# Symptoms and stages of chronic kidney disease, stage 4-5
Chronic kidney disease (CKD) in stage 4 and 5 corresponds to severely reduced kidney function. This text describes how symptoms develop and change as the kidneys work less well, and what that means for daily life.
Stage 4: Severely reduced kidney function
In stage 4, the kidneys work at only 15-29% of their normal function. Kidney damage has progressed, but people can usually still live without dialysis, although preparation for it begins.
Onset of symptoms
In this stage, many people notice serious complaints for the first time:
- **Fatigue and weakness** — usually the most noticeable symptom. This is caused by anemia (too few red blood cells because the kidneys produce less erythropoietin, a substance that stimulates blood cell production) and by accumulation of waste products.
- **Shortness of breath**, especially with exertion or lying down, because fluid builds up in the lungs.
- **Swelling** (edema) in legs, ankles, feet and sometimes face, because the body retains fluid.
- **Nausea and loss of appetite** — consequences of waste product accumulation (uremia).
- **Taste changes**, often a metallic taste.
- **Headaches and concentration problems** from fluid excess and waste products.
- **Itching**, sometimes severe, from elevated phosphate levels and uremia.
- **High blood pressure**, which is harder to control.
- **Restless legs** — restless feeling in the legs, especially at night.
- **Poor sleep** from itching, restless legs, frequent urination and anxiety.
- **Bone and joint pain**, from disturbed calcium and phosphate balance.
Impact on daily life
People in stage 4 can usually still go to work, but fatigue often forces them to rest. Household tasks become more difficult. Dietary restrictions begin to weigh more heavily — food must be low in potassium, phosphate and salt, which complicates cooking and social meals.
Regular hospital visits increase; blood tests happen every few weeks to months. Many people feel less confident about their body and future.
Figures
The average duration of stage 4 is several years, but this varies greatly from person to person — some remain stable here, others progress more quickly to stage 5. In large population studies, it was found that approximately 5-10% of people with stage 4 CKD progress to stage 5 per year (data from 2020-2023). Mortality in this stage depends heavily on age, other diseases (especially heart and cardiovascular diseases) and how well the underlying cause can be treated. Individual differences are enormous and depend on many factors per person.
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Stage 5: Kidney insufficiency / end-stage renal failure
In stage 5, the kidneys work at only 0-14% of normal. Without dialysis or kidney transplant, the body can no longer remove toxic waste products. This stage is also called "end-stage renal disease" (ESRD).
Onset of symptoms
The symptoms of stage 4 often worsen considerably, and new complaints may develop:
- **Severe fatigue and general weakness** — people can barely get out of bed.
- **Persistent nausea, vomiting and lack of hunger** — many people eat hardly at all.
- **Uremia odor** — in breath and sweat, from accumulation of nitrogen-containing waste products.
- **Severe itching**, sometimes unbearable, despite treatment.
- **Breathing problems** from fluid buildup in lungs (pulmonary edema) or fluid deficiency.
- **Heart and rhythm complaints** — palpitations, irregular heartbeat from elevated potassium levels.
- **Confusion, sleepiness or loss of concentration** from uremia and electrolyte disorders.
- **Muscle cramps**, especially at night.
- **Paleness** of skin and lips from severe anemia.
- **High blood pressure despite multiple medications**.
- **Vision problems** and other neurological symptoms in cases of very severe waste product accumulation.
- **Pain around the kidneys** or dull pain in the lower back (not always present).
In people not yet on dialysis, symptoms of fluid overload can also worsen: extreme swelling, severe shortness of breath, possible fluid buildup around the heart (pericardial effusion).
Impact on daily life
Stage 5 is usually unsustainable without treatment (dialysis or transplantation). Most people can no longer work. Self-care becomes difficult; daily tasks require help. Diet is severely restricted — many nutrients must be avoided.
Preparation for dialysis or waiting for a donor kidney dominates life. Psychologically this is heavy: people struggle with loss of health, independence and future plans. Many patients experience fear, depression and feel isolated.
Figures
Without treatment, stage 5 leads to serious life-threatening danger. With dialysis, average global survival is 5-10 years, but this varies greatly: younger patients can remain on dialysis for 20-30 years, older ones sometimes shorter. With a successful kidney transplant, survival can be much longer — kidneys from family members provide an average of 15-20 years (based on data from 2018-2023), kidneys from deceased donors an average of 10-15 years. These figures are population averages; individual outcomes depend on age, other illnesses, how well the donor and recipient 'match', and how well the transplant is maintained.
The timing of when dialysis starts varies. In many Western countries, it begins around a glomerular filtration rate (GFR) of 10-15 ml/min/1.73m², but this depends on symptoms, remaining kidney function, body size and the preference of patient and doctor. Some patients can wait longer than others.
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Fluid balance and blood pressure in stage 4-5
A particularly important problem in these stages is fluid buildup. Because the kidneys produce less urine, fluid accumulates in the body — not only in the legs and abdomen (visible swelling), but also in the lungs and around the heart. This makes breathing difficult and can become serious.
Blood pressure rises because fluid strains the blood (extra water = extra volume = extra pressure). This in turn leads to more kidney failure: a vicious circle. Therefore, fluid restriction (drinking less, avoiding salt) is essential in these stages.
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Electrolyte and mineral disorders
As kidney function declines, minerals and salts accumulate:
- **Potassium** (hyperkalemia) — can cause heart rhythm disturbances and even sudden cardiac death; symptoms are palpitations, weakness, nausea.
- **Phosphate** — leads to abnormal calcium-phosphate balance, causing calcification of blood vessels and soft tissues (secondary hyperparathyroidism).
- **Calcium** — can be too low (hypocalcemia), causing muscle cramps and bone pain.
These disorders require strict dietary management and sometimes medication.
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When to contact your doctor
Seek medical help immediately, without delay, if you:
- Suddenly worsen with shortness of breath, especially if sleeping lying down becomes impossible.
- Feel chest pain or pressure or notice irregularities in your heart rate.
- Cannot stop vomiting and nausea.
- Experience confusion, severe drowsiness or unresponsiveness.
- Get severe muscle cramps, especially around chest or heart.
- Stop producing urine (or very little) while you are swollen.
- Have severe pain in the kidney area.
Also arrange an appointment soon if symptoms slowly worsen — such as increasing fatigue, persistent itching despite medication, ongoing nausea, or weight gain without eating more — as this may indicate your kidney function is declining further and your treatment needs to be adjusted.
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_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._