A basic introduction to 'what's what' in renal medicine. This is suitable for anyone starting work in a renal unit, or for patients. The resources we link to are from all over the web, but chosen by us. Some are written by us, and from this pathway, most are from our sister website EdRen. When the words get silly you can find a glossary of renal words here.
Anatomy and Physiology
Where are the kidneys, what they do?
- How kidneys work from DaVita (US dialysis provider) - nice animations
- Anatomy and what normal kidneys do from EdREN
- Video on how the nephron works (YouTube) - more advanced and beyond 'Core' level. Excellent, but whose is it?
Diseases that affect the kidney
Some people are born with kidney problems, others are affected by different kinds of diseases.
- The types of problem that cause kidney diseases - there is a summary of common things causing complete kidney failure on our Textbook pages on CKD stages 4-5
- The EdRen Info pages provide quite a lot of information about individual diseases. However there are also useful pages on general topics such as proteinuria, nephrotic syndrome, CRF. You can also search the site or look at the Glossary for things that don't have a main page there.
Tests for kidney disease
These can be urine tests, blood tests, X-rays, or sometimes taking a biopsy of the kidney to look at a small piece under the microscope.
- Tests for kidney disease (EdRen, from the Normal Kidneys page)
- More detailed information about blood tests for kidney disease here (EdRen).
Acute renal failure (ARF)
Acute renal failure (also known as Acute Kidney Injury, AKI) is kidney failure that occurs suddenly. The most common causes aren't kidney diseases, but problems with blood pressure and circulation caused by infections, heart failure, or by poisoning or drug toxicity. However some very important and treatable kidney diseases cause some cases.
- More info about ARF in the Edren textbook
CKD & chronic renal failure
CKD (chronic kidney disease) means permanently damaged kidneys from any cause. Most people with minor to moderate damage have no symptoms from their kidney disease - symptoms of kidney failure only occur when damage is very severe. In most people, CKD doesn't go on to cause severe kidney failure, but people with CKD are at increased risk of heart and blood vessel diseases.
CKD is divided into stages 1 (mildest) to 5 (most severe). The priority in patients with CKD is to prevent the damage getting worse, and reduce the risks of cardiovascular disease by looking after blood pressure, cholesterol etc. Read about CKD stages 1-3 from the EdRen Textbook.
Chronic renal failure (CRF) is an older description that is usually reserved for the more advanced stages of CKD, when symptoms and complications start to develop, and the risk of completely losing kidney function becomes worrying.
Complications of renal failure
Symptoms are uncommon until kidney function is less than 20%, but complications become an increasing problem as kidney function falls below 30%. More detail about CKD complications from EdRen.
Anaemia - Haemoglobin falls slowly as kidney failure gets worse, but anaemia doesn't usually become a serious problem until function is less than 20% - unless there are other causes for anaemia in addition to CKD. Anaemia causes a lot of the exhaustion and breathlessness that you can get with renal failure, but can now be very effectively treated.
Bone disease - Renal bone disease, also known as renal osteodystrophy can become a serious problem for people who have longstanding severe CKD, or who are on dialysis. It is a complicated subject. Major causes are problems with vitamin D (which the kidney normally processes), and high phosphate levels in the blood that go with kidney failure and are often only partially helped by dialysis. Treatment involves diet, taking phosphate binders with food, vitamin D compounds, and attention to dialysis.
Nutrition - patients with severe kidney failure (acute or chronic) lose their appetites and then begin to feel sick and to vomit. If this continues, they can become seriously malnourished, which puts them at greatly increased risk of infections, and the loss of muscle makes it difficult for them to return to normal life. Prevention and treatment are both important and these explain the importance of diet and dietitians in the renal team. There's a lot more about renal diets from EdRen.
End stage kidney disease (ESRD, ESRF)
End stage kidney (renal) disease (ESRD or ESRF) means kidney failure so severe that without dialysis or a kidney transplant you will die in weeks to months. In the UK every year about 1-2 people per 10,000 start renal replacement therapy (dialysis or a kidney transplant) having reached this stage of kidney disease.
- 40,000 patients in the UK are kept alive by dialysis or a kidney transplant - about half with a transplant and half on dialysis. 4,000 in Scotland. This is rising each year as people who have started treatment live on.
- The frequency of ESRD is higher in some parts of the UK and in some racial groups, particularly in south asian and black races.
- Internationally ESRD is more common in North America and Germany and less common in some parts of Scandinavia.
- More about ESRF from EdRen (but there's more about treatment options below)
- More about some details of ESRF on our ESRD pathway
Dialysis & transplantation (Renal replacement therapy)
These are often referred to as Renal Replacement Therapies, RRT. Each has pros and cons and wherever possible the patient should be allowed to express their preference. We have more about treatment choice in the ESRD pathway.
About 80% of dialysis patients in the UK receive haemodialysis (HD). This can be provided in a big hospital unit (a 'hub' unit), in a satellite unit (usually run by nursing staff, not necessarily at a hospital, and nearer patients' homes), or in some cases at home (home haemodialysis). More info about HD from EdRen.
Peritoneal dialysis (PD)
Peritoneal dialysis is a very good treatment for some patients. It is almost always carried out at home, and is a daily treatment so the body doesn't have to cope with the big swings that you get from having intense haemodialysis three times each week. As you have the equipment, travel is much easier. But it's not for everyone and does have some problems. More info about PD from EdRen.
There's no doubt this is the best treatment if you can have one. Dialysis only partly replaces kidney function, a transplant returns you to a much better level of health - and also increases your chance of living longer. However there is a risk to the operation and the treatment to prevent rejection of the transplant, and there are not nearly enough kidneys available for everyone who could benefit to have a transplant. More information on kidney transplants from EdRen.
Dialysis can be a very difficult and indeed risky treatment for patients who have other illnesses, and in many patients the loss of kidney function is anyway very slow. Conservative management means trying not to use dialysis while allowing the best possible quality of life. It includes careful management of diet, and treatments to prevent anaemia and other complications of renal failure. More info about conservative management from EdRen.
End of life care At a time of severe irreversible illness, many patients who depend on dialysis choose to stop it. The considerations are the same as for patients who choose not to start.