Prune belly syndrome

25 de Aug de 2016

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Prune belly syndrome

  1. PRUNE-BELLY SYNDROME Gaurav Nahar DNB Urology Resident MMHRC, Madurai
  2. INTRODUCTION • A constellation of anomalies with variable degrees of severity. • Three characteristic findings: 1. a deficiency of abdominal musculature, 2. bilateral intra-abdominal testes, and 3. an anomalous urinary tract. • Single most important determinant of long-term survival- severity of the urinary tract anomaly, in particular, degree of renal dysplasia.
  3. Also known as: • Triad syndrome, • Eagle-Barrett syndrome, and • Abdominal musculation syndrome
  4. Urinary tract anomalies: variable degrees of • Hydronephrosis, • Renal dysplasia, • Dilated tortuous ureters, • Enlarged bladder, and • Dilated prostatic urethra Additional associated anomalies: • Respiratory tract, • Gastrointestinal tract, • Cardiac system, and • Musculoskeletal system.
  5. ...flashback • Frolich(1839) first described the characteristic abdominal wall in PBS. • Parker(1895) described the full triad of anomalies. • Osler(1901) coined the term Prune-belly syndrome d/t characteristic abdominal wall findings.
  6. EPIDEMIOLOGY • Incidence: 1 in 29,000 to 1 in 40,000 live births(similar as bladder exstrophy). • 95% cases in males. • PBS females exhibit abdominal wall deficiency and urinary tract dysmorphism without any gonadal anomaly. • Higher incidence noted in twins, blacks, and children born to younger mothers. • Incidence declining in developed countries because of prenatal diagnosis and a decision to terminate the pregnancy.
  7. GENETICS • Most cases sporadic with normal karyotype. • Reported association with  Turner syndrome  Monosomy 16  Trisomy 13  Trisomy 18  Beckwith Wiedemann syndrome. Proposed inheritance patterns- X-linked recessive, 2- step autosomal dominant, sex-influenced autosomal recessive & polygenic transmission.
  8. EMBRYOLOGY • Exact mechanism unclear. • Four main theories: (1) Early in utero posterior urethral obstruction resulting in severe dilation of urinary tract and possible fetal ascites and oligohydramnios. (2) Primary defect in lateral plate mesoderm (precursor of ureters, bladder, prostate, urethra, and gubernaculum). (3) Intrinsic defect of urinary tract leading to ureteral dilation and fetal ascites (4) A yolk sac defect.
  9. CLINICAL FEATURES GENITOURINARY ANOMALIES: Kidneys: • Spectrum of anomalies range from normal renal parenchyma to dysplasia. • Dysplasia in 50%. • Severe degree of renal collecting system dilatation- characteristic. • Calyceal morphology well-preserved.
  10. • Severely dysplastic or dilated kidney. • Non-obstructive hydronephrosis. • Primary or secondary UPJO.
  11. Ureters: • Dilated, tortuous & redundant. • Distal ureters more severely affected. • Vesicoureteral reflux(VUR) in 75% pts. • Histology- a lack of smooth muscle cells and an increase in fibrous connective tissue. • Ratio of collagen to smooth muscle cells in prune-belly ureters is elevated.
  12. • Decreased number of thick and thin myofibrils (ultrastructural examination) contributes to poor peristalsis. • UPJ & UVJ obstruction- uncommon. • Ineffective ureteral peristalsis because of poor ureteral wall coaptation. • Severity of urinary tract abnormalities is not proportional to flaccidity of abdominal wall.
  13. • Excretory urogram (A to C) demonstrating the variable degree of HUN in PBS. • Note the preservation of calyceal architecture, despite severe ureteral dilation in C. • D, Dilated tortuous refluxing ureters as seen on a voiding cystourethrogram
  14. Bladder: • Massively enlarged + Urachal pseudodiverticulum. • Patent urachus in 25-30%. • Despite being very thick, bladder wall is smooth. • Increased ratio of collagen to muscle fibers in the absence of obstruction. • Delayed first sensation to void and a large capacity.
  15. • A significant postvoid residual may result from a relative outlet obstruction and inability of bladder to generate sufficient pressure with a detrusor contraction. • Despite these limitations, 50% of PBS patients void spontaneously with normal voiding pressures, normal flow rates, and low postvoid residuals. • Trigone is splayed with ureteric orifices displaced laterally and superiorly(? cause of VUR).
  16. VCUG of a child with PBS demonstrating urethral atresia, urachal diverticulum, and VUR
  17. Prostate and Accessory Sex Organs: • Posterior urethral dilatation d/t prostatic hypoplasia, k/a type 4 valve- angulation of urethra during voiding. • Related to abnormal mesenchymal-epithelial development. • Reduction of both epithelial and smooth muscle cells and increase in connective tissue cells. • Various obstructive lesions of distal posterior urethra:- urethral atresia, valves, urethral stenosis, urethral membrane, and urethral diverticulum- occur in 20% of cases.
  18. • Prostatic hypoplasia may cause ejaculatory failure. • Vas deferens and seminal vesicles are atretic; may be dilated or thickened. • Epididymis may be poorly attached to the testis (as is seen commonly in abdominal undescended testes). • Lack of continuity between efferent ductules and rete testis. • Retrograde ejaculation because of an incompetent bladder neck.
  19. Anterior urethra: • Usually normal. • Most common anomalies: urethral atresia or hypoplasia and megalourethra. • Unless associated with a patent urachus, urethral atresia is lethal. • Spontaneous bladder rupture with fistula formation also may occur.
  20. In PBS, two types of megalourethra seen. Fusiform type: • a deficiency of corpus cavernosum + spongiosum. • Entire phallus dilates with voiding. • results from a mesenchymal deficiency of urethral folds. Scaphoid variety: • a deficiency of spongiosum only with preservation of glans and corpora cavernosa. • Ventral urethra dilates with voiding. • results from a mesenchymal deficiency of urethral supportive tissues.
  21. • Megalourethra is more commonly seen in PBS than any other syndrome. • Transient in utero obstruction of junction between glanular & penile urethra- proposed cause of megalourethra.
  22. Testes: • Bilateral intra-abdominal testes lying over iliac vessels and adjacent to dilated ureters- most typical findings. • Some authors found no difference in germ cell counts, Ad spermatogonia, and Leydig cells between PBS testes and non-PBS intra- abdominal testes; others found decreased numbers.
  23. • Infertility caused by a combination of testicular histologic abnormalities, structural defects of the ducts, and prostatic abnormalities. • No PBS pts.have fathered a child. More recently, paternity achieved by sperm retrieval techniques and intracytoplasmic sperm injection(ICSI). • Normal pregnancy with assisted vaginal delivery- described in a female PBS patient.
  24. EXTRA GENITOURINARY ABNORMALITIES: 75% have non–urinary tract abnormalities
  25. Abdominal wall defect: • Most characteristic feature in newborn- appearance of abdominal wall. • M.c.- uneven involvement, medial and inferior musculature most deficient. • Totally absent abdominal wall musculature, in some cases. • Appearance at birth is that of wrinkled, redundant skin with bulging flanks. Intra- abdominal organs can be discerned through the thinned abdominal wall.
  26. • The most severely affected areas may have skin, subcutaneous fat, and a single fibrous layer on the peritoneum. • More vulnerable to respiratory illness because their cough effectiveness is compromised • Good wound healing. • "Pot-belly" appearance in adults.
  27. Wrinkled abdomen in PBS newborns
  28. Cardiac Anomalies: • Occur in 10% of children with PBS • Patent ductus arteriosus, • Atrial septal defect, • Ventricular septal defect, and • Tetralogy of Fallot.
  29. Pulmonary: • Pulmonary hypoplasia (sec. to severe oligohydramnios related to renal dysplasia or severe bladder outlet obstruction) • Pneumothorax and pneumomediastinum can be seen • Pneumonia and lobar atelectasis( ineff. cough)
  30. Gastrointestinal Abnormalities • 30% of cases. • Result from incomplete rotation of midgut giving way to a wide mesentery • Int. malrotation, volvulus, atresia, stenosis • Splenic torsion • Omphalocele, gastroschisis, and anorectal abnormalities • Chr.constipation and acquired megacolon( sec. to dec. intra abd. pressure)
  31. Orthopedic: • 30% to 45%, • Result from compressive effects of oligohydramnios • Dimpling of lateral aspect of the knees is a common finding. • Talipes equinovarus (26%), hip dysplasia (5%), and congenital scoliosis(4%).
  32. PRENATAL DIAGNOSIS & MANAGEMENT • Prenatal ultrasonography- major role • Fetal hydronephrosis, • Distended bladder, • Irregular abdominal circumference. classic findings 30 weeks
  33. Massively dilated bladder filling most of the abdominal cavity. Note the lack of amniotic fluid.
  34. A dilated bladder with a urachal diverticulum(arrow) and an elongated and dilated posterior urethra
  35. Neonatal Presentation Spectrum of disease
  36. • Cardiac or pulmonary often should take precedence over the urinary tract( in the absence of BOO) Category 1 Category 2 Category 3 Oligohydramnios Marked Moderate to severe mild/nil BOO severe( uret. atresia) nil Pulm Hypoplasia severe mild nil Prognosis succumb within few days / still born variable good Urologic intervention Not usual- cath. drain Mx controversy nil or if rec. UTI/VUR Early reconstr. - for VUR/ red. cystoplasty (after 3 mths age) sx
  37. Adult Presentation • Incomplete forms of PBS- present into adulthood. • Symptoms of renal failure and hypertension. Female Syndrome- 5% • BOO with anorectal anomalies similar to males
  38. EVALUATION & MANAGEMENT • Requires a team consisting of a neonatologist, a nephrologist, and a urologist. • Major initial concern is that of management of cardiac and respiratory issues- do CXR. • Pts.with BOO- SPC initially. • BUN,creat,electrolytes - assess renal insuff, met. acidosis. • S.Creat <0.7 % predictive of adeq.renal function.
  39. • Circumcision is advisable- reduce risk of infant urinary tract infections. • Prophylactic antibiotic therapy is recommended- before VCUG. • VCUG- assess Bladder emptying, outlet( esp. in renal insuff) • Avoid early VCUG - in normal renal function, patent urachus. • DTPA/MAG3 to assess outflow obstruction in massive HN & stasis(4-6 weeks of age).
  40. SURGICAL MANAGEMENT Three components: • Urinary tract reconstruction, • Abdominal wall reconstruction, and • Orchidopexy Supravesical Urinary Diversion • Indications: Repeated upper tract infections or deterioration of renal function. • Cut. Pyeloplasty/ureterostomy( UPJO/UVJO)
  41. Cutaneous Vesicostomy • Indications: Acute renal failure, urinary sepsis, or bladder outlet obstruction from urethral atresia. • OR Excise large urachal diverticulum Internal Urethrotomy • True anatomic obstruction- rare in PBS • Used in "Unbalanced Urethrovesical function"- with large PVR. • Does not result in incontinence.
  42. Reduction Cystoplasty: • Poor bladder contractibility leads to incomplete and infrequent emptying. • Remodeling into a more spherical shape to better direct the contractible forces. • Simple excision of urachal diverticulum or excision of redundant mucosa with overlaping between flaps.
  43. Anterior Urethral Reconstruction: • Urethral atesia/hypoplasia- progresive UD not successful. • Urethroplasty with skin flaps / grafts • Megalourethra- redundant urethra excised, and reconstructed over catheter.
  44. Ureteral Reconstruction: • Indications: Repeated nonsuppressible UTI or with progressive upper tract deterioration. • Ureteral reimplantation may be technically challenging- abnormal bladder.
  45. Orchidopexy: • Timing of orchidopexy- early: to preserve normal hormonal function. • Transabdominal Orchidopexy- at 6 months current approach of choice. • If adequate mobilisation not possible - • Fowler-Stephens orchidopexy(Single or multi-staged) • Microvascular autotransplantation.
  46. Operative photograph showing increased vacularity along vas deferens 4 months after first-stage Fowler-Stephens orchidopexy
  47. Reconstruction of Abdominal Wall: • Mild degree- may show improvement with age. • Benefits- improved bladder emptying, more effective cough and improvement in defecation. • Timing - can be combined with other urinary tract reconstructions, even at 6 months.
  48. Prune-belly syndrome patient demonstrating preoperative appearance of abdominal wall (A), estimated extent of abdominal wall resection (B), and immediate postoperative appearance (C).
  49. A and B, Anterior and lateral views of the abdomen of a 14-year-old boy who underwent major surgical remodeling of the urinary tract during early infancy with good results. Note typical abdominal configuration. C and D, Anterior and lateral views of the same boy 1 month after undergoing abdominoplasty with the technique described by Monfort
  50. Techniques: Randolph Technique- • Transverse incision from 12th rib to pubic symphysis to opposite 12th rib with full- thickness removal of skin, lower abdominal musculature, and peritoneum. • Healthy fascia is then approximated to anterior iliac spines, pubic tubercle, and inferior fascia. • Disadv.- Lateral abdominal bulge persists.
  51. Ehrlich Technique- • Vertical midline incision, preservation of umbilicus on a vascular pedicle from inferior epigastric artery. • Skin and subcutaneous tissues are elevated off the muscle and fascial layers, and • an overlapping, vest-over-pants advancement of each side to contralateral flank is performed, preserving the less affected lateral muscles and fascia.
  52. Monfort Technique- • An elliptically oriented incision isolates the redundant skin, extending from the tip of xiphoid to pubis. A second incision is made around umbilicus to preserve it in situ. • Skin and subcutaneous tissue are dissected off the attenuated fascia and muscle with dissection extending laterally to anterior axillary line. • Vertical fascial incisions are made lateral to superior epigastric arteries, leaving a central fascial bridge. • If intraabdominal surgery is necessary, excellent exposure to urinary tract or abdominal testes is afforded through these lateral fascial incisions. • The lateral fascia is then advanced over central fascial bridge from both sides, alleviating redundancy and increasing thickness of abdominal wall.
  53. Modification of Ehrlich & Monfort technique
  54. LONG-TERM OUTLOOK • If the nadir value is less than 0.7 mg/dL, renal function tends to be stable • 30% of patients- with impaired renal function - develop ESRD at adolscence - need renal transplant.
  55. Thank you !!!