PEDIATRIC SURGERY: basic, approach, guide

pedia surg

1. PEDIATRIC SURGERY PGI MAE ANN G. BORJAL SAN JUAN DE DIOS HOSPITAL

2. “Those who daily operate upon adults, even with the greatest of skill, are sometimes appalled— or certainly are not at their best —when called upon to operate and care for a tiny patient. Something more than diminutive instruments or scaled-down operative manipulations are necessary to do the job in a suitable manner.” - Dr. Robert E. Gross; The Surgery of Infancy and Childhood

3. PITFALLS AND PEARLS

4. 1. Children are not little adults, but they are little people 2. Sick children whisper before they shout 3. Always listen to the mother and the father 4. Pediatric tissue must be handled delicately and with propound respect 5. Children suffer pain after surgery 6. Pay particular attention to the postoperative pediatric patient whose pain cannot be soothed by the administration of standard amounts of analgesic agents

5. GENERAL CONSIDERATIONS

6. Fluid and Electrolyte Balance Clinical signs of Dehydration : tachycardia, decreased urine output, reduced skin turgor, depressed fontanelle, absent tears, lethargy, and poor feeding. Clinical signs Fluid overload : onset of a new oxygen requirement, respiratory distress, tachypnea, and tachycardia

7. total body water: 12 weeks’ gestation: 94 cc/kg full term: 80 cc/kg 1 year of life: 60-65 cc/kg preterm: face additional fluid losses due to coexisting congenital anomalies or surgery

8. Normal daily maintenance fluids: 100 mL/kg for the first 10 kg plus 50 mL/kg for 11 to 20 kg plus 25 mL/kg for each additional kilogram of body weight thereafter. Because IV fluid orders are written as milliliters per hour, this can be conveniently converted to: 4 mL/kg/h up to 10 kg add 2 mL/kg/h for 11 to 20 kg add 1 mL/kg/h for each additional kilogram body weight thereafter. ex. 26-kg child has an estimated maintenance fluid requirement of: (10 × 4) + (10 × 2) + (6 × 1) = 66 mL/h in the absence of massive fluid losses or shock

9. newborn’s GFR: 21 mL/min/1.73 m2 2 years of age: adult levels Sodium requirements: 2 mEq/kg per day=term 5 mEq/kg per day=critically ill Potassium requirements: 1 to 2 mEq/kg per day IV Calcium and magnesium supplementation : prevent laryngospasm, dysrhythmias, and tetany

10. Acid-Base Equilibrium Acute metabolic acidosis: inadequate tissue perfusion intestinal ischemia from necrotizing enterocolitis (in the neonate), midgut volvulus, or incarcerated hernia, tx: aimed at restoring tissue perfusion by addressing the underlying abnormality first administration of sodium bicarbonate : base deficit × weight in kilograms × 0.5 (in newborns, 0.4 for smaller children, 0.3 for older children) metabolic alkalosis: gastric acid loss Respiratory acidosis: hypoventilation respiratory alkalosis: hyperventilation

11. Blood Volume and Blood Replacement BT: px age, primary dx, ongoing bleeding, coagulopathy, hypoxia, hemodynamically compromise, lactic acidosis, cyanotic heart ds, severity of illness baseline RBC: 7 to 13g/dL Hb transfusion: 70g/dL in stable critically ill children estimating blood volume for newborn infant: 80ml/kg of body wg. vol(ml) of PRBC to be transfused: (Target hematocrit-Current Hematocrit) x weight (kg) x 80/65 (65 represent estimated hematocrit of a unit of PRBC)

12. general rule: BT if childs perfusion is inadequate after 2 to 3 boluses of 20 ml/kg of isotonic crystalloid: 10ml/kg PRBC asap, Type O coagulation def may assume clinical significance after extensive BT: FFP (10-20ml/kg) and Platelet (1unit/5kg) if >30 ml/kg have been transfused. furosemide 1mg/kg: to excrete extra fluid load >30ml/kg loss with ongoing bleeding: 1:1:1 RBC:plasma:platelets

13. Parenteral Alimentation and Nutrition enteral is preferred parenteral: when GIT cannot be used bcoz of mech, ischemic, inflam or fx disorders. long term parenteral nutrition: supplemental copper, zinc, iron to prevent devt of trace metal def. major complication of prolonged TPN: nutrition associated cholestasis---liver failure to prevent: use enteral feeding, meticulous catheter care, tx infection, substituting omega-3 fish oil lipid emulsion for soybean-based emulsion.

14. Venous Access goal: place catheter in in least invasive, least risky, least painful manner, most accessible location, use of catheter without complications for as long as it is needed. CVC: infants: cutdown approach in antecubital fossa, external jugular vein, facial vein or proximal saphenous vein. infants over 3 kg and older children: percutaneous access of subclavian, internal jugular or femoral vein via Seldinger technique chest xray: confirm central location of catheter tip and exclude presence of pneumothorax or hemothorax. complications: sepsis or infection

15. Thermoregulation premature: thermogenesis is impaired:unable to shiver and lack stored of fat anesthetic and paralyzing agents heat conservation during transport of the infant to and from OR abd surgery: avoid wet and cold drapes. all fluids to irrigate chest or abd must be warmed to body temp. laparoscopic approaches: more stable thermoreg due to dec heat loss from smaller wound size. hypothermia: cardiac arrhythmias or coagulopathy.

16. Pain Control morphine and fentanyl EMLA cream regional anesthesia when narcotics are discontinued: symptoms of narcotic withdrawal may develop ( irritability, restlessness and episodes of htn and tachycardia: timely tx using naloxone

17. NECK MASSES

18. NECK MASSES mngt: location and length of time the mass is present midline : thyroglossal duct remnants, thyroid masses, thymic cysts or dermoid cyst. lateral : branchial cleft remnants, cystic hygromas, vascular malformations, salivary gland tumors, tortocollis and lipoblastoma. either midline or lateral: enlarged lymph nodes and rhabdomyosarcoma

19. Lymphadenopathy most common cause of neck mass in child tender LN: bacterial infection Staphylococcus or Streptococcus : tx of the primary cause (otitis media or pharyngitis) with antibiotics more chronic forms: atypical mycobacteria, cat scratch fever firm, fixed neck nodes, present in axillae or groin or hx suggests lymphoma : excisional biopsy chest xray: mediastinal mass-- cardiopulmo collapse due to loss of venous return

20. Thyroglossal Duct Remants residual thyroid tissue left behind during the migration of the thyroid gland may persist and present in the midline of the neck as thyroglossal duct cyst. 2-4 y/o at midline or below the hyoid bone and moves with up and down with swallowing or protusion of the tongue. mostly asymptomatic malignancy: cyst grow rapidly, US shows complex anechoic pattern or calcification

21. tx: if w/abscess: drainage and antibiotics--resection of the cyst plus ligation at the foramen cecum ( Sistrunk operation ) predictive of recurrence: 2 infections prior to surgery, <2 y/o, inadequate initial operation.

22. Brachial Cleft Anomalies embryologic comm b/w pharynx and external surface may persist as fistula fistula is MC w/ 2nd brachial cleft--N disappears and extends from Ant. SCM, inward thru bifurcation of the carotid art. 3rd brachial cleft fistula: posterior to carotid bifurcation brachial cleft remnants may contain small pieces of cartilage and cyst 2nd brachial cleft sinus: clear fluid draining from the external opening of the tract at ant.border of the lower 3rd of SCM brachial cleft anomaly + biliary atresia + congenital heart anomaly= Goldenhar’s complex

23. tx: complete excision of the cyst and sinus tract dissection of sinus tract: fine lacrimal duct probe thru the ext ernal opening into the tract and utilizing it as guide for dissection methylene blues 2-3 small transverse incisions in a ‘stepladder’ fashion if present as abscess: incision and drainage + antibiotics (to cover Staphylococcus and Streptococcus ) + excision of the cyst

24. Lymphatic Malformation (Cystic hygroma or lymphangioma) due to sequestration or obstruction of developing lymph nodes posterior triangle of the neck, axilla, groin, mediastinum cyst are lined by endothelium and filled with lymph troublesome variant: tongue, floor of the mouth, structures deep in the neck. 2 y/o may contain nests of vascular tissue--may bleed--rapid enlargement and discoloration of the lesion

25. dx: prenatal UTZ before 30 weeks gestation (large lesion cause obstruction to the airway--impairing ability to swallow amnioic fluid-- polyhydramnios --airway must be secured at time of delivery (orotracheal intubation, emergency tracheostomy while the infant is attached to placenta, EXIT procedure) tx: image-guided sclerotherapy as fist line therapy. cyst excision conservative excision and unroofing of the remaining cyst: preserve all adjacent crucial structures. closed suction drainage combined sclerotherapy/resectional approach: masses that extend to the base of the tongue or floor of the mouth

26. Torticollis lateral mass in infancy with rotation of the head towards the opposite side of the mass due to fibrosis of the SCM mass palpated in the affected muscle histologically: deposition of collagen and fibroblasts around atrophied muscle cells. tx: physical therapy based on passive stret c hing of the affected ms rarely: surgical transection

27. RESPIRATORY SYSTEM

28. Congenital Diaphragmatic Hernia ( Bochdalek) Bochdalek hernia: MC variant posterolateral defect defects allow abd viscera to fill the chest cavity abd cavity: small, underdeveloped and rem ai ns scaphoid at birth lungs: hypoplastic, dec bronchial and pulmo art branching MC at left (80-90%) surfactant def., trisomy 18 and 21 assoc anomalies: heart, ff by abd wall defects dx: prenatal UTZ at 15 weeks AOG ( herniated abd viscera in the chest, changes in liver pos, mediastinal shift away from herniated viscera) early antenatal diagnosis is assoc w/ worse outcome

29. index of severity: LHR (lung-to-head circumference) length x width of R lung at the level of cardiac atria divided by head circumference (m m ) LHR < 1.0 = very poor prognosis LHR > 1.4 = more favorable outcome o/e LHR (observed to expected LHR): to correct for gestational age o/e LHR <15%: extreme < 15-25 %: severe 26-35%: moderate 36-45%: mild the most important predictor of postnatal survival is absence of liver herniation

30. dx of CDH is made by CXR immediate respi distress due to 3 factors: 1. air filled bowel in chest compresses the mobile mediastinum 2. pulmo htn 3. lung on the affected side is often hypoplastic overall mortality: 50%

31. tx: mechanical ventilation(low setting, PaCO2 50-60 mmHg or higher, pH >/ 7.25) + ECMO to minimize pulmo htn: inhaled nitric oxide, bicarbonate soln severely hypoxic despite max ventila t o r y care: ECMO via VV or VA routes for 7-10 days VV: single cannula thru R IJV w/ blood removed from and infused into R atrium by separate ports. VA: RA is cannulated by means of IJV and aortic arch thru R CCA complications after 14 days : cannula malposition, bleeding in multiple location and infection.

32. abd or thoracic approach via open or minimally invasive technique. subcostal incision : abd viscera is withdrawn from the chest, exposing the the defect in the diaphragm--prosthetic mat to patch the def--suturing it to the diaphragmatic remnant or around the ribs or costal cartilage --single layer of nonabsorbable horizontal mattress suture to close the defect. minimally invasive technique via thoracoscopic repair: stable, > 2kg, no pulmo htn: longer operative time and higher recurrence all infants are ventilated postop to maintain preductal arterial oxygenation of 80-100 torr.

33. Congenital Lobar Emphysema (CLE) progressive hyperexpansion of one or more lobes of the lung--shifts the mediastinum to the opposite side and compromises the other lung life-threatening in newborn upper lobes (L>R)--R Middle --lower lobes mild respi distress to full-fledged respi failure w/ tachypnea, dyspnea, cough and late cyanosis. pathogneumonic: hyperexpanded hemithorax on the ipsilateral side chest xray: hyperlucent affected lobe w/ adjacent lobar compression and atelectasis tx: resection of the affected lobe: open or thorascopic after several months prognosis: excellent

34. Bronchopulmonary Foregut Malformations

35. Congenital Pulmonary Airway Malformations (CPAM) cystic proliferation of the terminal airway (lined by mucus-producing respi epithelium) and elastic tissue in the cyst walls without cartilage formation. type I: large and multiple type II:small more numerous type III: resembles fetal lung without macroscopic cyst left lower lobe asymptomatic to severe respi failure at birth, repeated infection, cough and fever in older infants and children. dx: confirmed by CT for surgical planning tx: resection is curative and performed urgently-- if unresected risk of malignant degeneration

36. Pulmonary Sequestration mass of lung tissues at left lower chest with systemic blood supply from aorta cause: abn budding of the developing lung that picks up sys bs and never becomes connected with bronchus or pulmo vessels Extralobar seq: small area of nonaerated lung separated from main lung mass, sys bs from ABOVE the L diaphragm :asymptomatic, dx incidental on chest Xray, resection is not necessary Intralobar seq: within the parenchyna of LLL, no major communication to the tracheobrochial tree, bs BELOW the diaphragm : dx prenatally and confirm on postnatal CT scan, repeated infections with cough, fever and consolidation in the pos basal segment of LLL

37. tx: removal of the entire LLL open or thorascopic approach (ideal) open: open the chest thru a low 6th or 7th ICS to gain access to the vascular attachments to the aorta prognosis: excellent failure to obtain adequate control of vessels: retraction of the abd--hemorrhage combined open + thora: vessels are clipped and divided thoracoscopically and then the lesion is safely removed thru limited thoracotomy

38. Bronchogenic cyst duplication cyst from the airway embryonic rests that have been pinched off from the main portion of developing tracheobrochial tree anywhere or respi tract, any age histo: hamartomatous, single cyst lined with epithelium, mesenchyme contains cartilage and smooth muscle sym: paratracheal region of the neck: airway compression and respi distress lung parenchyma: fever and cough chest xray: dense mass CT scan or MRI: precise anatomic location tx: resection of the cyst (open or lap) , emergency for airway or cardiac compression

39. Bronchiectasis abn and irreversible dilatation of the bronchi and bronchioles w/ chronic suppurative ds of airways. underlying pulmo anomaly, CF, immuno def can result from chronic infx sec to neglected foreign body sx: chronic cough, productive of purulent secretions, recurrent pulmo infx, hemoptysis dx: chest xray: inc bronchovascular markings on the affected lobe tx: medical antibiotics + postural drainage + bronchodilator therapy lobectomy or segmental resection: localized ds severe: lung transplantation to replaced the terminally damaged, septic lung

40. Foreign Bodies

41. Airway Ingestion toddler PEANUTS is the MC aspirated obj delay in dx: atelectasis and infx R main stem bronchus or R lower lobe cough or choke while eating, unilateral wheeze chest xray: radiopaque foreign body bronchoscopy: confirms dx and allows removal of foreign body smooth obj cannot be grasped easily rigid bronchoscopy is used in all cases and utilization of optical forceps facilitates grasping of inhaled obj epinephrine: to min bleeding

42. Foreign Bodies and Esophageal Injury MC obj in esophagus is COIN toddler 3 locations: cricopharyngeus, area of aortic arch, gastroesophageal junction initial sx: dysphagia, drooling, dehydration cough, stridor, wheezes chest xray for coin, esophagoscopy for nonradiopaque obj coin at upper eso in less than 24 hrs: Margill forceps during direct laryngoscopy sharp obj (safety pins): injure underlying eso, extreme care of extraction plus diligent follow up battery: strictures, can be surgical emergency as neg pole of the battery directly damages the surrounding tissue-- local tissue necrosis--treoesophageal fistula, aortic exsanguination and mediatinitis

43. ESOPHAGUS

44. Esophageal Atresia and Tracheoesophageal Fistula (EA and TEF) 5 major varieties: MC is type C: 85% type A: 8-10% type E/H-type: 8% type D: 2% type B: 1% assoc with VACTERRL syn

45. dx: inability to pass an orogastric tube into the stomach initial mngt: attention on respi status, decompresion of the upper pouch and appropriate timing of surgery, timely search of assoc anomalies. after dx: place an infant warmer with head elevated at least 30 degrees, sump catheter is placed in the upper pouch on continuous suction. IV antibiotics hemodynamically stable: 1 to 2 days after birth do definitive repair via primary esophagoesophagostomy

46. Corrosive Injury of the Esophagus strong alkali: liquefaction necrosis strong acids: coagulation necrosis strictures at anatomic narrowed areas of eso drooling, unable to swallow saliva dx: PE of the mouth and endoscopy w/ flexible or rigid esophagoscope endoscope only at the level of the burn in order to avoid perforation early barium swallow: extent of mucosal injury eso may be burned without evidence of injury to the mouth. antibiotics at acute period

47. stricture-- a string is inserted thru the eso-- fluoroscopically guided balloon dilation of stricture + esophagoscopy under gen anest mngt of eso perforation during dilation: antibiotics, irrigation, closed drainage of the thoracic cavity to prevent systemic sepsis. severe stricture that does not responds to dilation: eso replacement MC used eso rep is COLON and stomach feeding jejunostomy is placed at time of surgery and tube feedings once postop ileus has resolved.

48. Gastroesophageal Reflux (GER) passage of gastric contents into the eso GERD: reflux is symptomatic sx: failure to thrive, bleeding, stricture, reactive airway ds, aspiration pneumonia, apnea barium swallow: obs o f stomach or duodenum, malrotation freq and severity: 24 hr pH probe study , most accurate dx esophageal endoscopy w/ biopsy: esophagitis, length of intra ab d ominal eso, Barrett’s esophagus radioisotope “milk scan”: gastric emptying

49. tx: initially by conservative mngt propping and thickening the formula w/ rice cereal, prone head pos older children w/ severe GERD: PPI medical tx is successful neurologic problems: surgery least invasive: nasojejunal or gastrojejunal feeding tube. fundoplication : definitive tx for GER fundus is wrapped around distal eso either 360 (Nissen) or lesser degrees (Thal Toupet) via laporoscopy early postop complications: pneumonia, atelectasis late postop complications: wrap breakdown with recurrent reflux and dysphagia

50. Gastrointestinal Tract

51. Hypertrophic Pyloric Stenosis (HPS) nonbilious vomiting, projectile, days to weeks progressive thickening of the pylorus muscle--complete gastric outlet obs--no longer able to tolerate any feeds--inc dehydrated--wet diapers become less frequent, less passage of flatus 3 and 6 weeks of age 5M: 1F familial link: SNP: genome that reg cholesterol hypochloremic, hypokalemic metabolic alkalosis “olive” in RUQ, gastric waves in the abd UTZ: current standard of care, 95% accurancy criteria: channel length of over 16mm, pyloric thickness over 4 mm contrast radiography: delayed passage of contents from stomach thru pyloric channel, thickened pylorus

52. tx: never a surgical emergency fluid: 5% dextrose, 0.45% saline, potassium of 2-4 mEq over 24 hours at a rate of 150-175 ml/kg for 24 hours will correct the underlying deficit adeq urine output: > 2 cc/kg per hour: rehydration Fredet-Ramstedt pyloromyotomy: open or lap open pyloromyotomy: umbilical( cosmetically appealing) or RUQ transverse abd incision (easier access to antrum and pylorus) lap pyloromyotomy: cosmetic result is superior splitting the pyloric muscl e while leaving the underlying submucosa intact incision: proximal to pyloric vein of Mayo to gastric antrum, 1 to 2 cm postop: IV fluids for several hours then pedialyte, followed by formula or breast milk discharged 24 to 48 hours after surgery c o mplications: perforation of the mucosa, bleeding, wound infection, recurrent sx

53. Intestinal Obstruction in the Newborn cardinal sign: bilious emesis surgical emergency abd films in supine and upright (or lateral decubitus) : air-fluid levels or free air, how far downstream air has managed to travel determine if it is proximal or distal to ligament of Treitz Proximal intestinal obstruction : bilious emesis and minimal abd distention, flat or scaphoid abd, upright and supine abd radio will show paucity or absence of bowel gas Distal intestinal obstruction: bilious emesis and abd distention, passage of black-green meconium 24 to 38 hours.

54. Duodenal Obstruction malrotation and midgut volvulus must be be excluded dx on prenatal UTZ: stomach and proximal duodenum as two discrete cystic structures in the upper abd, polyhydramnios at 3rd trimester classic abd radio: “double bubble sign”= dilated stomach and duodenum tx: orogastric tube - to decompress the stomach and duodenum, IV fluids open approach : abd is entered thru transverse RUQ supraumbilical incision under gen endotracheal anesthesia duodenoduodenostomy : duodenal obstruction due to duodenal stenosis or atresia or annular pancreas premature: duodenal repair asap

55. Intestinal Atresia developmental defects in normal intestinal organogenesis due to disruption of various signaling pathways (fibroblast GF, bone morphogenic protein and B-catenin) jejunal or ileal atresia: bilious vomiting and progressive abd distention the more the distal the obst=more distended the abd becomes=greater no of obstructed loops on upright abd films clinical feature + straggered air-fluid levels on plain abd films: OR after resuscitation laparotomy: type 1: mucosal atresia with intact muscularis type 2: atretric ends connected by fibrous band type 3A: 2 ends of atresia are separated by a V-shaped defect in mesentery type 3B: “apple-peel” or “chritmas tree” deformity, bowel distal to atresia receives its blood supply in a retrograde fashion from ileocolic or right colic art type 4: multiple atresias with “ string of sausage” or “ string of beads” anastomosis using end-to-back technique in which the distal, compressed loop is “ fish-mouthed” along its antimesenteric border

56. Malrotation and Midgut volvulus genetic mutations disrupt the signaling critical for normal intestinal rotation. BCL6 = absence of left-sided expression o f its transcript= reversed cardiac orientation, defective ocular devt and malrotation. FOXF1 : intestinal malrotation with alveolar capillary dysplasia Ladd’s bands : if rotatio n is incomplete but the bands fixing the duodenum to retroperitoneum and cecum continue to form= potential for obstruction

57. M idgut volvulus volvulus may occur around the mesentery= obstruct the proximal jejenum and cuts off the blood supply to the midgut 1st few weeks of life 1st sign: bilious vomiting occurs clockwise and so untwisted counterclockwise: “turn back the hands of time”- -Ladd’s procedure to broaden the narrow mesenteric pedi c le to prevent volvulus from recurring--bands b/w cecum and abd wall and b / w duodenum and terminall ileum are divided sharply to splay out the SMA into RLQ and cecum into LLQ--appendix is removed if left untreated: short gut syndrome requiring intestine transplantation, bloody stools, circulatory collapsed

58. Meconium Ileus thick, highly viscous meconium impacted in the ileum and leads to high-grarde intestinal obstruction mutation in CFTR gene: infants w/ CF with pancreatic enzyme def and abn chloride secretion in the intestine uncomplicated : no intestinal perforation, terminal ileum is filled pellets of meconium complicated : with prenatal intestinal perforation or w/ vascular compromise of the distended ileum, intraperitoneal calcifications “eggshell” pattern on plain abd xray “ground glass appearance” -s mall bubbles of gas become entrapped in the inspissated meconium in the distal ileum dx confirm by contrast enema: microcolon

59. uncomplicated: nonoperative, dilute water-soluble contrast or NAC (mucomyst) is infused transanally via catheter unde r f luoroscopic control into dilated portion of the ileum--inability to reflux the contrast into the d i lated portion of the ileum signals assoc atresia or complicated meconium ileus and warrants exploratory laparotomy surgery: w/ NAC as a dilute contrast agent to irrigate-- resect the distended terminal ileum--meconium pellets are flushed from distal small bowel--end ileostomy--distal bowel is brought up as a m u cus fistula or sewn to the side ileum as classic “bishop koop anastomosis”

60. Necrotizing Enterocolitis (NEC) MC and most lethal GI disorder affecting the intestine of the stressed, preter m neonate risk factors: prematurity and initiation of enteral feeding 10 days postnatally when GIT is colonized by coliforms Enterobacter sakazakii : contaminated infants fed formula E. coli, Enterobacter, Klebsiella , coagulase-negative Staphylococcus : blood, peritoneal fluid and stool of infants w/ advanced NEC MC in terminal ileum, followed by colon gross: bowel distention with patchy areas of th inning, pneumatosis, gangrene or frank perforation. micro: “bland infarct” characterized by full thickness necrosis

61. life threatening sepsis by Bell and colleagues Bell stage I: feeding intolerance (vomiting or large residual vol from previous feeding in the stomach at the time of next feeding), bowel rest and IV antibiotics Bell stage II: abd distention and tenderness, bilious nasogastric aspirate and bloody stools: intestinal ileus and mucosal ischemia pathognomonic radio: pneumatosis intestinalis (invasion of ischemic mucosa by gas producing microbes) dec urine output, hypotension, tachycardia, noncardiac pulmo edema leukocytosis or leukopeni a , inc bands, thrombocytopenia, inc BUN and plasma creatinine Bell stage III: most advanced , abd radio shows pn e umoperitoneu m indicating intestinal perforation fulminant course w/ progressive peritonitis, acidosis, sepsis, DIC, death

62. premature + inc TLR4 expression: activation of TLR 4 by colonizing bacteria--severe proinflamatory response and devt of NEC breastmilk: protective against NEC by suppress TLR4 signaling tx: feedings are discontinued, NGT, broad antibiotics, inotrope to maintain perfusion Bell stage I: closely monitored and remain in NPO and IV antibiotics for 7 to 10 days Bell stage II: if px fail to improve after several days, exploratory lap Bell stage III: lap--gangrenous or perforated bowel is resected and intestinal ends are brought out as stomas.

63. Spontaneous Intestinal Perforation (SIP) vs NEC SIP: perforation in th e terminal ileum histo: mucosa is intact, not necrotic, no sign of ischemia, submucosa is thinned at the site of perforation, no pneumatosis intestinalis, better outcome, responds better to peritoneal drainage tx: surgical with intestinal resection and stoma creation followed by stoma reversal once child is stable

64. Short Bowel Syndrome (SBS) extremely morbid condition gastroschisis, malrotation, atresia and NEC may lead to SBS. multidiscliplinary approach to prevent infection, reduce cholestasis and improve nutrition and feeding independence

65. Intessusception leading cause of intestinal obstruction in young child segment of intestine becomes drawn into the lumen of the more proximal bowel. begins at terminal ileum and extend into ascending, transverse or descending colon cause: hyperthrophy of the Peyer’s patches in the terminal ileum from antecedent viral infection idiopathic: 6 to 24 months of age pathologic: beyond 24 months: polys, malignant tumor such as lymphoma, enteric duplication cysts, merkels diverticulum

66. preceded by GI viral illness paroxysms of crampy abd pain, intermittent vomitin g bloody mucus “currant jelly” stool passed per rectum, elongated mass in RLQ (Dance’s sign) tx: resuscitation + IV antibiotics + radiographic reduction ( if without peritonitis) or urgent laparotomy (if + peritonitis) stable px: air enema is both diagnostic and curative air is introduced with manometer, pressure shou l d not exceed 120 mmHg if not successful: repeat at t te mp t of reduction after few hours successful reduction: free reflux of air into multiple loops of small bowel and symptomatic improvement (pain free)

67. failure to reduce: open or lap reduction open reduction : RLQ incision, delivering intussuscepted mass into the wound--gentle distal pressure--intussusceptum is gently milked out of the intussusc i piens. lap reduction : 5mm laparoscope placed on umbilicus, 2 5mm ports in R and LLQ--bowel bowel is viable, reduction is performed by milking tne bowel or using gentle traction by atraumatic bowel graspers. IV antibiotics are continued until postop ileus subsides--clear fluids, DTA recurrence: repeat air enema

68. Appendicitis gen abd pain that localize at RLQ diagnostic delay due to childs inability to localize the pain--often present with perforation dx: CT is reliable, UTZ has good visualization, MRI high specificity and sensitivity boys: localized RLQ tenderness assoc with low g ra de fever and leukocytosis--surgical exploration girls: UTZ to exclude ovarian patho (cyst, torsion, tumor)--if all are neg but pain persist, diagnostic lap is performed--appendix is removed even if it appers to be normal

69. tx: IV fluids + 2nd gen cephalosporin lap appendectomy: small incision at umbilicus, 2 additional incision at lower abd , appendix is delivered at umbilicus, all incisions are closed with dissolvable sutures--solid food next day perforated appendicitis: abd pain, vomiting and diarrhea sym for 4 to 5 da y s: abscess is suspected, CT of abd to visualized and search for abscess, phlegmon or fecalith. if fecalith is outside the appendix, retrieve and remove it along with appendix

70. Intestinal Duplications mucosa-lined structures that are in continuity with GIT at ileum within the leaves of the mesentery. cystic masses recurrent abd pain, emesis, hematochezia, palpable mass short duplication: resection of the cyst and adjacent intestine with end to end anastomosis. long duplication: multiple enterotomies and mucosal stripping in the duplicated segment--allow the walls to collapse and become apparent.

71. Merkel’s Diverticulum remnant of portion of the embryonic omphalomesenteric (vitelline) duct. at antimesenteric border of the ileum, 2 ft of ileocecal valve perforation: if outpouching becomes impacted with food--distention and necrosis. ectopic gastric mucosa may produce leal ulcerations that bleed--marron-colore d stools tx: surgical if base is narrow and no mass at lumen of diverticulum: wedge resectio n of the diverticulum with t ransverse closure of ile u m if base is wide and mass of ectopic tissue, with inflammation: resection of the involved bowe l and end to end ileoileostomy

72. Mesenteric Cyst within mesentery do not contain mucosa or muscular wall Chylous cyst: result form congenital ly m phatic obstruction can cause i n testinal obstruction or present as abdominal mass. tx: surgical excision, resection of adjacent intestine partial excision or marsupialization: if close proximity to vital structures

73. Hirschsprung’s Disease absence of ganglion cells in Auerbach’s plexus and hypertrophy of assoc nerve trunks rectum and rectosigmoid mutation in GDN F , its receptor Ret and its coreceptor Gfra-I--- impaired neural crest migration in utero--Hirschsprung ds aganglionic colon does not permit normal peristalsis--functional distal int e stinal obstruction--abd distention, failure to pass meconium and bilious emesis. any infant who does not pass meconium beyond 48 hours of life should be investigated for Hirschrung ds complication: Enterocolitis: abd distention and tenderness and sys toxicity ( fever, failure to thrive, and lethargy) rec ta l exam: forceful expulsion of foul-smelling liquid feces

74. tx: rehydration,sys antibiotics, nasogastric decompression and rectal irrigation. decompressive stoma: if did not response to nonoperative mngt rectal biopsy: definitive diagnosis sample of mucosa and submucosa at 1 cm, 2 cm and 3cm from the dentate line surgery: colostomy at newborn--definitive pull-through operation after the child is 10kg barium enema : location of the b owel where the transition zone between ganglionic and aganglionic bowel exists--rese ct ing the aganglionic segment of the bowel--anastomosing the ganglionated bowel to either the anus or a cuff of rectal mucosa

75. 3 pull-through procedures: 1. Swenson : aganglionic rectum is dissected in the pelvis and removed down to the anus 2. Duhamel : dissection outside of the rectum at retrorectal space and the ganglionic colon is anstomosed posteriorly just above the anus ant wall of the ganglionic colon and posterior wall of aganglionic rectum are anastomosed using a stapler. 3. Soave : dissection entirely within the rectum rectal mucosa is stripped from the muscular sleeve and the ganglionic colon is brought thru this sleeve and anastomosed to the anus. anastomosis at least 5cm from the point at which ganglion cells are found to av o id the transition zone.

76. Anorectal Malformations congenital anomalies: imperforate anus and persistent cloaca embryogenic basis: failure of descent of urorectal septum imperforate anus: rectum fails to descend thru the external sphincter complex-- rectal pouch ends blindly in the pelvis--communicates more distally with GUS or perineum thru a fistulous tract.

77. surgical mngt of imperforated anus: determined by anatomic defect low lesion: perineal operation without colostomy high lesion: colostomy--pull-through procedure at 2 months age (PSARP procedure) persistent cloaca: urinary tract needs to be carefully evaluated at the time of colostomy formation to ensure that normal emptying can occur and to determine whether the bladder needs to be drained by means of vesicostomy

78. JAUNDICE

79. Biliary Atresia fibroproliferative obliteration of the biliary tree--hepatic fibrosis, cirrhosis and end stage liver failure juandice at birth or shortly thereafter acholic pale gray appearing stools fractionation of serum bilirubin: determine if hyperbilirubinemia is conjugated or unconjugated tx: Kasai portoenterostomy

80. Choledochal Cyst spectrum of congenital bi li ary tract disorders that were previously grouped under the name idiopathic dilation of common bile duct type I: fusiform dilatation of the bile duct, MC type I I: cyst appear as an isolated diverticulum protruding from the wall of CBD type III: from the intraduodenal portion of CBD , “choledochoceles” type IV A: multiple dilatations of intrahepatic and extrahepati c bile duct type IV B: multiple, extra hepatic BD type V: multiple, intra hepatic BD

81. 4F: 1M triad: abd pain, mass, jaundice if left undiagnosed: cholangitis and portal htn prenatal UTZ: screening abd UTZ: cystic structures arising from biliary tree CT: confirm, dimensions of cyst and its frel to vasculr structures in porta hepatis tx: surgical excision followed by biliary enteric reconstruction malignancy: complete cyst excision prognosis: excellent complication: cholangitis, intrehepatic stone

82. Deformities of the Abdominal Wall

83. Umbilical Hernia failure of umbilical ring to close resu l ts in a central def ec t in linea alba covered by normal umbilical skin and subcutaneous tissue, fascial defect allows protrusi o n of abdominal contents. <1 cm: close spontaneously by 4 to 5 years of life large : early repair signs of incarceration: abd pain, bilious emesis, tender hard mass protuding from the umbilicus--immediate exploration and repair of hernia to avoid strangulation outpatient : general anethesia , small curving incision at skin crease of the umbilicus is made--sac is dissected free from the overlying skin--absorbable, interrupted suture at transverse plane--skin is closed using subcuticular sutures

84. Patent Urachus d evt of coelomic cavity, there is free communication b/w urinary bladder and abd wall thru the urachus which exist adjacent to the omphalomesenteric duct--persistent of this duct results in communication b/w bladder and umbilicus 1st sign: moisture or urine flow from the umbilicus, recurrent UTI initial tx: drainage of infected cyst--cyst excision persistently draining umbilicus confirmed by umbilical exploration--urachal tract is excised and the bladder is closed w/absorbable suture

85. Omphalocele congenital defect of the abd wall in which the bowel and solid viscera are covered by peritoneum and amniotic membrane either small or giant omphalocele (>/4cm and co n tains liver) prematurity an d intrauterine growth restriction should be covered to reduce fluid loss no pressure should be place prophylactic broad spectrum antibiotics in case of rupture primary repair: resection of the omphalocele membrane and closure of the fascia--prosthetic mat for closure very large: no n perative approach: topical treatments to harden the sac to allow for more protective coverage where muscle and skin cannot be used open the base in order to allow the abd contents and liver to reenter the abd cavity--sewing synthetic material to achieve facial closure

86. Gastroschisis c ongenital defect char by defect of the AAW (at junction of umbilicus and normal skin) thru which the intestinal conte n ts freely protude no underlying sac, <4 cm umbilicus partly detached allowing free c ommunication with the abdominal cavity intestine is thick, edematous, discolored and covered with exudate. dx by prenatal US tx: urgent surgical vigorous fluid resuscitation 160-190 cc/kg/day intestine can be returned to abd cavity

87. plastic spring-loaded silo c a n be placed onto the bowel to cover it and allows for graduated reduction on a daily basis as the edema in the bowel wall decreases--surgical closure after 1 to 2 weeks--prosthetic piece to bring the edges of the fascia together

88. Prune Belly Syndrome extremely lax lower abd musculature, dilated urinary tract including the bladder, bilateral undescended testes wrink l ed AAW males comorb i dity: pulmo hypoplasia major GUT manifesta t ion: ureteral dilation bilateral orchidopexy is performed in conjunction with abd wall recon s truction at 6 to 12 months of age infertility (def of prostatic fluid and retrograde ejaculation) abdominoplasty for abd wall repair (transverse incision in the lower abdomen extending into the flanks)

89. Inguinal Hernia failure of closure of processus vaginalis--communication persists between peritoneal cavity and groin groin bulge all congenital hernias in children are by def indirect inguinal hernia R side >L side herniorrphaphy: closing the patent processus vaginalis high risk for incarceration of inguinal hernia--reduced by gentle pressure on the sac from below the direction of the internal inguinal ring--herniorrhaphy within 24 hours if cannot be reduced: lap and bowel resection

90. GENITALIA

91. Undescended Testis ( C ryptorchidism) interruption of the normal descent of the testis into the scrotum testicle may reside in the retroperineum, internal inguinal ring, inguinal canal, external ring preterm dx: supine pos: hypoplastic or poorly rugated scrotum unilateral undescended testis palpated at inguinal canal or in upper scrotum males with bilateral undescended testes are infertile--repositioned by 1 year of ag e, chorionic g o nadotropin micropenis + bilateral undescended testis: testosterone replacement surgical correction: if no testicular descent after 1 month of endocrine therapy-- combined groin and scrotal incision, cord vessel are fully mobilized, testicle is paced in adartos pouch within the scrotum + orchidopexy

92. Vaginal Anomalies

93. Ovarian Cyst and Tumors nonneoplastic : cysts, endometriosis and inflammatory lesions neoplastic : mesenchymal components of the urogenital ridge, germi nal epi overlying the urogenital ridge and germ cells migrating from the yolk sac MC variety is germ cell tumor MC germ cell tumor is teratomas least differentiated tumor are dysgerminomas abdominal pain, palpable abd mass, urinary obstruction, bowel obs, endocrine imbalance large cyst: 4-45cm should be resected

94. malignant: obtain tumor markers a-fetoprotein (teratomas) LDH (dysgerminoma) BHCG (choriocarcinoma) CA 125 (epithelial tumors) very sensitive to radiation and chemotherapy surgical approach: preservation of the ipsilateral fallopian tube and preservation of noninvolved ovary

95. Ambiguous Genitalia male phenotype: Y chromosome, SRY is normal without point mutations or deletions, testosterone and MIS must be produced by differentiated gonad---any disruption of orderly steps n sexual differentiation is reflected as variant of inntersex syndrome true hermaphroditism : rarest, with ovarian and testicular gonadal tissue, 46 XX, both testis and testicular portion of the ovotestis should be removed Male pseudo hermaphroditism : deficient masculization of the external genitalia, bilateral testes are present but the duct structures differentiate partly as phenotypic females, inability to convert testosterone to dihydrotestosterone due to 5a-reductase deficiency

96. female pseudohermaphroditism : MCC is congenital adrenal hyperplasia, 46 XX, overprod of intermediary steroid hormones which result in masculinizationn of the external genitalia of XX fetus mixed gonadal dysgenesis : dysgenetic gonads and retained mullerian structures, mosaic karyotype 45XO, 46 XY surgical reconstructi o n should be performed after a full genetic workup and with involvement of pediatric endo, plastic surgeon and ethicist w/ expertise in gender tissue

97. Pediatric Malignancy

98. Wilm’s tumor MC primary malignant tumor of kidney in children 1-5 y/o, peak at 3 asymptomati c mass in flank or upper abdomen abd and chest CT: characterized the mass, identify the presence of metastases, provide information on the opposite kidney goal of sugery: complete removal of tumor with sampling of regional lymph nodes nephroureterectomy + chemo and or radiation cure rate: 90%

99. Neuroblastoma 3rd MS pediatric malignancy low survival arise from neural crest and show diff level of differentiation tumor originate in the adrenal gla n ds, pos mediastinum, neck , pelvis, any sympa ganglion dx : elevated serum catecholamine (dopa, norepinephrine) or urine cathecholamine metabolites (VMA, HVA) goal of surgery: complete resection biopsy--preop chemo--surgical resection

100. Rhabdomyosarcoma primitive soft tissue tumor that arises from mesenchymal tissues MC site is head and neck , ectremities, GUT and trunk. tumor grows locally into surrounding structures and metasta size widely to lung, regional LN, liver, brain and bone marrow p rimary resection : when complete excision can be performed without causing disability. if primary resection is not possible: biopsy plus intensive chemotherapy--resection after decrease in size of tumor

101. Teratoma tumors composed of tissue from all three embryonic germ layers at midline structures th o r a cic teratomas: anterior mediastinal mass ovarian teratomas : abd mass with sym of torsion, bleeding or rupture retroperitoneal teratomas: flank or abd mass

102. Sacrococcygeal Teratoma large mass extending from sacrum in newborn dx: prenatal UTZ identified at birth and are benign complete resection asap for excellent cure rate recurrence: platinum based chemotherapy

103. Liver tumors >2/3 are malignant 2 histo: hepatoblastoma carcinoma: MC malignancy of liver in children , < 4 y/o, unifocal, if completely removed majority of px survives hepatocellular carcinoma: 10-15 y/o, invasive or multicentric abd mass that is painless, anorexia and weight loss liver fx test is normal, inc AFP abdominal CT scan: determine the resectability of the lesion. complete surgical resecti o n of tumor is primary goal and essential for cure unresectable: preop chemo to reduce the size of tumor and improve possibility of complete removal areas of locally invasive ds, diaphragm, should be resected at time of surgery

104. Trauma in Children

105. Mechanism of Injury most pediatric trauma is blunt penetrating injuries : gun violence, falls onto sharp obj, penetration by glass a fter falling thru windows male 14-18 y/o: exposed to contact sports, gun violence, drive motor vehicles . infant and todler: falls are common cause of severe injury mngt: airway is 1st priority px with signs of vol depletion: 20 ml/kg bolus of saline or LR--after 3 boluses and does not respond--BT (10mg/kg) plus search for source of bleeding (chest, abd, pelvis, extremity fractures or large scalp wounds)

106. Injuries to CNS CNS is the MC injured organ system and is the leading cause of death among injured children. toddler: nonaccidental trauma is the MCC of serious head injury abuse: retinal hemorrhage o n fundoscopy and intracranial hemorrhage without evidence of external trauma ( shaking injury )and fractures at different stages of healing on skeletal injury older: falls, bicycle and motor collision head CT: extent of injury severe head injury (GCS 8 is less): intracranial pressure monitoring snd undergoes craniotomy

107. Thoracic injuries pedia thorax is pliable due to incomplete calcifications of ribs and cartilage blunt chest injury: pulmo contusion that resolves with ventilatory mngt and volume resuscitation chest radio mngt: ventilation and tx of coexisting CNS or abd injuries

108. Abdominal Injuries small rib cage and min muscular coverage of the abd--significant injury after minor trauma liver and spleen unprotected and injured after blunt trauma from child abuse or injury from bicycle handlebar duodenal hematomas: resolve without surgery small intestinal injury: at jejenum in the are of fixatio by the ligament of Treitz. caused by rapid decelerationn in the setting of seat belt--small bowel injury

109. Fetal intervention in speficic circumstances where fetal surgery offer the best possibility for a successful outcome maternal viewpoint:may lead to uterine bleeding due to uterine relaxation fetus viewpoint : risk of premature labor and amniotic fluid leak

110. Fetal surgery for lower urinary tract obstruction group of ds characterized by obstruction of the distal urinary system causes: pos terior urethral valves and urethral atresia resultant massive bladder distention--reflux hydronephrosis--oligohydramnios--limb contractures, facial anomalies (Potter sequence) and pulmo hypoplasia vesicoamniotic shunting--relieving the obstruction and improving renal function, fetal growth and lung development may be preserved.

111. Fetal surgery for Myelomeningocele Myelomeningocele: spectrum of anomalies in which portion of the SC are uncovered by SC. ne u ral tissu e exposed to injurious effects of amniotic fluid and trauma from contact with uterine wall. nerve damage--lower ex paralysis, bowel and bladder dysfunction prenatalsurgery reduced the need for shunting and improved motor outcome at 30 months

112. EXIT procedure ex utero intrapartum treatment utilized where airway obstruction is predicted at time of delivery due to presence of large neck mass maintain uteroplacental perfusion cystic neck masses such as lymphangiomas have more favorable response to an exit procedure as compared to solid tumors such as teratomas in premature px.