Chronic Kidney Disease (CKD): When to Worry and When to See a Doctor

Chronic Kidney Disease (CKD) is often called a “silent condition” because it rarely causes symptoms in its early stages. By the time physical signs appear, the kidneys may have already lost a significant amount of their filtering capacity.

In the UK and US, approximately 1 in 10 adults suffer from some form of kidney damage. Understanding the warning signs and knowing when to request kidney function tests can prevent the progression to kidney failure.

Fortunately only 1 in 100 patients with CKD progress to kidney failure – and require dialysis or a kidney transplant.

10 Common Signs of Chronic Kidney Disease

Most patients with CKD have no symptoms. If CKD is advanced (especially with Stage 4 CKD, with a GFR of < 30 ml/min (see below)) you may have some of these symptoms.

1. Swelling (Oedema)

When kidneys fail to remove excess fluid and salt, it builds up in the body. You may notice swelling in your ankles, feet, or legs. Persistent puffiness around the eyes—especially in the morning—is another key indicator.

2. Changes in Urination

Since the kidneys produce urine, any change in habits should be noted. This includes:

• Nocturia: Needing to urinate more often at night.

• Foamy Urine: Bubbles that look like “scrambled eggs” can indicate protein in the urine (proteinuria).

• Blood in the Urine: Known as haematuria, this occurs when the kidney’s filters are damaged.

3. Persistent Fatigue

Healthy kidneys produce a hormone called erythropoietin (EPO), which tells your body to make red blood cells. As function declines, you may develop anaemia, leaving you feeling exhausted and weak.

4. Itchy Skin

When kidneys can’t maintain the balance of minerals and nutrients in your blood, the buildup of toxins can cause “uraemic pruritus”—severe, persistent itching.

5. Shortness of Breath

Fluid can build up in the lungs (pulmonary oedema) when the kidneys aren’t filtering correctly. Additionally, the anaemia associated with CKD can leave your body starved of oxygen.

6. Muscle Cramping

Imbalances in calcium and phosphate levels resulting from poor kidney function can lead to painful muscle spasms, particularly in the legs.

7. Nausea and Loss of Appetite

A buildup of waste products in the blood (uraemia) can make food taste “metallic” and cause a general feeling of sickness or a loss of appetite.

8. Difficulty Concentrating

A buildup of toxins doesn’t just affect the body; it affects the brain. You may experience “brain fog,” dizziness, or trouble focusing on tasks.

9. High Blood Pressure

Hypertension is both a cause and a symptom of CKD. Damaged kidneys cannot effectively regulate the pressure of blood flowing through them.

10. Poor Sleep

When the kidneys aren’t filtering properly, toxins stay in the blood rather than leaving the body through urine. This makes it difficult to sleep and is often linked to sleep apnoea.

When Should You See a Doctor?

If you have two or more of these symptoms, it does not automatically mean you have chronic kidney disease.

However, you should book an appointment with your GP (or via the GP to a hospital specialist), especially if you have:

1. Diabetes: High blood sugar is a leading cause of kidney failure.

2. High Blood Pressure: Hypertension puts immense strain on small blood vessels in the kidneys.

3. Blood GFR and creatinine levels (see below):
   • Stage 3A CKD (Mild-Moderate Reduction): eGFR 45–59 mL/min (creatinine < 120 mmcol/L, i.e. usually normal). Moderate loss of function
     • You should see your GP
   • Stage 3B CKD (Moderate-Severe Reduction): eGFR 30–44 mL/min (creatinine 120-200 mcmol/L). Moderate-to-severe loss of function
     • You should see a kidney specialist (nephrologist) soon (within 3 months)
   • Stage 4 CKD (Severe Reduction): eGFR 15–29 mL/min (creatinine > 200 mcmol/L). Severe loss of function
     • You should see a kidney specialist (nephrologist) very soon (within 4 weeks).

The Tests You Need

Your doctor will likely perform two simple tests to check your status:

• uACR (Urine ACR): A urine test to check for protein leakage.

• Blood eGFR (Estimated Glomerular Filtration Rate) and creatinine: Blood tests that measures how well your kidneys are filtering waste.

Summary

Early detection of CKD is vital because lifestyle changes and medications like SGLT2 inhibitors or ACE inhibitors can “freeze” the disease and prevent the need for dialysis later in life.