Left kidney: 91 × 41 mm; right kidney: 95 × 45 mm—Are these measurements normal?
Apr 26, 2022
Source: Cainiu Health
Dr. Zhao Xinju
Introduction
To assess kidney size, color Doppler ultrasound or CT imaging can be performed. Even if the two kidneys differ in size, there is generally no cause for concern, as mild asymmetry falls within the normal physiological range. However, clinically, some patients exhibit marked differences in kidney size due to unilateral renal atrophy—a pathological condition. Moreover, compensatory hypertrophy of the contralateral (healthy) kidney may occur in response to unilateral atrophy, leading to an increase in its volume.
At first glance, the two kidneys appear to differ in size. Whether this asymmetry is normal depends on the specific clinical context. Details are as follows:
It is generally not cause for excessive concern if a patient’s two kidneys differ slightly in size. Human organs are not perfectly symmetrical—rather, they exhibit natural anatomical asymmetry. It is common for the two kidneys to differ somewhat in size, provided both remain within normal physiological limits.
However, symptoms such as bilateral lower back or lumbar spine soreness, markedly foul-smelling urine, or increased urinary sediment may indicate renal pathology. If persistent anxiety remains, a renal function test is advisable.
Kidney size can be accurately assessed using renal color Doppler ultrasound or CT imaging. Clinically, some patients present with unilateral renal atrophy resulting in marked asymmetry between the two kidneys—an abnormal finding. In such cases, the contralateral kidney often undergoes compensatory hypertrophy to maintain overall renal function, leading to an increase in its volume. Additionally, hydronephrosis or perirenal fluid accumulation may cause the affected kidney to enlarge and assume a balloon-like appearance—a pathological condition requiring prompt evaluation and relief of any underlying urinary tract obstruction.
