Prune Belly Syndrome (Eagle Barret Syndrome)

Introduction

• Also called Eagle Barret Syndrome. Characteristic triad of Prune belly syndrome are: Bilateral intrabdominal testis, Genito urinary tract anomaly and deficiency of anterior abdominal wall musculature. Incidence:  1 in 29000 to 40000 live births. 95% of patients are boys. Rarely associated with other syndromes.

Potential Etiology 

• There is in-utero posterior urethral obstruction because of which there is proximal dilation. Primary defect in lateral plate mesoderm. Various inciting events lead to the defect between 6 to 8 weeks of gestation. There can be some intrinsic defect in the urinary tract.

Clinical Features

1. Kidney
   • Variable degree and laterality, potter’s sequence. Degree of dilation does not correlate with the degree of renal dysplasia or destruction, calyceal preservation. Renal infection rather than obstruction poses a greater risk.
2. Ureter
   • Typically dilated, tortuous, and redundant. Proximal ureter generally less abnormal. Distal ureter characterized by replacement of normal smooth muscle by connective tissue. VUR is present in 75% of patients. Obstruction is rare (stasis is more likely due to ineffective peristalsis)
3. Urinary Bladder
   • Minimally enlarged. Urachal pseudodiverticulum. Increased collagen as compared to muscle fiber. Normal bladder compliance, delayed primary sensation. Unbalanced voiding: relative outflow resistance prevents effective bladder emptying. 50% of patients are having normal voiding pressure, flow rate, and PVR.
4. Posterior Urethra
   • Dilated posterior urethra due to prostate hypoplasia. Dilation of the posterior urethra can also be due to various destructive lesions of the distal posterior urethra. Urethral atresia, valves, stenosis, and diverticulum in 20% of cases. These patients may have an ejaculatory failure (retrograde ejaculation), poor epididymal attachment, and undescended testicles. Lack of continuity in efferent ductules of testes. 
5. Anterior Urethra
   • Urethral atresia (lethal if no patent urachus is there): Urethra does not develop properly in urethral atresia, urine will not be able to come out, and there will be severe oligohydramnios. The patient may die inside the uterus. Megalourethra (more common in PBS as compared to other syndromes), there are two types of megalourethra.
   • Fusiform- Deficient corpus cavernosum and spongiosum. The entire phallus dilates during voiding.
   • Scaphoid- Deficient sporangium only with preserved glans and corpora. The ventral urethra dilates with voiding.

• 6. Tests
  • Bilateral intra-abdominal testis over the iliac vessels, is the most common finding. No difference in germ cell counts, prognosis is the same when compared with PBS and non-PBS in testis on biopsy. Infertility: Sperm retrieval is possible. Testicular histology is normal. 
• 7. Abdominal Wall
  • Usually uneven distribution pattern. Most severe areas have skin, subcutaneous fat, and a single fibrous layer on the peritoneum. Inferior and medical segments are most consistently affected.

Presentation

1. Prenatal Diagnosis And Management

• Resembles posterior urethral valve megacystis megaureter syndrome. Classic findings are not consistently seen at 30 weeks, so it is difficult to recommend termination of pregnancy. Hydroureteronephrosis. Distended bladder., irregular abdominal circumference. Degree of hydronephrosis does not correlate with post-natal renal function

2. Prenatal Intervention

• Generally, there is no proven benefit. Rare situations of prenatal intervention: Urethral atresia with progressive oligohydramnios. Decompression prevents dystocia.

Spectrum Of Disease

• 3 major sub-categories based on the spectrum of presentation.
  • Category I: Extremely poor prognosis, 20% of all PBS patients die in the in perinatal period. Marked oligohydramnios, severe bladder outlet obstruction, pulmonary hypoplasia, urethral atresia in patients (until patent urachus is present).
  • Category II: Moderate or unilateral renal insufficiency (degree of renal dysplasia determines long-term prognosis). Moderate to severe hydronephrosis. No pulmonary hypoplasia. Either stabilization of renal function at or below normal or progressive azotemia. 
  • Category III: Mild or incomplete features- Majority of patients with hydronephrosis. Well-maintained renal function. No pulmonary insufficiency. Appearance of the abdominal wall does not correlate with the degree of hydronephrosis or renal dysplasia. Incomplete prune belly syndrome (pseudo prune). Lack of typical abdominal wall features (delayed diagnosis). Uropathy and UDT present. Many go to renal failure.

Female Prune Belly Syndrome

• Found in 5% of patients. Abdominal wall deficiency and urinary trans anomalies. Bladder outlet obstruction. 40% of patients may have anorectal anomalies. 40% of patients have neonatal mortality.
  • CATEGORY I: Supportive care.
  • CATEGORY II: Individual tailor treatment (MAG3, DMSA, VCUG, Depending upon creatinine). There is controversy in management. Spontaneous improvement in urethral appearance and function may occur with growth. Untreated patients have survived for decades. Some PBS patients develop ESRD. 
  • CATEGORY III: Rarely requires urinary tract intervention and will still need testis and abdominal wall procedure. Interval USG and BUN/Cr.

Multidisciplinary Evaluation

• Basic metabolic panel: Cr< 0.7 mg/dL predicts adequate renal function throughout childhood in the absence of pyelonephritis.
• CXR: Pulmonary sequale.
• VCUG: Should be done when renal dysfunction is present. Avoid if normal renal creatinine is there and adequate bladder drainage/patent urachus is present. Must give antibiotics and utilize sterile technique as to not inoculate static system.
• Avoidance of UTI: Circumcision, give prophylactic antibiotics before instrumentation.
• Vesicostomy: Important to use the dome of the bladder to create a vesicostomy.
• Wide stoma: Stenosis is common.

Surgical Management

1. Urinary Tract Reconstruction- Urethra, Bladder, testes

Surgical Management of Bladder

• Urinary tract reconstruction is a tailored therapy. Supra vesical urinary diversion for obstruction (UPJ or UVJ obstruction): Go ahead with the cutaneous pyelostomy. Cutaneous vesicostomy: If there is ARF, sepsis, or bladder obstruction. Excise large diverticula if present. Create a large stoma due to increased stenosis risk. Reduction of Cystoplasty: May improve contractility. Removal of large diverticula is the only indication. CIC is a much better option.

Surgical Management of The Urethra

• Internal urethrostomy- True anatomic obstruction is rare although there is some element of partial outlet obstruction. No reported incontinence in this population.
  • Anterior urethral reconstruction- Urethral atresia (micro urethra): Go with the PADUA procedure. Megalourethra: Circumferential degloving, Excision of redundancy and reconstruction.
  • Urethral reconstruction- It is controversial. Indications for urethral reconstruction are: Recurrent UTI. Upper tract deterioration. Goal is to reduce stasis and risk of UTI.

Surgical Management of Testis

• Trans abdominal orchidopexy- 6 months for adequate spermatic vessel mobilization. Post-placement is challenging

2.ABDOMINAL WALL RECONSTRUCTION

Surgical Management Of The Abdominal Wall

• Mild to moderate abdominal wall laxity: these patients may improve with growth. Mild to severe laxity: This is psychologically crippling for the patient and treatment is needed. No proven benefit in pulmonary, genital, urinary, and GI function. It is more of a cosmetic purpose.

Randolph Technique 

• EMG Mapping of abdomen wall musculature. Transverse incision given from 12^th rib- pubic symphysis. Full thickness skin reconstruction, and musculation. Reapproximation of healthy fascia to ASIS, pubic tubercle, and inferior fascia.

Enrich Technique

• Vertical midline incision preservation of umbilicus on the vascular pedicle. Preserves inferior epigastric artery.

Monfort Technique

• Most common procedure done nowadays. If there is laxity of the abdomen, an elliptical incision is given, preserve the umbilicus as well (but skin surrounding that is removed in an elliptical manner), detach the lateral part of muscles and double press, and this is how the integrity of the abdominal wall is maintained.

Denes’ Technique

• It is the modification of the Randolph technique. Asymmetrical excision is done.

Predicting Renal Function

• Nadir creatinine <0.7 mg/dL in infancy: Tends to be stable unless recurrent UTI is there. 30% with impaired renal function at initial evaluation land up into ESRD. Need to put these patients under close follow up and prompt treatment of UTI is needed. Transplantation into a prune bladder is fine if there is a bladder emptying strategy in place.

Growth and Musculo Skeletal Development 

• Normal growth.
• No restricted activity.
• Physical therapy and exercise particularly swimming are important for term abdominal health.

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