A wide variety of medical conditions can cause enlargment of one or both kidneys. Symptoms are most likely to occur when the enlargement develops quickly, or acutely, such as with a kidney stone or kidney infection. Symptoms may not develop for many years with chronic conditions associated with abnormally large kidneys. Several signs and symptoms might occur with kidney enlargement. These vary depending on the underlying cause.
Pain in your abdomen or flank -- the area next to your spine below your ribcage and above your pelvic bones -- occurs with several kidney conditions that might lead to enlargement. The pain may radiate into the groin with some of these ailments. Examples include:
- Kidney or other urinary tract stone obstructing urine flow into the bladder
- Kidney infection, or pyelonephritis, which also commonly causes burning pain with urination
- Blood clot in the main or artery or vein of the kidney
- Acute interstitial nephritis (AIN) -- inflammation of the kidneys, often caused by a reaction to medication
Changes in the urinary frequency, the volume of urine produced and/or appearance of your urine might signal a kidney condition associated with enlargement of the organs. For example, blood in the urine commonly occurs with a kidney infection, urinary tract stone, a blood clot in a major kidney blood vessel and kidney cancer. A decrease or increase in the volume of urine produced can signal failing kidney function, which could be due to AIN or diabetic kidney disease, among others. Increased urinary frequency with a small amount of urine produced could indicate a kidney infection.
Ailments that significantly impair kidney function often lead to water retention. This occurs when the kidneys cannot keep up with demands to filter the blood and maintain water and electrolyte balance in the body. Water retention commonly manifests with one or more signs and symptoms, such as sudden weight gain or swelling of the lower legs, feet or hands, and/or puffiness around the eyes.
Other Signs and Symptoms
A variety of other signs and symptoms can occur with disorders that lead to kidney enlargment. These might include:
- Fever and chills
- Nausea and vomiting
- Loss of appetite
- Lack of energy
- Unintended weight loss
- Abdominal distention
- Generalized itchiness
- High blood pressure
Other Considerations, Warnings and Precautions
Because kidney enlargement often causes no symptoms, it is often discovered incidentally on an imaging study such as an an abdominal ultrasound, x-ray or CT scan. Although oversized kidneys often signal a medical problem, this is not always the case. For example, some people are born with only one kidney which grows larger than usual to compensate for lack of a second kidney. Similarly, when one kidney is damaged, the other might enlarge to compensate.
Kidney enlargement must be investigated to determine the underlying cause. Often the enlargement is temporary and does not cause permanent organ damage, such as with a kidney infection or urinary stone. If a chronic kidney disorder is diagnosed, your doctor will advise you about how best to preserve your kidney function.
Seek urgent medical attention if you experience any warning signs or symptoms, including:
- Severe or worsening flank or abdominal pain
- Fever or chills
- Sudden decrease in urine production or lack of urination
Reviewed and revised by: Tina M. St. John, M.D.
- Journal of the American Osteopathic College of Radiology: Unilateral Renal Enlargement
- Radiopaedia: Bilateral Renal Enlargement
- Renal Fellow Network: Differential Diagnosis for Large Kidneys
- American Family Physician: Diagnosis and Management of Acute Interstitial Nephritis
- Cleveland Clinic Center for Continuing Education: Renal Cell Carcinoma
- Annual Review of Medicine: Polycystic Kidney Disease
- Merck Manual Professional Version: Chronic Kidney Disease