14 Common Causes of Kidney Disease

2. Injury to the Kidneys

Injury to the kidneys can cause sudden or long-term damage. Sudden kidney damage is often called acute kidney injury and can develop within hours or days. A hard blow to the lower back can bruise or tear the kidneys. Car accidents, sports injuries, or falls often cause these injuries.

Severe blood loss or major surgery can also reduce blood flow to the kidneys and harm them. Some medicines may injure the kidneys when used in high doses or for a long time. These include certain pain relievers, some types of antibiotics, and contrast dyes used in imaging tests.

Serious infections can also damage kidney tissue. If an infection spreads through the blood, it may reduce kidney function quickly. When the kidneys cannot filter waste well, toxins build up in the blood. Blocked urine flow can injure the kidneys as well. Kidney stones, an enlarged prostate, or tumors may stop urine from draining.

Over time, this pressure can slowly weaken kidney tissue. Symptoms of kidney injury may include less urine, swelling in the legs, fatigue, or confusion. In some cases, there are no clear signs at first and without timely care, the damage may become permanent.

3. Heart Attack

A heart attack happens when blood flow to part of the heart muscle is blocked. This can weaken how well the heart pumps blood, so less blood reaches the kidneys. The kidneys need steady blood flow to filter waste and extra fluid from the body.

If blood pressure drops after a heart attack, kidney tissue may receive too little oxygen, which can cause sudden kidney injury in a short time. Fluid may also build up in the body when the kidneys cannot remove excess fluid well. Some people develop heart failure after a heart attack. When the heart continues to pump less efficiently, the kidneys remain under constant strain.

Over time, this stress may contribute to chronic kidney disease. Certain treatments used after a heart attack may also affect the kidneys. Medicines such as some blood pressure drugs and diuretics, along with contrast dyes used in imaging tests, can place additional stress on kidney function.

4. Heart Disease

Heart disease can increase the risk of kidney damage over time. The heart and kidneys work closely together to circulate blood and remove waste from the body. When heart function weakens, circulation slows and the kidneys receive less oxygen and fewer nutrients. Because the kidneys rely on steady blood flow to filter waste and excess fluid, reduced circulation can gradually weaken their function and may lead to chronic kidney disease.

Heart failure is a common example because the heart cannot pump enough blood to meet the body’s needs. As blood flow declines, the kidneys may struggle to maintain normal filtering activity. High blood pressure and narrowed or blocked arteries often link heart disease and kidney disease.

Damaged blood vessels reduce blood supply to both organs, which can gradually worsen their function. The relationship can also work in the opposite direction. When the kidneys cannot remove excess fluid, fluid may build up in the body. This extra fluid can raise blood pressure and place additional strain on the heart.

5. Infection

Infections can damage the kidneys when bacteria or viruses enter the urinary tract and spread upward. Many kidney infections begin as bladder infections that move upward through the urinary tract. If not treated promptly, the infection may reach one or both kidneys, where it inflames kidney tissue and interferes with the ability to filter waste from the blood.

Severe infections may also spread into the bloodstream and cause sudden kidney injury. Repeated infections can lead to scarring in kidney tissue, and scar tissue does not function like healthy tissue. Over time, this may gradually reduce kidney function and increase the risk of chronic kidney disease.

Certain conditions can increase the risk of kidney infections. Blockages in the urinary tract, such as kidney stones, can trap bacteria and raise the chance of infection. People with weakened immune systems, including those with diabetes or long-term illness, are also more vulnerable. Common signs of kidney infection include fever, back or side pain, nausea, and painful urination.

6. Liver Failure

Liver failure can lead to kidney disease through a condition called hepatorenal syndrome. This condition develops in people with severe liver damage and affects kidney function even when the kidneys are initially structurally healthy. The liver normally helps regulate blood flow, remove toxins, and maintain fluid balance in the body.

When the liver fails, less blood reaches the kidneys. Because the kidneys rely on steady blood flow to filter waste and produce urine, their filtering ability decreases. Waste products then build up in the blood, urine output may decrease, and the body may retain more sodium and fluid. The kidneys usually do not show direct inflammation or blockage in this condition.

Hepatorenal syndrome most often develops in people with advanced cirrhosis or sudden liver failure. It is more common in those hospitalized with serious liver disease. Fluid buildup in the abdomen, infections, or heavy alcohol use can further increase the risk.

7. Too Much Aspirin

Aspirin is a nonsteroidal anti-inflammatory drug commonly used to treat pain, swelling, and fever. Many people can obtain it without a prescription. Problems may occur when someone takes more than the recommended dose or uses high doses for long periods. Aspirin can reduce blood flow to the kidneys, which rely on steady circulation to filter waste from the body.

When this happens, the tiny filtering units inside the kidneys cannot function properly. Waste products may build up in the blood, urine output may decline, and sudden kidney injury can develop or existing kidney disease may worsen. Long-term use of high doses may gradually damage kidney tissue.

Taking more than directed, combining aspirin with other nonsteroidal anti-inflammatory drugs, or using it during illnesses that cause fluid loss can further increase the risk. Certain groups face a higher chance of kidney problems from aspirin. People with chronic kidney disease, diabetes, or high blood pressure are more vulnerable.

8. Severe Dehydration

Severe dehydration occurs when the body loses more fluid than it takes in. Severe dehydration often develops during prolonged vomiting, diarrhea, high fever, heavy sweating, or poor fluid intake. This reduces the amount of fluid circulating in the bloodstream and lowers blood flow to the kidneys.

The kidneys rely on adequate fluid and steady blood flow to filter waste from the blood. When circulation drops, the kidneys cannot filter waste efficiently. Waste products begin to build up in the blood, urine output may fall, and kidney tissue can become injured if dehydration continues too long. Certain groups face a higher risk of severe dehydration.

Older adults, young children, and people with chronic illnesses are more vulnerable. Individuals who already have kidney disease also face a greater chance of complications. Warning signs of severe dehydration include very dark urine or little to no urine, dry skin, dizziness, a rapid heartbeat, and confusion.

9. Blood Clots

Blood clots can interrupt blood flow to the kidneys. When circulation is reduced, the kidneys receive less oxygen and fewer nutrients, which can quickly injure kidney tissue. Clots may form directly in the blood vessels connected to the kidneys. A clot in the renal artery prevents blood from reaching the kidney, while a clot in the renal vein prevents blood from draining away. In both situations, normal circulation is disrupted and pressure may rise inside the kidney, damaging its tiny filtering units.

Some clots begin in other parts of the body and travel through the bloodstream. For example, a clot from the heart or large blood vessels may move until it reaches a narrow vessel in the kidney, where it becomes lodged. The effects often depend on the size of the clot and how quickly it develops. Symptoms may include sudden pain in the side or lower back, blood in the urine, swelling, or a decrease in urine output.

10. Drugs and Alcohol

Drugs and alcohol can harm the kidneys when used heavily or for long periods. The kidneys filter waste and toxins from the blood, so frequent exposure to harmful substances places extra strain on kidney function. Some medicines may affect kidney function when taken in high doses or used for long periods. The risk increases when people use certain pain relievers, some antibiotics, or other strong medications without medical guidance.

Mixing different drugs can further increase the chance of kidney problems. Illegal drugs can also reduce blood flow to the kidneys. When circulation drops, kidney tissue receives less oxygen and nutrients, which can lead to sudden kidney injury. Heavy alcohol use can also affect the kidneys by causing dehydration. This makes it harder for the kidneys to maintain proper fluid balance.

Alcohol can also raise blood pressure, and long-term high blood pressure is a major risk factor for kidney disease. Alcohol may also damage the liver and when the liver does not function well, the kidneys face additional strain. People who combine drugs and alcohol face an even greater risk because toxic effects can build up more quickly and increase the likelihood of lasting kidney damage.

11. Cancer

Cancer can damage the kidneys when abnormal cells grow uncontrollably within kidney tissue. In adults, the most common type begins in the kidney’s tiny filtering units. As the tumor develops, it gradually replaces healthy tissue and interferes with the kidney’s ability to filter waste from the blood. Over time, this loss of healthy tissue can weaken kidney function.

Cancer from other parts of the body can also spread to the kidneys. When this occurs, invading cancer cells may interfere with how well the kidneys filter waste and regulate fluid balance. The disease may affect one kidney or both and as a tumor enlarges, it may press on nearby structures or block normal urine flow.

Some cancer treatments may also place added stress on the kidneys. Certain medicines, imaging dyes, or reduced fluid intake during treatment can further affect kidney function. This disruption can lead to symptoms such as swelling, pain in the side or back, or blood in the urine.

12. Diabetes

Diabetes is one of the most common causes of kidney disease. Both type 1 and type 2 diabetes can lead to kidney damage. Over time, high blood sugar levels can damage the small blood vessels and tiny filtering units inside the kidneys. Each kidney contains millions of tiny filtering units that remove waste and extra fluid from the blood.

When these structures are damaged, the kidneys cannot clean the blood as effectively. This damage usually develops slowly and may not cause noticeable symptoms in the early stages. As kidney function declines, waste and fluid may begin to build up in the body.

High blood pressure often occurs along with diabetes and places additional strain on the kidneys. When high blood pressure and diabetes occur together, the risk of kidney failure rises. About one in three adults with diabetes develops chronic kidney disease. Many people do not notice kidney problems until the condition becomes more advanced.

13. Kidney Stones

Kidney stones are hard deposits that form in the kidneys from minerals and salts in the urine. They can range in size from a grain of sand to a small pearl. Stones develop when urine becomes concentrated and substances such as calcium, uric acid, or other minerals crystallize and stick together.

Low fluid intake increases the risk because it makes urine more concentrated. Other factors such as family history, certain dietary patterns, and repeated urinary tract infections can also increase the chance of stone formation. Some stones pass out of the body on their own, but others can become lodged in the urinary tract.

When a stone blocks the normal flow of urine, pressure can build up inside the kidney. This blockage may cause severe pain in the back or side. A person may also notice blood in the urine, cloudy urine, or a burning sensation during urination. Fever, chills, or vomiting can occur if an infection develops.

Most kidney stones do not cause permanent kidney damage. However, repeated stones or untreated blockages can injure kidney tissue over time. Ongoing pressure inside the kidney may gradually reduce its ability to filter waste from the blood.

14. High Blood Pressure

High blood pressure is a leading cause of kidney disease. It occurs when blood pushes with excessive force against the walls of the arteries. Over time, this pressure damages blood vessels throughout the body. The kidneys contain many tiny blood vessels and filtering units that remove waste and extra fluid from the blood.

When high pressure injures these vessels, they can become narrow and stiff. As blood vessels narrow, blood flow to the kidneys decreases. Reduced circulation limits the kidneys’ ability to filter waste and maintain fluid balance. Long-term pressure can also damage the tiny filtering units inside the kidneys, which further reduces kidney function.

When kidney function declines, waste and fluid can build up in the body. This buildup may raise blood pressure even further, creating a cycle that worsens kidney damage. High blood pressure often has no clear symptoms, so many people do not know they have it until routine testing shows high readings or kidney problems appear.