Kidney Disease

What is kidney disease?

Kidney disease is any condition that damages the kidneys and reduces their ability to do their job. The kidneys are two bean-shaped organs, each about the size of a fist, that sit just below the rib cage on either side of the spine. They filter waste products and excess fluid out of the blood to make urine, help control blood pressure, balance minerals such as potassium and phosphorus, and support red blood cell production and bone health.

When people ask what is kidney disease, they usually mean chronic kidney disease, often shortened to CKD. Chronic means long-lasting. In CKD, kidney function declines gradually over months or years, and the damage is usually permanent. Doctors describe CKD in five stages based on how well the kidneys filter blood. Stage 1 is mild, and stage 5 is kidney failure, sometimes called end-stage kidney disease, when the kidneys can no longer keep a person healthy without dialysis or a transplant.

Kidney disease can also be acute. Acute kidney injury (AKI) is a sudden drop in kidney function over hours or days, usually triggered by a severe illness, dehydration, a blocked urinary tract, or certain medications. It is often reversible if the cause is treated quickly, but it can also leave lasting damage.

Kidney disease affects people of all ages, although it is more common in older adults and in people with diabetes or high blood pressure. Many people live with early kidney disease for years without knowing it, because the kidneys can keep working reasonably well even after losing a significant part of their filtering capacity.

Kidney disease symptoms

Early kidney disease symptoms are often absent or very mild, which is why the condition is frequently discovered by chance on a routine blood or urine test. As kidney function falls, waste and fluid build up in the body and symptoms become more noticeable. Common symptoms include:

• Tiredness, weakness, or difficulty concentrating
• Swelling (edema) in the ankles, feet, legs, hands, or around the eyes
• Changes in urination, such as passing urine more often at night, less urine than usual, or urine that is foamy, dark, or contains blood
• Shortness of breath, caused by fluid in the lungs or by anemia (a low red blood cell count)
• Loss of appetite, nausea, vomiting, or a metallic taste in the mouth
• Persistent itching or dry skin
• Muscle cramps, especially at night
• High blood pressure that is difficult to control
• Pain in the side or lower back, which is more typical of kidney stones, infection, or polycystic kidney disease than of CKD

Symptoms vary by type and stage. In stages 1 to 3 of CKD, most people feel well, and the only clues may be protein or blood in the urine or a mildly abnormal blood test. In stages 4 and 5, fatigue, swelling, nausea, itching, and breathlessness tend to become more prominent. Acute kidney injury may cause a sudden fall in urine output, confusion, or swelling over a short period. Glomerulonephritis, which is inflammation of the kidney filters, sometimes causes visible blood in the urine, puffiness, and high blood pressure. Kidney infections usually cause fever, back or flank pain, and painful urination.

Because these symptoms overlap with many other conditions, they do not confirm kidney disease on their own. Only testing can show whether the kidneys are affected.

Causes and risk factors

Kidney disease causes fall into a few broad groups: conditions that damage the small blood vessels and filters in the kidney over time, diseases that inflame kidney tissue, inherited disorders, blockages, and injury from toxins or medications.

• Diabetes. Persistently high blood sugar damages the tiny blood vessels in the kidney filters. Diabetic kidney disease is one of the leading causes of CKD worldwide.
• High blood pressure (hypertension). Over years, high pressure scars the kidney’s blood vessels. Kidney disease can also raise blood pressure, creating a cycle of worsening damage.
• Glomerulonephritis. Inflammation of the glomeruli, the microscopic filtering units, triggered by immune system disorders, infections, or unknown causes.
• Polycystic kidney disease. An inherited condition in which fluid-filled cysts grow in the kidneys and gradually replace healthy tissue.
• Urinary tract obstruction. Long-standing blockage from an enlarged prostate, kidney stones, or a tumor can cause urine to back up and damage the kidneys.
• Repeated kidney infections. Frequent or severe infections of the kidney (pyelonephritis) can leave scarring.
• Medications and toxins. Long-term or heavy use of certain painkillers, some antibiotics, contrast dyes used in imaging, and some herbal products can injure the kidneys, especially when they are already vulnerable.
• Autoimmune diseases. Conditions such as lupus, in which the immune system attacks the body’s own tissues, can involve the kidneys.

Risk factors make kidney disease more likely but do not guarantee it will develop. They include older age, a family history of kidney disease, heart disease, obesity, smoking, and a previous episode of acute kidney injury. Being born with a low birth weight or an abnormal kidney structure also raises risk. Some ethnic groups have higher rates of kidney disease, partly because of higher rates of diabetes and high blood pressure. People with several risk factors are usually advised to have their kidney function checked regularly, even if they feel well.

Kidney disease diagnosis

Because symptoms are unreliable, kidney disease diagnosis rests on tests. Doctors usually start with a medical history, a physical examination that includes blood pressure measurement and a check for swelling, and simple tests of the blood and urine.

• Blood test for creatinine and eGFR. Creatinine is a waste product from muscle that healthy kidneys remove from the blood. The laboratory uses the creatinine level, together with age and sex, to estimate the glomerular filtration rate (eGFR), a measure of how much blood the kidneys filter each minute. An eGFR below 60 for three months or longer is one of the standard criteria for CKD, and an eGFR below 15 indicates kidney failure.
• Urine test for albumin. Albumin is a protein that should stay in the blood. When it leaks into the urine, the kidney filters are damaged. The urine albumin-to-creatinine ratio (uACR) is the usual test, and persistent albumin in the urine is another criterion for CKD, even when the eGFR is normal.
• Urinalysis. A general urine test can detect blood, infection, and abnormal cells that point toward particular kidney conditions.
• Additional blood tests. Doctors may check potassium, sodium, acid levels, hemoglobin for anemia, and minerals such as calcium and phosphorus, which become abnormal as kidney function falls.
• Imaging. Ultrasound is the most common scan. It shows kidney size, cysts, stones, blockages, and scarring. CT or MRI may be used for more detail, and Doppler ultrasound can assess blood flow.
• Kidney biopsy. In selected cases, a thin needle removes a tiny piece of kidney tissue for examination under a microscope. This helps identify the exact type of glomerulonephritis or other specific disease and guides treatment.

Doctors define CKD as kidney damage or reduced function lasting at least three months, so tests are often repeated over time before the diagnosis is confirmed. Staging combines the eGFR category with the amount of albumin in the urine, which together indicate how advanced the disease is and how quickly it may progress. Specialists in kidney disease are called nephrologists. At Acibadem, kidney disease is evaluated and managed by the nephrology department, with input from urology, endocrinology, and cardiology when needed.

Kidney disease treatment options

Most chronic kidney damage cannot be reversed, so kidney disease treatment options focus on treating the underlying cause, slowing further loss of function, managing complications, and, in advanced disease, replacing the work of the kidneys. The right approach depends on the type, stage, and cause of the disease and on a person’s overall health.

Monitoring and lifestyle measures

In early stages, treatment often centers on regular monitoring and measures that protect the kidneys: keeping blood pressure and blood sugar within target ranges, stopping smoking, maintaining a healthy weight, staying physically active, and limiting salt. A dietitian may recommend adjusting protein, potassium, or phosphorus intake depending on test results. People with kidney disease are usually advised to avoid non-steroidal anti-inflammatory painkillers, such as ibuprofen and naproxen, and to check with a pharmacist or doctor before starting any new medicine or supplement.

Medications

Blood pressure medicines known as ACE inhibitors or angiotensin receptor blockers (ARBs) lower pressure inside the kidney filters and reduce protein leakage; they are commonly prescribed even when blood pressure is only mildly raised. A class of medicines called SGLT2 inhibitors, originally developed for diabetes, has been shown to slow kidney decline in many people with CKD, with or without diabetes. Other medications may control cholesterol, treat anemia, correct high potassium or acid levels, manage bone and mineral problems, or relieve fluid buildup with diuretics (water pills). Where glomerulonephritis or an autoimmune disease is the cause, medicines that calm the immune system, such as corticosteroids, may be used.

Procedures and surgery

Some causes can be treated directly. Blockages from kidney stones or an enlarged prostate may be relieved with procedures or surgery. Narrowed kidney arteries can sometimes be opened. Kidney infections are treated with antibiotics, occasionally in the hospital. Large cysts or tumors may require surgical removal.

Dialysis

When the kidneys fail, dialysis takes over some of their functions. Hemodialysis filters the blood through a machine, usually at a dialysis center several times a week, although home hemodialysis is possible for some people. Peritoneal dialysis uses the lining of the abdomen as a natural filter, with fluid exchanged through a soft tube, and is usually done at home. Dialysis does not cure kidney disease and does not do everything healthy kidneys do, but it can sustain life for many years. Preparation, including creating an access point for hemodialysis, often begins months before it is needed.

Kidney transplant

A kidney transplant places a healthy kidney from a living or deceased donor into the body. For suitable candidates, it generally offers better quality of life and longer survival than long-term dialysis, but it requires major surgery, lifelong medicines to prevent rejection, and careful follow-up. Not everyone is a candidate, and waiting times for a deceased-donor kidney can be long. Evaluation is usually coordinated through a specialized organ transplantation unit.

Conservative management

Some people with kidney failure, particularly those who are frail or have other serious illnesses, choose not to have dialysis or a transplant. Supportive care focuses on relieving symptoms, protecting remaining kidney function for as long as possible, and maintaining quality of life. This is a recognized treatment path, decided together with the care team and family.

Living with kidney disease and outlook

The outlook varies widely. Many people with early-stage CKD never progress to kidney failure, particularly when blood pressure, blood sugar, and protein leakage are well controlled. Others decline more quickly, especially if the underlying cause is aggressive or hard to control. Doctors cannot predict an individual’s course with certainty, but regular testing shows the trend over time and allows treatment to be adjusted.

Kidney disease increases the risk of heart disease and stroke, and for many people these cardiovascular problems are a greater threat than kidney failure itself. This is why treatment plans usually address cholesterol, blood pressure, and smoking alongside kidney-specific measures.

Living well with kidney disease usually involves practical habits: taking medications as prescribed, attending follow-up tests, following dietary advice tailored to your stage, staying active within your limits, and telling every healthcare provider about your kidney condition so that medication doses and imaging dyes can be adjusted. Vaccinations against influenza, pneumonia, hepatitis B, and COVID-19 are commonly recommended because kidney disease weakens the immune response. Anxiety and low mood are common, and counseling or patient support groups may help. For people who reach kidney failure, both dialysis and transplantation can support a meaningful life, including work, travel, and family activities, although each has its own demands.

Frequently asked questions

What is kidney disease in simple terms?

Kidney disease means the kidneys are damaged and cannot filter blood as well as they should, so waste products and fluid can build up in the body. The most common form is chronic kidney disease, which develops slowly over years, most often because of diabetes or high blood pressure. Acute kidney injury is a sudden, often temporary, drop in kidney function.

What are the first kidney disease symptoms?

Often there are none. When early symptoms do appear, they are usually vague, such as tiredness, mild ankle swelling, needing to urinate more at night, or foamy urine. Because these signs are easy to overlook, people at higher risk are typically screened with blood and urine tests rather than waiting for symptoms.

What are the most common kidney disease causes?

Diabetes and high blood pressure are the two leading causes of chronic kidney disease. Other important causes include glomerulonephritis, polycystic kidney disease, long-standing urinary blockage, repeated kidney infections, autoimmune diseases, and damage from certain medications or toxins. In some cases the cause is never identified.

How is kidney disease diagnosis confirmed?

Doctors usually confirm kidney disease with two tests repeated over at least three months: a blood test that estimates the kidneys’ filtering rate (eGFR) and a urine test that measures albumin, a protein that leaks when the filters are damaged. An ultrasound and, in selected cases, a kidney biopsy may be used to find the cause.

Can kidney disease be cured?

Chronic kidney disease usually cannot be cured because scarred kidney tissue does not regrow. However, treatment can often slow or stabilize the decline for many years. Acute kidney injury, by contrast, is frequently reversible if the trigger is corrected promptly. A transplant replaces lost function but does not cure the original disease, which can sometimes affect the new kidney.

What are the kidney disease treatment options at each stage?

In early stages, treatment focuses on controlling blood pressure and blood sugar, protective medicines such as ACE inhibitors, ARBs, or SGLT2 inhibitors, and lifestyle changes. As disease advances, additional medicines manage anemia, mineral imbalance, and fluid. At kidney failure, the options are dialysis, transplantation, or supportive care without dialysis. Your doctor may tailor the plan to your situation and preferences.

When to see a doctor

Anyone with diabetes, high blood pressure, heart disease, or a family history of kidney disease should ask about regular kidney function testing, even without symptoms. A medical review is also advisable if you notice persistent tiredness, swelling of the ankles or around the eyes, changes in how often or how much you urinate, foamy or blood-tinged urine, or blood pressure that is newly high or hard to control.

Seek urgent medical care, including emergency services if necessary, for any of these red-flag signs:

• Little or no urine for many hours, or a sudden sharp drop in urine output
• Severe shortness of breath, or breathlessness when lying flat
• Chest pain or pressure, or an irregular or very slow heartbeat
• Confusion, extreme drowsiness, seizures, or loss of consciousness
• Severe, uncontrolled vomiting or inability to keep fluids down
• Sudden, severe pain in the side or back with fever and chills
• Visible blood in the urine with pain or fever
• Rapid swelling of the face, legs, or abdomen
• For people on dialysis: bleeding or signs of infection at the access site, or worsening symptoms after a missed treatment

Sudden loss of kidney function and dangerously high potassium can be life-threatening but are treatable when recognized quickly. If you are unsure whether a symptom is serious, it is safer to be assessed.