Protecting your body’s filters
Our kidneys sit on either side of our abdomen, between the back of our pelvis and the bottom of our ribcage. They are about the size of a computer mouse, averaging 13cm in length, and are shaped, as the name would suggest, like a kidney bean.
Unless you are unfortunate enough to have kidney problems, you probably never give them a thought – yet, every day, they ensure our bodies are free of toxic waste, and the balance of our fluid and salts is at a healthy level.
So how do they work, and how do you know if yours are healthy or not?
The primary role of our kidneys is to remove excess fluid and other waste products from our body, and excrete this via the bladder as urine. They perform this complex job by a series of filtration steps that take place in the glomeruli (a network of tiny blood vessels in the outer part of the kidney).
If the glomeruli and associated tubules and vessels are working properly, our bodies can maintain a healthy equilibrium of fluid, electrolytes and acids. Once the kidneys have produced urine, it is passed into the bladder via the ureters, and is stored there before being excreted from the body via the urethra when you go to the toilet.
Other functions our kidneys perform include:
❚ Maintaining a healthy blood pressure via the production of a hormone known as ‘‘renin’’;
❚ Producing erythropoietin, a hormone crucial for the production of red blood cells;
❚ Ensuring our bones are healthy and strong by converting vitamin D into its active metabolite calcitriol;
❚ Removing certain drugs from our bodies.
To work effectively, our kidneys need good blood supply, and plenty of fluid – dehydration can ‘‘stress’’ the kidneys, and increases the likelihood of conditions such as renal stones. Smoking, obesity, excess alcohol, and conditions such as diabetes, impair our circulation, making it harder for the kidneys to do their job.
It can be hard to tell initially if your kidneys aren’t working as they should be – quite often kidney impairment can progress ‘‘silently’’ for years, until the effects become really obvious, by which stage it may be too late to reverse the process.
However, there are symptoms that might raise a ‘‘red flag’’ in terms of your kidney health. It is also important to consider your individual risk factors, and be proactive if you think you fall into a highrisk category or have any worrying symptoms:
❚ High blood pressure – this can indicate kidney problems, and will also lead to kidney damage if left untreated: either way, getting your kidneys checked if your blood pressure is high is a good idea. If high blood pressure runs in your family, especially in younger people, you could have inherited a tendency to an underlying ‘‘congenital’’ kidney problem, such as renal artery stenosis or polycystic kidney disease.
❚ Diabetes – like high blood pressure, poorly controlled diabetes affects our blood vessels, and impairs kidney function. Diabetics will get regular tests of their kidney function as part of their routine check-ups. If you have a strong family history of diabetes, the sooner you get diagnosed, the less the impact on your kidneys.
❚ Inherited kidney problems – as mentioned above, there are several types of kidney disease that can be passed on, including polycystic kidneys, and certain types of glomerulonephritis (an inflammation of the glomeruli or filter systems). Diabetes and high blood pressure also tend to run in families, so if you have any close family members who have had kidney problems, it is worth getting yours checked.
Symptoms that might indicate kidney or bladder problems – if you notice a change in your normal urine ‘‘habits’’, it is worth taking note and talking to your doctor if it persists. This might include urine that looks different from normal for a few days in a row (for example, dark urine might indicate tiny amounts of blood in your urine), smells very different, or is much more concentrated or diluted than usual.
Any visible blood always needs checking, as does pain, frequency changes, or an inability to completely empty your bladder – these are usually associated with simple urinary tract infections, but can indicate something more serious if they persist. If you find that you are passing urine a lot more often than usual, especially at night, this can be a sign your kidneys are struggling, as can
It can be hard to tell initially if your kidneys aren’t working as they should be – quite often kidney impairment can progress ‘‘silently’’ for years, until the effects become really obvious, by which stage it may be too late to reverse the process.
extreme fatigue, and fluid build-up, or puffiness of the ankles, hands and around the eyes.
If you do think you have any of these symptoms, or are at particular risk of kidney problems, there are some simple things your GP or nurse can do to be able to reassure you. These include measuring your blood pressure, and testing a urine sample for the presence of protein, white cells (indicating infection), blood and sugar.
If they are concerned based on your symptoms or the results of these tests, blood tests will help assess exactly how well your kidneys are performing, and an ultrasound scan can check your kidneys, bladder and urinary tract look normal.
Your GP can also make a referral to a kidney specialist, known as a renal physician, or a urologist, who deals with the urinary tracts, if it looks like you have a kidney problem. Don’t be alarmed if this happens: the sooner any kidney disease gets detected, the better the chances of successful treatment.