Secondary VUR: Reflux in Neurogenic Bladder and Posterior Urethral Valves

In primary vesicoureteral reflux, the problem is that the ureter's tunnel of entry into the bladder is too short or wrongly positioned; in secondary reflux, the tunnel is usually normal to begin with, but the pressure inside the bladder rises so high that the valve cannot withstand it and urine backs up toward the kidney.

In neurogenic bladder (spina bifida, spinal cord injury, sacral agenesis, and the like), the coordination between the bladder muscle and the outlet valve is disrupted; the bladder generates high pressure at small volumes, and this pressure is transmitted back to the kidneys.

Posterior urethral valves (PUV) are a congenital membrane in the posterior part of a male infant's urethra that blocks the outflow of urine; the obstruction raises bladder pressure starting from before birth, and about half of these infants have vesicoureteral reflux, often bilateral.

In secondary reflux, endoscopic injection or ureteral reimplantation comes into play if the reflux persists and continues to cause harm even after the underlying cause has been treated.

Follow-up in secondary reflux is more intensive than in primary reflux and also covers bladder function.

• Regular CIC and medication adherence: pressure control is itself the treatment of the reflux.
• Daily management of constipation; a full bowel raises bladder pressure.
• Ultrasound (kidney dilation, bladder wall, residual urine) usually every 6–12 months; more often if needed.
• Blood pressure, urinalysis, and blood creatinine; DMSA (renal scan) 4–6 months after a febrile infection.
• Repeat urodynamics at set intervals or with any clinical change.
• Seek prompt medical attention for fever, foul-smelling urine, or difficulty or bleeding with catheterization.