55  Obstructive Uropathy

55.1 Introduction

Obstructive uropathy refers to any structural or functional impediment to the normal flow of urine along the urinary tract, leading to an increase in intraluminal pressure and, ultimately, damage to the kidneys. The obstruction may occur at any point from the renal pelvis to the urethral meatus and may be acute or chronic, partial or complete, unilateral or bilateral.

In children, the condition is of particular concern because prolonged obstruction, even if partial, can lead to irreversible renal parenchymal damage, which has lifelong implications for growth, development, and renal function. Early recognition and prompt intervention are therefore essential.

In Ghana and other parts of sub-Saharan Africa, obstructive uropathy in children is not uncommon. The causes vary with age, ranging from posterior urethral valves in neonates and infants to ureteropelvic junction obstruction and acquired causes such as stones or iatrogenic injury in older children.

55.2 Basic Anatomy and Physiology

The urinary tract consists of:

  • Kidneys: Filter blood to form urine.
  • Ureters: Conduct urine from the kidneys to the bladder.
  • Bladder: Stores urine temporarily.
  • Urethra: Expels urine from the body.

Normal urine flow is maintained by a combination of:

  1. The peristaltic activity of the ureters,
  2. The presence of competent valves (such as the vesicoureteric junction),
  3. Coordinated bladder contraction and sphincter relaxation.

Any lesion disrupting these mechanisms can cause obstruction and consequent back pressure on the kidneys, resulting in hydronephrosis and possible renal impairment.

55.3 Pathophysiology

When urine flow is obstructed, several changes occur in the urinary tract and renal parenchyma:

  1. Increased pressure proximal to the obstruction: Leads to dilatation of the collecting system (hydronephrosis) and stretching of the renal capsule.
  2. Altered renal blood flow: Initially, renal blood flow increases but eventually declines as interstitial pressure rises, leading to ischemic injury.
  3. Tubular dysfunction: Impaired concentrating ability and reduced glomerular filtration rate (GFR).
  4. Inflammation and fibrosis: Chronic obstruction leads to tubular atrophy, interstitial inflammation, and fibrosis, resulting in progressive loss of renal function.

The reversibility of renal damage depends on the duration and severity of the obstruction. Complete obstruction for more than a few weeks can cause irreversible renal scarring.

55.4 Classification

55.4.1 Based on Duration

  • Acute Obstructive Uropathy: Sudden onset (e.g., calculus obstruction, trauma).
  • Chronic Obstructive Uropathy: Long-standing (e.g., posterior urethral valves, congenital stenosis).

55.4.2 Based on Site

  • Upper tract obstruction: Affecting renal pelvis or ureter.
  • Lower tract obstruction: Involving the bladder or urethra.

55.4.3 Based on Laterality

  • Unilateral: One kidney affected (may preserve overall renal function).
  • Bilateral: Both kidneys affected (risk of renal failure).

55.4.4 Based on Nature of Lesion

  • Intrinsic: Due to lesion within the urinary tract (e.g., valves, stricture, stone).
  • Extrinsic: Due to external compression (e.g., tumour, retroperitoneal fibrosis).

55.5 Aetiology

The causes of obstructive uropathy in children vary by age group:

55.5.1 Neonates and Infants

  • Posterior urethral valves (PUV): The most common cause in male infants.
  • Ureteropelvic junction (UPJ) obstruction
  • Ureterovesical junction (UVJ) obstruction
  • Prune-belly syndrome
  • Congenital megaureter

55.5.2 Older Children and Adolescents

  • Urolithiasis
  • Urethral stricture (post-infective or traumatic)
  • Pelvi-ureteric junction obstruction (if not detected earlier)
  • External compression (tumours, retroperitoneal fibrosis)
  • Neurogenic bladder dysfunction

55.5.3 Acquired Causes (relevant in Ghana and sub-Saharan Africa)

  • Schistosomiasis (S. haematobium): Chronic infection can lead to ureteric fibrosis and obstruction.
  • Tuberculosis: Genitourinary TB may cause ureteric strictures.
  • Trauma: Pelvic trauma from road traffic accidents or traditional circumcision mishaps.
  • Iatrogenic injuries: Following urethral catheterisation or pelvic surgery.

55.6 Epidemiology and Local Context

In Ghana, the exact incidence of obstructive uropathy in children is not well documented due to limited national registry data. However, tertiary centres such as Komfo Anokye Teaching Hospital and Korle Bu Teaching Hospital frequently report cases, often presenting late with significant renal compromise.

Key local factors contributing to delayed diagnosis include:

  • Limited access to antenatal ultrasound screening,
  • Late referral from peripheral hospitals,
  • Reliance on traditional herbal treatments before hospital presentation,
  • Scarcity of paediatric urologists and specialized imaging facilities.

Commonly observed patterns:

  • Posterior urethral valves remain the most frequent congenital cause in male infants.
  • Schistosomiasis-related strictures and ureteric calculi are notable acquired causes in endemic rural areas, especially along the Volta Basin and northern Ghana.

55.7 Clinical Features

The presentation of obstructive uropathy depends on:

  1. The site and degree of obstruction,
  2. The duration (acute vs. chronic),
  3. The age of the child.

55.7.1 Neonates and Infants

  • Antenatal hydronephrosis: Detected on prenatal ultrasound.
  • Poor urine stream or dribbling of urine (especially in boys with PUV).
  • Palpable bladder or abdominal distension.
  • Failure to thrive or recurrent urinary tract infections (UTIs).
  • Azotaemia or features of renal failure (e.g., vomiting, lethargy).

55.7.2 Older Children

  • Flank or abdominal pain (colicky if due to stones).
  • Urinary frequency, urgency, or incontinence.
  • Haematuria.
  • Recurrent UTIs.
  • Palpable kidney or bladder on examination.
  • Hypertension in chronic cases.
  • Signs of chronic renal insufficiency (pallor, growth retardation).

55.8 Investigations

Investigations aim to:

  1. Confirm the presence and site of obstruction,
  2. Identify the underlying cause,
  3. Assess renal function and the degree of damage.

55.8.1 Laboratory Investigations

  • Urinalysis: Proteinuria, haematuria, pyuria, or evidence of infection.
  • Urine culture and sensitivity: To guide antibiotic therapy.
  • Serum urea, creatinine, and electrolytes: Assess renal function.
  • Full blood count: Anaemia or infection.
  • Urine specific gravity: Low in chronic cases due to tubular dysfunction.

55.8.2 Imaging Studies

55.8.2.1 Ultrasound (USS)

  • First-line investigation.
  • Detects hydronephrosis, hydroureter, bladder wall thickening, and residual urine.
  • Antenatal ultrasound can detect hydronephrosis as early as the second trimester.

55.8.2.2 Micturating Cystourethrogram (MCUG)

  • Essential for diagnosing posterior urethral valves and vesicoureteric reflux.
  • Should be performed after treating any active UTI.

55.8.2.3 Diuretic Renogram (using MAG3 or DTPA)

  • Differentiates between obstructive and non-obstructive dilatation.
  • Provides functional information on differential renal function.

55.8.2.4 Intravenous Urography (IVU)

  • May show delayed excretion, dilated calyces, or level of obstruction.
  • Limited use in children due to radiation exposure and replaced largely by renography.

55.8.2.5 Other Imaging

  • CT Urography or MRI Urography: For complex cases or extrinsic causes.
  • Cystoscopy: Direct visualization of posterior urethral valves or strictures.

55.9 Management

Management depends on the site, cause, and severity of the obstruction, as well as the presence or absence of renal failure.

55.9.1 General Principles

  1. Prompt relief of obstruction.
  2. Preservation of renal function.
  3. Treatment of infection and prevention of recurrence.
  4. Correction of underlying cause.
  5. Long-term follow-up for renal growth and function.

55.9.2 Initial Stabilization

  • Assess hydration status and correct electrolyte imbalance.
  • Treat infections aggressively with appropriate antibiotics.
  • Bladder decompression using catheterization if there is lower tract obstruction.
  • Nephrostomy or ureterostomy for upper tract obstruction if necessary.

55.9.3 Specific Treatment Based on Cause

55.9.3.1 Posterior Urethral Valves

  • Initial management: Catheterization for bladder drainage.
  • Definitive management: Endoscopic valve ablation (fulguration).
  • In cases with severe renal impairment, temporary vesicostomy may be indicated.

55.9.3.2 Ureteropelvic Junction (UPJ) Obstruction

  • Observation if mild and renal function preserved.
  • Surgical correction (pyeloplasty) if obstruction is significant or progressive.

55.9.3.3 Ureterovesical Junction (UVJ) Obstruction / Megaureter

  • Reimplantation surgery or tailoring of the ureter as needed.

55.9.3.4 Urolithiasis

  • Hydration and analgesia.
  • Medical expulsive therapy for small distal stones.
  • Surgical removal (ureteroscopy or open surgery) for larger or impacted stones.

55.9.3.5 Schistosomiasis

  • Praziquantel (40 mg/kg single dose) for all infected individuals.
  • Management of resultant strictures may require endoscopic or surgical correction.

55.9.3.6 Neurogenic Bladder

  • Clean intermittent catheterization (CIC).
  • Anticholinergic medications to reduce detrusor overactivity.
  • Bladder augmentation in refractory cases.

55.9.4 Chronic Management

  • Monitoring renal function periodically.
  • Blood pressure control with antihypertensives if needed.
  • Treatment of recurrent infections.
  • Nutritional support to promote growth.
  • Parental counseling regarding long-term prognosis.

55.10 Complications

  • Hydronephrosis
  • Recurrent UTIs
  • Hypertension
  • Chronic kidney disease (CKD)
  • Bladder dysfunction
  • Growth retardation
  • Electrolyte disturbances

In Ghana, late presentation often means that children may already have advanced CKD by the time of diagnosis. This underscores the importance of early detection through antenatal screening and newborn examination.

55.11 Prevention and Early Detection

  1. Antenatal ultrasound for detection of hydronephrosis.
  2. Neonatal screening for poor urinary stream in male infants.
  3. Public education on early symptoms and the need for prompt medical evaluation.
  4. Training of peripheral health workers to identify signs of obstructive uropathy.
  5. Mass treatment and prevention of schistosomiasis in endemic regions.

55.12 Prognosis

Prognosis depends on:

  • Age at diagnosis,
  • Duration and completeness of obstruction,
  • Residual renal function,
  • Presence of infections.

With early diagnosis and appropriate intervention, many children can achieve good long-term outcomes. However, delayed cases may progress to chronic renal failure, requiring dialysis or renal transplantation — services that are still limited in many parts of Ghana.

55.13 Key Points

  • Obstructive uropathy is a major cause of preventable renal failure in children.
  • Posterior urethral valves are the most common congenital cause in male infants.
  • Early detection through antenatal and postnatal screening is critical.
  • Management requires a multidisciplinary approach involving paediatricians, urologists, and nephrologists.
  • In endemic areas, schistosomiasis remains a significant preventable contributor.

55.14 Further Reading

  1. Anochie IC, Eke FU. Paediatric obstructive uropathy in Port Harcourt, Nigeria. Nigerian Journal of Paediatrics. 2005;32(1):1–6.
  2. Ducket JW. Posterior urethral valves: Concepts and management. J Urol. 1992;148(5):1671–1675.
  3. Odetunde OI, et al. Spectrum and outcome of paediatric urological disorders in Enugu, Nigeria. Afr J Paediatr Surg. 2010;7(2):84–87.
  4. Osifo OD, Okolo JC. Posterior urethral valves in Benin City, Nigeria. Ann Afr Med. 2010;9(2):82–86.
  5. Anumba DOC, et al. Prenatal diagnosis of urinary tract abnormalities in Africa: Prospects and challenges. Trop Med Int Health. 2013;18(11):1373–1381.
  6. Cheeseman SH, Shortliffe LD. Obstructive uropathy in children. In: Behrman RE, Kliegman RM, Jenson HB (eds). Nelson Textbook of Pediatrics. 21st ed. Elsevier; 2020.
  7. Ghana Health Service. National Guidelines for Schistosomiasis Control in Ghana. Accra: GHS;
  8. World Health Organization. Paediatric Urology: Global Overview and Recommendations. Geneva: WHO; 2020.