Ectopic Kidney
 


National Kidney and Urologic Diseases Information Clearinghouse 

National 

Institute of 

Diabetes and 

Digestive 

and Kidney 

Diseases 

NATIONAL 

INSTITUTES 

OF HEALTH 

U.S. Department 

of Health and 

Human Services 

What is an ectopic kidney? 

An ectopic kidney is a birth defect in which 

a kidney is located in an abnormal position. 

In most cases, people with an ectopic kidney 

have no complaints. In other cases, the 

ectopic kidney may create urinary problems, 

such as urine blockage, infection, or urinary 

stones. Researchers estimate that ectopic 

kidney occurs once in every 1,000 births. 

What are the kidneys? 

Kidneys are bean-shaped organs, each 

about the size of your fist. Most people 

have two kidneys located near the middle 

of the back, just below the rib cage. The kidneys filter wastes and extra fluid from your 

blood. The wastes and extra fluid become 

urine, which drains from the kidneys to the 

bladder through tubes called ureters. Urine 

is stored in the bladder until it is released 

from the body when you urinate. 

What causes an ectopic 

kidney? 

During fetal development, a baby’s kidneys 

first appear as buds inside the pelvis, near 

the bladder. As the fetal kidneys develop, 

they climb gradually toward their normal 

position near the rib cage in the back. 

Sometimes, one of the kidneys fails to 

make the climb. It may stop after making 

part of the climb. Or it may remain in the 

pelvis. Rarely does a child have two ectopic 

kidneys. 

Some kidneys climb toward the rib cage, 

but one may cross over so that both kidneys 

are on the same side of the body. When a 

An ectopic kidney may remain in the pelvis, close to 

the bladder. 

An ectopic kidney may cross over and become fused 

with the other kidney. 
crossover occurs, the two kidneys may grow 

together and become fused. 

What are the symptoms of

an ectopic kidney? 

An ectopic kidney may not cause any symptoms and may function normally, even 

though it is not in its usual position. Many 

people have an ectopic kidney and do not 

discover it until they have tests done for 

other reasons. Sometimes, a doctor may 

discover an ectopic kidney after feeling a 

lump in the abdomen during an examination. In other cases, an ectopic kidney may 

cause abdominal pain or urinary problems. 

What are the possible 

complications of an ectopic 

kidney? 

When a kidney is out of the normal position, drainage problems are likely. Sometimes, urine can even flow backwards from 

the bladder to the kidney, a problem called 

vesicoureteral reflux, or simply reflux. 

Abnormal urine flow can set the stage for a 

number of problems. 

•	 Infection. Normally, urine flow 

washes out bacteria and keeps them 

from growing in the kidneys and urinary tract. When a kidney is out of the 

normal position, urine may get 

trapped in the ureter or in the kidney 

itself. Urine that remains in the urinary tract gives bacteria the chance to 

grow and spread. Symptoms of a urinary tract infection include frequent or 

painful urination, back or abdominal 

pain, fever, and chills. The urine may 

be cloudy or have an unusual smell. 

•	 Stones. Urinary stones form from substances found in the urine, such as calcium and oxalate. Urine that remains 

too long in the urinary tract increases 

the risk that these substances will have 

time to form stones. Symptoms of urinary stones include extreme pain in 

the back, side, or pelvis; blood in the 

urine; fever or chills; vomiting; and 

burning during urination. 

•	 Kidney failure. If urine backs up all 

the way to the kidneys, damage to the 

kidneys can occur. As a result, the 

kidneys can’t filter wastes and extra 

fluid from the blood. Symptoms of 

kidney failure include swelling in the 

legs or abdomen, feeling very tired, 

headaches, or nausea. If total kidney 

failure occurs, you will need dialysis or 

a kidney transplant. Total kidney failure happens only when both kidneys 

are damaged. One ectopic kidney, 

even when it has no function, won’t 

cause kidney failure. 

•	 Trauma. If the ectopic kidney is in the 

lower abdomen, or pelvis, it may be susceptible to injury from blunt trauma. 

People with ectopic kidney who want to 

participate in body contact sports may 

wish to wear protective gear. 

2	 Ectopic Kidney 
What tests will the doctor 

order? 

Your doctor can get the most information 

about your condition by looking at pictures 

of the ectopic kidney. Several different 

imaging tests are available. 

•	 Ultrasound. During an ultrasound 

examination, a medical technician will 

glide a device called a transducer over 

your skin—either on your side, your 

abdomen, or your pelvis—depending 

on the location of the kidney. The 

transducer sends harmless sound 

waves into your body. The sound 

waves bounce off your kidney and back 

to the transducer. The equipment 

reads the sound waves and creates a 

black and white image of the kidney 

on a television screen. 

•	 X ray. Your doctor may use conventional x-ray equipment to perform an 

intravenous pyelogram (IVP) or a 

voiding cystourethrogram (VCUG). 

In an IVP, a special dye is injected into 

a vein, usually in the arm. The radiologist takes a series of snapshots as the 

dye circulates through the blood and 

reaches the kidneys. The structures of 

the kidneys show up on the x rays as 

the dye is filtered from the blood and 

passes through the kidneys to the 

ureters. An IVP can show whether 

urine is backing up into the ectopic 

kidney. In children, ultrasounds are 

usually done instead of IVPs. 

In a VCUG, a thin hollow tube called 

a catheter is placed into the bladder so 

that it can be filled with x-ray contrast 

material. X rays are then taken as the 

patient urinates. The VCUG gives 

information about the bladder and 

reveals whether urine is backing up 

toward the kidneys during urination. 

•	 Nuclear scan. In a nuclear scan, a 

small amount of a radioactive drug is 

injected into a vein, and pictures are 

taken of the kidney over a period of 

time after the injection. Sometimes a 

diuretic medicine is also given to 

increase urine flow. This test can 

reveal whether the ureters—tubes that 

drain urine from the kidneys—are 

blocked and how well the kidneys 

work. Sometimes, a nuclear scan may 

be done to find the location of an 

ectopic kidney. 

•	 Computerized tomography (CT) scan. 

A CT scan uses multiple x-ray images 

to create a cross-section view of your 

body on a computer screen. You will 

lie on a table that passes through a 

doughnut-shaped machine where the 

scanning takes place. CT scans aren’t 

usually needed in the evaluation of an 

ectopic kidney, but they may be done 

in a few cases. 

3	 Ectopic Kidney 
•	 Magnetic resonance imaging (MRI). 

MRI technology uses radio waves and 

magnets to create pictures of internal 

organs. No exposure to radiation is 

required. With most MRI machines, 

you lie on a table that slides into a tunnel that may be open-ended or closed 

at one end. Some newer machines are 

designed to allow you to lie in a more 

open space. Like CT scans, MRIs are 

rarely needed to evaluate an ectopic 

kidney. 

In addition to imaging tests, the doctor may 

order blood tests to determine how well 

your kidneys are working. These tests are 

almost always normal in patients with an 

ectopic kidney, even if it is badly damaged, 

because the other kidney usually has completely normal function. 

What are the treatments for 

an ectopic kidney? 

If your urinary function is normal and the 

doctor finds no blockage, no treatment for 

ectopic kidney is needed. Your doctor 

should continue to monitor your condition 

in case a change occurs. 

If tests show that obstruction is present, 

you may need surgery to correct the position of the kidney to allow for better 

drainage of urine. To correct reflux, the 

surgeon may reattach the ureter to the 

bladder so that urine can’t reflux into the 

kidney. 

If extensive kidney damage has occurred, 

the surgeon may need to remove the kidney. As long as the other kidney is working 

properly, losing one kidney is not a problem. Many people live a normal life after 

donating a kidney for transplant. Some 

people are even born with only one kidney 

and lead full, healthy lives without discovering their condition. 

With the right testing and treatment, if 

needed, an ectopic kidney should cause no 

serious long-term health problems. 

4	 Ectopic Kidney 
Hope Through Research 

Researchers from universities and Government agencies are working to understand the causes of kidney and urinary

tract birth defects and to find more

effective treatments. Through its Pediatric Urology Program, the National

Institute of Diabetes and Digestive and

Kidney Diseases funds research into

bladder and urinary tract development.

Additionally, the National Institute of

Child Health and Human Development

has established the Birth Defects Initiative to study the genetic and molecular

mechanisms underlying the developmental processes of the fetus.

You may also find additional information

about this topic by visiting MedlinePlus at

www.medlineplus.gov.

For More Information 

American Society of Pediatric Nephrology

3400 Research Forest Drive, Suite B

The Woodlands, TX 77381

Phone: 281–419–0052

Fax: 281–419–0082

Email: info@aspneph.com

Internet: www.aspneph.com

American Urological Association 

Foundation

1000 Corporate Boulevard, Suite 410

Linthicum, MD 21090

Phone: 1–866–RING–AUA (746–4282) 

or 410–689–3700

Email: patienteducation@auafoundation.org

Internet: www.auafoundation.org

www.UrologyHealth.org

March of Dimes

1275 Mamaroneck Avenue

White Plains, NY 10605

Phone: 914–997–4488

Email: askus@marchofdimes.com

Internet: www.marchofdimes.com

National Institute of Child Health and 

Human Development

Information Resource Center

P.O. Box 3006

Rockville, MD 20847

Phone: 1–800–370–2943

Email: NICHDInformationResourceCenter

@mail.nih.gov

Internet: www.nichd.nih.gov

5 Ectopic Kidney
National Kidney and 

Urologic Diseases 

Information Clearinghouse 

3 Information Way 

Bethesda, MD 20892–3580 

Phone: 1–800–891–5390 

Fax: 703–738–4929 

Email: nkudic@info.niddk.nih.gov 

Internet: www.kidney.niddk.nih.gov 

The National Kidney and Urologic Diseases 

Information Clearinghouse (NKUDIC) is a service of the National Institute of Diabetes and 

Digestive and Kidney Diseases (NIDDK). The 

NIDDK is part of the National Institutes 

of Health of the U.S. Department of Health and 

Human Services. Established in 1987, the Clearinghouse provides information about diseases of 

the kidneys and urologic system to people with 

kidney and urologic disorders and to their families, health care professionals, and the public. The 

NKUDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government 

agencies to coordinate resources about kidney and 

urologic diseases. 

Publications produced by the Clearinghouse are 

carefully reviewed by both NIDDK scientists 

and outside experts. The NKUDIC would like to 

thank the following members of the American 

Society of Pediatric Nephrology Clinical Affairs 

Committee for their review of this fact sheet: 

Maria Ferris, M.D.; Barbara Fivush, M.D.; Joseph 

Flynn, M.D.; Ann Guillot, M.D.; Tej Mattoo, 

M.D.; Cynthia Pan, M.D.; Jeff Saland, M.D.; and 

Steve Wassner, M.D. 

This publication is not copyrighted. The 

Clearinghouse encourages users of this fact 

sheet to duplicate and distribute as many 

copies as desired. 

This fact sheet is also available at 

www.kidney.niddk.nih.gov. 

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES 

National Institutes of Health 

NIH Publication No. 07–5869 

April 2007