease causing kidney failure

anaemia - a lack of red blood cells in the bloodstream causing tiredness, breathlessness and lethargy.

angina – heart pain caused by partial blockages in the arteries of the heart leading to a lack of oxygen in the heart muscle.

angiogram – an investigation that allows an x-ray picture to be taken of the blood supply to an organ e.g. the kidney or heart. Also known as an arteriogram. See separate leaflet on renal angiogram.

antibody – a special protein made by the body to defend it against bacteria and viruses

anticoagulants - drugs used to delay or prevent the bloods natural clotting processes e.g. heparin

anuria - no urine production

APD - Automated Peritoneal Dialysis. This form of peritoneal dialysis uses a machine (usually overnight) to carry out exchanges over 10-12 hours

artery – a blood vessel that carries blood away from the heart to the tissues of the body

arteriogram - see angiogram

bacteria - the medical term for germs. They are found everywhere. Antibiotics are used to kill them when they cause an infection.

bicarbonate – a substance found in the blood that counteracts blood acidity. It is also used in dialysis fluids.

biopsy – the removal of a tiny piece of tissue for examination under a microscope. See separate leaflets on transplant & non-transplant kidney biopsy.

bladder - an organ in the body. Urine drains from the kidneys to the bladder where it is stored until being released when you pass water

blood pump – a pump in the dialysis machine that pumps blood from the patient to the machine

blood pressure (BP) - the pressure that blood exerts against the walls of the arteries of the body. See separate leaflet on 'Hypertension/High Blood Pressure'

brain stem death – permanent damage to the part of the brain that is responsible for vital signs and primitive responses from which a patient will not recover and where the patient is on a ventilator – see the leaflet on organ donation

cadaveric donation/transplant – organ donation/transplant from someone who has died

calcium – a chemical important with phosphate in the maintenance of healthy bones

CAPD - Continuous Ambulatory Peritoneal Dialysis, a form of dialysis that uses the peritoneal membrane that lines the abdomen, to dialyse the patient. The patient is taught to use gravity to administer bags of a dialysate into the abdominal cavity several times a day. This is done via a surgically installed access point. A patient may have to carry out the procedure 3 or 4 times a day.

catheter - any tube that may be introduced into the body to transport fluids either into or out of the body. See Tenckhoff

CCPD - Continuous Cyclic Peritoneal Dialysis – as for CAPD but instead of the patient administering bags of a dialysate, a machine is used to pump dialysate in and out of the abdominal cavity overnight to achieve the same result.

Chronic Renal Failure (CRF) - gradual and irreversible loss of kidney function. Typically occurs months or years after the beginning of kidney disease or injury.

creatinine - creatinine is a chemical produced by the muscles of the body. The more muscle you have, the more creatinine you produce. It is a waste product, the result of normal wear and tear of the muscles. One of the kidney's tasks is to clean the blood of creatinine. In kidney failure this does not happen as effectively. So, measuring levels of creatinine in the blood is one way to assess how well the kidneys are working. The higher the creatinine, the worse the kidneys are working. However, because the amount of muscle you have dictates how much creatinine you may have in your blood a more accurate measure of kidney function is to measure the amount of creatinine found in the urine, after the kidney has done its work. This measure is taken from a urine specimen collected over 24 hours.

creatinine clearance - creatinine clearance is the amount of blood that is "cleared" of creatinine in a given period of time, usually measured in mls per minute. The normal creatinine clearance of an adult is 120 ml/min. Commonly, an adult requires dialysis because of the appearance of symptoms of kidney failure at a clearance of less than 10 ml/min. Creatinine clearance is measured by a 24 hour urine collection and blood sample which provides a more accurate estimate of kidney function than creatinine levels measured in the blood because it does not depend on the amount of muscle one has. Lower than normal levels of creatinine in the urine indicates that the kidneys are not working properly.

cross-match - cross-matching is the final test, which takes place immediately before transplantation and involves mixing serum (a part of the blood) from the patient and cells from the donor to see if the patient has any antibodies that react to the donor kidney and will cause rejection. Transplant only proceeds if the cross-match is negative. Patients are also always cross-matched before receiving donated blood to remove the risk of a patient reacting to a blood transfusion

cytomegalovirus (CMV) – a virus belonging to the herpes family of viruses. See separate leaflet on CMV and transplant.

diabetic kidney disease - or diabetic nephropathy, kidney disease resulting from the damage and destruction of blood vessels in the kidney leading to chronic renal failure in some diabetic patients.

dialysis - the removal, by artificial means, of excess water and waste products from the bloodstream.

Dialysis Co-ordinator – a health worker usually with a nursing background who supports patients with renal failure as they make choices about their treatment

dialysate - the fluid used in dialysis

dialyser - the machinery or apparatus used in dialysis. Also known as the artificial kidney.

dry weight - the patients body-weight that is aimed for at the end of a haemodialysis session and all the time when using peritoneal dialysis.

dwell time - the length of time fluid is kept in the peritoneum during CAPD, APD or CCPD

echocardiogram (ECHO) – an ultrasound investigation of the heart

electrocardiogram (ECG) – a test performed by attaching leads to the chest, wrists and ankles that allow a tracing of the electrical activity of the heart to be recorded.

electrolyte – any chemical with the potential to conduct an electric current when in solution because of their ability to accept a positive or negative charge. In the body, electrolytes are associated with the control of differences between fluids inside and outside cells. Important electrolytes are potassium, sodium, chloride, calcium, magnesium, bicarbonate and phosphate.

end-stage renal failure (ESRF) or end-stage renal disease (ESRD) in the USA - permanent, non-reversible kidney failure requiring renal replacement therapy in order to carry on the tasks of the kidney by artificial means.

erythropoietin (EPO) - a hormone that is produced by the kidneys which causes bone marrow to make red blood cells. It is now made artificially and used to treat anaemia in many dialysis patients.

EPO Co-ordinator – a specialist nurse responsible for helping patients who are taking EPO.

exit-site infection – infection of the skin and tissue around a Tenckhoff catheter used in peritoneal dialysis

ferritin - a protein that stores iron in the body. Measurements of the amount of ferritin in the blood are used as an indication of iron loss caused by dialysis

fistula - a form of access that allows haemodialysis to take place. It is created by joining an artery to a vein directly, usually in the arm. This creates a bulging of the vessels that allows a needle to be more easily put into the vessels, allowing blood to be drawn into the dialysis machine and back again.

fluid overload - the dangerous build up of water in the body beyond the capacity of the body to cope with it. May be caused by taking in too much water between dialysis sessions, or not taking enough water off in a session.

glomeruli – the microscopic filters in the kidneys. Each kidney contains about 1 million glomeruli. the first step in the formation of urine is filtering fluid from the blood through the glomeruli.

glomerulonephritis – inflammation of the kidneys not caused by bacteria. Affects the glomeruli, the microscopic blood filters, of the kidney. Affects both kidneys equally when it occurs.

graft – a transplanted organ

haematocrit – or PCV (packed cell volume) is the measure of the amount of red blood cells in the bloodstream

haematuria – blood in the urine

haemodialysis - the removal of waste products and excess water from the blood and regulation of important chemicals necessary to the body by passing the blood through an artificial kidney outside of the body.

haemofiltration – the removal of fluid and electrolytes by a process of ultrafiltration and convection.

haemoglobin (hb) - contained within the red blood cells of the bloodstream, haemoglobin is a chemical compound that allows oxygen to be carried around the body from the lungs. Haemoglobin is used as a measure of a patient’s anaemia as it is contained within the red blood cells. The lower the amount of haemoglobin you have, the more anaemic you are.

hepatitis - inflammation of the liver, usually caused by viral infection. Patients are now tested under Renal Association guidelines for hepatitis viruses B & C every three or six months respectively. See separate leaflet on hepatitis.

hormone – a substance that is excreted by glands of the body directly into the bloodstream. The hormone causes a response in another part of the body, e.g. EPO is released by the kidneys and stimulates red blood cell production in the bone marrow.

hyperkalaemia - high levels of potassium in the blood

hypokalaemia - low levels of potassium in the blood

hyperparathyroidism - the term used to describe the condition that results when parathyroid glands work harder then normal producing too much parathyroid hormone. Se separate leaflet on 'Hyperparathyroidism & Renal Bone Disease'

hypertension - abnormally high blood pressure

hypotension - abnormally low blood pressure

IgA Nephropathy – a common type of glomerulonephritis which is often mild. See leaflet on IgA Nephropathy

immunosuppressants - medications used to damp down the body’s natural defence mechanisms. Used in almost all kidney transplant patients in order to prevent the rejection of the donated organ. e.g. cyclosporin (Neoral), tacrolimus.

inflammation - a normal reaction of the body to allergy or infection by bacteria, virus and parasite. Tissues swell, become hotter and full of white blood cells.

intravenous - ‘into a vein’, the process of introducing medicines and materials directly into the blood stream by means of a vein.

IPDIntermittent Peritoneal Dialysis, a form of peritoneal dialysis that takes place 2-3 times a week for 12 hours as opposed to 4.

K - see potassium

link nurse – a nurse working in a ward with responsibility for creating a link between the ward and a specialist nurse in a specialist role e.g. EPO co-ordinator. The role includes acting as: a first point of contact for patients requiring the specialist service; a resource for colleagues and educating staff in the ward on developments

Living Related Donor (LRD) - a person donating a kidney who is related to the recipient of the kidney

LFTs - abbreviation for Liver Function Tests. See separate leaflet on 'Understanding Your Blood Results'

mature fistula – a fistula that is ready to be used for dialysis

mid-stream urine (MSU) – a specimen of urine collected by saving the middle part of a stream of urine achieved by starting to urinate, stopping, collecting the next burst of urine and finally passing the last part of the urine into the toilet. the specimen is sent to the laboratory to be tested for the presence of infection.

MRSA (methicillin/multiple resistant staphylococcus aureus)– a special type of bacteria identical to the ones that normally cause spots and boils but resistant to most antibiotics.

myeloma – a cancer of the white blood cells. See separate notes on myeloma.

needling - the process of introducing needles into an access point e.g. a fistula in order to obtain blood for haemodialysis

nephrectomy - the removal of a kidney through surgery.

nephritis - inflammation of the kidneys

nephrologist - a doctor specialising in the care and treatment of kidney patients.

nephrology - the study of the kidney, its function and diseases.

nephron – the filtering unit of the kidney which includes the glomerulus, the actual filter. There is one glomerulus to every nephron. The kidney is made up of millions of nephrons.

nephropathy - any kidney disease

nephrostomy - a tube inserted in the lower back under local anaesthetic to drain urine from a kidney when the normal drainage pathway is blocked for some reason.

nephrotic syndrome - a type of glomerulonephritis characterised by excessive protein loss from the blood into the urine caused by an abnormality of the glomeruli.

oedema – swelling of the tissues, often the legs and face usually caused by fluid overload or in patients with kidney failure.

oliguria – too little urine production

outflow time – the time taken for dialysate to drain out of the abdomen in peritoneal dialysis.

overload - see fluid overload

parathyroidectomy - surgical removal of the parathyroid glands. See separate leaflet on 'Parathyroidectomy'

peritoneal dialysis (PD) - the use of the peritoneal membrane for dialysis. See APD, CAPD & CCPD. A solution (dialysate) is introduced into the abdominal cavity that removes excess water and waste products from blood passing through the peritoneal membrane and regulates the amounts of important chemicals necessary to the body. At the end of each treatment, the solution is drained from the abdominal cavity. See separate leaflet ‘Introduction to peritoneal dialysis’.

Peritoneal Equilibration Test (PET) - a test used in peritoneal dialysis to measure the rate that waste products in the blood pass into the dialysis fluid in the peritoneum. It provides doctors and nurses with information on how your peritoneum is working. From this information your dialysis prescription may be changed to meet your individual needs. These changes may include increasing or decreasing bag volume, the number of bags or the use of automated peritoneal dialysis. 

peritoneum - a semi-permeable membrane that lines the inside of the abdomen

peritonitis - an infection of the peritoneum that occurs in patients using peritoneal dialysis. Symptoms include pain and peritoneal dialysis fluid becoming cloudy

phosphate a chemical important with calcium in maintaining healthy bones. See separate leaflet on phosphate binders.

platelets - these are cells in the blood that helps blood to clot

plasmapheresis – the process of filtering & removing components of blood plasma to treat certain diseases. see separate leaflet on vasculitis

polycystic kidney disease (ADPKD) – an inherited kidney disease. See separate leaflet on Autosomal Dominant Polycystic Kidney Disease

potassium (K) - a chemical element present in all living creatures. Potassium is used by the body in the transmission of signals through nerve pathways. The kidneys operate to keep potassium in the body at the right level. Both too much and too little potassium is dangerous. In kidney disease the danger usually comes from having too much potassium. Some kidney patients have to be careful not to eat foods rich in potassium.

pre-dialysis – any patient who has chronic renal failure, but does not yet require dialysis but will do so in the near future is considered to be in a pre-dialysis phase.

proteins – large molecules made up of amino acids, in turn made up of a combination of carbon, hydrogen, oxygen and nitrogen plus or minus iron, sulphur and phosphorus. There are many different types of proteins, performing a variety of functions in the body such as helping with chemical reactions, transporting substances in the blood e.g. haemoglobin or acting as chemical messengers in the form of hormones e.g. erythropoietin and defending the body against harmful agents in the form of antibodies.

pulmonary oedema - the name of the condition in which fluid builds up in the lungs. This causes breathlessness. It can occurs in people on haemodialysis who have fluid overload due to drinking too much between dialysis sessions or not having enough fluid removed during a dialysis session.

pyelonephritis – kidney infection, usually bacterial, spread from bladder

red blood cells - cells in your blood that contain haemoglobin which carries oxygen to the tissues of the body. A decrease in haemoglobin is called anaemia.

reflux nephropathy – see separate leaflet

rejection – rejection is the result of the body identifying a transplanted organ as foreign and attempting to the destroy the tissue of the organ. See separate leaflet on kidney rejection after transplantation.

renal biopsy – a special test whereby a fine needle is inserted into a kidney to remove a tiny core of tissue for examination under a microscope. See separate leaflets on transplant and non-transplant renal biopsy.

renal bone disease – a weakening of the bones also known as renal osteodystrophy resulting from kidney failure. See leaflets on hyperparathyroidism and phosphate binders.

renal calculus – an abnormal inorganic mass that occurs inside the kidney. More commonly known as a kidney stone.

run-in time – the time taken for dialysis fluid to run into the body during peritoneal dialysis

saline – saline in a medical context is sterile salt water

simple kidney cysts – see separate leaflet

sodium – the commonest form of electrolyte in the body. It is found in all body fluids including blood as well as bone. The kidneys control the normal balance of sodium in the body. Kidney failure is often accompanied by excess sodium in the body. Excess sodium causes high blood pressure and/or swelling (oedema). Sometimes a reduction of sodium in the diet is needed to help to restore a normal balance.

subcutaneous – literally ‘under the skin’ usually used to describe a form of drug delivery in which the drug is injected, shallowly, under the skin

stenosis – a narrowing or stricture of a duct or canal of the body e.g. stenosis of an artery, vein, urethra

systemic lupus erythematosus (SLE) – a disorder of the connective tissues of the body, characterised by inflammation. Often affects the skin, joints, kidneys, lungs, heart and gastrointestinal tract. See separate leaflet

Tenckhoff - a catheter/tube that allows access into the abdominal cavity for peritoneal dialysis. Named after Dr H. Tenckhoff who developed it in 1968.

tissue type – besides blood group, all tissues of the body carry special markers that are inherited from parents. The body recognises its own markers or tissue type, but will attack any different tissue type. Transplant gives the best results when the tissue types of the donor and the recipient are as close as possible. See separate leaflet on tissue typing.

Transplant co-ordinators – health workers usually with a nursing background who are responsible for the arrangement and organisation of transplants

ultrafiltration (UF) – a term used in dialysis to describe the removal of fluid from the blood using a pressure gradient.

ultrasound scan – a test whereby sound waves are sent out from a special microphone into the body and the echoes are recorded by the same microphone and then displayed on a TV screen. This test is used very commonly to help to determine kidney size, shape and the type of disease.

uraemia - describes the signs and symptoms of chronic renal failure (such as nausea, vomiting and loss of appetite) caused by the excessive levels of urea and other chemicals in the blood that occur when your kidneys are no longer functioning normally.

urea - urea is a waste product that occurs as a result of the body’s normal processes, breaking down food and converting it into energy. One of the kidney's tasks is to clean the blood of urea. In kidney failure this does not happen as effectively. So, measuring levels of urea in the blood is one way to assess how well the kidneys are working. The higher the urea, the worse the kidneys are working. Similar to creatinine.

ureter – the tube connecting the kidney to the bladder through which urine flows.

urethra – the tube leading from the bladder to the outside of the body through which urine is passed.

vascular access - access into the bloodstream of a patient for the purpose of haemodialysis.

vein – a blood vessel that returns blood to the heart from the tissues of the body.

virus - A virus is an organism that lives and reproduces itself by taking over the cells of a host. It causes the cell to make more viruses rather than doing whatever it is should do. These burst out of the host cell and proceed to infect other cells.

vitamin D – a vitamin, of which the active form is produced by the kidneys, that is important in the maintenance of strong healthy bones by helping the body to absorb calcium from the food we eat. Patients with kidney failure may need to take vitamin D capsules.

VRE (vancomycin resistant enterococcus) – a special type of bacteria resistant to many antibiotics. It tends to live in the lower bowel.

wash back – a method using saline (sterile salt water) to wash blood back from the dialysis circuit at the end of dialysis to minimise blood loss

white blood cells – White blood cells are responsible for the production of antibodies or immunoglobulins, which circulate in the blood and attack any bacteria and viruses that invade the body. See also the section on blood tests.


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