What Are the Most Common Kidney Diseases?

Each kidney is about the size of a fist.

The most common type of kidney disease is chronic kidney disease (CKD). Other diseases include acute kidney injury, stones, infections, cysts, and cancer. 

Kidneys perform essential functions such as filtering blood to remove waste products and excess fluid from the body. Kidneys also play a key role in maintaining blood pressure, hemoglobin levels, electrolyte balance, and more. 

There are many conditions that can damage your kidneys. Here are six of the most common kidney diseases.

1. Chronic kidney disease (CKD)

CKD slowly damages the kidneys over time. CKD affects about 37 million adults in the United States. The disease is divided into different stages depending on the severity of kidney damage. 

Diabetes is the most common cause of CKD. Other causes include high blood pressure (hypertension), heart diseases, and certain genetic conditions such as polycystic kidney disease.

Early stages of CKD may not cause any symptoms. The following symptoms and signs generally appear when there is considerable kidney damage:

• Swelling in the feet, legs, face, or hands
• Muscle cramps
• Dry, itchy skin
• Chest pain
• Numbness
• Fatigue
• Poor appetite
• Weight loss
• Nausea
• Vomiting
• Shortness of breath

2. Acute kidney injury (AKI)

Also called acute renal failure (ARF). AKI causes kidney damage or failure within a short period of time. AKI may damage other organs as well, such as the heart, lungs, and brain.

Causes may include major burns, shock (a sudden drop in blood pressure), excessive bleeding, severe dehydration, or medication use. It occurs more often in older individuals and hospitalized patients, especially those who require intensive care. 

Symptoms may differ depending on the cause and severity of AKI. Some people may be asymptomatic. When present, the signs and symptoms of AKI may include the following:

• Decreased urine volume
• Puffiness around the eyes
• Swelling over the ankles and feet
• Nausea
• Shortness of breath
• Fatigue
• Confusion
• Chest pain or pressure
• Seizures

3. Kidney stones

Also called renal stones, kidney stones are hard deposits of minerals or salts formed inside the kidneys. They can form inside the ureter (tubes that carry urine from the kidneys) or urinary bladder (the structure that receives urine from the kidneys via the ureters). 

Kidney stones generally occur when there is an excess of mineral salts, such as calcium oxalate or calcium phosphate, or uric acid in the body.

Some patients may have no symptoms, while others may complain of the following signs and symptoms:

• Pain in the flanks, lower abdomen, or groin
• Blood in the urine (pink, brown, or red urine)
• Pain or burning when urinating
• Frequent urination
• Difficulty passing urine
• Cloudy or foul-smelling urine
• Nausea or vomiting
• Fever with chills (if there is an infection)
• Repeated urinary tract infections (UTIs)

4. Kidney infections

Kidney infections or pyelonephritis is a special type of urinary tract infection (UTI), which typically occurs in any part of the urinary tract (kidneys, ureters, urinary bladder, or urethra). 

Kidney infections occur when infection from the urethra or the urinary bladder travels upward to the kidneys. Less commonly, the infection may spread from other sites in the body to the kidneys via blood or following kidney surgery.

The following are the signs and symptoms of a kidney infection:

• Fever
• Chills
• Nausea
• Vomiting
• Pain in the flanks, back, abdomen, or groin
• Increased urine frequency or urge to urinate
• Pain or burning when urinating
• Cloudy or foul-smelling urine
• Blood in the urine (pink, brown, or red urine)

5. Kidney cysts

A kidney cyst is a fluid-filled pouch or sac-like structure. Also called simple kidney cysts, these are different from a genetic condition called polycystic kidney disease (PKD) that causes the formation of numerous cysts that damage the kidneys. 

The exact cause of simple kidney cysts is not known. They may be acquired when injury or damage to the kidneys causes fluid to accumulate in a small area, leading to cyst formation.

Kidney cysts may not cause any symptoms until a cyst bursts, bleeds, or grows bigger and starts pressing on adjacent structures, such as nerves. Symptoms may include:

• Pain in the flanks, back, or abdomen
• Increased urine frequency
• Blood in the urine (pink, brown, or red urine)
• Fever

6. Kidney cancer

Kidney cancer occurs when the cells in the kidney grow out of control. The most common type of kidney cancer is called renal cell carcinoma, accounting for about 90% of all kidney cancers. Other types of kidney cancer include transitional cell carcinoma, Wilms tumor (nephroblastoma), and renal sarcoma. 

While the exact cause of kidney cancer is unknown, certain factors may increase the risk, such as smoking, family history of kidney cancer, obesity, and high blood pressure.

Kidney cancer generally does not cause any symptoms until it is in its advanced stages. Symptoms and signs may include the following:

• Blood in the urine
• Pain in the flanks, back, or abdomen
• Lump or swelling in the flanks
• Unexplained weight loss
• Fatigue
• Pale appearance
• Loss of appetite