Congenital Renal Conditions
Wilms Tumor & Bladder Exstrophy
Comprehensive Nursing Notes
Wilms Tumor (Nephroblastoma)
Wilms tumor (also known as nephroblastoma) is the most common primary renal malignancy in children. It typically presents as an asymptomatic abdominal mass and primarily affects children between the ages of 2 and 5 years.
Clinical Pearl
Wilms tumor is the most common renal tumor in children, accounting for approximately 6-7% of all childhood cancers. The peak incidence occurs between 2-5 years of age, with 90% of cases diagnosed by age 7.
Quick Facts
- Most common childhood renal malignancy
- Most cases diagnosed by age 5
- Often presents as asymptomatic abdominal mass
- Associated with WT1 gene mutations
- ~5% are bilateral
- High overall survival rate (>85%)
Figure 1: Wilms Tumor (Nephroblastoma) showing the classic triphasic histological pattern
Pathophysiology
Wilms tumor develops from embryonic renal precursor cells that fail to mature properly. The tumor typically demonstrates a triphasic histological pattern consisting of three components:
Triphasic Histological Components
1. Blastemal
Small, densely packed undifferentiated cells with hyperchromatic nuclei and little cytoplasm. Represents the most primitive component.
2. Epithelial
Cells organized into tubular and glomerular-like structures. Shows attempts at renal differentiation.
3. Stromal
Spindle-shaped cells resembling fibroblasts, smooth muscle, or skeletal muscle. Represents mesenchymal differentiation.
Several genetic mutations have been identified in Wilms tumor, with the WT1 gene on chromosome 11p13 being the most well-known. This gene normally functions as a tumor suppressor involved in urogenital development. Other genetic alterations include mutations in WT2, WTX, and CTNNB1 genes.
Mnemonic: “GRoW WiTh” for Wilms Tumor Genetic Associations
- Genitourinary abnormalities (hypospadias, cryptorchidism)
- Renal involvement (WT1 gene)
- WAGR syndrome (Wilms tumor, Aniridia, Genitourinary abnormalities, mental Retardation)
- Wilms tumor is associated with Beckwith-Wiedemann syndrome
- Triphasic histology (blastemal, epithelial, stromal)
- hemisomatic hypertrophy
Clinical Presentation
| Clinical Feature | Description |
|---|---|
| Abdominal Mass | Most common presentation (80% of cases) – typically a non-tender, firm, smooth mass felt in the flank or upper abdomen |
| Abdominal Pain | Present in 30-40% of cases, may be due to rapid tumor growth or hemorrhage within the tumor |
| Hematuria | Occurs in 12-25% of cases, may be gross or microscopic |
| Hypertension | Present in 25% of cases, caused by increased renin production |
| Fever | Nonspecific symptom seen in about 20% of cases |
| Associated Syndromes | WAGR syndrome, Denys-Drash syndrome, Beckwith-Wiedemann syndrome |
Diagnosis and Staging
Diagnosis of Wilms tumor typically involves:
- Imaging studies: Abdominal ultrasound (initial screening), CT or MRI (extent of tumor, metastasis)
- Chest X-ray/CT: To evaluate for lung metastases (most common site)
- Laboratory tests: CBC, renal function tests, urinalysis, liver function tests
- Histopathology: Tissue examination after nephrectomy or biopsy
| Stage | Description |
|---|---|
| Stage I | Tumor limited to kidney and completely resected |
| Stage II | Tumor extends beyond kidney but is completely resected |
| Stage III | Residual nonhematogenous tumor confined to abdomen (lymph node involvement, tumor spillage, peritoneal implants) |
| Stage IV | Hematogenous metastases (lung, liver, bone, brain) |
| Stage V | Bilateral renal involvement at diagnosis |
Wilms Tumor Treatment Approach
Surgery
- Radical nephrectomy (primary treatment)
- Lymph node sampling
- Nephron-sparing surgery (selected cases)
- Exploration of contralateral kidney
Chemotherapy
- Vincristine, dactinomycin (VA) for low-risk
- Add doxorubicin (VAD) for higher risk
- Cyclophosphamide, etoposide for anaplastic or recurrent disease
- May be neoadjuvant or adjuvant
Radiation Therapy
- For stage III, IV and anaplastic histology
- Flank or whole abdomen radiation
- Lung radiation for pulmonary metastases
- Dose based on age and stage
Nursing Considerations
Preoperative
- Avoid abdominal palpation to prevent tumor rupture
- Monitor for hypertension and initiate treatment if present
- Provide age-appropriate explanations about procedures
- Assess family understanding and provide support
- Prepare child for post-operative expectations
Postoperative
- Monitor vital signs, fluid balance, and pain levels
- Assess surgical site for bleeding or infection
- Monitor renal function with lab studies
- Position to avoid pressure on surgical site
- Encourage early ambulation as tolerated
- Provide emotional support to child and family
Chemotherapy Care
- Monitor for side effects (nausea, vomiting, myelosuppression)
- Implement neutropenic precautions when indicated
- Administer antiemetics as prescribed
- Monitor for cardiotoxicity with doxorubicin
- Educate on infection prevention
- Maintain adequate hydration
Long-term Follow-up
- Monitor for tumor recurrence
- Screen for late effects of treatment
- Assess renal function regularly
- Provide psychosocial support
- Educate about signs of recurrence
- Support transition to survivorship care
Clinical Pearl
The “Classic Triad” of Wilms Tumor (flank mass, hematuria, and abdominal pain) is actually present in less than 10% of cases. Most children present with only an asymptomatic abdominal mass discovered by parents during routine care.
Bladder Exstrophy
Bladder exstrophy is a rare congenital anomaly where the bladder develops outside the fetus during embryonic development. It is characterized by an open bladder exposed on the lower abdomen, with the posterior wall of the bladder visible externally.
Clinical Pearl
Bladder exstrophy occurs in approximately 1 in 50,000 live births, with a male-to-female ratio of 2:1 to 6:1. It is part of the exstrophy-epispadias complex spectrum of anomalies.
Quick Facts
- Incidence: 1 in 50,000 live births
- Male predominance (2:1 to 6:1)
- Part of exstrophy-epispadias complex
- Associated with widened pubic symphysis
- Requires multidisciplinary approach
- Surgical repair typically in stages
Figure 2: Anatomical appearance of bladder exstrophy showing the exposed posterior bladder wall and associated defects
Embryology & Pathophysiology
Bladder exstrophy results from a defect in the development of the cloacal membrane and lower abdominal wall. The normal development sequence is disrupted during the 4th to 10th week of gestation.
Developmental Pathophysiology
1. Failure of Mesoderm Migration
The infraumbilical mesoderm fails to migrate between the ectodermal and endodermal layers of the cloacal membrane. This results in an unstable cloacal membrane that ruptures prematurely.
2. Premature Rupture of Cloacal Membrane
When the cloacal membrane ruptures before the urorectal septum descends completely, the developing bladder is exposed and everts through the abdominal wall defect.
3. Associated Developmental Anomalies
The defect also affects the development of the bony pelvis, abdominal wall, and external genitalia. The pubic symphysis fails to close, resulting in a widened pubic diastasis.
Mnemonic: “EXPOSED” for Bladder Exstrophy Features
- Everted bladder mucosa on abdominal wall
- X-appearing pelvic bones (widened pubic symphysis)
- Patulous ureteral orifices with continuous urine drainage
- Opened anterior bladder wall
- Short penis with epispadias in males
- External genitalia abnormalities
- Diastasis of rectus abdominis muscles
Clinical Presentation
| Feature | Description |
|---|---|
| Exposed Bladder | Everted, exposed posterior bladder wall on the lower abdomen with visible ureteral orifices that continuously leak urine |
| Abdominal Wall Defect | Lower abdominal wall defect with separation of rectus muscles and umbilicus positioned lower than normal |
| Pelvic Bone Abnormalities | Widened pubic symphysis (pubic diastasis) with external rotation of the pelvic bones |
| Male Genital Defects | Short, broad penis with dorsal chordee and complete epispadias; undescended testes may be present |
| Female Genital Defects | Bifid clitoris, separated labia, short vagina, and anteriorly displaced vaginal orifice |
| Anorectal Anomalies | Anteriorly displaced anus, anal stenosis, or rectal prolapse may be present |
| Associated Anomalies | Vesicoureteral reflux, inguinal hernias, cryptorchidism, spinal abnormalities |
Diagnosis
Bladder exstrophy is typically diagnosed:
- Prenatally: Through ultrasound findings including absent filling of the bladder, lower abdominal mass, abnormal genitalia, and widened pubic rami.
- At birth: Through obvious physical findings of the everted bladder on the abdominal wall.
- Additional imaging: Renal ultrasound to evaluate upper urinary tract and pelvic X-ray to assess pubic diastasis.
Management Approach
Bladder Exstrophy Management Timeline
Initial Care (Birth)
- Protect exposed bladder (sterile, moist saline dressings)
- Prevent infection
- Initial assessment
- Parental counseling
- Transfer to specialized center
Primary Repair (48-72 hrs)
- Closure of bladder
- Abdominal wall closure
- Pelvic osteotomy (if needed)
- External fixation of pelvis
- Urethral reconstruction
Secondary Repair (6-12 months)
- Epispadias repair in males
- Genital reconstruction
- Continence procedures if needed
Bladder Neck Reconstruction (4-5 years)
- Continence procedures
- Augmentation if needed
- Mitrofanoff procedure if needed
Nursing Considerations
Newborn Period
- Protect exposed bladder with sterile, moist dressings
- Position to prevent pressure on the defect
- Monitor for signs of infection
- Observe for additional congenital anomalies
- Provide emotional support to parents
- Educate parents on care of exposed bladder
Postoperative Care
- Immobilization to protect pelvic osteotomy and repair
- Pain management
- Proper positioning (avoid hip abduction)
- Care of external fixators if present
- Monitor urinary output and catheters
- Wound care and infection prevention
- Management of urinary diversion
Long-term Follow-up
- Continence assessment and training
- Clean intermittent catheterization teaching
- Monitor for urinary tract infections
- Assess renal function
- Puberty and sexuality counseling
- Psychosocial support for body image issues
- School accommodations for bathroom needs
Family Education
- Importance of long-term follow-up
- Signs of complications to report
- Continence management strategies
- Connect with support groups
- Preparation for school environment
- Addressing psychosocial challenges
- Future fertility considerations
Clinical Pearl
Prompt closure of the exposed bladder is critical not only for cosmetic and functional purposes but also to preserve the bladder mucosa. When the bladder mucosa is exposed to air, it undergoes metaplastic changes that can affect future bladder capacity and function. Proper bladder cycling (filling and emptying) is essential for optimal bladder development and function.
Quality of Life Considerations
Urinary Continence
Approximately 70-80% of patients achieve reasonable urinary continence following complete reconstruction. Some may require intermittent catheterization or continent urinary diversion (Mitrofanoff).
Sexual Function & Fertility
Males may experience challenges with sexual function due to penile abnormalities. Female patients typically have normal fertility but may require cesarean section for delivery due to pelvic anatomy. Psychological support around sexuality is important.
Psychosocial Impact
Body image concerns, especially during adolescence. School accommodations may be needed for bathroom access. Support groups can be valuable for families and patients to share experiences and coping strategies.
Differential Diagnosis: Wilms Tumor vs. Other Pediatric Renal Masses
| Condition | Key Characteristics | Age of Presentation | Distinguishing Features |
|---|---|---|---|
| Wilms Tumor | Triphasic histology (blastemal, epithelial, stromal) | 2-5 years | Associated with WT1 gene mutations, WAGR syndrome |
| Neuroblastoma | Small round blue cell tumor derived from neural crest cells | Infancy to 5 years | Elevated catecholamines, often crosses midline, calcifications on imaging |
| Renal Cell Carcinoma | Originates from renal tubular epithelium | Adolescents/adults | Classic triad: hematuria, flank pain, palpable mass; hypervascular |
| Mesoblastic Nephroma | Benign spindle cell tumor | First 3 months of life | Most common renal tumor in neonates, often diagnosed prenatally |
| Clear Cell Sarcoma | Aggressive tumor with metastasis to bone | 1-4 years | High tendency for bone metastasis, “bone-seeking” tumor |
| Rhabdoid Tumor | Highly aggressive with poor prognosis | < 2 years | INI1/hSNF5 mutations, high metastatic potential |
| Multicystic Dysplastic Kidney | Non-malignant developmental abnormality | Often prenatal diagnosis | Multiple non-communicating cysts, non-functional kidney |