Kidneys and CKD: 10 Questions and Answers

Kidneys and CKD: 10 Questions and Answers

In this article we describe 10 frequently asked questions (FAQs) about the kidneys and chronic kidney disease (CKD).

Keep track of your kidney data with PKB

1. Where are the kidneys located?

They are near the middle of your lower back, on either side of spine.

This diagram shows the location of the kidneys. The right kidney is slightly lower (and smaller), and is pushed down by the liver.

2. What do the kidneys do? (7 functions)

The kidneys primary role is to be the body’s dustmen. But, in fact, this is only one of their 7 functions.

The kidney has 3 excretory functions – i.e. removes things:

• Waste removal (dustmen role)
• Excess water removal
• Acid removal.

And 4 metabolic functions – i.e. or makes or activates (strengthens) substances:

• Blood pressure control (makes renin)
• Stimulate blood production (makes erythropoietin, EPO)
• Strengthens bones by activating Vitamin D (cholecalciferol)
• Make chemical called prostaglandins (multiple roles).

3. What is CKD (chronic kidney disease)?

The phrase CKD means either:

1. a long-term reduction in kidney function OR
2. an abnormal kidney structure (with normal function).

A mild form is very common – affecting up to 10% of the population.

For many of these, CKD is really a risk factor for a more serious problem later in life. This can be addressed which is why only 1 in 100 people end up requiring dialysis or a kidney transplant

4. How is CKD diagnosed?

This is done using a blood test called a GFR (glomerular filtration rate). This puts you in one of 5 stages in the CKD/GFR classification. Normal human GFR is 90-120 ml/min – the higher the GFR the better.

 5 Stages of CKD

The GFR is calculated from the blood creatinine level (normal range 60-120 mcmol/L) –  i.e. the lower the creatinine, the higher is the GFR, the better.

What do these 5 stages of CKD mean?

• CKD1+2 – risk factors for CKD (eGFR 60-120 ml/min)
• CKD3A – mild CKD (eGFR 45-59 ml/min)
• CKD3B – mild-moderate CKD (eGFR 30-44 ml/min)
• CKD4 – moderate CKD (eGFR 15-29 ml/min)
• CKD5 – severe CKD (kidney failure) (eGFR < 15 ml/min)

But what do these stages really mean?

• CKD1-2 means you can have an abnormal kidney structure with normal kidney function
• CKD3 means you may have a mild or moderate problem with kidney function
• CKD4 means you do have significantly reduced kidney function, and may require dialysis or a kidney transplant one day
• CKD5 means you will require dialysis, or a kidney transplant, or supportive care (no dialysis).

5. What are the 7 causes of CKD?

There are 7 groups of causes:

1. Unknown (often with small kidneys). This is the ‘cause’ in 30% of patients
2. Diabetes (mainly type 2). This is the cause in 20% of patients, i.e. the second commonest
3. Renovascular (kidney artery) disease (RVD)
4. Obstructive nephropathy. This means a blockage in the drainage system of the kidneys – i.e. ureters, bladder, or prostate (in men)
5. Glomerulonephritis (GN) / vasculitis. These are rare ‘autoimmune’ diseases (and there are 7 types). This means the body’s immune system (normally its defender) attacks the small blood vessels within the kidneys
6. Tubulointerstitial disease (TID). This is not really just one diagnosis. The phrase refers to a group of kidney conditions that mostly affect the tubules
7. Polycystic kidney disease (PKD). This is the only common familial (inherited) cause.

6. What are the symptoms of CKD?

CKD is largely asymptomatic until CKD stages 4 or 5. In other words, up until that point, it is a silent disease.

Even when symptoms do occur, many are non-specific (e.g. tiredness, itching and being off your food); and are features of other diseases (like heart failure and anaemia).

Shortness of breath and ankle swelling are red flag symptoms, and occur at these later stages.

Here is more about the symptoms of CKD.

7. What treatment can a doctor offer someone with CKD?

Even though CKD is not normally curable, there is alot doctors and the NHS can do. Does everyone with CKD need treatment? No.

The treatment of CKD is complicated and varies quite alot depending on the cause. Here is more information on the treatment of CKD.

8. What can I do to help myself?

There are the THREE important things you can do to help yourself.

1. Know (and write down) your numbers. The blood and urine tests can be performed and monitored by your GP, but you can do a lot of this yourself; to help your GP and nephrologist (hospital kidney specialist) if you have one.
   • Creatinine blood test. This is the most reliable measure of kidney function; the higher the number the worse the kidney function. It should be below 120 mcmol/L. It should be measured at very variable rates; from every 2 weeks to 12 months – i.e. more frequently, as CKD worsens
   • GFR. The blood creatinine level determines your GFR (glomerular filtration rate) and hence CKD stage – the higher the creatinine, and lower GFR, the higher (i.e. worse) CKD stage [“yes it is confusing” Ed]. GFR should be above 60 mls/min, ideally above 90 mls/min. It should be also measured regularly; again at very variable rates – from every 2 weeks to 12 months
     Note. You can chase your own blood tests using the Patient Knows Best (PKB) website
   • Urine protein in the urine. Some patients need urine protein measurements as well. This is calculated with a simple urine test. When the kidneys leak extra protein it is a sign of strain. It is called a ‘ACR’ (albumin-to-creatinine ratio). Again, you should chase the protein level – again via Patient Knows Best.
2. Blood pressure – make this a primary focus
   • Having normal or low blood pressure is the single most useful thing you can do for your CKD
   • So, buy a BP machine from any chemist or large supermarket or Amazon – prices vary, approximately £20-£40. ‘A&D’ is a good make
   • Take your own BP once a week until stable.
3. Know your medication
   • Many people with CKD take alot of medication: to lower blood pressure (especially two types of blood pressure medicine, ACE inhibitors and ARBs); remove fluid (diuretic, i.e. water tablet), control blood glucose, and lower cholesterol.
   • In more advanced CKD they may take vitamin D, a phosphate binder and erythropoietin (EPO)
   • It is important to understand your medications, and take them as prescribed
   • Do not run out.

Get your BP checked. Better still buy your own machine and check it yourself.

9. How often do I need my eGFR/creatinine measured?

This is very variable. It can be anything from once a week to once a year.

Here is more information on how often GFR/creatinine should be measured in CKD.

10. What is the outlook for CKD?

It is generally good, but (again), very variable. The majority of people have CKD1-3 and do not progress to CKD4-5.

Here is more information on the outlook for patients with CKD.

Summary

We have described 10 FAQs and answers about kidneys and CKD. We hope it has been helpful.