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GS64 General Surgery and Thoracic Surgery
Pediatric Surgery
Toronto Notes 2019
Condition
Hirschsprung’s Disease
Epidemiology and Risk Factors
1:5000 births
M:F = 3:1 to 4:1, approaches 1:1 when whole colon involved Can have aganglionosis of small bowel as well Familial Hirschsprung’s in <5% of cases
2-5% of term males – most of these descend spontaneously by 6mo of age
1% of males do not spontaneously descend Suspect in prematurity
Most common cause
of bowel obstruction between 6-36 mo 26:100,000 newborns M:F = 3:2
Pathologic lead points: enlarged Peyer’s patches due to viral infections
of the GI tract, polyps, Meckel’s diverticulum CF, lymphoma, IBD may increase risk
1:3,000-1:4,500
5% of all term newborns 2x risk and more likely bilateral if pre-term M:F = 4:1
Low birth weight increases risk
1/5 inguinal hernias will become incarcerated if patient is <1 yr Incarceration is more common in females Associated with other conditions: androgen insensitivity, connective tissue diseases
Pathophysiology
Defect in migration
of neurocrest cells
to intestine resulting
in aganglionic bowel that fails to peristalse and internal sphincter that fails to relax (internal anal sphincter achalasia) causing functional and partial mechanical obstruction, respectively; always starts in the rectum and variable involvement proximally; RET mutation
Idiopathic
Descent is mediated by descendin which is created in response to testosterone
Descent usually begins at 28 wk
Idiopathic is most common
Usually starts at ileocecal junction Telescoping of bowel into itself causing
an obstruction and vascular compromise
Associated anomalies in 50%: VACTERL association
All infant hernias
are indirect: descent of intra-abdominal contents through the internal inguinal ring through a patent tunica vaginalis
Inguinal hernia can be reducible, incarcerated (unreducible), or strangulated
Clinical Features and History
Failure to pass meconium spontaneously within 48 h of life is the classic history (95% pass meconium within 24h, 5% within 48h)
Symptoms of bowel obstruction: abdominal distension, constipation, bilious emesis Enterocolitis/sepsis
Failure to thrive
Palpable testicle within inguinal canal or testicle which can
be milked down into scrotum (called retractile testis) Occasionally no palpable testis as it is intra-abdominal Consider other congenital abnormalities
Acute onset of abdominal
pain which is classic episodic “colicky” pain
Vomiting ±bilious
Abdominal mass
Currant-jelly stool suggests mucosal necrosis and sloughing
Varies with type of fistula
May have history of maternal polyhydramnios May present after several months (if no associated esophageal atresia) of non-bilious vomiting, coughing, cyanosis with feeds, respiratory distress, recurrent pneumonia, frothy bubbles of mucus in mouth and nose that return after suctioning
Most common presentation: painless intermittent mass in groin, may also note extension into scrotum (scrotal mass in absence of inguinal mass is a hydrocele)
If incarcerated: tender, vomiting, firm mass, erythema then cyanosis of mass may be noted
Physical Exam
±abdominal distension Squirt/blast sign
Investigations
Treatment
Prognosis
Most have normal/ near-normal anorectal function Complications: decal incontinence and constipation, post- operative enterocolitis (medical emergency if progresses to sepsis)
Orchidopexy Decreased risk of torsion and blunt trauma to testicle
No effect on malignant potential of testicle Descent can preserve spermatogenesis if performed by 1 yr
10% recurrence rate
If recurrent =more likely non-idiopathic
If successfully reduced by enema in older children allow 2wk resolution of edema then perform SBFT to rule out pathologic lead points
Complications: pneumonia, sepsis, reactive airways disease Following repair: esophageal stenosis and strictures at
repair site, GERD
and poor swallowing (i.e. dysphagia, regurgitation)
Risk of recurrence after surgical reduction <3% but higher if repair done in premature infants or if hernia was incarcerated/ strangulated at repair
Cryptorchidism
Intussusception
Scrotal asymmetry Bi-annual testicular exam with palpation Distinguish truly undescended testis from retractile testis (which
is “high” testis due to hyperactive cremasteric muscles)
Abdominal exam
Palpate for masses (especially sausage shaped upper abdominal mass) and tenderness
Signs of bowel obstruction: distended abdomen
Look for localized peritonitis which suggests transmural ischemia
Rectal biopsy (gold standard) – look for aganglionosis and neural hypertrophy
AXR
Contrast enema to find narrow rectum and transition zone
Anal manometry unreliable in infants – classic finding is absence of rectoanal inhibitory reflex
Depends on age of presentation
Older child: LH, FSH, MIS, hCG stimulation test for gonadotropin production Infant: U/S, FSH,
LH, karyotype, MIS, 17-hydroxy-progesterone
If non-palpable: Exam under anesthesia, exploratory laparoscopy
AXR for signs of bowel obstruction or perforation U/S if suspect pathology
X-ray: anatomic abnormalities, NGT curled in pouch
Physical exam is gold standard
U/S only if physical exam uncertain (e.g. in small infants where exam can be difficult)
Duhamel pull-through procedure: surgical resection of aganglionic intestinal segment
and anastomosis of remaining intestine
to anus
Either in newborn period or staged if extensive aganglionosis
hCG to stimulate testosterone production and descent Orchidopexy – especially if undescended by age
6 mo-2 yr
If peritonitis, then consider operative management Non-operative management involves reduction via air contrast enema
Operative reduction can be done open or laparoscopically Resection of involved colon if failure to reduce or bowel appears compromised
Investigate for other congenital anomalies, early repair by surgical ligation to prevent lung damage and maintain nutrition and growth
Manual reduction – in the ER to relieve acute symptoms (then repair) For reducible hernia: repair within a few weeks (if <1 yr) vs. elective repair (if >1 yr)
For incarcerated hernia: repair immediately (emergency) Herniorraphy – definitive treatment by reduction of herniated contents and high ligation of sac for indirect hernias Laparoscopic or open techniques
Tracheoesophageal Fistula (TEF)
Inguinal Hernias
Palpate for “bag of worms” suggests possible testicular varicocele
Biannual testicular exam + palpation along inguinal canal to evaluate for any masses “Silk sign” – palpable thickening of cord
Mass palpated at external inguinal ring and reducible through inguinal canal into abdomen
Must always try reduction to confirm that hernia is not incarcerated
All inguinal hernias of infancy and childhood require repair at the earliest convenience; emergent repair if incarcerated/strangulated