Unusual lower back pain? Don't ignore these 10 subtle kidney warning signs

World Kidney Day: Doctor highlights subtle signs like foamy urine, swelling and frequent urination that could signal trouble long before serious symptoms appear

Most of us rarely think about our kidneys until something goes seriously wrong. These two bean-shaped organs filter waste, balance fluids and help regulate blood pressure every single day. But when kidney problems begin, the body often sends subtle signals long before serious symptoms appear.

 

Sometimes the signals are easy to overlook or dismiss as stress, ageing, or dehydration. But doctors say persistent changes in the body should not be ignored.

 

According to Dr Ahmed Kamaal, director, kidney transplant – urology, ShardaCare-Healthcity, early kidney dysfunction often develops gradually and can remain unnoticed for a long time.

 

“Persistent fatigue, swelling of eyes or feet and ankles, urine habits, and loss of appetite without any explanation are some of the initial causes of concern. People may also notice that their urine appears foamy or that they need to urinate more often, particularly at night,” says Dr Kamaal.

 

 

“These symptoms are usually mistaken for ageing, stress, or dehydration effects. However, the key difference is persistence and progression,” he adds.

 

If these symptoms persist for weeks or occur alongside conditions such as diabetes or high blood pressure, they may indicate that the kidneys are not filtering waste and excess fluid effectively.

So, what should you watch out for?

Here are 10 subtle kidney warning signs that doctors say you shouldn’t ignore.

1. Persistent fatigue or low energy

Feeling constantly tired without a clear reason can sometimes signal kidney problems. When the kidneys are not filtering waste effectively, toxins can build up in the bloodstream, leading to fatigue.

 

Kidney disease can also contribute to anaemia, which further reduces energy levels, says Dr Kamaal.

2. Swelling around the eyes, feet, or ankles

According to Dr Kamaal, when kidneys struggle to remove excess fluid from the body, swelling (also known as oedema) may develop.

 

This swelling often appears in the legs, ankles, feet, or around the eyes, especially in the morning.

3. Frequent urination, especially at night

Waking up multiple times at night to urinate, a condition called nocturia, may sometimes signal kidney dysfunction.

 

Dr Kamaal explains that when kidney filtering ability declines, they may struggle to concentrate urine properly.

 

“If someone wakes up multiple times every night to urinate, notices increased urine output without increased fluid intake, or experiences accompanying symptoms such as swelling, fatigue, or foamy urine, it could signal an underlying kidney problem,” he says.

 

Persistent nocturia (the need to wake up one or more times per night to urinate), especially in people with diabetes or hypertension, should be evaluated by a doctor.

4. Foamy or bubbly urine

Foamy urine may indicate excess protein in the urine, one of the earliest markers of kidney damage.

 

While occasional bubbles may occur due to urine flow, persistent foamy urine should be checked by a doctor.

5. Changes in urine colour

Urine that appears dark, reddish, or cloudy can sometimes indicate infection, blood in the urine, or kidney-related issues.

 

Any persistent change in urine appearance deserves medical attention.

6. Reduced urination

In some cases, people may notice that they are urinating less than usual, which may suggest declining kidney function or fluid imbalance.

7. Loss of appetite

A sudden or unexplained loss of appetite can sometimes occur when toxins build up in the bloodstream due to impaired kidney function.

8. Persistent flank or lower back pain

Many people experience back pain due to muscle strain or posture problems. But kidney-related pain tends to feel different.

 

It usually occurs in the flank region, on either side of the spine, just below the rib cage.

 

“Contrary to muscular pain, which in most cases is aggravated by movements, bending or lifting, kidney pain is often deeper, more persistent and may not be relieved by posture or rest,” says Dr Kamaal.

 

The pain may sometimes radiate to the abdomen, groin, or inner thigh.

9. Burning or discomfort during urination

Pain or burning while urinating may signal a urinary tract infection or a kidney infection, both of which require medical attention.

10. Nausea, fever, or blood in urine along with pain

In some cases, kidney-related pain may occur alongside fever, nausea, blood in urine, or frequent urination, particularly in conditions like kidney stones or infections.

 

These symptoms should not be ignored. 

Who is at higher risk of kidney disease?

Some groups are more vulnerable to kidney problems and should be particularly attentive to early symptoms.

 

People with diabetes and high blood pressure are at the highest risk because both conditions can damage the small blood vessels in the kidneys over time.

 

Dr Kamaal says individuals who are overweight, smokers, older adults, those with a family history of kidney disease, or people who use painkillers for long periods are also at increased risk.

 

“What makes kidney disease particularly concerning is that in many high-risk individuals it can progress silently without obvious symptoms in the early stages,” he says.

 

Because symptoms often appear late, regular screening becomes important. 

Which tests can detect kidney problems early?

If warning signs persist, doctors usually recommend simple diagnostic tests.

 

A urine routine and urine albumin test can detect protein, blood or infection in urine, which are early indicators of kidney damage.

 

A blood test measuring serum creatinine helps estimate the glomerular filtration rate (eGFR), which shows how well the kidneys are filtering waste from the blood.

 

In some cases, doctors may also recommend a kidney ultrasound to check for structural abnormalities, stones or obstruction.

 

Early screening is especially important for people with diabetes or hypertension.

How can you protect your kidney health?

Preventing kidney disease largely depends on maintaining overall metabolic health.

 

Experts recommend controlling blood sugar and blood pressure, maintaining a healthy weight, exercising regularly, and limiting excess salt and processed foods.

 

Adequate hydration and avoiding unnecessary use of over-the-counter painkillers without medical supervision are also important for protecting kidney function.

 

For people with risk factors, annual blood and urine tests can help detect kidney problems early.

About World Kidney Day

World Kidney Day is observed annually on the second Thursday of March to raise awareness about kidney health and the importance of early detection of kidney disease.

 

The global campaign was established in 2006 by the International Society of Nephrology (ISN) and the International Federation of Kidney Foundations (IFKF).

 

The theme for World Kidney Day 2026 is “Are Your Kidneys OK? Detect Early, Protect Kidney Health.” The campaign encourages people to recognise early warning signs, get tested if they are at risk, and adopt lifestyle habits that help protect kidney health.  For more health updates, follow #HealthWithBS 

This content is for informational purposes only and is not a substitute for professional medical advice.