1. Persistent tiredness and low energy

• When the kidneys cannot clear waste products efficiently, these substances build up in the blood and can leave you feeling persistently tired and washed out. Kidney disease also commonly causes anaemia — a shortage of red blood cells — because the kidneys produce a hormone that signals the body to make them. Fatigue from anaemia tends to come on gradually and is often dismissed as overwork or ageing.

2. Swelling in the feet, ankles, or face

• When the kidneys cannot remove excess fluid and salt, this fluid accumulates in the body, often first noticeable as puffiness around the eyes in the morning or swelling of the feet and ankles by the end of the day. Swelling has many causes, but new or worsening swelling deserves a kidney check.

3. Changes in urination

• Changes in how you pass urine can be an important clue. These include passing urine more often at night, producing noticeably more or less urine than usual, foamy or frothy urine (which can indicate protein leakage), or blood in the urine giving it a pink or cola-coloured appearance. Any blood in the urine should always be investigated.

4. Foamy urine

• Urine that appears persistently foamy, rather like the head on a beer, can be a sign that protein is leaking through damaged kidney filters. A small amount of bubbling is normal, but persistent foam is worth mentioning to a doctor.

5. Itchy skin

• Advanced kidney disease can cause persistent, widespread itching that is not relieved by moisturisers. This is related to the build-up of waste products and disturbances in calcium and phosphate balance.

6. Poor appetite, nausea, or a metallic taste

• A build-up of waste products in the blood can reduce appetite, cause nausea, and produce an unpleasant metallic taste in the mouth. Some people notice they have gone off meat or certain foods. Unintentional weight loss can follow.

7. Difficulty concentrating or feeling “foggy”

• When waste products accumulate, they can affect the brain, leading to difficulty concentrating, poor memory, and a general sense of mental fogginess.

8. Muscle cramps

• Disturbances in the levels of minerals such as calcium, phosphate, and potassium — which the kidneys normally regulate — can cause muscle cramps, particularly in the legs.

9. High blood pressure that is hard to control

• The relationship between blood pressure and the kidneys runs in both directions. High blood pressure can damage the kidneys, and kidney disease can raise blood pressure. Blood pressure that is newly high, or suddenly harder to control than before, can sometimes be a sign of underlying kidney disease.

• An honest word about these symptoms It is important to be realistic: every one of these symptoms can be caused by conditions that have nothing to do with the kidneys. Tiredness, swelling, and poor appetite are common and usually have other explanations. The point is not to cause alarm, but to encourage a simple check — a blood test and a urine test — if these symptoms are persistent, especially if you also have diabetes, high blood pressure, or a family history of kidney disease.

• The reassuring reality is that these tests are inexpensive, widely available, and quick. If your kidneys are fine, you will have peace of mind. If there is a problem, finding it early gives you the best possible chance of slowing it down.

• Persistent symptoms like these, particularly alongside diabetes or high blood pressure, are worth discussing with a nephrologist. A simple assessment can give you clarity.