Urinary reflux is when urine flows backward from the bladder into the ureter and sometimes the kidney, usually because of a birth defect of the urinary tract.
Each kidney continuously filters waste from the blood to produce urine. The urine then drains through the ureters into the bladder at a low pressure. From the bladder, urine drains through the urethra to exit the body. In males, the urethra is located in the penis. In females, the urethra ends in the vulvar area (the area of the external female genital organs).
A Look Inside the Urinary Tract
Causes of Urinary Reflux
People normally have 2 ureters. One ureter connects the left kidney to the bladder, and the other ureter connects the right kidney to the bladder. Many birth defects of the bladder or birth defects of the ureters involve the junction where a ureter connects to the bladder. Normally the junction allows urine to flow only 1 way, from the kidneys to the bladder. Defects of the junction can allow urine to flow back up the ureter and sometimes into the kidneys. In addition, other defects that block the flow of urine can increase the pressure in the bladder and cause urinary reflux. Reflux can affect 1 side or both sides.
Complications of urinary reflux
Urinary reflux can cause frequent urinary tract infections (UTIs). Severe reflux and frequent infections can damage the kidneys and ureters over time. Kidney damage can cause high blood pressure and rarely kidney failure.
Symptoms of Urinary Reflux
Urinary reflux itself does not cause symptoms. But children may have symptoms if a urinary tract infection develops. Then children may have fever, may have pain in their abdomen or back, and may urinate more than normal or have burning when they urinate.
Diagnosis of Urinary Reflux
Voiding cystourethrography or radionuclide cystography
Doctors suspect urinary reflux if babies or young children have a urinary tract infection that is severe enough to cause fever. Some children are brought to a doctor because they have a sibling who was diagnosed with urinary reflux, and siblings of children with urinary reflux are at increased risk of developing the disorder. In both cases, doctors usually do ultrasound of the urinary tract to look for abnormalities.
If the ultrasound results are abnormal or if the child keeps having urinary tract infections, doctors may do a more complicated test called voiding cystourethrography. For voiding cystourethrography, a catheter is passed through the urethra into the bladder, a liquid that shows up on x-rays (contrast agent) is put through the catheter, and x-rays are taken before and after the child urinates.
Radionuclide cystography is similar to voiding cystourethrography except that a radioactive agent is placed in the bladder and images are taken using a nuclear scanner. This test exposes the child's ovaries or testes to less radiation than voiding cystourethrography. Urinary reflux can be diagnosed only with radionuclide cystography or voiding cystourethrography.
Urine tests also are done to detect an infection such as a UTI.
Treatment of Urinary Reflux
Sometimes preventive (prophylactic) antibiotics
Sometimes surgery
Treatment of urinary reflux depends on the specific birth defect and also on the severity of the complications.
Children who have few symptoms and no complications usually do not require treatment because many will outgrow the reflux.
Daily antibiotics to prevent infection are sometimes given to children who have severe reflux, frequent UTIs with fever, or both. Children with severe reflux also may need surgery to correct the problem and ensure urine drains properly.
