Ryan Em C. DalmanMD MBA

 Present a case of Imperforate Anus  Discuss the pathophysiology and management of Imperforate Anus

Patient History

 Live preterm baby boy, born via primary CS for non-reassuring-fetal-heart-rate pattern and IUGR, at 35 weeks AOG, born on January 25, 2011

 30 year-old G3P1 (0121)  Pre-ecclampsia  Maternal PMH: unremarkable

 1 st trimester  Premature contractions—admitted for 1 week, given duphaston  2 nd trimester  UTI by urinalysis 3x, given 7 days unrecalled antibiotics for each week  ~30weeks AOG, BP 150/100, started on methyldopa 250mg BID  BP at home was uncontrolled  3 days PTA, (+) headache, methyldopa increased to 500mg q6h, but was persistent and was admitted

 unremarkable

Physical Exam

 BW 1040g  BL 35 cm  HC 28 cm  AC 21 cm  AS 9,9  MT 35 weeks, AGA

 Active, good cry  Fontanels - flat  Pupils - brisk  Muscle tone - normal  Strength of extremities- normal  Extremities – no deformities  Chest expansion- normal  Breath sounds clear and equal  Abdomen - soft  Anus - imperforate  Spine – intact  Color - pink  Cord - dry  Skin - clear  Pulses - strong  CRT <3 sec  Edema - none

Case Discussion

 Imperforate anus

 None  There is no differential diagnosis for an imperforate anus

 Abnormal termination of the anorectum  Ranges from anal stenosis to persistence of cloaca  Most common defect  Imperforate anus with a fistula between the distal colon and urethra in boys or the vestibule of the vagina in girls

 Associated anomalies: VACTER-L  Vertebral  Anal  Cardiac  Tracheal  Esophageal  Renal  Limb

 Male defects:  Perineal Fistula – rectum opens in the perineum  Rectourethral bulbar fistula – rectum communicates with the lower posterior portion of the urethra called bulbar

 Female defects:  Perineal Fistula – rectum opens in the perineum  Vestibular fistula – rectum opens through an abnormally narrow orifice located in the vestibule of the genitalia immediately outside the hymen

 Female defects:  Rectovaginal Fistula – fistula between rectum and vagina

 Pathophysiology  Embryogenesis of malformations still unclear  Rectum and anus develop from hindgut or cloacal cavity when lateral ingrowth of the mesenchyme forms the urorectal septum in the midline.  Bladder&urethra  septum  rectum&anal canal  Cloacal duct – small communications bet. these 2 ▪ Should close by 7 th week of gestation

 Pathophysiology  Ventral urogenital external opening forms first; dorsal anal membrane opens later  Anal development ▪ Fusion of the anal tubercles and an external invagination (proctoderm) which deepens toward the rectum but separated from it by an anal membrane ▪ Anal membrane should desintegrate by 8 th week

 There are known risk factors that predispose a person to have a child with imperforate anus  A genetic linkage is sometimes present

 CBC, blood typing and screening  Presence of meconium in the urine (males)  Filtering with a gauze pad  Urinalysis ▪ If a patient has perineal fistulas, vestibular fistula, or a single patent orifice, UA is unot indicated

 Invertogram  Cross table lateral on prone position

 Prone cross table buttocks with elevation

 Abdominal Ultrasound  Visualized liver, gallbladder, kidneys  Obscured pancreas probably due to overlying bowel gas  Undefined gallbladder  Bilateral hyrocoele, both testicles within scrotal sac  Minimal ascites  No frank congenital problems on solid organs

 Medical  NPO, IV hydration  Treat other life-threatening co-morbidities first  If urinary fistula is suspected, give broad- spectrum antibiotics

 Invertogram  < 1cm: Immediate Anoplasty  > 1cm: colostomy, then definitive surgery after a few months  Males with meconium in urine: colostomy, then definitive surgery after a few months

 1 newborn per 5000 live births (US)

 All patients with anorectal malformations with no significant life-threatening co- morbidities should survive  Prognosis best determined by the probability of primary fecal incontinence