Differential Diagnosis for One Kidney Smaller than the Other on CT Scan
Single Most Likely Diagnosis
- Chronic pyelonephritis: This condition is a common cause of asymmetric kidney size due to recurrent or persistent infection leading to scarring and atrophy of the affected kidney.
Other Likely Diagnoses
- Renal artery stenosis: Narrowing of the renal artery can lead to reduced blood flow to the kidney, resulting in atrophy and a smaller size.
- Renal vein thrombosis: A blood clot in the renal vein can cause damage to the kidney, leading to atrophy and reduced size.
- Congenital anomalies: Variations in kidney development can result in one kidney being smaller than the other.
- Nephrosclerosis: Scarring of the kidney tissue due to conditions like hypertension or diabetes can lead to a smaller kidney size.
Do Not Miss Diagnoses
- Renal cell carcinoma with metastasis: Although less likely, a smaller kidney could be due to a tumor that has metastasized, making it crucial not to miss this potentially life-threatening diagnosis.
- Renal infarction: A blockage of the blood supply to the kidney can cause tissue death, leading to a smaller kidney size, and is a medical emergency.
- Ureteropelvic junction obstruction: A blockage in the urinary tract can cause kidney damage and atrophy if not promptly addressed.
Rare Diagnoses
- Renal dysplasia: A rare congenital condition where the kidney does not develop properly, leading to an abnormal and often smaller kidney.
- Multicystic dysplastic kidney: A rare condition where the kidney is replaced by multiple cysts, often resulting in a smaller kidney size.
- Tuberculosis: Although rare in some regions, renal tuberculosis can cause scarring and atrophy of the kidney, leading to a smaller size.
- Sickle cell disease: This genetic disorder can lead to kidney damage and atrophy due to sickling of red blood cells within the kidney.