Talk to our team

Kidney problems

Swollen feet: could it be my kidneys?

Swollen feet and ankles have many causes, most of them harmless, such as heat or long periods of standing. Sometimes swelling is linked to the heart, liver, veins or kidneys. A clinician can tell the difference with an examination and simple tests.

Written by: Mombasa Kidney Care editorial team

Swollen feet and ankles are very common, especially in a hot, humid city like Mombasa. Most of the time the cause is harmless and settles on its own. Sometimes, swelling is a sign that the heart, liver, veins or kidneys need to be checked. Many people describe it simply as "miguu imevimba".

This page explains why feet swell, how kidney-related swelling can look, what a clinician usually checks, and when to seek care.

Why feet swell

Swelling happens when extra fluid collects in the tissues under the skin. Doctors call this oedema. Because of gravity, the fluid tends to settle in the lowest parts of the body, so the feet and ankles are usually the first places you notice it. If you press a finger into the swollen area for a few seconds and it leaves a dent, this is called pitting oedema.

Swelling can be in one leg or both. That difference matters, because the likely causes are different.

Common causes of swelling

Everyday causes

  • Heat. Blood vessels widen in hot weather and fluid leaks into the tissues more easily.
  • Standing or sitting for long periods, for example at work, or on a long bus or matatu trip.
  • Pregnancy, especially in the later months.
  • A salty diet, which makes the body hold on to water.
  • Carrying extra body weight.

Medicines

Some medicines can cause ankle swelling as a side effect. These include some blood pressure medicines, anti-inflammatory painkillers (NSAIDs), steroids and some diabetes medicines. If swelling started after a new medicine, tell your doctor. Do not stop the medicine yourself.

Health conditions a clinician may consider

  • Vein problems, where the leg veins struggle to return blood to the heart. This is common with age and varicose veins.
  • Heart conditions, such as heart failure, where the heart does not pump strongly enough.
  • Liver disease, which can lower the level of albumin (a protein) in the blood.
  • Kidney conditions, described below.
  • Low protein levels from poor nutrition or long illness.
  • An underactive thyroid gland.

Swelling in one leg only

One swollen leg can be caused by an injury, an infection of the skin (cellulitis), or a blood clot in a deep vein (deep vein thrombosis, or DVT). A clot needs same-day medical care. In coastal Kenya, long-standing swelling of one leg can also have other causes, including lymphatic filariasis, which a clinician may consider.

How the kidneys can cause swelling

The kidneys control how much salt and water the body keeps. When they are not working well, the body can hold on to extra salt and fluid, and swelling can appear in the feet, ankles and legs.

Swelling can also happen when the kidney filters leak protein into the urine. The main protein lost is albumin, which normally helps hold fluid inside the blood vessels. When a lot of albumin is lost, fluid moves into the tissues. A group of findings with heavy protein loss, low blood albumin and swelling is called nephrotic syndrome.

Signs that may point a clinician towards the kidneys include:

  • puffiness around the eyes, often worse in the morning;
  • swelling in both legs that does not settle overnight;
  • urine that is persistently foamy or frothy (see foamy urine);
  • passing less urine than usual;
  • having diabetes, high blood pressure, or a known kidney condition.

These signs are not proof of a kidney problem. Many people with early kidney disease have no swelling at all. The only way to know is through tests.

What a clinician usually checks

A doctor will ask when the swelling started, whether it is in one leg or both, and about your medicines and other health conditions. They will examine your legs, heart, lungs and abdomen, and check your blood pressure and weight. Tests that may be used include:

  • Urine dipstick or urine ACR, to look for protein. See urine ACR test.
  • Creatinine and eGFR, to estimate kidney filtering. See eGFR explained.
  • Blood albumin and liver tests.
  • Blood sugar, if diabetes has not been checked recently.
  • Heart tests, such as an ECG or a heart ultrasound (echocardiogram), if a heart cause is possible.
  • An ultrasound of the leg veins, if a clot is suspected.

When to seek care

Book an appointment with a doctor or clinical officer, ideally within the next few days, if:

  • both feet or ankles have been swollen for more than a few days without an obvious reason;
  • the swelling is getting worse or spreading up the legs;
  • you also notice puffy eyes, foamy urine or passing less urine;
  • you have diabetes, high blood pressure, heart disease or a kidney condition;
  • the swelling began after starting a new medicine.

If you are pregnant, tell your antenatal clinic about any new swelling, especially of the face or hands.

When to get medical help urgently

Go to the nearest hospital emergency department, or call 999 or 112, if you have:

  • swelling with breathlessness, especially when lying flat;
  • chest pain;
  • one leg that is suddenly swollen, painful, warm or red;
  • very little or no urine;
  • during pregnancy, sudden swelling of the face or hands with a severe headache, vision problems or pain under the ribs.

While you wait for an appointment

Raising your legs when you sit, and avoiding standing still for long periods, can make you more comfortable. Keep taking your usual medicines. Avoid buying water tablets (diuretics) from a chemist without a prescription: they can upset salt levels and kidney function, and they can hide the cause of the swelling. Write down when the swelling started and anything that makes it better or worse, and bring any recent test results to your appointment.

Learn moreProtein in urine Understand your next stepKidney function tests Ready for careFind kidney care in Mombasa

Sources

  1. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. kdigo.org
  2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Kidney disease health information. niddk.nih.gov
  3. National Kidney Foundation. Kidney health information. kidney.org

This page explains what a test or condition involves. It is not a diagnosis and does not replace advice from a doctor who knows your history. Your results should be interpreted together with your symptoms, other tests and a clinical assessment. Medical disclaimer.