Pediatric Surgery-2 Surgery-2
By Dr. Gulilat
Hir Hirschs schspr prun ung g Dise Diseas ase e • Congenital megacolon • Is developmental disorder of the enteric nervous system system
• HD is characterized by the absence of myent yenteri ericc and submuc submucosa osall ganglio anglion n cell cellss in the distal alimentary tract; resulting in decreased motility in the affected bowel segment.
Hir Hirschs schspr prun ung g Dise Diseas ase e • Congenital megacolon • Is developmental disorder of the enteric nervous system system
• HD is characterized by the absence of myent yenteri ericc and submuc submucosa osall ganglio anglion n cell cellss in the distal alimentary tract; resulting in decreased motility in the affected bowel segment.
Pathophysiology • Hirschsp Hirschsprung rung disease disease results results from from the absence absence of parasympathetic ganglion cells in the myenteric and submuco submucosal sal plexus plexus of the the rectum rectum and/or and/or colon. • Ganglion cells, which are derived from the neural crest, migrate migrate caudally with with the vagal vagal nerve fibers fibers along the intestine. • These ganglion cells arrive in the proximal colon by 8 weeks of gestational age and in the rectum by 12 weeks of gestational age. • Arrest in migration leads to an aganglionic segment.
Pathophysiology Cont. • This absence of normal parasympathatic • • • •
innervation prevents gut peristalsis, leading to functional constipation. The proximal colon hypertrophied by trying to overcome functional obstruction. Transitional zone exists between normal and abnormal aganglionic intestine. Thus failure of the internal sphincter to relax with rectal distention is pathognomonic. Acetylcholine concentrations in aganglionic segments are threefold lower than in ganglionic segments.
Frequency • • •
approximately 1 per 5000 live births. Sex: 4 times more common in males than females. Age: – Nearly all children with Hirschsprung disease are diagnosed during the first 2 years of life. – one half are diagnosed before they are aged 1 year. – Minority not recognized until later in childhood or adulthood.
•
20% have associated abnormalities: Downsyndrome (8%), cardiac defects (8%),genitourinary abnormalities (6%),gastrointestinal abnormalities (4%) Mortality/Morbidity: – The overall mortality of Hirschsprung enterocolitis is 25-30%, which accounts for almost all of the mortality from Hirschsprung disease.
•
Classification
• Classical HD (75% of cases): Rectosegmoid • Long segment HD (20% of cases) • Total colonic aganglionosis (3-12% of cases) • rare variants include the following: – Total intestinal aganglionosis – Ultra-short-segment HD (involving the distal rectum below the pelvic floor and the anus)
Clinical presentation: Newborns : – Failure to pass meconium within the first 48 hours of life – Abdominal distension that is relieved by rectal stimulation or enemas – Vomiting – Neonatal enterocolitis Symptoms in older children and adults include the following: – Severe constipation – Abdominal distension – Bilious vomiting – Failure to thrive
Complicatons Complications of Hirschsprung`s disease include
• intestinal perforation (particularly at the appendix)
• enterocolitis, • water intoxication, malnutrition, failure to thrive, and anemia.
Enterocolitis • Most feared complication of Hirschsprung’s disease • Responsible for much of the associated mortality. • Enterocolitis is rare (10%) in the first month but rises to 33% in the second and third months.
Clinical signs and symptoms: • Early: Abdominal distention, borborygmus, diarrhea. • May progress to fever, emesis, explosive diarrhea, fluid/electrolyte disorders, gram negative sepsis, colonic perforation. • Recall that diarrhea may be a late sign.
diagnostic workup • • • •
Plain abdominal radiography Contrast enema Manometry Biopsy
Diagnosis • Diagnosis should be suspected on rectal exam when the rectal vault is found devoid of stool and the anal canal feels narrow with increased tone.
• KUB often shows gaseous distention, in the neonate absence of gas in the pelvis is suggestive.
Diagnosis • Barium enema will reveal a transition zone with narrow segment and dilated proximal portion. Late films will show retention of barium at 24- 48 hours.
• Rectal biopsy is the most reliable diagnostic measure.
Abdomenal X-Ray • Dilated bowel • Air-fluid levels. • Empty rectum
barium enema • Transition zone • Abnormal, irregular contractions of aganglionic segment
• Delayed evacuation of barium
Ba-enema- delayed emptying
Manometry Absence
of normal relaxation of the internal sphincter when the rectum is distended with a balloon.
Biopsy • Types: – rectal suction biopsy – full-thickness rectal biopsy.
• In HD, the biopsy reveals: – absence of ganglion cells – hypertrophy and hyperplasia of nerve fibers, acetylcholinesterase-positive nerve fibers in the – increase in acetylcholinesterase-positive lamina propria and muscularis mucosa.
treatment • The treatment is surgical removal or bypass of the aganglionic bowel, • This can be performed by means of:
– preliminary colostomy followed by a definitive pull-through procedure or, procedure. – primary definitive procedure.
•
Examples Examples include: – Soave pull-through procedure, – Duhamel procedure, – Swenson procedure.
Entrocolitis Rehydration, intravenous antibiotics and colonic irrigations. Enterocolitis mandates emergent diverting colostomy
Post-operative Complications • Early : Anastomotic leak Infection
• Late
: Obstruction Enterocolitis Incontinence
Anorectal Anomalies • Incidence 1/1500 live births • Failure of separation of GU sinus and hindgut at 5-6weeks. • Classification: high/low, Describe defect • 90% have a fistula • 10% rectal atresia without fistula: Down’s syndrome
Anorectal malformations The cloaca
(which is a common chamber into the hindgut and allantois)
Separated into:
The bladder
post-allantoic gut (rectum) Proctadeum (epiplastic bud)
Downward growth of a septum
Fusion during the 3rd month of intrauterine life when there is imperfect fusion
imperforate anus
Imperforate anus • Includes agenesis and atresia of the rectum and anus • Etiology: unknown • Incidence: 1 in 5000 • SEX: 60% male
Imperforate anus Low abnormalities
High abnormalities
Termination of bowel below the pelvic floor
Termination of bowel above the pelvic floor
Easy to Dx
Often have a fistula into the urinary tract with deficient pelvic floor
Simple to ttt Outlook is good
Difficult to ttt 1)Covered anus 2)Ectopic anus 3) Stenosed anus 4)Membranous stenosis
1)Anorectal agenesis 2)Rectal atresia 3)cloaca
1)Covered anus Anal canal covered by a bar of skin with a track running forwards to the perineal raphe. This track is called “Bucket Handle” midline Raphe fistula.
2)Ectopic anus Anus situated anteriorly in ♂, it opens in perineum in ♀, it opens in vulva
(more commonly)>>
or vagina (rare)
vulval ectopic anus
3)Stenosed anus i.e. microscopic anus There is a minute opening that can be seen if examined carefuly
4)Membranous stenosis • Rare • Anus is
normally sited
covered with a thin membrane that bulges with retained meconium
High abnormalities Could be associated with: a fistulas connection between the blind rectal stump and the bladder or other pelvic structures abnormalitie
1)Anorectal agenesis • Rare • Blind rectal pouch lies just above the pelvic floor anterior aspect attached to the bladder & often there • In ♂ is a rectovesical fistula or rectourethral fistula (manifested by passage of gas or meconium in the urine) or perineal fistula fistula to the vestibule or posterior fornix >> • In♀ rectovestibular (or rectovaginal) low RVF easy to correct postop. Function is good high RVF difficult to correct postop function is poor
2)Rectal atresia • Rare • Anal canal is normal but ends blindly at the level of pelvic floor & the rectum also ends blindly above the pelvic floor without a fistulas opening.
3)cloaca • Occurs only in ♀ • Bowel, urinary & genital tracts all open into a common wide cavity
• Commonly associated with other developmental abnormalities e.g. tracheoesophagial fistula
History • Failure to pass meconium within the 1st 24 hours of life.
• Patients with anterior ectopic anus may present in childhood or in adulthood. These patients have lifelong histories of constipation and painful defecation and usually have required laxatives or enemas for management.
Examination Inspection alone is sufficient for management plan in 90% of patients. Low •Bucket handle defect •Gas/meconium from perineum •Perineal fistula if skin bridge between vestibule and fistula. •Anterior ectopic anus i.e. normal sized anus surrounded by normal muscle. •Urine free of meconium (NB average of 20 hrs for meconium to appear in urine).
High •Flat bottom •Short sacrum •Little muscle contraction •Meconium per urethra •Rectovestibular fistula if within mucosal margin of the vestibule. •Sphincter located close to the scrotum or bifid scrotum often associated with a Prostatic Fistula. •Cloacae are often missed if urethral opening is not identified in female with a “recto-vaginal” fistula. •Furthermore, cloacae often have small openings and may be a cause of referral for ambiguous genitalia.
Differential Diagnosis of Conditions That May Be Associated with Failure to Pass Meconium in the Newborn •
Hirschsprung's disease >>Tight anus, empty rectum, transition zone
•
Meconium plug syndrome >> Meconium plugs
•
Meconium ileus >> Abdominal distention at birth, cystic fibrosis
•
Anorectal malformation >> Absent anus, tight anus or fistula
•
Small left colon syndrome >>Transition zone* at splenic flexure
•
Hypoganglionosis >> Transition zone*
•
Neuronal intestinal dysplasia type A >>Transition zone*, mucosal inflammation
•
Neuronal intestinal dysplasia type B >> Megacolon
•
Megacystis-microcolon-intestinal hypoperistalsis syndrome >> Microcolon, megacystis
*--Transition zone (from small- to large-diameter bowel) refers to radiographic visualization on contrast study.
Investigation Very Important to: 1. Exclude other anomalies!! 2.Determine whether abnormality is high or low!!
1. Exclude other anomalies!! • Anal atresia may occur as a part of the VACTERL group of anomalies V Vertebral body segmentation defect A Anal atresia C Cardiovascular (PDA, VSD) TE Tracheo esophagial fistula R unilateral Renal agenesis L Limb anomaly (radial ray hypoplasia) So, very careful examination of the baby must be made to exclude these anomalies
Associated abnormality
Investigation
"V" Vertebral Abnormality (butterfly vertebrae, hemi-vertebrae)
Spinal ultrasound, Spinal x-ray
"C" Cardiac, Heart Abnormality Cardiac ECHO (VSD, ASD, PDA)
Cardiac ECHO
"R" Renal, Kidney abnormality (solitary Renal ultrasound, Voiding cystokidney, horse shoe kidney) urethra-gram (VCUG) "TE" tracheoesophogeal abnormality (TEF)
Physical examination, X-rays
"L" Limb deformity
Physical examination, x-rays
2.Determine whether abnormality is high or low!! 1)Invertogram: •
with a metal button or a coin strapped to the site of the anus or a metal bougie inserted into the blind anal canal. • Infant is held upside down for 3-4 minutes • Then radiograph in the inverted lateral position ( both the greater trochanters should be on the same line) • The gas in the rectum will rise to the top indicates the distance between the site of the metal indicator and the blind end of the rectum >>> if the distance > 2.5 cm, the abnormality is high!! • if the rectum ends above the PC line (pubococcygeal line = from the symphysis pubis to the last vertebra), the abnormality is Low & vise versa or according to ischeal line (between ant.-sup. Iliac spines). When to be done? Although it is a useful method, sometimes vitiated by a plug of meconium in the rectum causing an apparent gap far in excess of that actually present. So, it may be necessary to wait until the baby is 24 hrs old before rectal gas appears
Metal button
PC line
gas in the rectum
2)Urine culture: Presence of meconium Presence of proteus or pseudomonas usually signifies that a fistula is present
3)US: To evaluate the lesion type
4)MRI: If we suspected complex malformation
5)Micturating cystourethrogram: By injecting a dye in the urethra
Treatment of Low abnormalities: Medical Keep NPO IV rehydration. Treat life treatening condition 1st . If urinary fistula suspected Broad spectrum antibiotics.
Surgical treatment. 1)Covered anus: The track should be opened by scissors Followed by routine dilatation of the anus 2)Ectopic anus: Plastic “cut-back” operation 3)Stenosed anus: Regular dilatation
Treatment of High abnormalities: Very difficult problem & each case must be considered on its merits The possibilities are: • Two-stage operation: 1st stage laparotomy Division of rectourethral fistula Transverse colostomy 2nd stage rectal “pull-through” operation • One-stage operation: laparotomy Division of fistula “pull-through” operation • Division of fistula & rectal “pull-down” operation through the perinum ( know rarely used)
Surgical therapy • Colostomy • Definitive repair
Colostomy Newborn boys • • • • •
Rectobulbar urethral fistula rectoprostatic urethral fistula rectovesical fistula imperforate anus without fistula rectal atresia
Newborn girls Colostomy • • • • •
Rectovestibular fistula imperforate anus without fistula persistent cloaca rectal atresia rectovaginal fistula
COLOSTOMY
Cont. Treatment of High abnormalities:
• The new technique is post-sagittal rectoplasty (PSARP)
• colostomy only ( for cloaca)
PSARP
Prognosis In high % of cases, imperforate anus is associated with other congenital abnormalities especially of the urinary organs & nearly 50% of deaths in cases of imperforate anus are due to other malformations
In a Summary • 1 opening >>> Cloaca • 2 openings >>> anorectal agenesis with rectovaginal •
• • •
fistula 3 openings >>> ectopic anus, stenosed anus, membranous anus, rectal atresia or even normal anus!!! The most important investigation is the invertogram It is very important to rule out other anomalies The best & the newest operation is PSARP
Cloaca
Anorectal agenesis and rectovestibular fistula.
Anourethral fistula
imperforate anus and a rectoperineal fistula .
imperforate anus and a bucket-handle malformation
Covered anus
