CHAPTER 29: Surgery

Disorder characterized by pulmonary hypoplasia due to intrauterine compression of the developing lungs by herniated viscera.

EPIDEMIOLOGY

• Incidence is 1000 per year (1:2000–1:5000 live births); female:male 2:1

• 7–10% gestations end in fetal demise

• Defects more common on left side (about 80%)

• Associated with anomalies (10–35%) including: Central nervous system (CNS) lesions, tracheobronchial abnormalities, omphalocele, cardiovascular (CV) lesions, skeletal and syndromes (trisomy 13, 18, 21, Beckwith–Weidemann, Brachmann–de Lange, and Pallister–Killian, among others)

ETIOLOGY

• Unknown currently, though several pharmacologic and environmental factors have been implicated, including a possible role for vitamin A deficiency and/or retinoid regulated gene defects

• Embryologic theory: Lack of closure of the posterolateral pleuroperitoneal canals in the 8th week of gestation fails to separate the thoracic and abdominal cavities

• Portions of the diaphragm and pulmonary parenchyma arise from thoracic mesenchyme and if disrupted may lead to absence of part of hemidiaphragm and pulmonary hypoplasia

• Most cases are sporadic; familial cases occur (2%)

DIFFERENTIAL DIAGNOSIS

• Cystic adenomatoid malformation, cystic teratoma, pulmonary sequestration, bronchogenic cyst, neurogenic tumors, primary lung sarcoma, diaphragmatic eventration

PATHOPHYSIOLOGY

• Herniation of abdominal contents into thoracic cavity through posterolateral foramen of Bochdalek

• Diaphragmatic defect may be small or may include entire hemidiaphragm

• Pulmonary vasculature has increased muscularization of pulmonary arterioles and decreased branching of vessels resulting in pulmonary hypertension

• Lungs are hypoplastic due to chronic compression, with decreased numbers of bronchial branches on both ipsilateral and contralateral sides

CLINICAL MANIFESTATIONS

• Most patients present with respiratory distress within the first hours of life secondary to severe pulmonary hypoplasia and associated pulmonary hypertension

• 10–20% may have delayed presentation characterized by less severe pulmonary hypoplasia and pulmonary hypertension, as well as gastrointestinal (GI) symptoms (e.g., vomiting, abdominal pain, constipation)

• Pneumothorax

• On exam: Absence of breath sounds; bowel sounds in chest; scaphoid abdomen; increased anterior-posterior diameter of chest; shifted heart sounds

DIAGNOSTICS

• Prenatal ultrasound able to detect defect as early as 11th week, mean gestational age (GA) at diagnosis is 24 weeks; accuracy has been reported to be between 40 and 90%

• Antenatal diagnosis is associated with more severe defects and a worse prognosis; if diagnosed by ultrasound, fetal MRI should be performed

• During fetal period, a lung-head ratio (LHR, area of contralateral lung to fetal head circumference by ultrasound) of <1 indicates severe disease

• Observed-to-expected LHR (O/E LHR) accounts for changes in LHR with GA, and O/E LHR <25% suggests severe CDH

• Echocardiography and amniocentesis to detect other anomalies

• Chest x-ray

MANAGEMENT

Initial Medical Management

• Initial resuscitation includes correction of hypoxia, hypercarbia, acidosis, and hypothermia as they increase pulmonary vascular resistance and worsen pulmonary hypertension

• Intubate early to avoid inflation of the stomach with bag-mask ventilation

• Nasogastric decompression to decrease bowel distension

• Umbilical arterial and venous lines should be placed in severe cases

• Peripheral oxygen saturations and/or blood gases should be obtained to determine adequacy of gas exchange

• Echocardiography to determine cardiac anomalies and determine severity of pulmonary hypertension and shunting

• Permissive hypercapnia and gentle ventilation may improve survival and decrease need for extracorporeal membrane oxygenation (ECMO); avoid paralysis

• Surfactant has not been clearly shown to improve outcomes

• Response to nitric oxide is inconsistent

• Persistent right-to-left shunting may require ECMO

Surgical Management

• Repair typically performed “electively” (age 3–15 days) when/if clinically stable

• Abdominal surgical approach most common. Large defects may require the use of a synthetic patch or muscle flap. Minimally invasive approaches (both laparoscopic and thoracoscopic) have been utilized successfully in selected candidates

• In-utero reduction and repair have been successfully performed but have not consistently shown to benefit survival. Trials of fetoscopic tracheal occlusion are underway

Prognosis

• Poor prognosis seen with “liver up” CDH, associated major anomaly, symptoms prior to 24 hours, distress requiring ECMO, delivery in nontertiary center and bilateral defects

• Survival 60–97% with initial stabilization, then surgical repair

• Long-term sequelae may include neurodevelopmental problems, gastroesophageal reflux, nutritional deficiencies, skeletal anomalies, and bronchopulmonary dysplasia

• CDH lungs never reach normal alveolar number or structure, leading to persistent risk of emphysema, pneumonia, bronchiolitis, and pulmonary hypertension

Anatomic lesions, which may be congenital or acquired and involve a blind pouch of the esophagus, are often associated with a fistula to the trachea.

EPIDEMIOLOGY

• Esophageal atresia seen in 1:2500–4500 live births

• 90% of infants with esophageal atresia have an associated tracheoesophageal fistula (TEF)

• Associated with trisomy 18 or 21, DiGeorge, Feingold, Pierre Robin and Potter syndromes, among others

• 30% of affected infants are born prematurely

• Associated anomalies in greater than 50%: Musculoskeletal (rib and vertebral anomalies), cardiovascular, GI (duodenal atresia, intestinal malrotation), GU (choanal atresia): VATER association (Vertebral and Vascular, Anal, Tracheal, Esophageal, Radial, Renal) or VACTERL association (Vertebral, Anal, Cardiac, Tracheal, Esophageal, Renal, Limb), CHARGE association (Coloboma, Heart disease, choanal Atresia, Retarded growth and development, Genital hypoplasia, and Ear anomalies)

PATHOPHYSIOLOGY (FIGURE 29-1)

• Esophageal atresia with distal TEF: Most common type (>85% cases). Proximal esophagus is dilated and thickened, and ends around level of third thoracic vertebra. Fistula at distal esophageal segment enters back wall of lower trachea (Figure 29-1)

• Pure esophageal atresia (without TEF): 3–5% of cases. Proximal esophageal pouch ends around third thoracic vertebrae and distal pouch is usually short

• Isolated TEF without atresia: 3–6% of cases. “H”-type fistula; level of thoracic inlet. Majority of fistulas are single

• Esophageal atresia with proximal fistula: 2% of cases; narrow and short fistula

• Esophageal atresia with fistulas to upper and lower tracheal segment: 3–5% of cases. Similar to most common type with additional short, narrow fistula from proximal pouch to trachea

CLINICAL MANIFESTATIONS

• Association with polyhydramnios, though uncommonly diagnosed prenatally

• May present shortly after birth with excessive secretions and need for frequent suctioning because infant is unable to swallow secretions

• May have aspiration events

• Feeding leads to immediate regurgitation with choking, coughing, and sometimes cyanosis

• Detection of H-type fistula may be delayed

DIAGNOSTICS

• Typically noted by the inability to pass a naso/orogastric tube to the level of the stomach

• x-ray will show coiled catheter in upper esophageal pouch

• Air in abdomen on x-ray confirms a distal TEF; gasless abdomen is evidence of esophageal atresia without distal fistula

• Contrast studies of upper esophagus are not routinely necessary, except to diagnose “H”-type

• Echocardiogram and renal ultrasound to evaluate for associated abnormalities

• “ H”-type is more difficult to diagnose and often presents (beyond the newborn period) with history of recurrent pneumonia

• Rigid bronchoscopy provides definitive diagnosis

MANAGEMENT

• Avoid pneumonia from aspiration of upper pouch secretions—Use double lumen repogle tube and position patient to maximize drainage

• Surgical repair is either primary or staged

• Staged repair: Usually reserved for critically ill or very low birthweight neonates and involves initial ligation of fistula and placement of gastrostomy tube for feeding followed by future esophageal anastomosis

• Contrast swallow should be done 4–7 days after anastomosis to evaluate for anastomotic leak. Oral feedings are then initiated

• Complications: Dysphagia, anastomotic stricture, tracheomalacia, airway obstruction, vascular compression, reflex apnea

• Morbidity and mortality in neonates are related to cardiopulmonary comorbidity

Derived from Greek word meaning “belly cleft,” a defect in the abdominal wall lateral to the intact umbilical cord

EPIDEMIOLOGY

• Incidence 2–5:10,000; male>female

• Associated with young maternal age, low socioeconomic status, maternal smoking, alcohol use, medications (aspirin, ibuprofen, acetaminophen, pseudoephedrine)

• Occasionally associated with intestinal atresia, volvulus, and/or perforation; “complicated gastroschisis” carries a worse prognosis

ETIOLOGY

• Postulated to be result of vascular accident during embryogenesis

• Recent studies suggest a possible inherited tendency

PATHOPHYSIOLOGY

• In utero, abdominal viscera herniate through abdominal defect lateral to the umbilicus (usually to the right) and float in the amnion

• Contains midgut and may contain stomach and/or gonad

• Normal bowel rotation and fixation do not occur

CLINICAL MANIFESTATIONS

• Herniation of viscera through lateral abdominal wall, with or without a skin bridge between the cord and the defect

• Intact umbilical cord

• Absence of peritoneal sac covering bowel

MANAGEMENT

• Delivery may be vaginal or cesarean section

• Protect exposed viscera with saline-moistened sterile wraps or plastic bag immediately

• May need fluids 2.5–3.0 times above maintenance rate because of increased losses

• Up to 75% may be candidates for primary surgical closure performed when clinically stable

• Remaining 25% have prosthetic, extra-abdominal compartment or “silo,” which allows for gradual manual reduction

• Postoperative complications include prolonged ileus, parenteral nutrition-related cholestatic liver disease, sepsis, and necrotizing enterocolitis

PROGNOSIS

• Survival ≥90%

Most common cause for neonatal intestinal obstruction, including complete discontinuity of the small bowel, severe stenoses, and webs.

EPIDEMIOLOGY

• Duodenal atresia incidence 1:6000–10,000 births

• Jejunoileal atresia incidence 1–2:10,000 births

• Up to 50% of affected infants with duodenal atresias may have another congenital anomaly, compared with 25–35% of those with jejunoileal atresias

• Often associated with trisomy 21, annular pancreas, malrotation, congenital heart disease, esophageal atresia, and anorectal malformations

ETIOLOGY

• Duodenal atresia thought to result from failure of recanalization following obliteration of the intestinal lumen after the 6th week of gestation—85% occur in second part of duodenum (Table 29-1)

• Jejunoileal atresias likely reflect mesenteric vascular compromise in later gestation (Table 29-1)

CLINICAL MANIFESTATIONS

• Presentation may be variable depending on level of obstruction; polyhydramnios/emesis more common with proximal obstruction, abdominal distention more common with distal obstruction

• Most prenatally diagnosed atresias are duodenal

DIAGNOSTICS

• Plain x-ray findings for duodenal atresia include “double bubble” appearance

• Jejunoileal atresias often show dilated proximal loops of bowel with air/fluid levels

• In duodenal atresia, echocardiography and renal ultrasonography should be performed to evaluate for other midline defects

MANAGEMENT

• Gastric decompression to minimize bowel distention is imperative; note presence of bile in aspirate

• Intravenous fluid resuscitation should be provided and basic laboratory tests obtained

• Operative repair should be undertaken as soon as can safely be performed; duodenoduodenostomy is routinely performed for duodenal atresia, and treatment of jejunoileal atresia may vary depending on the nature of the bowel defect

• All patients should be evaluated for malrotation and volvulus, and Ladd’s procedure should be performed if present. If malrotation cannot be excluded, laparotomy should be pursued

• Tapering enteroplasty may be necessary in the setting of significant size mismatch between proximal and distal limbs

• Evaluate for multiple atresias

A central defect of the umbilical ring through which bowel and abdominal viscera herniate. The abdominal contents are covered with a membrane composed of the inner layer of peritoneum fused to outer layer of amnion.

EPIDEMIOLOGY

• Occurs in 1:2500–5000 live births

• Up to 30–50% of affected infants have associated karyotypic anomaly (e.g., trisomy 13 or 18)

• Can be associated with Beckwith–Wiedemann and pentalogy of Cantrell (combination of severe defects of the sternum, heart, diaphragm, and abdominal wall)

• Greater than 50% have other malformations: cardiovascular anomalies most common; also renal, skeletal, neural tube, sternum, diaphragm, and bladder

• 10% have “giant” omphalocele where liver and intestine herniate through an 8- to 10-cm defect

PATHOPHYSIOLOGY

• Failure of migration and fusion of embryonic folds

• Most are lateral fold defects, and all involve the umbilicus

• Failure of the gut to migrate from the yolk sac to the abdomen

• Extruded abdominal contents (may contain midgut, liver, spleen, and/or gonad) are covered by a two-layered membrane; umbilical cord inserts into membrane

• Size >4 cm and contents distinguish omphalocele from umbilical cord hernia

DIAGNOSTICS

• Detected in second trimester ultrasound

• Associated with increased α-fetoprotein (AFP) and acetylcholinsesterase in maternal serum and amniotic fluid

• Amniocentesis: To evaluate for associated chromosomal abnormalities

MANAGEMENT

• May be delivered vaginally or via cesarean section

• Cover exposed membranous sac with sterile saline-soaked dressings to prevent heat and fluid losses

• Correct fluid and electrolytes preoperatively

• Extra-uterine echocardiogram before surgical repair to evaluate for cardiac defect

• Surgical primary repair when possible. Staged closure for large defects

• Nonoperative techniques include placement of a “silo” for sequential reduction or use of eschar-producing agents (“paint and wait”) when primary repair is not possible due to loss of abdominal domain

PROGNOSIS

• Survival 70–95%

• Mortality is generally related to comorbidities

Inflammation of the appendix caused by obstruction of the appendiceal lumen. Classically difficult to diagnose in children, because typical signs and symptoms may be absent in more than half of the patients presenting to the emergency department.

EPIDEMIOLOGY

• Approximately 1 in 12 people will have appendicitis in their lifetime, occurs in 1/1000 children per year

• Peak incidence in adolescence, uncommon in children younger than 5 years of age

• Slight male predominance

DIFFERENTIAL DIAGNOSIS

• Mesenteric adenitis, bacterial enterocolitis (especially with Yersinia enterocolitica and Campylobacter jejuni), intussusception, Meckel’s diverticulitis, urinary tract infection, right lower lobe pneumonia, testicular torsion, and gynecologic etiologies such as ectopic pregnancy, ovarian torsion, and pelvic inflammatory disease

PATHOPHYSIOLOGY

• The appendix is a blind pouch that can be obstructed by fecaliths, hypertrophied lymphoid follicles, parasites, or foreign bodies

• Can also have bacterial invasion without previous obstruction

• This closed-loop obstruction causes edema, inflammation, and vasocongestion, which lead to necrosis and perforation

• Once this process starts, children are more prone to earlier perforation and development of peritonitis than adults

CLINICAL MANIFESTATIONS

• Classically, pain begins in periumbilical region and moves to right lower quadrant (RLQ), nausea, vomiting, anorexia, and fever; presentation can be variable, especially in younger children

• Can have dysuria

• In children, particularly younger than 2 years, clinical signs can be more vague and misleading and can include irritability, upper respiratory infection symptoms, lethargy, abdominal rigidity, or refusal to walk

• Perforation usually occurs 36–48 hours after symptom onset and should be considered in context of patient with persistent symptoms, high fevers, and peritoneal signs

• Abdominal tenderness: Typically in the RLQ; can also be diffuse

• Bowel sounds usually normal or hyperactive, occasionally hypoactive but are unreliable

• Coughing, driving over a bump, or standing on the toes and dropping the heels may worsen the pain (indicative of peritonitis)

• Presence of one or more of the following may suggest appendicitis (few pediatric studies):

  • ✓ Rovsing’s sign: Palpation of left lower quadrant (LLQ) causes pain in RLQ

  • ✓ Psoas sign: Patient flexes right hip against resistance. Increased abdominal pain indicates positive sign

  • ✓ Obturator sign: Raise patient’s right leg with the knee flexed. Rotate the leg internally at the hip. Increased abdominal pain indicates a positive sign

• Rectal exam can show rectal masses, abdominal abscesses, or right-sided rectal tenderness, but is often nonspecific and not necessary in most cases

• Guarding and rebound more likely with perforation

DIAGNOSTICS

• Difficult to diagnose, particularly in young children

• 3–6% overall negative appendectomy rate, though rates are considerably higher in children under 5 (15–25%) and somewhat higher in females (5–10%) versus males (1–5%)

• Can be diagnosed on basis of history and physical exam alone, but adjunctive radiologic studies often helpful

  • ✓ Abdominal flat plate films have limited utility. Findings include fecalith, localized ileus, soft tissue mass, splinting, loss of peritoneal fat stripe, or free air

  • ✓ Ultrasound can be diagnostic; sensitivity and specificity vary among studies. Findings include increased appendiceal diameter or thickened wall, target sign, echogenicity surrounding the appendix, appendicolith, pericecal or perivesical free fluid

  • ✓ CT has sensitivity of 87–100% (increased with oral and rectal contrast) and specificity of 83–97%. Findings include fat streaking, increased appendiceal diameter, cecal apical thickening

• Concerns about risk of malignancy following exposure to ionizing radiation during early childhood have led to efforts to reduce the use of CT in diagnosing appendicitis. Recent studies suggest that children evaluated at non-pediatric specialty centers are more likely to undergo CT scans during workup

• No laboratory study sensitive and specific for appendicitis

• Should obtain urine pregnancy test in females of reproductive age

• CBC, urinalysis, CRP frequently ordered

• Often see leukocytosis and high percentage of neutrophils on CBC with differential; one of these is elevated in 90–96% of cases, but specificity of these studies is unclear

MANAGEMENT

• Patient should have nothing by mouth

• Fluid resuscitation as needed for dehydration or sepsis

• Standard of care is urgent appendectomy in uncomplicated appendicitis; cases with known perforation may require prolonged period of antibiotics

• Patients with uncomplicated cases of acute appendicitis should receive a single dose of preoperative broad-spectrum antibiotic

• Broad-spectrum IV antibiotics that cover enteric aerobes and anaerobes in cases of perforation or sepsis (e.g., ampicillin-sulbactam ± aminoglycoside, ticarcillin-clavulanate, ampicillin + gentamycin + metronidazole, or ciprofloxacin + metronidazole); length of administration should be determined by clinical criteria (fever, pain, bowel function, WBC count) in nonoperative management of perforation

• Following appendectomy, children with evidence of perforation should receive either 5 days of IV antibiotics or 7 days of oral therapy

Extracorporeal life support may include venoarterial cardiorespiratory support or venovenous access for respiratory support with or without less severe secondary cardiac failure.

EPIDEMIOLOGY

• As of 2013, the Extracorporeal Life Support Organization registry lists over 45,000 pediatric patients managed with ECMO, including over 32,000 neonates

• Survival is approximately 85% in neonates with respiratory indications and 55–65% for all other indications and age groups

MECHANICS

• Circuit comprised of a pump, a membrane oxygenator, and a heat exchanger, along with invasive monitoring devices

• Venoarterial cannulation generally achieved via jugular vein and carotid arteries and/or femoral vein and artery, though when ECMO is employed in patients unable to wean from cardiorespiratory bypass intraoperatively, cannulation may be performed in the chest

• Venovenous access may be achieved via cannulation of two different veins or using a double-lumen venous cannula

• Venovenous configuration preferable (less morbidity) in the absence of cardiac disease

• In children, cannula size to achieve adequate flow may compromise entire vessel lumen, leading to distal ischemia

INDICATIONS

• Oxygenation Index (OI) = [(Mean airway P × FiO₂)/Post ductal PaO₂] × 100

• ECMO may be considered for OI >20, and is routinely indicated for OI >40

• Clinical signs of decreased perfusion, including end-organ damage, shock, and cardiac arrest

• Primary diagnoses may include CDH, meconium aspiration syndrome, ARDS, sepsis, congenital cardiac defect, cardiomyopathy, trauma, or cardiac arrest, among others

CONTRAINDICATIONS

• Prematurity—ECMO should not be used in newborns younger than 30 weeks’ gestation or weighing less than 1.5 kg due to a high risk of intracranial bleeding

• Existing intracranial hemorrhage >grade 2

• Profound neurologic impairment, multiple congenital anomalies, or other condition with poor prognosis

• Relative contraindications include prolonged mechanical ventilation (due to high incidence of bronchopulmonary dysplasia and irreversible fibroproliferative pulmonary disease), CDH with severe pulmonary hypoplasia, multiorgan system failure, severe burns, immunodeficiency, or active bleeding

MANAGEMENT

• Heparin should be titrated to maintain therapeutic anticoagulation during extracorporeal life support

• Generally, activated clotting time should be maintained at 50–60% above normal levels

• Management of the ECMO patient requires a coordinated care team, including surgical/neonatal intensivists, ICU nurses, and ECMO perfusionists

• During ECMO perfusion, ventilator settings should be maintained at low levels to provide lung rest; recruitment maneuvers will generally be required to transition off extracorporeal support

• Blood volume should be titrated to a right atrial pressure of 5–10 mm Hg; fluid management should be aimed at achieving and maintaining dry weight

• Cannula sites should be meticulously cleaned and maintained in accordance with institutional protocols

COMPLICATIONS

• Bleeding associated with heparinization

• Technical failure (15%); includes circuit thrombus (26%), cannula issues (10%), oxygenator failure (10%), pump malfunction (2%), and air embolus (4%)

• Neurologic sequelae (seizures (10–13%)

• Pneumothorax (5–15%)

• Hemolytic anemia (6–12%)

• Chronic pulmonary disease (60%)

• Growth delay (40%)

• Neurologic abnormalities in up to 50% with detailed testing

• Infection

Congenital aganglionic megacolon; abnormal innervation of the bowel beginning in the internal anal sphincter and extending proximally

EPIDEMIOLOGY

• Incidence 1:5000 live births; males:females 4:1

• Most common cause of lower intestinal obstruction in neonates

• Associated with Down syndrome, Laurence–Moon–Bardet–Biedl syndrome, Waardenburg syndrome, and cardiovascular abnormalities (especially defects in cardiac septation or Tetralogy of Fallot)

ETIOLOGY

• Multifactorial genesis and complex pattern of inheritance (up to 25% familial)

PATHOPHYSIOLOGY

• Absence of ganglion cells in the bowel wall, which extends proximally from the anus for variable distance

• Arrest of neuroblast migration from proximal to distal bowel

• Limited to the rectosigmoid colon in 75% of patients and involves the entire colon in 10% of patients

• Histologically, absence of Meissner and Auerbach plexus and hypertrophied nerve bundles—Increased nerve endings in aganglionic bowel results in increased acetylcholinesterase

CLINICAL MANIFESTATIONS

• Often presents with delayed passage of meconium; 99% of normal full-term infants pass meconium within 48 hours of birth

• Constipation is presenting symptom later in life

• Bowel dilatation proximal to transition zone leading to increased intraluminal pressure, resultant decreased blood flow and deterioration of the mucosal barrier may lead to stasis and proliferation of bacteria with subsequent enterocolitis

• Patients with enterocolitis (about 10%) may present with fever, abdominal distention and diarrhea, confusing the diagnosis

• Failure to pass stool leads to dilatation of proximal bowel and abdominal distention

• On exam: Palpable fecal mass in left lower abdomen but absence of stool in rectum

• Rectal exam reveals normal anal tone but is often followed by massive release of gas and feces

DIAGNOSTICS

Roentgenographic (Barium Contrast Enema)

• First-line study for suspected Hirschsprung disease at many centers

• Use water-soluble contrast for neonates

• Transitional zone seen after 1–2 weeks of age as a funnel-shaped area of intestine by barium contrast enema

Rectal Biopsy

• Obtained no closer than 2 cm to dentate line because there is a normal area of hypoganglionosis at anal verge

• Early rectal biopsy should be avoided in premature infants due to physiologic immaturity of normal ganglion cells

• Need submucosa to accurately evaluate

• Specimen is stained for acetylcholinesterase, which should reveal a characteristic pattern of expression throughout the mucosa and submucosa

• H&E staining shows aganglionosis and hypertrophied nerve bundles

• Positive specimens rarely, if ever, stain for calcitonin

MANAGEMENT

• Initially, decompression with nasogastric tube; repeated emptying of rectum using rectal tubes and irrigations

• Resuscitation should include IV fluids and broad spectrum antibiotics to cover multiple enteric pathogens

• Associated anomalies should be addressed prior to operative repair

• Definitive treatment is surgical resection: Swenson’s technique, Duhamel–Grob technique, Soave-endorectal pull-through

• Postoperative complications: Recurrent enterocolitis (about 25%), constipation (about 20%), stricture(about 6%), prolapse(2%), fecal soiling (about 5%)

A protrusion into the groin of contents of the abdominal cavity, most commonly small bowel, into a persistently patent processus vaginalis. There are three types: indirect, direct, and femoral. Indirect hernias enter the inguinal canal through the internal inguinal ring and are by far the most common in children (>95%). Femoral hernias are rare in children.

EPIDEMIOLOGY

• Incidence of approximately 1–5% in children; male:female 3:1–10:1

• More common in premature infants (16–25% incidence); typically present in infancy

• Approximately 10% of inguinal hernias are complicated by incarceration

• Likelihood of incarceration decreases sharply with time; the risk is greatest during the first 6 months of life

• More often right-sided (60%) but bilateral in approximately 10%

• Patients with abdominal wall defects, connective tissue disorders, chronic respiratory disease, or undescended testes are at higher risk. Processes causing increased intra-abdominal pressure such as ascites, ventriculo-peritoneal shunting, or peritoneal dialysis can lead to high incidence of previously unrecognized inguinal hernias

DIFFERENTIAL DIAGNOSIS

• Lymphadenopathy, lymphoma, undescended or retractile testes, hydrocele, testicular torsion

• May be difficult to differentiate hydrocele from inguinal hernia. Hydroceles typically transillu-minate, but hernias may as well. Unlike hydroceles, neck of hernia can often be felt at the inguinal ring. Also, hydroceles may get larger over the course of the day, but cannot be fully reduced and do not fluctuate in size

PATHOPHYSIOLOGY

• Embryologically, the processus vaginalis is a diverticular portion of the peritoneum, which herniates through the abdominal wall and into the inguinal canal. The testes descend into the scrotum by the 29th week of gestation external to the processus vaginalis. The processus vaginalis usually fuses and is obliterated by the time a pregnancy reaches term or shortly thereafter. Partial or complete failure to obliterate results in a range of inguinal anomalies from hydroceles to hernias

• With increased intra-abdominal pressure, bowel (or ovary in females) can slip into this communication with risk for possible incarceration (being unable to reduce the hernia), strangulation (compromised blood supply), and subsequent necrosis

CLINICAL MANIFESTATIONS

• Most children are asymptomatic unless incarceration and/or strangulation occurs

• Characterized by intermittent groin, scrotal, or labial swelling that spontaneously reduces; more prominent with Valsalva

• Examine testes first because retractile testes can be mistaken for hernias

• Classically, an inguinal bulge is noted at the inguinal ring or a scrotal/labial swelling that is reducible or changes in size

• Causing infant to cry or having older child stand can increase intra-abdominal pressure to make diagnosis easier

• Recent evidence indicates that digital photos taken by family members may be useful to document the diagnosis of equivocal cases

• Incarcerated hernia may present with signs of obstruction (emesis, poor feeds, abdominal distention, lack of bowel movements)

• With time, area surrounding an incarcerated hernia will become indurated, tender, and erythematous

MANAGEMENT

• Once an asymptomatic inguinal hernia is diagnosed, the patient should be scheduled for an elective operative repair; recent data suggests that repair within 2 weeks may decrease the rate of incarceration

• An incarcerated hernia must be immediately reduced to avoid strangulation, necrosis, and perforation. Manual reduction is done by placing a calm child in Trendelenburg position and applying gentle upward pressure while trying to milk herniated tissues back into peritoneal cavity

• Consider analgesia and sedation for difficult or painful reductions. Unsuccessful reductions require immediate surgical repair

• In cases of successful manual reduction, prompt surgical repair can be electively scheduled as outpatient with strict instructions to return to emergency department in case of reincarceration

• In cases where intestinal obstruction is present, patient needs nasogastric tube, laboratory studies, fluid resuscitation, and immediate surgical consultation

• Current data supports the use of trans-inguinal laparoscopic evaluation of the contralateral side in patients with a preoperative diagnosis of unilateral inguinal hernia in younger patients

An invagination of a proximal portion of the bowel and its mesentery (the intussusceptum) into an adjacent distal bowel segment (the intussuscipiens)

EPIDEMIOLOGY

• Incidence 1–4:2000

• 2:1 male to female ratio

• Majority of cases occur between 3 months and 2 years with peak incidence between 3 and 9 months of age

• Occasionally associated with cystic fibrosis (CF) and Henoch–Schönlein purpura (HSP)

• Seasonal incidence with peaks in winter and summer

• More common in underweight children

• Occurs in neonates, older children, and adults but usually secondary to a pathologic lead point

ETIOLOGY

• Cause is unknown in approximately 90% of cases

• Incidence follows peak seasons of viral gastroenteritis. Postulated theory is that Peyer’s patches become inflamed secondary to viral infection and serve as a lead point

• Pathologic lead points occur in 1.5–12% of cases; causes include Meckel’s diverticulum, intestinal polyps, B cell lymphoma, submucosal hemangioma, carcinoid tumor, and Ascaris lumbricoides infestation

• Certain conditions such as CF, HSP, Peutz–Jeghers syndrome, and hemolytic-uremic syndrome predispose to lead points

• Can also occur as a postoperative complication following a laparotomy

DIFFERENTIAL DIAGNOSIS

• Gastroenteritis, incarcerated hernia, Meckel’s diverticulum, malrotation with midgut volvulus

• For patients who present with lethargy, consider vast differential for change in mental status

PATHOPHYSIOLOGY

• Proximal portion of bowel and its mesentery telescopes into distal portion—Usually ileocolic, but can be ileoileal or colocolic as well

• Constriction of the mesentery causes engorgement of the intussusceptum and venous congestion with eventual bowel necrosis

CLINICAL MANIFESTATIONS

• Classic triad is intermittent colicky abdominal pain, vomiting, and “currant jelly” stools (due to mucosal sloughing)

• However, this triad is present in less than half of cases and grossly bloody stool is often a late finding

• Pain typically occurs in screaming spells every 20–30 minutes during which the child draws up his/her legs. Children often look healthy and even playful between these episodes

• Emesis becomes bilious as obstruction progresses

• Up to 10% of patients present with only lethargy or hypotonia

• Can be febrile and have other abnormal vital signs

• Even in infants without grossly bloody stools, stools will be guaiac-positive in approximately 75% of cases

• Sausage-shaped mass in the right upper quadrant

• Abdomen often distended; bowel sounds high-pitched or normal

• Up to 20% may reduce spontaneously

DIAGNOSTICS

• Plain abdominal x-ray: Can see paucity of intestinal gas, minimal stool in the colon, small bowel obstruction, and right upper quadrant soft tissue mass; however, plain films may be normal

• Upright or decubitus film: Rule out intraperitoneal air

• Ultrasound has recently been shown to be an effective and cost-efficient first test aimed at decreasing the number of negative studies involving radiation; may see pseudokidney sign, target sign, or complex hyperechoic mass

• Barium or water-soluble contrast enemas: Gold standard study for diagnosis and treatment of intussusception, which classically has a “coiled spring” appearance. Air contrast enemas have been shown to be as effective as barium enemas in diagnosis and treatment and can decrease the risks associated with a potential perforation

  • ✓ Obtain surgical consultation before attempted reduction because (1) risk of intestinal perforation during reduction and (2) failed reduction attempt requires surgical correction

  • ✓ Barium contraindicated if clinical peritonitis or free air on abdominal x-ray

• May see nonspecific lymphocytosis and electrolyte abnormalities consistent with dehydration

MANAGEMENT

• Patient should not eat (NPO). Begin antibiotics (e.g., ampicillin-sulbactam, cefazolin) and fluid resuscitation in preparation for barium or air enema

• Surgery and anesthesiology staff should be standing by in case radiologic reduction is unsuccessful. In this event, laparotomy is performed with manual reduction and appendectomy

• Enemas are successful in 60–90% of patients, but are less successful in patients younger than 1 year, those who have had symptoms for more than 48 hours, when bowel obstruction is obvious on plain films or multiple ultrasound findings are present

• Recurrence of intussusception after barium or air reduction can occur in up to 10% of cases, and usually within the first 24 hours

• If the intussusception recurs, repeated radiologic reduction may be attempted once before surgical reduction. Recurrence is rare following surgical resection (about 2%)

Malrotation, an abnormal midgut development, results in anomalous positioning of the small intestine, cecum, and ascending colon. Abnormal bands of tissue are present (Ladd bands) from attempts at colonic fixation. A midgut volvulus occurs when the malrotated intestine twists on the axis of the superior mesenteric artery (SMA) compromising intestinal blood flow.

EPIDEMIOLOGY

• Detected in 0.2% of live births, but in 1–2% of autopsy studies

• Approximately 30% of cases detected by 1 week of age, 60% by 1 month, and 90% by 1 year. Remaining 10% may present at any age

• Up to 70% of patients have associated anomalies that include abdominal heterotaxia, omphalocele, gastroschisis, congenital diaphragmatic hernia, intestinal atresia, mesenteric cysts, Hirschsprung disease, anorectal anomalies, situs inversus, atrial septal detect, ventricular septal detect, transposition of the great vessels, dextrocardia, anomalous systemic or pulmonary venous return, asplenia, and polysplenia

DIFFERENTIAL DIAGNOSIS

Bilious (green or yellow) emesis in a neonate is a midgut volvulus until proven otherwise!

• Malrotation is in the differential diagnosis for failure to thrive, cyclic vomiting, chronic abdominal pain, intermittent apnea, testicular torsion, and incarcerated hernia

PATHOPHYSIOLOGY

• Normally, in the 5th–6th week of development, intestinal size exceeds the space of the abdominal cavity causing them to protrude into the umbilical cord. As the embryo grows, the midgut structures (duodenum, jejunum, ileum, ascending colon, and half of the transverse colon) reposition in the abdominal cavity, rotating 270 degrees around the SMA in a counterclockwise direction

• Malrotation occurs when the normal counterclockwise rotation of the midgut is incomplete; great variation in degree of abnormality in rotation

CLINICAL MANIFESTATIONS

• Varies from acute intestinal obstruction to chronic, intermittent abdominal pain

• Delayed presentation of a midgut volvulus and significant intestinal necrosis includes shock (septic or hypovolemic) with hematochezia or melena and abdominal distention

• With a midgut intestinal obstruction, the abdomen should be flat or scaphoid. Abdominal distention suggests a more distal small bowel or colonic obstruction

• Abdominal wall distention, edema, erythema, and crepitus suggest gangrenous or necrotic bowel. Bowel viability is time-dependent

DIAGNOSTICS

• Abdominal radiograph: Gastric and duodenal dilation with a paucity of distal gas suggests a midgut obstruction. However, a normal film does not exclude the possibility of malrotation with or without volvulus

• An upper GI series is the best test to diagnose intestinal malrotation:

  • ✓ To exclude malrotation, the duodenum should be in the retroperitoneal position on lateral projections, the ligament of Treitz should cross the midline to the left of the spine and rise to a level of the pylorus

• Ultrasound and CT scan may be used. A midgut volvulus on ultrasound has a “barber pole” or “whirlwind” appearance of the small intestine wrapping clockwise around the axis of the SMA

MANAGEMENT

• Given the potential for volvulus and obstruction, with rare exception, a patient with a diagnosis of malrotation requires operative intervention

• Ladd procedure: Counterclockwise volvulus reduction, lysis of adhesive bands, conservative (necrotic) bowel resection, appendix removal, and repositioning of small intestine to RLQ and cecum to LLQ

• May need repeat operations to assess bowel viability (24–48 hours) if ischemia present at initial operation

• Postoperative course may be complicated by wound infection, shock, sepsis, intra-abdominal abscess, small bowel obstruction, recurrent volvulus, bowel necrosis, intussusception, short gut syndrome, strictures, and dysmotility

Infection of the perirectal area via spread from the anal crypts to the anal ducts and glands

EPIDEMIOLOGY

• 68–90% of affected children are male

• May be related to androgen levels in infants <12 months of age; in later childhood/adolescence often occur in the setting of inflammatory bowel disease

ETIOLOGY

• Small tears in the anal mucosa may lead to infection, or infection may arise from the anal glands and extend into the anal crypts

• When cultured, abscesses usually are polymicrobial. Most frequent organisms isolated are Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and anaerobes (e.g., Bacteroides species)

CLINICAL MANIFESTATIONS

• 42% of children younger than 2 years of age have history of diarrhea

• Fever (81%), rectal pain (69%), rectal mass (40%), pain on sitting (27%), pain with defecation (21%), abnormal gait (19%)

• On exam, there is erythematous, painful swelling in the perirectal area with or without fluctuance or drainage

MANAGEMENT

• Most patients require surgical drainage or needle aspiration followed by antibiotic therapy (e.g., cephalexin, amoxicillin-clavulanate, clindamycin) and sitz baths

• 10–20% may progress to fistula-in-ano, for which first-line treatment involves identification and either excision or incisional drainage of the fistulous tract

• MRI may be of use in the setting of Crohn’s disease to delineate complex fistulae

• IV antibiotic therapy (e.g., cefazolin, ampicillin-sulbactam) may be required for non-immunosuppressed patients with extensive abscesses or evidence of systemic disease

Collection of extrapulmonary air within the chest

EPIDEMIOLOGY/ETIOLOGY

• Often due to penetrating or blunt thoracic trauma

• Can result from disruption of pulmonary parenchyma, injury to tracheobronchial tree, bleb or esophageal rupture

• Occurs in 5% of children hospitalized for asthma

• Occurs in 10–25% of patients older than 10 years old with CF

• Spontaneous pneumothorax far more common among males (18–28:100,000/year versus 1.2–6:100,000 females)

• Iatrogenic: Tracheotomy, subclavian line placement, thoracentesis, and transbronchial biopsy

• Bilateral pneumothoraces are rare beyond neonatal period

• Tension pneumothorax will develop in up to 20% of patients with simple pneumothorax

• Other: Lymphoma or other malignancies, staphylococcal pneumonia

DIFFERENTIAL DIAGNOSIS

• Localized/generalized emphysema, extensive emphysematous bleb, congenital cystic adenomatoid malformation, diaphragmatic hernia, gaseous distention of stomach

PATHOPHYSIOLOGY

• Tension pneumothorax: A one-way entry of air into the pleural space. This collection of air causes collapse of the ipsilateral lung and compression of the contralateral lung. Mediastinal structures may shift, and there may be a decrease in venous return to the heart and cardiovascular compromise

• Primary spontaneous pneumothorax: Occurs in patients without trauma or underlying lung disease (e.g., Ehlers–Danlos disease, Marfan syndrome)

• Secondary spontaneous pneumothorax: Arises secondary to underlying lung disorder but without trauma. Examples include pneumonia with empyema, pulmonary abscess, gangrene, infarct, rupture of cyst, rupture of emphysematous bleb, foreign body

CLINICAL MANIFESTATIONS

• Onset may be abrupt; may be asymptomatic; severity of symptoms depends on extent of lung collapse

• Pain, dyspnea with respiratory distress, cyanosis, splinting on involved side, agitation, increased pulse rate

• Respiratory distress: Retractions, tachypnea, cyanosis

• Crepitus

• Decreased breath sounds on auscultation of affected lung

• Percussion of area involved is tympanitic

• Larynx, trachea, and/or heart may be shifted to unaffected side

DIAGNOSTICS

• Chest x-ray: Expiratory views emphasize the contrast between lung markings and area of pneumothorax. Tension pneumothorax limits expansion of contralateral lung

Chest CT Scan: May be obtained after re-expansion of the lung to detect predisposing anatomic abnormalities (e.g., bleb)

MANAGEMENT

Medical

• Small (less than 15%) or moderate sized pneumothorax in healthy child may spontaneously resolve within 1 week without intervention

• Because a small pneumothorax can quickly progress to a tension pneumothorax, even asymptomatic trauma patients with pneumothorax should be admitted for observation

• Recent data suggests that blunt trauma patients with occult pneumothorax (visible on CT scan but not on plain x-ray) may be safely observed without intervention despite requirement for positive pressure ventilation

• Administration of 100% oxygen may increase nitrogen pressure gradient between pleural air and blood and shorten time to resolution

• Analgesia: Consider respiratory depressant effects of codeine, morphine

Surgical

• Tube thoracostomy: Indicated for symptomatic patients and, generally, those receiving positive pressure ventilation. Tube is placed at the midaxillary line at level of the fifth intercostal space (approximately nipple level) over the top of the rib to avoid the intercostal neurovascular bundle

• Needle decompression for tension pneumothorax: Needle is placed in midclavicular, second intercostal space of the ipsilateral side; an immediate release of air is noted, and tube thoracostomy must be performed (see Pneumothorax Needle Decompression in Chapter 25)

• Recurrent pneumothorax: May use sclerosing agent that induces an adhesion between the lung and chest wall (tetracycline, talc, silver nitrate), or induce mechanical adhesions via laparoscopic or open approaches

• Video-Assisted Thoracoscopic Surgery (VATS) allows for plication of blebs, closure of fistula, stripping of pleura, basilar pleural abrasion and has largely replaced open thoracotomy in the surgical treatment of recurrent pneumothorax

Enlarged pylorus with increased muscular thickness, which generally leads to gastric outlet obstruction and bilious emesis

EPIDEMIOLOGY

• Occurs in approximately 3–6 per 1000 infants

• Male:female 4:1; more common in white infants

• 10–20% of infants of mother with history of pyloric stenosis

ETIOLOGY

• Hereditary and environmental factors thought to be involved

• Other factors: Abnormal muscle innervation, erythromycin therapy during first 2 weeks of life, maternal stress in third trimester, and B and O blood groups

• Underlying defect is thickened pyloric musculature leading to a gradual obstruction

CLINICAL MANIFESTATIONS

• Typically presents between 2 and 8 weeks of age (most common 3–5 weeks)

• Nonbilious vomiting is initial symptom

• Weight loss and dehydration

• Patients are often hungry and eager to feed

• “Olive-shaped” mass may be palpated in the midepigastrium beneath the liver edge

• Gastric peristaltic wave may be visible in a distended stomach

• Jaundice occasionally present

DIAGNOSTICS

• Clinical diagnosis possible in 60–80% of patients

• Electrolyte panel: Hypokalemic, hypochloremic metabolic alkalosis due to loss of gastric HCl (may be acidotic if severe dehydration)

• Abdominal x-ray: Dilated stomach bubble

• Abdominal ultrasound: Radiologic study of choice (sensitivity around 90%); positive ultrasound characterized muscle thickness ≥4 mm and/or channel length ≥14 mm

• Upper GI series: Sensitive and specific, but risk for aspiration. Barium studies may show elongated pyloric channel, bulge of pylorus into antrum, and parallel streaks of barium in the channel

MANAGEMENT

Medical

• Initial IV fluids: 5% dextrose with normal saline

  • ✓ Risk of hyponatremia if hypotonic saline is used

• Potassium chloride can be added to IV fluids when urine output is established

• Correction of alkalosis to bicarbonate less than 30 essential to prevent postoperative apnea

Surgical

• Delay surgery until adequate rehydration and electrolyte correction established

• Ramstedt pyloromyotomy is procedure of choice. This involves splitting the pyloric muscle without violating the mucosa

• Can be performed laparoscopically or through small incision

• Families should be counseled preoperatively to expect vomiting after the procedure; in most cases, feeds can begin within a few hours of the procedure and patients should continue to be fed despite vomiting to improve oral tolerance

Twisting of the ovary or adnexa resulting in venous and lymphatic congestion and eventual loss of arterial perfusion with resulting ovarian necrosis

EPIDEMIOLOGY

• Incidence 4.9:100,000 in girls 1–20 years old

• Rare in children, occurs predominantly in neonates and early adolescence

ETIOLOGY

• Torsion typically occurs in the setting of enlarged ovaries containing either follicular cysts or tumors; however, normal ovaries can also torse

• Torsion is the most common complication of ovarian tumors in children occurring in 3–16% of patients. Ovarian tumors that undergo torsion are more commonly benign

DIFFERENTIAL DIAGNOSIS

• Appendicitis, gastroenteritis, ruptured ovarian cyst, ectopic pregnancy, pelvic inflammatory disease, tubo-ovarian abscess, nephrolithiasis

PATHOPHYSIOLOGY

• Ovarian mass (follicle, cyst, tumor) acts as a “weight” to promote twisting of the ovary on its vascular pedicle

• Right ovarian torsion is more common than left (3:2)

• Initially, venous and lymphatic drainage are compromised, leading to an enlarged ovary. If prolonged (greater than 8 hours), arterial supply is affected and necrosis, gangrene, and peritonitis can result

• Neonatal ovarian torsion typically occurs in ovaries with large (>5 cm) follicular cysts that are believed to develop in response to exposure to maternal hormones. Torsion can occur either in utero or postnatally

CLINICAL MANIFESTATIONS

• Presentation is highly variable: Abdominal pain (90–100%); nausea/vomiting (70–80%); fever (5–20%); leukocytosis (20%); palpable abdominal mass (20%); dysuria (14%)

• Patients note pain on abdominal (RLQ, LLQ) and pelvic exam

DIAGNOSTICS

• Pelvic ultrasound with Doppler: The preferred imaging modality. Can show complex echogenic pelvic mass and absence of blood flow. Normal US and Doppler flow does not exclude ovarian torsion. If clinical suspicion is high, prompt surgical evaluation

• Pelvic CT scan: Helpful if ultrasound unavailable and can help to rule out other abdominal processes

• B-HCG: Quantitative to rule out ectopic pregnancy and germ cell tumors

• α-fetoprotein: Order if tumor diagnosed; abnormal with teratoma or endodermal sinus tumors

MANAGEMENT

• Prompt laparoscopy (preferably by 8 hours from onset of symptoms) with detorsion or salpingo-oophorectomy (if necessary)

• Management of a normal torsed ovary should be as conservative as possible; detorsion and careful observation is recommended to preserve fertility in the ovary, and recent literature suggests that up to 70% of adnexae can be salvaged following torsion. If viability is in doubt, consider a second look procedure

Surgical emergency of males in which testis and spermatic cord twist, leading to acute ischemia of testis

EPIDEMIOLOGY

• Incidence 1:4000 males under 25 years old; not common in newborns

• Peaks at 1 year of age and onset of puberty (weight of testes)

ETIOLOGY

• Most common in individuals with “bell-clapper deformity” in which the tunica vaginalis extends up to the spermatic cord, suspending the testes freely within the tunica cavity

• Deformity is frequently bilateral and can be detected by examining testes for a horizontal lie

• Undescended testes are ten times more likely to torse

• Intravaginal torsion (associated with bell-clapper deformity) is typically seen in adolescents

• Extravaginal torsion (torsion of the cord and coverings) tends to occur in neonates secondary to highly mobile testes

• Can result from contraction of cremasteric muscle after sex, trauma, cold, or exercise; can occur at rest

DIFFERENTIAL DIAGNOSIS

• Torsion of appendix testis, epididymitis, orchitis, scrotal trauma, incarcerated inguinal hernia, HSP, idiopathic scrotal edema, varicocele

PATHOPHYSIOLOGY

• Spermatic cord twists within the tunica vaginalis

• Arterial blood flow interrupted: Leads to ischemia

• Prolonged torsion: Leads to infarction and necrosis

• Recurrent episodes if spontaneously untwists before significant damage done (one-third of patients have had past transient episodes)

• Can result in abnormal spermatogenesis and infertility

CLINICAL MANIFESTATIONS

• Acute onset testicular pain (89%); vomiting (39%), dysuria or frequency (5%), history of similar pain or swelling (36%)

• Scrotal pain can radiate to the abdomen, thigh, flank

• Usually afebrile, no dysuria or penile discharge

• On exam: Swollen and tender testis, scrotal edema and erythema, high-riding testicle (twisted cord) with horizontal lie, thickened tender spermatic cord, absent cremasteric reflex, palpable secondary hydrocele

• Fever and erythema are late signs

DIAGNOSTICS

• Doppler ultrasonography is study of choice, but very operator-dependent. Blood flow on Doppler does not rule out torsion

• 99m-Technetium radioisotope scan (rarely available)

MANAGEMENT

• Surgical emergency: Obtain immediate consultation

• Detorsion: Cord is untwisted and the testis wrapped in warm saline-soaked gauze while reperfusion is assessed. Necrotic testes are removed, orchiopexy (attach testes to tunica vaginalis) viable testicle. Orchidopexy of the contralateral testis

• Testis removed if not viable because of the risk of infertility secondary to the development of anti-sperm antibodies