The role of high blood pressure in kidney disease

Your kidneys are your filtration system, removing waste products and excess fluid from your body. You may not think high blood pressure could influence their functioning, but in fact it’s a leading cause of kidney disease, says a Mediclinic expert. 

Dr Nivesh Sewlall, a specialist physician at Mediclinic Morningside, explains that waste products and excess fluid are removed through your urine. “The production of urine involves highly complex steps of excretion and reabsorption,” he says. “This process is necessary to maintain a stable balance of body chemicals.”

Your kidneys are hardworking organs – they also produce a form of vitamin D that promotes strong, healthy bones, control the production of red blood cells, and release hormones that regulate blood pressure. In fact, your blood pressure (BP) plays a key role in the health of your kidneys.

High BP, or hypertension, is a leading cause of chronic kidney disease (CKD). This is because high pressure, when consistently exerted against the walls of your arteries, can damage the blood vessels over time. When your blood vessels become damaged, the nephrons – tiny filtering units in your kidneys that clean your blood – don’t receive the oxygen and nutrients they need to function well. This then reduces the blood supply to your kidneys and other vital organs.

As a result, your kidneys may stop filtering blood and regulating the fluid, hormones, acids, and salts in the body, which can lead to kidney disease. In addition, the extra fluid in your blood vessels may build up and raise your BP even more. This is called renovascular hypertension, or renal artery stenosis.

“Renovascular hypertension can also be a complication of kidney disease,” says Dr Sewlall. Healthy kidneys produce a hormone called aldosterone to help your body regulate blood pressure. Diseased kidneys are less able to help regulate BP and as a result, it increases.

Symptoms of kidney disease may include swelling of your legs; feeling tired; vomiting; loss of appetite; and confusion. The symptoms of loss of kidney function, together with complications of chronic kidney failure – heart disease, high BP and anaemia – are most often what lead patients to seek medical assistance.

You can usually lower your BP by eating a healthy, low-salt diet; exercising regularly; managing stress; not smoking; maintaining a healthy weight; and limiting your caffeine and alcohol intake. However, these lifestyle changes, along with medication, might not be enough to control renovascular hypertension. In this case your doctor might recommend balloon angioplasty of your renal artery to improve BP control and prevent further damage to the kidneys. If your kidney function has decreased to the point of an end-stage renal disease diagnosis, you’ll require regular dialysis.

Mediclinic Renal Services provides high-quality, innovative renal care by giving patients in the community access to world-class equipment and expertise.