Have you ever wondered what abnormalities of the kidneys and urinary tract are babies born with? What are their symptoms? Can they lead to kidney failure? Read this article to find out more.
What’s normal?
Babies are usually born with two kidneys. The kidneys filter waste and excess water from the blood. This filtered waste is then used to make urine. The urine then drains from the kidneys to the bladder through the ureters (tubes connecting the bladder and kidneys). Following this, the urine then leaves the bladder through the urethra (another tube) when we got to the toilet.
Click here to learn more about the kidneys’ function.
Tell me more about abnormalities
Abnormalities that we’re born with are called ‘congenital’. Congenital abnormalities of the kidneys and urinary tract are birth defects affecting the form and function of the kidneys and urinary tract. These abnormalities can be found in each part of the urinary tract.
A diagram of the urinary tract
Abnormalities of the kidneys
- One kidney may be missing (renal agenesis)
- One or both kidneys may be abnormally small (renal hypoplasia)
- One or both kidneys may have formed abnormally (renal dysplasia)
- The kidneys may be joined to form a single arched or horseshoe kidney
- The kidneys may be in the wrong position – e.g. a pelvic kidney
- One or both kidneys may have fluid-filled cysts (polycystic kidney disease or multicystic kidney disease).
Abnormalities of the ureters
- A blockage may occur in the area where the kidney attaches to the ureter (pelvi-ureteric junction obstruction, PUJ).
- A blockage may occur in the area where the ureter attaches to the bladder (ureterovesical junction obstruction or ureterocele).
- The ureters may attach to the bladder in a way that allows urine to flow back up to the kidney (vesicoureteral reflux or reflux nephropathy).
- A single kidney may drain to the bladder with two ureters instead of one (duplex system).
Above are some images of different duplex kidney systems. B and C are particularly useful as one side is normal in each, and the other has two ureters. See the cartoon of the urinary tract above to see what normal looks like.
Abnormalities of the urethra
Extra flaps of tissue may develop in the urethra. This may slow or block the flow of urine out of the bladder (urethral valves). This affects boys.
Hydronephrosis
When the flow of urine from the kidneys is blocked or slowed urine can build up in the kidney and cause it to swell, a condition known as hydronephrosis. This can also occur if urine is able to flow backward to the kidney.
Hydronephrosis is often the first sign of a congenital kidney and urinary tract problem, as the enlarged kidney can be seen in routine prenatal ultrasound images.
Summary
We have described what abnormalities of the kidneys and urinary tract are babies born with. We hope it has been helpful.
Click here to learn 10 facts about the kidneys.
Last Reviewed on 30 October 2023