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Necrotizing Enterocolitis

Acquired neonatal disorder that causes serious intestinal injury Combination of vascular, mucosal, and metabolic insults Unknown cause


What is the most common GI emergency in preterm infants?

Necrotizing enterocolitis


Sequence of necrotizing enterocolitis

Initial ischemic / toxic mucosal damage Loss of mucosal integrity Availability of suitable substrate (enteral feedings) Bacterial proliferation Invasion of damaged mucosa by gas-producing organisms Intramural bowel gas Transmural necrosis or gangrene Intestinal perforation Peritonitis


Most commonly involved areas of necrotizing enterocolitis

Terminal ileum Proximal colon


Appearance of necrotizing enterocolitis (gross and microscopic)

Gross: irregularly dilated with hemorrhagic or ischemic areas of frank necrosis Microscopic: mucosal edema, hemorrhage, ulceration


Risk factors for necrotizing enterocolitis

Prematurity is the primary risk factor -Immature GI system -Immature immune response -Impaired circulatory dynamics


How is breast milk protective against NEC?

IgA Macrophages, lymphocytes Complement components Lysozyme, lactoferrin Acetylhydrolase


GI and systemic signs of NEC

GI: feeding intolerance, abdominal distension, abdominal tenderness, emesis, occult/gross blood in stool, abdominal mass, erythema of abdominal wall Systemic: lethargy, apnea/respiratory distress, temperature instability, hypotension, acidosis, glucose instability, DIC, positive blood cultures


Timeline for NEC presentation

The closer to full term the child is, the more acute the onset will be (full term = 3 days;


Sudden onset NEC

Full term or preterm infants Acute catastrophic deterioration Respiratory decompensation Shock/acidosis Marked abdominal distension Positive blood culture


Insidious onset NEC

Usually preterm Evolves during 1-2 days Feeding intolerance Change in stool pattern Intermittent abdominal distension Occult blood in stools


Dx of NEC

Abdominal x-rays Supportive of NEC: abnormal gas patterns, ileus, fixed sentinel loop of bowel, areas suspicious for pneumatosis intestinalis Confirmatory of NEC: intramural bowel gas (pneumatosis intestinalis), intrahepatic portal venous gas


Pneumatosis Intestinalis

Hydrogen gas within the bowel wall -Linear streaking pattern ("hallmark" of NEC) -Bubbly pattern


Portal venous gas

Extension of pneumatic intestinalis into portal venous circulation -Linear branching lucencies overlying the liver and extending to the periphery -Associated with severe disease and high mortality



Free air in the peritoneal cavity secondary to perforation -Falciform ligament may be outlined ("football" sign) SURGICAL EMERGENCY


Stage I: suspected NEC

Systemic: nonspecific-- apnea, bradycardia, lethargy, temp instability Intestinal: feeding intolerance, gastric residual, guiac + stool Radiologic: normal or nonspecific


Stage II-A: Mid NEC

Systemic: similar to stage I Intestinal: abdominal distension, no BS, +/- tenderness, gross blood in stool Radiographic: ileus w/ dilated loops w/ focal pneumatosis intestinalis


Stage II-B: Moderate NEC

Systemic: Stage I plus mild acidosis and thrombocytopenia Intestinal: Increased distension, abdominal wall edema, tenderness, +/- palpable mass Radiographic: extensive pneumatosis and early ascites, +/- portal venous gas


Stage III-A: Advanced NEC

Systemic: resp/metabolic acidosis, assisted vent-- apnea, decreased BP and urine output, neutropenia, coagulopathy Intestinal: increased edema, erythema, or discoloration, induration of abdominal wall Radiographic: prominent ascites, paucity of bowel gas, persistent sentinel loop


Stage III-B: Advanced NEC

Systemic: Generalized edema, decreased vital signs/lab values, shock, DIC Intestinal: tense, discolored abdomen with ascites Radiographic: absent bowel gas, intraperitoneal free air


BASIC NEC Protocol

NPO; TPN NG tube for decompression Close monitoring of VS and head circumference Abx-- ampicillin/gentamicin Monitor for GI bleed Monitor I&O Remove K from IV fluids if hyperkalemic or anuric Labs: CBC, CMP, ABGs (every 6-8 hours) -Check for sepsis X-rays (every 6-8 hours)


When to get surgical consult

Suspected or proven NEC


Indications for surgery in NEC

Portal venous gas; pneumoperitoneum Clinical deterioration Positive paracentesis Fixed intestinal loop on serial x-rays (over 24 hours) Erythema of abdominal wall (peritonitis)


NEC complications

Feeding difficulties FTT Malabsorption Strictures (most common) Fistulas Hepatic dysfunction secondary to long term TPN Long term sequelae from neuro or renal damage IF bowel resected: short gut syndrome, nutritional deficiencies, obstruction (Adhesions), long term morbidity with ostomies


What presentation has the best prognosis?

Late onset NEC



Incomplete rotation of the intestine during fetal development-- genetic mutations Most common: failure of cecum to move in the RLQ


Malro with Volvulus: Features

Presents within first few weeks of life BILIOUS VOMITING Acute small bowel obstruction (closed loop) Early: irritability, distended, rigid abdomen, bilious emesis, decreased stool Late: vascular compromise-- bloody stools, circulatory collapse Older children: abdominal pain/asymptomatic; incomplete obstruction


Dx: Midgut volvulus

Abdominal x-ray: double bubble sign-- initial study of choice; diagnostic Other: Upper GI series, Barium enema


Tx: midgut volvulus

Surgical emergency


How does volvulus twist?

Clockwise --Untwist it counterclockwise "Turn back the hands of time"


Volvulus procedure

Untwist (Detorse) the bowel Ladd procedure with appendectomy



congenital defect of the abdominal wall in which the bowel and solid viscera are covered by peritoneum and amniotic membrane and the umbilical cord inserts into the sac -Associated with prematurity and IUGR


Omphalocele: associated anomalies

Cardiac Chromosomal: Exstrophy of the cloaca (vesicointestinal fissure) Beckwith-Wiedemann constellation of anomalies (macroglossia, macrosomia, hypoglycemia, visceromegaly, omphalocele) Cantrell's pentalogy (lower thoracic wall malformations, ectopia cordis, epigastric omphalocele, anterior midline diaphragmatic hernia, cardiac anomalies)


Omphalocele: initial management

Monitor vital signs-- esp. body temp Blood glucose monitoring Cover to reduce fluid loss (dry dressings or topicals) Avoid pressure on the sac (risk of rupture) Prophylactic broad-spectrum abx


Omphalocele: Repair

Primary: resection of omphalocele membrane and closure of fascia Giant: cannot close primarily-- treat with topicals 2-3 months, skin will grow, attempt closure of anterior abdominal wall. Requires complex measures to achieve skin closure-- use of biosynthetic materials or component separation



Defect in anterior abdominal wall through which the intestinal contents freely protrude No overlying sac and size of defect is usually


Gastroschisis: Tx

Urgent surgical repair -Vigorous fluid resuscitation (evaporative losses) -Possible primary surgical closure at birth (preferred) -Intestinal function does not return for weeks-- requires TPN, followed by feeding advancements


Gastroschisis: thick, swollen bowel

Cannot reduce primarily Plastic spring-loaded silo placed on bowel and secured beneath fascia or sutured silastic silo Covers bowel, allows for graduated reduction on daily basis as edema decreases Surgical closure occurs within 1-2 weeks