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Overview

Kidney Disease Overview

Kidney disease is a broad term for damage or reduced function in one or both kidneys. Healthy kidneys filter waste and extra fluid from the blood while helping control minerals, blood pressure, and hormone production. Kidney problems may develop suddenly, or they may continue for months or years as chronic kidney disease. Kidney disease can affect adults and children.

Symptoms

Kidney Disease Symptoms

Early kidney disease often causes no noticeable symptoms. When signs appear, they can differ according to the cause, how quickly the problem developed, and how severe it is. Kidney pain is not present in every type of kidney disease, so the absence of pain does not rule out a problem.

  • Swelling in the ankles, legs, feet, hands, or around the eyes (edema)
  • Changes in urination, such as urinating more or less often
  • Blood in the urine (hematuria)
  • Foamy urine, which may indicate excess protein
  • Fatigue or reduced energy
  • Nausea or loss of appetite
  • Itching (pruritus)
  • Muscle cramps
  • Trouble concentrating or feeling mentally slowed

Seek medical advice

Severe symptoms need prompt care

Seek prompt medical attention for very little urine, breathing difficulty, confusion, or rapidly worsening swelling. These symptoms can signal a serious decline in kidney function or another urgent condition.

Causes

Causes of Kidney Disease

Ongoing damage, inflammation, blockage, inherited conditions, or sudden injury can reduce the kidneys’ ability to filter blood. This may also disrupt the balance of fluid, minerals, acids, and hormones in the body. Some causes lead to chronic kidney disease, while others cause an acute and potentially reversible fall in kidney function.

  • Diabetes can damage the small blood vessels and filtering units in the kidneys over time.
  • High blood pressure can strain and damage kidney blood vessels, gradually reducing filtration.
  • Glomerular diseases can inflame or injure the kidney’s filtering units.
  • Polycystic kidney disease causes inherited cysts that can enlarge and damage kidney tissue.
  • Recurrent kidney infections or urinary obstruction can injure the kidneys or prevent normal urine flow.
  • Some medicines, supplements, chemicals, or toxins can cause kidney injury, particularly when used unsafely or in high amounts.
  • Acute illnesses, severe dehydration, infection, low blood flow, or other sudden stresses can rapidly reduce kidney function.

Risk Factors

Risk Factors for Kidney Disease

Risk factors that can be changed or treated

  • Diabetes increases the risk of kidney damage, especially when blood sugar remains high.
  • High blood pressure can damage the blood vessels that support kidney function.
  • Smoking can harm blood vessels and increase the risk of worsening renal disease.
  • Obesity can contribute to diabetes, high blood pressure, and kidney stress.
  • Cardiovascular disease is linked with a higher risk of reduced kidney function.
  • A high-salt eating pattern can raise blood pressure and increase fluid retention.
  • Frequent or unsafe use of certain medicines, including nonsteroidal anti-inflammatory drugs, may injure the kidneys.

Risk factors that cannot be changed

  • Older age is associated with a greater likelihood of reduced kidney function and other health conditions.
  • A family history of kidney disease may indicate an inherited or shared risk.
  • Inherited kidney conditions can affect kidney structure or function from childhood or later in life.
  • A previous kidney injury may leave lasting damage or increase vulnerability to future problems.
  • Some racial or ethnic backgrounds have higher rates of kidney disease because of a combination of genetic, social, and health factors; local clinical guidance can help assess individual risk.

Complications

Kidney Disease Complications

  • Fluid buildup can cause swelling, weight gain, or breathing problems.
  • Electrolyte and acid-base changes can affect muscles, nerves, and heart rhythm.
  • Anemia can develop when damaged kidneys make less of the hormone that supports red blood cell production.
  • Bone and mineral problems can weaken bones and disrupt calcium and phosphorus balance.
  • High blood pressure can both result from and further worsen kidney damage.
  • Cardiovascular disease, including heart attack and stroke risk, becomes more likely as kidney function declines.
  • Nerve problems may cause numbness, tingling, or uncomfortable sensations.
  • Malnutrition can occur when appetite falls or dietary restrictions make it difficult to meet nutritional needs.
  • Kidney failure is advanced loss of kidney function that may require dialysis, transplantation, or conservative kidney care.

Kidney failure symptoms can develop as filtration becomes severely reduced and waste and fluid build up in the body. Severe breathing problems, confusion, chest symptoms, or markedly reduced urination require urgent assessment.

Diagnosis

How Kidney Disease Is Diagnosed

  • An estimated glomerular filtration rate from a blood test estimates how well the kidneys filter waste.
  • Urine albumin testing checks for albumin leaking through damaged kidney filters.
  • Urinalysis looks for blood, protein, infection, and other signs of kidney problems.
  • Blood pressure measurement helps identify a major cause and consequence of reduced kidney function.
  • Imaging, such as an ultrasound, can show kidney size, structure, cysts, stones, or blockage.
  • Selected genetic testing may help identify inherited kidney conditions.
  • A kidney biopsy may be used in selected cases to examine kidney tissue and clarify the cause of damage.

Chronic kidney disease is assessed by evidence of kidney damage or reduced filtration that persists over time. Chronic kidney disease stages are based mainly on estimated glomerular filtration rate; stage 3 kidney disease indicates a moderate reduction in function, while stage 4 kidney disease indicates a severe reduction. Clinicians also consider urine findings, symptoms, and the underlying cause.

Treatment & Management

Kidney Disease Treatment and Management

  • Controlling blood pressure can reduce stress on the kidneys and help protect kidney function.
  • Managing blood sugar can slow diabetes-related kidney damage.
  • Kidney-protective medicines may be recommended when appropriate for the cause and stage of disease.
  • Treating the underlying cause, such as infection, obstruction, inflammation, or an inherited condition, may improve or stabilize kidney function.
  • Medicine doses may need adjustment because damaged kidneys process some medicines more slowly.
  • An individualized nutrition and fluid plan can help manage sodium, protein, potassium, phosphorus, and fluid intake when needed.
  • Avoiding tobacco supports kidney and cardiovascular health.
  • Regular monitoring visits help track kidney function, urine findings, blood pressure, medicines, and complications.

Treatment options for advanced kidney failure

Advanced kidney failure may require referral to a kidney specialist, called a nephrologist. Depending on overall health, preferences, kidney function, and symptoms, care may include dialysis, evaluation for a kidney transplant, or conservative kidney care focused on comfort and quality of life. No single option is appropriate for every patient, so decisions should be made with the treating team.

Prevention

Can Kidney Disease Be Prevented?

  • Manage blood pressure and diabetes according to a clinician’s treatment plan.
  • Maintain a healthy weight through sustainable eating and activity habits.
  • Avoid smoking and seek support to stop if needed.
  • Stay physically active in a way that is safe for your health.
  • Limit excess sodium, especially if you have high blood pressure or fluid retention.
  • Use pain medicines safely, and ask a clinician or pharmacist before frequent use of nonsteroidal anti-inflammatory drugs.
  • Treat urinary, kidney, or cardiovascular conditions as directed and complete recommended follow-up.

Talk with a clinician

Ask whether kidney checks are needed

There is no single routine screening schedule for everyone. People with diabetes, high blood pressure, cardiovascular disease, or a family history of kidney disease may need periodic blood and urine testing to monitor kidney function.

Outlook and Prognosis

Kidney Disease Outlook and Prognosis

Some kidney problems improve when the cause is treated, while chronic kidney disease may remain stable for years or progressively worsen. Kidney failure means advanced loss of function, but it is not an inevitable outcome for every person with kidney disease. Early evaluation, treatment, and regular monitoring can help protect remaining kidney function.

  • The underlying cause influences whether kidney damage can improve, remain stable, or progress.
  • Estimated glomerular filtration rate helps show the current level of kidney function.
  • Urine albumin level provides information about kidney damage and future risk.
  • Blood pressure and diabetes control can affect the rate of kidney function decline.
  • Cardiovascular health influences overall outlook and the risk of serious complications.
  • Taking medicines as prescribed can help control the cause and protect kidney function.
  • Access to follow-up care supports timely testing, treatment changes, and management of complications.

When Should You See a Doctor

When Should You See a Doctor for Kidney Disease?

  • Arrange a medical appointment for persistent changes in urination.
  • Arrange an evaluation for blood in the urine or urine that remains unusually foamy.
  • Discuss unexplained swelling with a clinician.
  • Seek medical advice for ongoing fatigue without a clear explanation.
  • Have persistent kidney pain assessed, especially if it occurs with fever or urinary changes.
  • Ask about kidney testing if you have diabetes, high blood pressure, cardiovascular disease, or a family history of kidney disease.

Get urgent help

Recognize emergency warning signs

Seek urgent care for very little or no urine, severe shortness of breath, chest pain, new confusion, fainting, rapidly worsening swelling, or severe symptoms after a possible kidney injury. Call emergency services when symptoms are severe or life-threatening.

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