Vesicoureteral Reflux in Paediatrics

A congenital or acquired back‑flow of urine from bladder to kidney that predisposes to infection and scarring. Diagnosis relies on imaging, and treatment balances infection control with surgical correction.

Definition and diagnosis

Vesicoureteral reflux (VUR) is the retrograde flow of urine from the bladder into the ureter and kidney. It is most often congenital, but can be secondary to bladder outlet obstruction or infection.

• Voiding cystourethrogram (VCUG): Shows the direction and grade of reflux; the gold standard for diagnosis. A positive study confirms VUR.
• Renal ultrasound: Detects hydronephrosis or scarring; used when VCUG is unavailable or to monitor progression.
• DMSA scan: Identifies renal scarring; useful when infection has occurred.

• Congenital defect of the ureterovesical junction (UVJ)
• Secondary causes: bladder outlet obstruction, neurogenic bladder, post‑renal infection

Severity and staging

VUR is graded I–V based on the extent of reflux and renal damage. Higher grades carry greater risk of scarring and hypertension.

• Grade I–II: reflux to pelvis, minimal damage
• Grade III–IV: reflux to calyces, moderate scarring
• Grade V: reflux to renal parenchyma, severe scarring

Causes, most likely first

The primary cause is a faulty UVJ valve. Secondary causes are common in low‑resource settings and can mimic or worsen VUR.

• Congenital UVJ defect
• Bladder outlet obstruction (e.g., posterior urethral valves in boys)
• Neurogenic bladder (spina bifida)
• Chronic urinary tract infection
• Sickle cell disease (recurrent infections)
• Herbal remedies causing bladder irritation

How it presents

Presentation ranges from asymptomatic to recurrent febrile UTIs. In young children, a single febrile UTI warrants evaluation for VUR.

• Recurrent febrile UTIs
• Hypertension in older children
• Abdominal pain or flank pain during infection
• Growth faltering if chronic infection

Investigations

Select investigations based on availability and clinical urgency.

• Urine culture: Confirms infection; guides antibiotic choice.
• Urinalysis: Detects pyuria or hematuria indicating infection.
• VCUG: Diagnoses VUR and grades severity.
• Renal ultrasound: Assesses hydronephrosis; used when VCUG is not available.
• DMSA scan: Detects scarring; important if infection has occurred.

Red flags and complications

Complications can be life‑threatening if not recognised early.

• Blood pressure: Hypertension may indicate scarring; monitor in all children with VUR.
• Growth parameters: Failure to thrive can signal chronic infection or scarring.

• Acute pyelonephritis
• Renal scarring leading to hypertension
• End-stage renal disease
• Sepsis

Management

Management balances infection control with prevention of scarring and considers resource constraints.

• Antibiotic prophylaxis: Reduces recurrence of UTIs; chosen for low‑grade VUR or when surgery is not feasible.
• Surgical reimplantation: Indicated for grades IV–V or persistent infection; restores valve function.

• Prophylactic antibiotics (e.g., amoxicillin or trimethoprim‑sulfamethoxazole) to prevent recurrent UTIs
• Prompt treatment of acute infection with appropriate antibiotics
• Surgical correction (ureteric reimplantation) for high‑grade or refractory cases
• Monitoring with ultrasound or VCUG as resources allow

Follow-up and prevention

Regular follow‑up ensures early detection of complications and adherence to prophylaxis.

• Annual BP and growth checks
• Repeat imaging if infection recurs
• Education on hydration and hygiene
• Vaccination against common pathogens (e.g., pneumococcus)

Often confused with

Conditions that mimic VUR or share similar presentations.

• Acute pyelonephritis without reflux
• Urinary tract obstruction (e.g., posterior urethral valves)
• Nephrolithiasis

Where results can mislead

Certain tests may give false negatives or positives in low‑resource settings.

• Urine dipstick: May miss low‑grade infection; confirm with culture.
• Ultrasound: Can underestimate scarring; consider DMSA if available.

• Urine culture may be negative if antibiotics were taken recently
• Ultrasound may miss mild hydronephrosis
• VCUG requires catheterisation and fluoroscopy, often unavailable

Questions an examiner may ask

• A 2‑year‑old boy presents with a febrile UTI. What is the first investigation you would order? — Urine culture to confirm infection and guide antibiotics.
• A child with grade III VUR is on prophylaxis but develops a second febrile UTI. What is the next step? — Re‑evaluate with VCUG; consider surgical correction if infection persists.
• Why is a VCUG preferred over ultrasound for diagnosing VUR? — VCUG visualises the direction and grade of reflux; ultrasound only shows hydronephrosis.
• A patient with VUR develops hypertension. What is the likely mechanism? — Renal scarring reduces nephron number, activating the renin‑angiotensin system.
• Which antibiotic is avoided in VUR patients with penicillin allergy? — Fluoroquinolones are avoided due to risk of cartilage damage in children.
• A low‑resource hospital cannot perform VCUG. What alternative imaging can you use? — Renal ultrasound to look for hydronephrosis and DMSA scan if available for scarring.

When to seek help

• Severe flank pain with fever >38.5°C
• Hypertension >95th percentile for age
• Persistent or worsening UTIs despite treatment
• Signs of sepsis (tachycardia, hypotension)

Quick questions

What is the most common cause of VUR in children?

A congenital defect of the ureterovesical junction that fails to act as a one‑way valve.

Why is antibiotic prophylaxis used in low‑grade VUR?

It reduces the frequency of febrile UTIs and limits renal scarring when surgery is not immediately available.

When is surgery indicated?

High‑grade reflux (IV–V) or recurrent infections despite adequate prophylaxis and monitoring.