What is kidney atrophy?
In kidney atrophy either one or both kidneys have shrunk and have become smaller. This is also called renal atrophy. Kidney atrophy is not usually reversible.
The kidneys shrink because of a loss of nephrons, the tiny filtering units of the kidney. There are several reasons these nephrons may be lost. Kidney atrophy is different from kidney hypoplasia, where individuals are born with smaller kidneys that have fewer nephrons.
What causes kidney atrophy?
Several conditions can cause kidney atrophy, including:
- Reduced blood flow in the arteries which carry blood to the kidneys. This is usually caused by a build-up of fatty materials, called atherosclerosis which leads to narrowing and hardening of the artery walls.
- A problem in urine flow from the kidneys, for example long-term blockage by a kidney stone. Over time, this can cause urine to build up in the kidneys, increasing the pressure inside them causing damage.
- Advanced chronic kidney disease (CKD).
- Persistent infections in the kidney, sometimes called chronic pyelonephritis.
How is kidney atrophy diagnosed?
Doctors use medical imaging techniques to look at the size of the kidneys. This includes ultrasound, CT and MRI scans.
If kidney atrophy is identified, further tests may be performed to look for the cause, for example a renal angiogram to look at the blood vessels in the kidneys.
Tests to check kidney function may also be done, such as eGFR and uACR tests.
What are the treatments for kidney atrophy?
Treatment will depend on the cause of kidney atrophy. Although kidney atrophy is not reversible, treating the cause may prevent further damage to the kidneys. If both kidneys are affected this can lead to chronic kidney disease (CKD).
You can read about treatments for stage 1-5 CKD on the following pages:
Help look after your kidneys by controlling your blood pressure, not smoking, treating your diabetes if you have it, keeping a healthy weight, and eating a low salt healthy diet.
References
Davran, R. Helvaci, MR. and Davarci, M. Left renal atrophy. Int J Clin Exp Med [online]. 2014; 7(6): 1603–1606. [Accessed 18 November 2025]. Available from: <PMCID: PMC4100972 PMID: 25035786>
Cain, JE. Giovanni, VD. Smeeton J. and Rosenblum, ND. Genetics of Renal Hypoplasia: Insights Into the Mechanisms Controlling Nephron Endowment. Pediatric Research [online]. 2010; 68: 91–98. [Accessed 18 November 2025]. Available from: <doi.org/10.1203/PDR.0b013e3181e35a88>
Caps, MT. Zierler, RE. Polissar, NL. Bergelin, RO. Beach, KW, Cantwell-Gab, K. Casadei, A. Davidson, RC. Strandness Jr. DE. Risk of atrophy in kidneys with atherosclerotic renal artery stenosis. Kidney Int [online]. 1998; 53(3):735-42. [Accessed 18 November 2025]. Available from: <doi: 10.1046/j.1523-1755.1998.00805.x>
Sohail, MA. Sedor, J. Kirksey, L. Blaha, SC. and Hofmann, H. Unilateral atrophic kidney in a 45-year-old woman [online]. 2022; 89(8):465-471. [Accessed 18 November 2025]. Available from: <doi: 10.3949/ccjm.89a.21015>
Valentini, RP. Langenburg, S. Imam, A. Mattoo, TJ. and Zerin, JM. MRI detection of atrophic kidney in a hypertensive child with a single kidney [online]. 2005; 20(8):1192-4. [Accessed 18 November 2025]. Available from: <doi: 10.1007/s00467-005-1914-9>
Singla, RK. Kadatz, M. Rohling, R. and Nguan, C. Kidney Ultrasound for Nephrologists: A Review [online]. 2022; 4(6). [Accessed 18 November 2025]. Available from: <doi: 10.1016/j.xkme.2022.100464>
Reviewed March 2026 by reviewed by Dr Melanie Chan, Honorary Consultant Nephrologist, Imperial College Healthcare NHS Trust.
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