Kidney Failure Symptoms: Early Signs & Warning Signs

Quick Glance: Common Kidney Failure Symptoms

Common kidney failure symptoms may include:

Feeling unusually tired or weak
Swelling of the feet, ankles, hands or face
Passing much less urine or changes in urination
Nausea or vomiting
Poor appetite
Itchy skin
Muscle cramps or weakness
Difficulty concentrating, confusion or reduced mental alertness

Symptoms can vary from person to person and may depend on how quickly kidney function has declined. Some people may have few or no noticeable symptoms until kidney disease has advanced.

Symptoms of Kidney Failure That Should Not Be Ignored

The table below highlights kidney failure symptoms that may indicate a significant reduction in kidney function or complications requiring medical assessment:

Symptom	What It May Indicate	Possible Complication or Disease Progression
Very little or no urine	Markedly reduced kidney filtration or acute kidney injury	Significant fluid and waste buildup
Swelling in the legs, feet or face	Retention of sodium and fluid	Fluid overload and worsening kidney function
Shortness of breath	Fluid accumulation affecting the lungs	Significant fluid overload
Persistent nausea or vomiting	Buildup of waste products in the blood	Advanced kidney failure and dehydration
New confusion or difficulty concentrating	Uraemia or electrolyte and metabolic disturbances	Severe kidney dysfunction
Severe muscle weakness	Significant electrolyte imbalance, including high potassium	Potentially serious heart complications
Markedly irregular heartbeat	Abnormal electrolyte levels, particularly potassium	Potentially dangerous cardiac rhythm disturbances
Sudden or rapidly worsening symptoms	Acute decline in kidney function or a serious complication	Need for urgent medical assessment

These symptoms do not confirm kidney failure, as several other conditions can cause similar problems. However, persistent, severe or rapidly worsening symptoms should be medically assessed.

Why Do Kidney Failure Symptoms Occur?

Kidney failure occur when the kidneys can no longer remove enough waste and excess fluid from the blood, or maintain normal levels of electrolytes and other substances. The kidneys also produce hormones that help regulate blood pressure and red blood cell production. When kidney function becomes severely reduced, these processes can become disrupted.

Kidney failure can lead to:

Buildup of Waste Products When the kidneys cannot filter blood effectively, waste products remain in the bloodstream. This buildup can contribute to nausea, vomiting, poor appetite, itching, tiredness and changes in concentration or mental alertness.
Excess Fluid Retention Reduced kidney filtration can cause the body to retain sodium and water. This may cause edema, commonly seen as swelling around the ankles, feet, hands or face. If excess fluid accumulates in the lungs, it can contribute to shortness of breath.
Changes in Urine Production Kidney failure can cause urine output to fall significantly. However, urine volume does not always decrease in kidney disease, so normal or increased urination does not necessarily indicate normal kidney function.
Electrolyte and Mineral Imbalance The kidneys help maintain appropriate levels of electrolytes and minerals in the blood. Advanced kidney failure can disrupt potassium, phosphorus, calcium, and acid-base balance, which may contribute to muscle cramps, weakness, and abnormal heart rhythms.
Reduced Red Blood Cell Production Healthy kidneys produce the hormone erythropoietin, which signals the bone marrow to make red blood cells. Reduced kidney function can lower erythropoietin production and contribute to anaemia, which may cause tiredness and weakness.

Symptoms of Kidney Failure That Require Immediate Medical Attention

Seek urgent medical care if kidney failure symptoms are severe, sudden or rapidly worsening, particularly when accompanied by:

Very little or no urine
Severe shortness of breath or difficulty breathing
Chest pain or pressure
New confusion, extreme drowsiness or difficulty staying awake
Seizures or loss of consciousness
Severe weakness or a markedly irregular heartbeat
Persistent vomiting with signs of dehydration
Sudden swelling accompanied by breathing difficulty

Acute kidney injury can develop quickly and may cause reduced urine output, fluid accumulation, confusion, weakness or electrolyte-related complications. Severe symptoms require urgent medical assessment.

Symptoms of Kidney Failure Based on Type

The table below compares the symptoms of kidney failure based on type:

Type	Symptom
Acute kidney injury (AKI)	Sudden reduction in urine, swelling or breathlessness, nausea and weakness, and confusion or abnormal heart rhythm.
Chronic kidney failure	Persistent tiredness, swelling of feet or ankles, itchy skin and poor appetite, and changes in urination and concentration problems.

Symptoms of Kidney Failure in Men

Most kidney failure symptoms are similar in men and women. However, advanced kidney disease or kidney failure may be associated with sexual health changes, including reduced sexual desire or difficulty achieving or maintaining an erection.

These symptoms can have several possible causes, including hormonal changes, anaemia, medicines and other health conditions. Therefore, they should not be assumed to be caused by kidney failure without medical assessment.

Symptoms of Kidney Failure in Women

Advanced kidney disease or kidney failure in women may cause menstrual irregularities, changes in sexual health or fertility problems. Since these symptoms can have several other causes, they should not be assumed to indicate kidney failure. However, persistent or unexplained menstrual or reproductive changes should be assessed by a healthcare professional.

Symptoms of Kidney Failure in Children

Kidney failure symptoms in children may be less specific than in adults. Depending on the child's age and severity of kidney dysfunction, symptoms may include:

Poor appetite or difficulty feeding
Nausea or vomiting
Tiredness or weakness
Swelling around the eyes, hands or feet
Changes in urination
Poor growth
Headaches
Difficulty concentrating or changes in behaviour

These symptoms can overlap with many other childhood illnesses, and thus, persistent or unexplained symptoms should be assessed by a paediatrician or other qualified healthcare professional.

Can You Have Kidney Failure Without Symptoms?

Yes, kidney problems can sometimes cause few or no noticeable symptoms, particularly in the earlier stages of chronic kidney disease. Kidney function can decline before a person feels unwell, which is why early kidney disease can be described as a “silent” condition.

As kidney function falls further, symptoms such as swelling, tiredness, nausea, itching and changes in urination may become more noticeable. People at increased risk, including those with diabetes, high blood pressure, heart disease or a family history of kidney failure, may need regular kidney testing even when they feel well.

When Can Kidney Failure Symptoms Become Life-Threatening?

The table below explains serious complications of kidney failure that can become life-threatening and the symptoms or effects they may cause:

Life-Threatening Condition	What Can Happen
Severe Fluid Overload	Excess fluid can buildup in the body and lungs, causing severe breathlessness and requiring urgent medical assessment.
Dangerous Electrolyte Imbalance	Severe changes in potassium and other electrolytes can interfere with the heart's normal rhythm and become an emergency.
Severe Uraemia	A substantial buildup of waste products can affect the nervous system, causing confusion, extreme drowsiness or loss of consciousness.
Seizures or Loss of Consciousness	Severe kidney dysfunction and associated metabolic disturbances can affect brain function and require emergency medical care.

How are Kidney Failure Symptoms Diagnosed?

Symptoms alone cannot confirm kidney failure. Doctors usually combine medical history and physical examination with blood and urine tests to assess kidney function, identify complications and investigate the underlying cause.

The table below explains the main tests used to assess kidney function and identify kidney failure:

Diagnostic Test	Purpose
Serum creatinine	Measures waste products in the blood used to estimate kidney function.
Estimated glomerular filtration rate (eGFR)	Estimates how well the kidneys filter blood; an eGFR below 15 mL/min/1.73 m² is generally classified as kidney failure.
Urine albumin-to-creatinine ratio (UACR)	Checks for albumin in urine, which can indicate kidney damage.
Urinalysis	Checks urine for blood, protein and other abnormalities.
Blood electrolyte tests	Measures substances such as potassium, sodium and bicarbonate that may become abnormal when kidney function declines.
Blood urea nitrogen (BUN)	Measures urea-related waste in the blood.
Complete blood count (CBC)	Can help identify anaemia associated with chronic kidney disease.
Ultrasound or other imaging	May help identify structural abnormalities or urinary blockage when clinically indicated.

An eGFR below 15 mL/min/1.73 m² is generally classified as kidney failure, but healthcare professionals interpret the result alongside other findings and the clinical situation. A single test result does not explain the cause of reduced kidney function.

FAQs

Q1. What is the first symptom of kidney failure?

Ans: There is no single first symptom of kidney failure. Early chronic kidney disease may cause few or no noticeable symptoms, while advanced kidney failure can cause tiredness, swelling, changes in urination, nausea, itching or difficulty concentrating.
Q2. Can kidney failure develop without symptoms?

Ans: Yes, kidney failure can be preceded by chronic kidney disease that causes few or no noticeable symptoms. Kidney function can decline before a person feels unwell, so people at a higher risk of kidney disease may need regular testing.
Q3. Which symptoms of kidney failure should never be ignored?

Ans: Very little or no urine, severe breathlessness, chest pain, new confusion, seizures, loss of consciousness, severe weakness or a markedly irregular heartbeat are symptoms of kidney failure that should not be ignored. These symptoms may indicate a serious complication and require prompt medical assessment.
Q4. Are kidney failure symptoms different in men and women?

Ans: Most kidney failure symptoms are similar in men and women. However, kidney failure may be associated with sexual health changes in men and menstrual or reproductive changes in women. These symptoms can also have other causes and do not by themselves confirm kidney failure.
Q5. What are the early warning signs of kidney failure?

Ans: Early warning signs of kidney failure may include persistent tiredness, swelling, changes in urination, poor appetite, nausea, itchy skin, muscle weakness and difficulty concentrating. However, early chronic kidney disease may cause no noticeable symptoms.
Q6. When should I see a doctor about kidney failure symptoms?

Ans: See a healthcare professional if you develop persistent or concerning changes in urination, swelling, unexplained tiredness, nausea or other symptoms that may indicate kidney problems. People with risk factors such as diabetes or high blood pressure should also discuss appropriate kidney testing with their doctor.
Q7. Can kidney failure symptoms vary in intensity?

Ans: Yes, kidney failure symptoms can vary depending on how much kidney function has been lost, how quickly kidney function has changed and whether complications such as fluid or electrolyte imbalance have developed. Acute kidney injury may cause symptoms suddenly, while chronic kidney disease can progress gradually.
Q8. Which kidney failure symptoms indicate an emergency?

Ans: Kidney failure symptoms, such as severe difficulty breathing, chest pain, very little or no urine, seizures, loss of consciousness, severe confusion or symptoms suggesting a dangerous heart rhythm, require urgent medical attention. These symptoms may indicate serious complications and should not be managed through self-diagnosis.