Living With One Kidney: Causes, Check-ups and Daily Life

🔍Why some people live with one kidney

NIDDK and the National Kidney Foundation (NKF) describe several ways a person ends up with a solitary kidney, summarised below:

2Is life with one kidney normal, and how does the kidney adapt?

According to the NKF, most people live full, healthy lives with one kidney, and many never know because they have no symptoms. Kidney Care UK says most people with one kidney have a normal lifespan.

Kidney Care UK explains that the remaining kidney can grow larger and take on more of the workload. After donation, the same source says kidney function drops to 50% but often recovers to about 75% of the pre-donation level.

⚠️Possible long-term risks

NIDDK describes complications as rare, but they may include:

• High blood pressure.
• More protein (albumin) in the urine, a sign the kidney is under strain or damaged.
• Reduced glomerular filtration rate (GFR), which can rarely lead to kidney failure.

According to the NKF, when kidney function loss occurs in people born with one kidney or with dysplasia, it usually starts after 25 years or more, is usually mild, and life span is not affected. However, a 2020 review in Frontiers in Physiology notes that some children born with one working kidney develop high blood pressure or kidney problems earlier, so follow-up should start in childhood. For donors, NHS Organ Donation states that significant kidney disease develops in less than one in 200 (0.5%). If function keeps falling, it is assessed as chronic kidney disease and a nephrologist may become involved.

🔬How it is diagnosed and what follow-up you need

A solitary kidney is often found by chance on a scan or X-ray done for another reason, according to Kidney Care UK. NIDDK notes it can be found before birth, and extra ultrasounds before and after birth may be advised. Assessment usually includes:

• An ultrasound, or a CT scan if more detail is needed.
• A blood test to estimate GFR (eGFR).
• A urine albumin-to-creatinine ratio (uACR) test for protein.
• A blood pressure check.

The NKF recommends checking kidney function and blood pressure at least once a year, and Kidney Care UK advises a yearly eGFR blood test with blood pressure and urine protein checks, because raised blood pressure and protein can signal that the kidney is overworking. Read more about kidney function tests.

5Diet, fluids and lifestyle

According to NIDDK and the NKF, most people with one healthy kidney do not need a special diet. The sources advise:

• Drinking enough fluids to stay well hydrated.
• Cutting down on salt; Kidney Care UK suggests reducing it if you eat more than 6g a day.
• A balanced, varied diet with more fruit and vegetables.
• Avoiding excessive weight gain.
• Not smoking, which Kidney Care UK says damages blood flow to the kidneys.

If kidney function is reduced, or after a kidney transplant, any diet changes should be set by your doctor or a registered dietitian.

6Medicines and tests to be careful with

• Non-steroidal anti-inflammatory painkillers (NSAIDs): the NKF and Kidney Care UK advise avoiding this group of painkillers because they can reduce blood flow to the kidneys. Ask a pharmacist or doctor first.
• Contrast dye: according to the NKF, the dye used in CT scans and angiograms can sometimes cause kidney problems; this is rare and may be preventable, so discuss it with your doctor before the test.

NIDDK advises always telling health professionals that you have a solitary kidney before any medicine, test or procedure. Any treatment is chosen by your doctor.

7Sport and pregnancy with one kidney

Sport: physical activity is good for you, and Kidney Care UK notes studies showing exercise can improve kidney function. On the other hand, NIDDK says certain sports are more likely to injure the kidney, especially in children, and the NKF notes that some professionals advise avoiding contact sports such as American football and boxing; padding lowers the risk but does not remove it. Decide with your doctor.

Pregnancy: NIDDK lists high blood pressure in pregnancy (pre-eclampsia) among the uncommon complications of a solitary kidney. According to NHS Organ Donation, most women who have donated a kidney have uncomplicated pregnancies, with a slightly increased risk of gestational hypertension or pre-eclampsia. The NKF advises discussing pregnancy plans with your obstetrician, ideally before becoming pregnant.

⏰When to see a doctor urgently

Based on NHS guidance on kidney infection and kidney stones, get urgent medical help if you have:

• Signs of kidney infection: high temperature or shivering, pain in the back or side under the ribs, being sick, burning when you pee or cloudy urine.
• Blood in your urine.
• Not passing urine all day.
• Severe pain in the side or lower back that may spread to the groin, especially with fever, which can mean a stone; see kidney stone treatment.
• Kidney infection symptoms during pregnancy.
• Confusion, drowsiness or difficulty speaking: the NHS advises going to A&E immediately.

A urologist assesses problems such as stones, blockage and tumours, and refers to a nephrologist when needed.

❓Frequently asked questions

10Sources

1. Solitary or Single-functioning Kidney
2. Living With One Kidney
3. Living with one kidney
4. Can you live with one kidney?
5. Five Surprising Ways You Could Be Damaging Your Kidneys
6. Kidney infection
7. Kidney stones
8. Physiology and Pathophysiology of Compensatory Adaptations of a Solitary Functioning Kidney (Frontiers in Physiology, 2020)