Where are my kidneys and what do they do?

You have two kidneys in your back, just above the level of your elbows.

Your kidneys are responsible for filtering the blood and removing toxins, correcting electrolytes and fluid balance, as well as removing medications from the body. Your kidneys also produce hormones that affect your blood pressure, vitamin D levels and amount of red blood cells.

What is chronic kidney disease?

The National Kidney Foundation defines chronic kidney disease (CKD) as the presence of kidney damage (usually detected on urine or blood tests and sometimes by kidney biopsy) or decreased kidney function for a period of at least 3 months. In other words, CKD means having kidneys that are not functioning at full efficiency or show signs of damage or inflammation over a period of at least a few months. CKD used to be referred to as chronic renal failure or chronic renal insufficiency, among other terms.

What are the stages of chronic kidney disease?

CKD is classified into 5 stages roughly corresponding to the percent of kidney function out of a normal of 100%. Stage 1 is the mildest stage and stage 5 is the latest and most severe stage.

Stages of CKD GFR (glomerular filtration rate) or % of kidney function (out of 100%)
1 more than 90
2 60 to 89
3 30 to 59
4 15 to 29
5 less than 15

GFR stands for glomerular filtration rate, which is a measure of how well your kidneys are filtering your blood. Your GFR is calculated from a blood test result called the creatinine. Generally speaking, a GFR of greater than 90 ml/min/1.73m2 is normal. However, if you are older than 60 years old a GFR lower than 90 may still be normal, if there are no other signs of kidney damage by urine tests. (for more information, see this brochure.)

What are symptoms of chronic kidney disease?

Chronic kidney disease typically does not result in symptoms in stages 1 to 3 and often not even in stage 4. When symptoms start, they are generally subtle or vague, like fatigue, leg swelling, shortness of breath, nausea, loss of appetite, loss of taste or abnormal tastes, itching, forgetfulness or confusion. However, these symptoms are not unique to CKD and just because you have some or all of these symptoms may not mean they are due to kidney disease. Back pain is not a symptom of CKD. Because CKD does not have symptoms until late stages, it is important to monitor the status and progress of your kidney disease by blood and urine tests.

What causes chronic kidney disease?

The most common causes of CKD are diabetes and high blood pressure. However, long-term use of certain prescription or over-the-counter medications, as well as autoimmune diseases can also result in CKD.

How do I know I have chronic kidney disease?

Because CKD does not have symptoms until advanced stages and since the symptoms are not unique or can be vague, it is important to detect kidney disease by doing blood and urine tests.

If I have chronic kidney disease, do I have kidney failure?

Chronic kidney disease is the new term that encompasses older terms such as kidney failure or kidney insufficiency, which all refer to kidney function that is abnormally low or kidneys that show signs of damage.

How severe is my kidney disease?

The severity of your kidney disease is expressed by your GFR (glomerular filtration rate), which roughly correlates with the percentage of kidney function. For example, a GFR of "50" can be roughly considered as a kidney function of 50% out of a normal of 100%. For chronic kidney disease or kidney disease that has been present for months, severity is also described by the stages of CKD, with stage 1 being mildest and stage 5 being the most severe.

For kidney disease or kidney damage that happened suddenly or over only a short time (like a few days or few weeks), your doctor will not use a staging classification, but usually speak in terms of percentage of kidney function.

Are both of my kidneys affected?

We all can live normally with normal blood tests when only one kidney is functioning. Therefore, when your kidney blood tests or GFR is abnormal, this means both your kidneys are affected.

Is my back pain due to kidney disease or failure?

Chronic kidney disease or kidney failure do not result in back pain. Some common kidney ailments that can result in back pain are kidney stones or kidney infection. The pain from these two conditions are usually quite sudden in onset or associated with fevers and bloody urine. Dull, constant pains of the lower back are usually not due to kidney disease.

What can I eat (or not eat) to help my kidneys?

Due to the fact that diabetes and high blood pressure are the two most common causes of CKD, diets high in sugars, carbohydrates and salt have the most negative impact on your kidney function. Foods that help improve your blood sugar and blood pressure will also help maintain your kidney function.

When do I need dialysis?

Most people develop bothersome or debilitating symptoms from kidney disease when their GFR is below 10 ml/min/1.73m2 or in stage 5 of CKD. Dialysis is generally recommended when your doctor feels that these symptoms from very low GFR might imminently become life threatening or are detrimental to health and wellbeing.

Can I have a kidney transplant instead of going on dialysis?

For some individuals, kidney transplant is possible just before the need for dialysis arises. This is usually called a preemptive transplant. However, a preemptive transplant requires a significant amount of planning and coordination, as well as a living kidney donor. Therefore, one should see a kidney and transplant specialist well before developing symptoms from CKD.

For individuals who develop kidney damage suddenly, but have the prospect of recovering their kidney function and stopping dialysis, kidney transplant is not appropriate.

Can I do dialysis at home?

There are two options for home dialysis, peritoneal dialysis and home hemodialysis. These two options both require advanced training of the individual who will be undergoing dialysis and/or any available caregivers.

For more information about dialysis and kidney disease in general, we recommend attending a local kidney education class, which our office can help arrange for you. You may also want to review one or more of the websites below;

National Kidney Foundation: www.kidney.org
National Kidney Disease Education Program: nkdep.nih.gov
American Association of Kidney Patients: www.aakp.org