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 one way, from the kidneys to the bladder. Defects of the junction can allow urine to flow back up the ureter and sometimes into the kidney. Other defects that block the flow of urine can increase the pressure in the bladder and cause urinary reflux. Reflux can affect one side or both sides. In addition, children with urinary reflux frequently have constipation, which expands the rectum. Expansion of the rectum puts pressure on the bladder, which increases urinary reflux.
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 UTI develops. Symptoms of a UTI in children may include fever, pain in the abdomen or back, and urinating more than normal or feeling a burning sensation when they urinate. A UTI may also cause children to feel an urgent need to urinate or to have accidents (urinary incontinence).
Infants and children under 2 years of age who have a UTI may have fever, vomiting, abdominal pain, or foul-smelling urine.
Diagnosis of Urinary Reflux
Ultrasonography
Voiding cystourethrography
Sometimes 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 such cases, doctors do an ultrasound of the kidneys, ureters, and bladder before and after the child urinates to look for abnormalities.
If the ultrasound results are abnormal or if the child keeps having UTIs, doctors may do a more complicated test called voiding cystourethrography (VCUG). For this test, 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 VCUG except that a radioactive agent is placed in the bladder and images are taken using a nuclear scanner. Urinary reflux can be diagnosed with certainty only with VCUG or radionuclide cystography.
Urine tests also are done to detect an infection such as a UTI.
Treatment of Urinary Reflux
Sometimes preventive (prophylactic) antibiotics
Sometimes medications or injections of medications into the bladder wall
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, and the reflux may go away as the child grows.
Daily antibiotics to prevent infection are sometimes given to children of any age who have severe reflux, frequent UTIs with fever, or both. Children are also encouraged to try to urinate frequently to decrease the risk urinary tract infections.
Because constipation can increase pressure in the bladder and increase urinary reflux, doctors treat constipation with behavioral measures and medications as needed.
Sometimes, children are given anticholinergic or other medications that lower bladder pressure and decrease urinary reflux. Doctors may also inject gel-like substances into a child's bladder wall near the opening of the ureter to resolve or decrease reflux.
Children with severe reflux also may need surgery to correct the problem and ensure urine drains properly.
