Section 7: Gastroenterology/Nutrition/Hepatology

INTRODUCTION

Nutrition support intervention varies depending on which phase of illness a patient may be in. Three phases of critical illness are highlighted.^1–3

FIRST PHASE OF ILLNESS: ACUTE PHASE

• Duration: 6 to 8 hours after onset of illness or trauma

• Characteristics: Fever, tachycardia, hypoglycemia

• Nutrition intervention: Usually NPO during resuscitation with fluids, inotropes, pressors, and/or blood products

Please note, though, that growth is inhibited at this time. Energy metabolism is diverted toward the stress or injury.

SECOND PHASE OF ILLNESS: EBB PHASE

• Duration: Varies

• Characteristics:

  • INCREASED: Catecholamines, counterregulatory hormones (glucagon, cortisol) → hyperglycemia, growth hormone, cytokine production, free fatty acids → possible hypertriglyceridemia, antidiuretic hormone (ADH), gluconeogenesis

  • DECREASED: Insulin level, insulin growth factor-1, acute decrease in metabolic rate

• Nutrition intervention: These metabolic and hormonal changes are not reversed or impaired by providing an increased amount of calories. Calories should be limited because providing an excess amount of nutrients could be deleterious.

Weights most likely will reflect increased fluid status due to increased ADH and not reflect the true somatic status of the patient.

THIRD PHASE OF ILLNESS: FLOW PHASE

TWO SUBCATEGORIES: CATABOLIC AND ANABOLIC

Catabolic Flow Phase

• Duration: Varies

• Characteristics: Hypermetabolism due to endogenous catabolism of fat, carbohydrate, and protein stores; active inflammatory processes; hyperglycemia; glucose intolerance; lipolysis; and negative nitrogen balance

• Nutrition intervention: Until the metabolic and hormonal alterations subside, nutrient provision should remain toward basal metabolic needs with the exception of providing an increased amount of protein as permissible per renal and liver status. Amino acids are pulled from muscle, connective tissue, and the gut (if inactive) to promote gluconeogenesis and production of acute-phase proteins, such as C-reactive protein (CRP).

There will be a decrease in synthesis of visceral protein stores of albumin and prealbumin.

Anabolic Flow Phase

• Duration: Varies

• Characteristics: Restoration of tissue composition, depleted energy reserves, and positive nitrogen balance

• Nutrition intervention: Nutrient provision should now be increased to promote nutrition repletion. Patient is now approaching convalescence and growth will resume; thus, more calories will be needed.

COMPONENTS OF ENERGY EXPENDITURE

Total energy expenditure = Basal metabolic rate + Energy from thermogenesis + Energy for activity* + Energy for growth* + Energy for healing process⁴

*Please note patients in the PICU are usually not active nor are they growing, so these components are excluded in determining energy needs.⁵

CONSIDERATIONS FOR DETERMINING ENERGY NEEDS

1. Phase of illness

2. Severity and duration of illness

3. Respiratory status: intubated vs. O₂ (mask ventilation/nasal cannula) vs. room air

4. Sedation status

5. Muscle relaxed or pentobarbital coma

6. Injury or stress factors, such as fever, sepsis, wounds, burns, cardiac failure, status post surgery

7. Baseline calorie needs (especially if chronically ill)

CALCULATING CALORIE PROVISIONS

There are many predictive equations, of which none are based on the critically ill pediatric population except for the White equation. This equation includes many patient variables (based on age, weight, weight for age Z score, body temperature, number of days after intensive care admission, and primary reason for admission) and is not easy to calculate.⁶ Table 62-1 provides a basic approach to calculating calorie needs.

The gold standard for determining calorie needs is to measure the patient's calorie needs by indirect calorimetry, otherwise known as a metabolic cart study, which is reviewed in Chapter 9.⁷ A metabolic cart may be available in the PICU and be conducted by the appropriate trained personnel.

See Table 62-1 for the predictive equation to use to estimate resting energy expenditure (REE = Basal metabolic needs X Factor for thermogenesis) needs during the acute and ebb phases of illness⁸:

As the patient's acute illness status improves, the energy needs may increase, with the goal of moving toward the patient's usual baseline calorie needs.⁹

PROTEIN NEEDS

• Protein needs during acute illness are usually more than when healthy (Table 62-2)

• Increased protein provision can help promote a positive nitrogen balance (16% of protein molecule is nitrogen)

NUTRITION SUPPORT

Enteral mode: Use of the gut is always preferred.

Contraindications: Gastrointestinal surgery, prolonged ileus, severe emesis, and/or diarrhea.

Formula selection: Formulas available vary per institution. Selection of the type of formula is based on the patient's acute clinical/medical status to discern the use of a standard intact, semi-elemental, or elemental formula.

Please note the use of fiber-containing formula may be prudent, as constipation may be an issue due to use of sedation agents in the PICU (formulas for children >1 year old contain fiber).

Mode of delivery: Continuous versus bolus

Continuous feeds are recommended if the patient is sedated and/or muscle relaxed or if concern for aspiration/reflux.

Bolus feeds can be started if the patient is more alert and concern for reflux/aspiration is absent. Bolus feeds mimic a more physiologic feeding pattern.

NJ versus NG is a debated issue. If there is increased concern for reflux or aspiration post-pylorus (transpyloric tube—ND or NJ), it may help to reduce occurrence of reflux/aspiration.⁶ Transpyloric tubes need to be placed by a trained health care provider or interventional radiologist.

NG feeds reflect more normal feeding route and are easily placed by bedside nurse.

Note: Cannot provide bolus feeds via an NJ tube.

Total parenteral nutrition (TPN) mode: Less physiologic, more expensive, and increased risk of complications, including infection and line placement problems.¹⁰

TPN is individually tailored to the patient by determining the amount of macronutrients and micronutrients to provide.

Dextrose: 3.4 kcals/gm (gm = % dextrose × volume)

Amino acids: 4 kcals/gm

Fat (20% IV fat solution): 10 kcals/gm or 2 kcals/mL

Recommended ratio of calories = 50% to 60% carbohydrate, 10% to 20% protein, 30% to 55% fat¹⁰

Indications for use are the contraindications for enteral mode.

LABORATORY VALUES

During critical illness, shifts in fluid and electrolyte status can occur. Monitoring electrolytes (sodium, potassium, chloride, bicarbonate, glucose, blood urea nitrogen [BUN], creatinine, and calcium) is helpful to assess changes and possible need for electrolyte supplementation or adjustments.^1–3

TPN labs (electrolytes, ionized calcium, magnesium, phosphorus, and triglyceride) should be checked with every change in TPN concentration.¹⁰

C-reactive protein (CRP) levels can help indicate current acute illness status of patient, and obtaining serial measurements can better guide patient's nutrient provision.¹¹

Prealbumin level is a marker of visceral protein stores. During acute illness, prealbumin levels decline. Prealbumin synthesis may resume when the first few phases of illness subside. Serial measurements can indicate the trend of the illness and better guide how much protein to provide (given that CRP levels are within normal limits at the time).¹¹

FORMULA LIST

Premature Infant Formulas

Preterm formulas

Preterm post-discharge formulas

Full-Term Infant Formulas

Infant standard intact formulas

Infant cow's milk protein–based, lactose-free formulas

Infant soy-based formulas

Infant cow's milk–based with thickening agent formula

Infant cow's milk–based with low mineral content formula

Infant impaired long chain fat digestion/absorption formulas

Infant casein hydrolysate formulas

Infant elemental protein formula

Children formulas (1–10 years of age)

Children standard intact formulas (milk protein based)

Children standard intact formulas (soy protein based)

Children semi-elemental protein formulas

Children elemental protein formulas

Children calorie-dense formulas

Children semi-elemental protein, calorie-dense formulas

Children impaired long chain fat digestion/absorption formulas

Adolescent and Adult Formulas (>10 years old)

Adolescent and adult standard intact formulas

Adolescent and adult calorie-dense formulas

Adolescent and adult semi-elemental protein formulas

Adolescent and adult elemental protein formulas

Adolescent and adult renal formulas

Oral Supplements for Children (1–10 years) and Adolescents/Adults (>10 years)

Ketogenic formulas

Metabolic formulas

INTRODUCTION

Gastrointestinal (GI) bleeding is categorized into upper GI bleed (UGIB), bleeding from a source proximal to the ligament of Treitz, and lower GI bleed (LGIB) occurring distal to this duodenojejunal junction point.

TYPICAL CLINICAL PRESENTATIONS

• Upper GI bleed: hematemesis (bright red blood or coffee ground) and/or melena

• Lower GI bleed: hematochezia (bright red blood per rectum)

ETIOLOGY

• Likelihood of various etiologies depends on age and geography.

• Upper GI causes include coagulopathy, gastric or duodenal ulcer, gastritis, Mallory-Weiss tear, varices, esophagitis, and foreign body.

• Lower GI causes include anal fissure, milk protein colitis, coagulopathy, vascular malformations, necrotizing enterocolitis, malrotation with midgut volvulus, intussusception, infectious colitis, Meckel's diverticulum, inflammatory bowel disease, hemolytic uremic syndrome (HUS), Henoch-Schonlein purpura (HSP), lymphonodular hyperplasia, and graft-versus-host disease.

DIAGNOSTIC EVALUATION

• Physical exam: Look for evidence of shock in vital signs, pulses, and perfusion. Evaluate for abdominal distension or tenderness, ascites, jaundice. Examine the anus for fissures.

• History: Ask about Timing/frequency, abdominal pain, severity/amount of blood loss, comorbid conditions, medication exposure, and associated symptoms.

• Serum labs: Coagulation factors, complete metabolic panel, amylase, lipase, complete blood count

• Stool guaiac in lower GI bleed

• Stool for testing for infectious etiology if indicated by the history and symptoms

MANAGEMENT

• Initial evaluation should focus on assessment and treatment of shock in cases of severe and/or brisk bleeding.

• If patient is hemodynamically unstable, follow resuscitation pathway for hemorrhagic shock.

  • Establish IV access, preferably two large-bore IVs.

  • Initial labs should include type and cross-match of blood. If patient has significant hemodynamic instability, obtain universal donor blood products quickly.

  • Resuscitation of hemodynamics should focus on giving blood products. Guidelines for traumatic hemorrhagic shock resuscitation recommend high ratio of plasma:packed red blood cells. Ratio of 1:1 or 1:2 (plasma:PRBC) is appropriate.

• Gastric lavage via nasogastric tube to evaluate for presence of ongoing gastric bleeding is an option, though negative lavage does not entirely rule out bleeding.

• Initiate proton pump inhibitor, which may help to reduce UGIB.

• Consider prophylactic antibiotics in patients with UGIB from esophageal varices.

• In ongoing UGIB, octreotide or somatostatin may be helpful to diminish bleeding, especially in variceal bleeding.

• Endoscopy/colonoscopy is often indicated for diagnosis and/or therapy to stop bleeding.

• Endoscopy is ideally performed once patient has been resuscitated and bleeding is better controlled. In cases of ongoing severe bleeding, endoscopy may be indicated for acute therapeutic interventions.

• If source of bleeding is not identified via endoscopy, other diagnostic modality options include angiography, tagged red cell scan, or video capsule endoscopy.

SUGGESTED READINGS

GENERAL PERIOPERATIVE CONSIDERATIONS

Gastrointestinal emergencies are a frequent cause of hospitalization in children, and despite a wide range of etiologies, many of the principles in management are the same. Initial therapy should always include adequate resuscitation with establishment of stable IV access, IV fluid administration with isotonic solution such as Ringer's lactate, correction of electrolyte abnormalities, and consideration of a Foley catheter for careful monitoring of fluid shifts. Patients should be made NPO, and insertion of a nasogastric tube may be considered in cases of refractory vomiting or concern for an obstructive or ischemic process. Additionally, prompt administration of broad-spectrum IV antibiotics is often indicated when underlying infection or sepsis is suspected.

NECROTIZING ENTEROCOLITIS (NEC)

BACKGROUND

Necrotizing enterocolitis affects 5% to 10% of all infants admitted to the neonatal intensive care unit. Ninety percent of patients with NEC are also premature. Although the exact etiology is unknown, the hypothesized mechanisms include the presence of bacteria in an immature gut, inflammatory response, failure of the intestinal immunologic barrier, and resultant coagulation necrosis. Well-established risk factors include prematurity and low birth weight.

FINDINGS

Signs and symptoms may range from mild and nonspecific to an acute abdomen with evidence of intestinal perforation.

1. Symptoms: Abdominal distention, gastric residuals, bloody stools, abdominal wall erythema, apnea, hemodynamic instability.

2. Labs: Leukocytosis or leukopenia, thrombocytopenia, elevated C-reactive protein (CRP), metabolic acidosis

3. Imaging (plain radiographs): Ileus gas pattern, pneumatosis, portal venous gas, pneumoperitoneum (Figure 64-1)

STAGING: MODIFIED BELL'S STAGING CRITERIA (TABLE 64-1)

Differential diagnosis – sepsis, medical ileus

MANAGEMENT

1. Medical management (stage I–II): Bowel rest, gastric decompression, IV fluids and resuscitation, broad-spectrum antibiotics. Obtain blood and urine cultures prior to initiation of antibiotics. Follow with serial abdominal exams and radiographs. Clinical deterioration or failure to improve are indications for surgical management.

2. Surgical management (stage III): Laparotomy, resection of necrotic bowel, second-look laparotomy for areas of questionable ischemia, ostomy creation. Primary anastomosis performed selectively. Placement of a Penrose drain alone, without laparotomy, used as definitive management in some neonates <1 kg.

PEARLS

1. Focal intestinal perforation (FIP)

   1. Spontaneous, isolated perforation occurring primarily in extremely premature neonates

   2. May be managed with peritoneal drainage alone in some cases

2. Complications

   1. Short gut syndrome – NEC is leading cause of short gut syndrome, accounting for >50% of cases

   2. Stricture – feeding intolerance after medical management should prompt contrast studies (contrast enema followed by upper GI series) to assess for strictures. Strictures occur most frequently in the colon and distal ileum.

3. Future directions

   1. A Cochrane review found that probiotic administration in premature neonates may reduce the incidence of necrotizing enterocolitis.¹ Clinical trials are underway to further delineate this relationship.

MALROTATION/VOLVULUS

BACKGROUND

Normal intestinal rotation during gestation is 270 degrees in the counterclockwise direction. Failure of normal rotation results in Ladd's band (adhesions crossing from the abdominal wall to the cecum, which may compress the duodenum) and a narrow-based mesentery, which is prone to midgut volvulus.

FINDINGS

1. Signs and symptoms:

   1. Acute presentation: Acute-onset bilious emesis is assumed to be malrotation with midgut volvulus until proven otherwise. Abdomen can be distended or scaphoid and is tender to palpation. Prompt surgical intervention is required to avoid bowel ischemia, peritonitis, shock, and potential loss of the entire small bowel.

   2. Chronic: Malrotation without volvulus can present with feeding intolerance, failure to thrive, and intermittent abdominal pain. Symptoms are due to duodenal obstruction by Ladd's bands and/or intermittent partial volvulus.

2. Labs: Leukocytosis and metabolic acidosis (seen variably)

3. Imaging:

   1. No imaging indicated if clinical presentation concerning for midgut volvulus with bowel ischemia. Proceed immediately with operation.

   2. Abdominal radiograph (two-view) – gastric distention, gasless abdomen, “double bubble” sign of duodenal obstruction. Radiographic findings are variable.

   3. Upper GI – This is the definitive study for malrotation. The ligament of Treitz fails to cross to the left of midline and return to the level of the pylorus in the cranial-caudal axis. Corkscrew sign or “beaking” concerning for volvulus (Figure 64-2).

   4. Ultrasound – “whirlpool sign” of superior mesenteric vein (SMV) around superior mesenteric artery (SMA).

MANAGEMENT

1. Acute presentation (concern for volvulus): Fluid resuscitation, NG decompression, broad-spectrum IV antibiotics, immediate laparotomy for reduction of volvulus, resection of necrotic bowel, and Ladd procedure.

2. Chronic presentation (malrotation without volvulus): Elective Ladd procedure (laparoscopic or open). Components of Ladd procedure include (1) division of Ladd's bands to relieve duodenal obstruction, (2) appendectomy, (3) broadening of mesentery, and (4) positioning the small bowel in the right and large bowel in the left hemi-abdomen.

SMALL BOWEL OBSTRUCTION

BACKGROUND

Common causes in pediatric population include adhesive disease, internal hernia, incarcerated inguinal hernias, intussusception, volvulus, omphalomesenteric band, and intestinal stricture.

FINDINGS

1. Signs and symptoms: Crampy abdominal pain, bilious emesis, abdominal distention, obstipation

2. Labs: May be normal or show signs of dehydration, metabolic acidosis, leukocytosis

3. Imaging:

   1. Abdominal radiograph – distended loops of intestine, paucity of gas in rectum, air fluid levels

   2. Computerized tomography – useful for identifying transition point, distinguishing between complete and partial small bowel obstruction (SBO), and identifying emergent findings such as internal hernia.

MANAGEMENT

1. Nonoperative: IV hydration and NG decompression indicated for patients without peritonitis or other signs of bowel ischemia, especially in the setting of partial obstruction attributable to adhesions.

2. Operative: Laparoscopy or laparotomy indicated for any signs of peritonitis, any obstruction without explanation (e.g., no prior abdominal operations), and/or failure to improve with nonoperative management (typically within 48–72 hours).

PEARLS

1. Intussusception

   1. Primary intussusception may occur after gastroenteritis or respiratory viral infection. Secondary intussusception occurs due to a lead point (e.g., Meckel's).

   2. Most common between ages 3 months and 3 years old. Atypical cases include older children and teenagers where other etiologies and lead points such as tumors should be considered.

   3. Although a “target sign” is sometimes visible on plain radiograph, diagnosis is typically made by ultrasound.

   4. First-line treatment in typical patients is with air or water-soluble contrast enema reduction and is successful in up to 85% of patients. Delayed reduction enema can be utilized if the initial reduction is partially successful, and repeat reduction may be attempted for recurrences. Recent studies do not demonstrate an increased incidence of complication with repeat enemas.²

2. Meckel's band

   1. Consider omphalomesenteric band if patient has obstruction without previous abdominal surgeries or other known etiology.

   2. Diverticulum may also serve as lead point in intussusception.

3. Hernias

   1. Incarcerated inguinal hernia is a common cause of intestinal obstruction, especially in babies.

   2. A complete physical exam is crucial in patients with obstruction.

4. Stricture

   1. Important consideration in patients with previous necrotizing enterocolitis (NEC) or bowel ischemia

   2. Diagnosed with upper and lower contrast studies

ACUTE APPENDICITIS

BACKGROUND

Appendicitis occurs due to obstruction of the appendiceal lumen resulting in inflammation, ischemia, necrosis, and eventually perforation. Obstruction may be due to a variety of causes, including fecal material (fecalith), hyperplasia of lymphoid tissue, or foreign bodies. Infection is usually polymicrobial, and enteric organisms are most commonly seen.

FINDINGS

Presentation is widely variable and may not follow the classic pattern of diffuse periumbilical pain followed by localized right lower quadrant (RLQ) tenderness, particularly in young children. Common signs and symptoms include abdominal pain, fever, nausea/vomiting, and tachycardia. Exam is often notable for focal peritonitic pain in the RLQ. Laboratory findings are also variable, but a leukocytosis with left shift is common. Diagnosis can be confirmed by imaging. Ultrasound (US) is typically the first-line imaging in children, with computerized tomography (CT) or magnetic resonance imaging (MRI) reserved for those with nondiagnostic ultrasound.

MANAGEMENT

Children with acute, nonperforated appendicitis are managed with appendectomy and can be discharged home within 24 hours of operation, often on the same day. Non-operative management of acute appendicitis is currently under investigation in a number of clinical trials, but is still considered experimental. Those with complicated (perforated) appendicitis have more complex management challenges, which may occasionally necessitate ICU care.

1. Initial management

   1. Most children presenting with clinical and imaging findings concerning for perforation still benefit from up-front appendectomy. Early appendectomy is associated with lower costs and fewer readmissions compared to those who undergo initial nonoperative management.

   2. In rare cases, perforated appendicitis can involve the base of the appendix at the cecum, necessitating ileocecectomy.

   3. Those presenting with a well-defined abscess may benefit from initial image-guided drainage and antibiotic therapy tailored to the culture results.

   4. For those who undergo initial nonoperative management, delayed “interval appendectomy,” typically after 6 to 12 weeks, is recommended by some surgeons to avoid recurrence.

2. Routine postoperative management of perforated appendicitis

   1. Patients who undergo appendectomy for perforated appendicitis require fluid resuscitation, careful monitoring of intake and output, and a prolonged course of antibiotic therapy.

   2. Most surgeons keep these children on broad-spectrum IV antibiotics (piperacillin-tazobactam or ceftriaxone/metronidazole) until they are afebrile, tolerating a general diet, and pain free.

   3. Some check a complete blood count (CBC) and/or C-reactive protein (CRP) prior to discharge.

   4. Patients can then be discharged home to complete a course of oral antibiotics.

3. Postoperative abscess

   1. Postoperative abscess occurs in 20% to 25% of patients who undergo appendectomy for perforated appendicitis.

   2. Patients with fever, pain, and/or feeding intolerance persisting beyond 5 to 7 days should undergo CT scan to assess for abscess.

   3. Postoperative abscess is managed by image-guided drainage (or, rarely, by operative drainage) followed by prolonged antibiotic therapy (typically 10–14 days) tailored to the culture results. Patients with smaller, undrainable collections may be managed by antibiotics alone.

COLITIS

BACKGROUND

Variety of etiologies, including infectious and inflammatory causes.

CLINICAL FINDINGS

Fever, abdominal distention, diarrhea, leukocytosis.

MANAGEMENT

Although management is dependent on the etiology of colitis, initial management is usually nonoperative except in cases of perforation or septic shock.

ETIOLOGIES

1. Ulcerative colitis with toxic megacolon

   1. Emergent surgical intervention may be required for those presenting with fulminating disease with abdominal distention, bloody diarrhea, severe cramping, fever, tachycardia, and sepsis.

   2. Abdominal radiograph demonstrates massively dilated colon.

   3. Surgical management of patients presenting acutely is typically with a three-stage procedure: (1) acute intervention with total colectomy with end ileostomy; (2) subsequent completion proctectomy, ileoanal pouch creation, and loop ileostomy; and (3) final ileostomy closure.

2. Clostridium difficile

   1. Septic shock from fulminant colitis is a rare but serious complication of C. difficile infection.

   2. Bacteria release exotoxins, which cause mucosal injury and inflammation of the colon, leading to pseudomembrane formation, ulceration, and systemic toxicity.

   3. Toxic megacolon is a clinical diagnosis based upon radiographic evidence of extreme colonic dilation in the setting of severe sepsis.

   4. Failure to improve with resuscitation and appropriate antimicrobial therapy is an indication for emergent colectomy.

3. Hirschprung-associated enterocolitis (HAC)

   1. HAC is a potentially life-threatening complication of Hirschsprung’ s disease (HD). It may be the initial presenting finding in children with undiagnosed HD, or it may occur after definitive pull-through procedure.

   2. The etiology is bacterial overgrowth in the setting of distal obstruction due to aganglionosis of the bowel and internal sphincter.

   3. Initial management is with fluid resuscitation, broad-spectrum antibiotics, and prompt rectal irrigations.

4. Neutropenic enterocolitis

   1. A necrotizing infection of the intestine occurring in patients with neutropenia, usually as a result of cytotoxic chemotherapy. The etiology is not fully understood but is likely due to mucosal injury and loss of host defenses secondary to chemotherapy, often seen in patients with hematologic malignancies. It was first described in the pediatric population with acute leukemia undergoing induction therapy.

   2. Historically referred to as “typhlitis,” it most commonly occurs in the ileocecal region. However, it may be found anywhere in the small bowel or colon. Usually a polymicrobial infection.

   3. Important to consider for a child with fever and abdominal pain in the setting of severe neutropenia (absolute neutrophil count <500 cells/µL); CT is diagnostic imaging of choice.

   4. Optimal medical management includes bowel rest, gastric decompression, IV fluids, correction of coagulopathy, and broad-spectrum IV antibiotics. Surgical intervention is rarely required and reserved for frank perforation, clinical deterioration, or persistent GI bleed.

FOREIGN BODIES/INGESTIONS

BACKGROUND

The most frequently swallowed items include coins, toys, and batteries. The most common area of impaction is the esophagus below the cricopharyngeus muscle. The majority of foreign bodies that pass into the stomach will pass through the remainder of the GI tract uneventfully. Plain radiograph is usually sufficient to demonstrate the object.

ESOPHAGEAL FOREIGN BODIES

1. Clinical findings include drooling, poor feeding, neck or throat pain

2. Three main areas of impaction: the upper esophageal sphincter, level of the aortic arch, and lower esophageal sphincter.

3. Items impacted in upper and mid-esophagus usually require retrieval by rigid or flexible endoscopy or Foley balloon extraction under fluoroscopy.

4. Protect the airway and avoid inadvertently dropping the object into the airway during extraction from the esophagus.

GASTROINTESTINAL FOREIGN BODIES

1. Once an object reaches the stomach, removal is rarely indicated (see later for exceptions)

2. Potential areas of impaction include the pylorus and the ileocecal valve

3. Acute onset of pain warrants a two-view radiograph to exclude free air

SPECIFIC INGESTIONS

1. Batteries

   1. May release low-voltage current or leak alkali solution – causes liquefaction necrosis.

   2. Look for double contour rim on x-ray (Figure 64-3).

   3. Injury may occur in as little as 60 minutes; needs immediate removal when in esophagus.

   4. Complications include perforation, stricture, tracheoesophageal fistula (TEF).

2. Alkali ingestion (lye)

   1. More dangerous with greater extent of injury than acidic ingestions, causes liquefactive necrosis with penetration into deeper tissues.

   2. High risk of esophageal perforation during reparative phase of healing (5–10 days).

   3. Scar formation results in high risk of stricture.

   4. Management includes resuscitation and supportive care.

   5. Endoscopy should be performed on all symptomatic patients between 24 and 48 hours after injury to evaluate extent of injury (see Table 64-2).

   6. Contrast esophagram utilized as clinically indicated to assess for stricture.

3. Magnets

   1. Problematic when (1) multiple and (2) separated along the length of the gastrointestinal system. May attach across intestinal wall in two separate areas of lumen causing perforation, obstruction, or fistula formation.

   2. Managed with close observation and serial exams

4. Sharp objects

   1. Low risk of perforation; however, close observation is warranted until the object passes into the colon.

   2. May flush GI tract with polyethylene glycol to assist with clearance.

SPECIAL CONSIDERATIONS

ESOPHAGEAL PERFORATION

Background

The majority of esophageal perforations are due to iatrogenic injuries; causes include endotracheal intubation, NG tube placement, or stricture dilations. Other common causes include foreign body ingestion, caustic ingestions, or trauma. The most common location for perforation is in the thoracic esophagus.

Clinical Findings

1. Dysphagia, respiratory distress, fever, chest pain, subcutaneous emphysema

2. Chest x-ray may demonstrate pneumothorax, pleural effusion, pneumomediastinum, pneumopericardium, or subcutaneous emphysema.

3. Contrast esophagram with evidence of leak is diagnostic study of choice. Water-soluble contrast is used initially, but may be followed by barium if no leak identified.

Management

1. Initiation of broad-spectrum antibiotics

2. If identified early (<24 hr), may undergo primary surgical repair. If there is a delay in diagnosis, diversion with drainage of leak is preferred.

3. The majority will heal spontaneously with appropriate diversion.

DUODENAL PERFORATION

Background

Etiologies for perforation include trauma, obstruction (atresia), ulcers (rare), Crohn's disease, or iatrogenic injury. Signs and symptoms are similar to other intestinal perforations and include abdominal pain, distention, nausea and vomiting, leukocytosis, sepsis, and free air on imaging. Management is made more difficult by the inability to resect the affected portion of bowel and the high risk of leak with primary repair.

Management

1. Principles of operative management rely on wide drainage of the injury in addition to repair.

2. Pyloric exclusion may be performed (suturing closed the pylorus) with gastrojejunostomy for complete but temporary diversion of gastric secretions from repaired area. This reduces the incidence of duodenal fistula.

3. Feeding jejunostomy should be considered for enteral access and nutrition.

ABDOMINAL COMPARTMENT SYNDROME

Background

Sustained intra-abdominal hypertension that is associated with new-onset organ dysfunction or failure. Increased pressure on capillary beds leads to decreased perfusion of abdominal viscera, resulting in ischemia, acidosis, and eventual cardiopulmonary collapse. Causes include trauma, sepsis, and massive fluid resuscitation.

Clinical Findings

1. Firm, distended abdomen, oliguria, decreased tidal volumes with increased peak, and plateau pressures on ventilator

2. Elevated intra-abdominal pressure >20 mmHg

Management

1. Measure serial bladder pressures. Should be measured with child paralyzed in supine position.

2. Decrease abdominal wall compliance with sedation and paralysis. Optimize fluid balance.

3. Decompressive laparotomy and diuresis until decrease in edema allows for tension-free closure.

DEFINITIONS

Inflammation of the peritoneal lining of the abdominal cavity

• Primary: without an intra-abdominal source

• Secondary: caused by viscus rupture/perforation, bowel necrosis, or extension of an intraperitoneal organ infection or abscess

ETIOLOGY

Most commonly associated with nephrotic syndrome, liver failure, acute abdominal infections (i.e., appendicitis)

COMMON ORGANISMS

• Pneumococci

• Group A streptococci

• Gram-negative enteric organisms: Escherichia. coli, Klebsiella

• Staphylococci

• Enterococci

• Candida

• Pasteurella multocida

• Mycobacteria tuberculosis

CAUSES OF SECONDARY PERITONITIS

• Ruptured appendicitis

• Incarcerated hernia

• Midgut volvulus

• Meckel's diverticulum

• Intussusception

• Necrotizing enterocolitis (NEC)

• Hemolytic uremic syndrome (HUS)

• Ruptured peptic ulcer

• Trauma

• Genital tract infections and pelvic inflammatory disease (PID): mixed flora, Neisseria, Chlamydia, anaerobes

• Foreign bodies: ventriculoperitoneal (VP) shunts, peritoneal dialysis (PD) catheters

• Autoimmune disorders: systemic lupus erythematosus (SLE)

CLINICAL MANIFESTATIONS

• Fever, abdominal pain, anorexia, vomiting, diarrhea, acute abdomen, mental status changes, toxic appearance, shock.

• Clinical signs may be unreliable; therefore, have a low threshold for diagnostic paracentesis.

DIAGNOSIS

LABORATORY EVALUATION

• Complete blood count (CBC): increased white blood cells (WBCs) with neutrophil predominance

• Urinalysis (UA): proteinuria

• Ascitic fluid: >250 polys/mm², increased lactate, decreased pH (<7.35), Gram stain with organisms

IMAGING

• Upright abdominal x-ray: may show free air in patients with ruptured viscus

TREATMENT

See Surviving Sepsis Guidelines to reverse shock.

ANTIMICROBIAL THERAPY

• Empiric IV antibiotics:

  • Ampicillin or ceftriaxone + an aminoglycoside

  • Anaerobic coverage (metronidazole or clindamycin) if secondary peritonitis suspected

• Switch to enteral antimicrobial: afebrile and able to tolerate enteral medications

• Narrow antimicrobial therapy: based on culture results

• Duration: 10 to 14 days

SURGICAL INTERVENTION

• Drainage of abscess

• Repair of perforated viscus

• Excision of necrotic bowel

• Removal of foreign body

SUGGESTED READINGS

CLINICAL PRESENTATION

• Symptoms may include nausea, vomiting, itching, fever.

• Signs may include encephalopathy, ascites, scleral icterus/jaundice.

• Though there are no strict diagnostic criteria, consider acute liver failure if all of these are present:

  • Hepatic failure within 8 weeks of onset of hepatic disease

  • Elevated serum AST, ALT, and/or bilirubin

  • Coagulopathy (PT >15, INR >1.5) does not correct with vitamin K

  • No prior history of chronic liver disease

  • Encephalopathy (confirmatory, not required)

ETIOLOGY

• Likelihood of various etiologies depends on age and geography

• Causes can be classified into the following categories:

  • Infectious

  • Metabolic

  • Autoimmune

  • Toxin or drug mediated

  • Indeterminate

  • Other

DIAGNOSTIC EVALUATION

• Physical exam: look for jaundice, encephalopathy, Kayser-Fleischer rings.

• History: ask about timing of symptom onset, family history, medications or recreational drugs, and fever.

• Serum labs: coagulation factors, complete metabolic panel, amylase, lipase, complete blood count, acetaminophen level, ammonia, lactate

• Secondary testing once diagnosis of acute liver failure is confirmed:

  • If cytopenia is present in two cell lines perform hemophagocytic lymphohistiocytosis (HLH) testing with ferritin, triglyceride, and fibrinogen.

  • If older than 5 years perform Wilson's disease testing with serum ceruloplasmin.

  • Viral hepatitis serology, viral PCR (herpes simplex virus [HSV], Epstein-Barr virus [EBV], cytomegalovirus [CMV], adenovirus, parvovirus, enterovirus)

  • Perform tests for specific genetic etiologies based on age of patient and newborn screening results.

• Liver biopsy may be indicated if etiology remains unknown.

MANAGEMENT

• Acute liver failure may lead to rapid systemic decompensation, so PICU admission is often appropriate.

• Frequently monitor for hyponatremia, hypoglycemia, hypokalemia, and hypophosphatemia.

• Manage fluids to avoid fluid overload. Consider continuous renal replacement therapy early in the treatment course.

• Routine monitoring of coagulation factors:

  • Give vitamin K one time to assess response in coagulopathy.

  • Empiric correction of coagulopathy with plasma infusion is not indicated, unless done prior to an invasive procedure.

• Respiratory support: respiratory failure requiring mechanical ventilation is common due to fluid overload, pulmonary edema or hemorrhage, encephalopathy, or sepsis.

• Frequently reassess the clinical exam, including assessment of encephalopathy staging. See Table 66-1.

• Neurologic care in early stages of hepatic encephalopathy (grades 0–II):

  • Head of bed elevated 30 degrees

  • Oxygen saturation >96%

  • Temperature control to maintain normothermia

  • Maintain adequate blood pressures to ensure good cerebral perfusion pressure (CPP)

  • Target serum sodium 145 to 150 mEq/L and serum osmolarity 300 to 320 mOsm/L with hypertonic saline

  • Baseline EEG

  • Obtain baseline head imaging to evaluate for cerebral edema (MR ventricle with diffusion weighted imaging [DWI]).

• Neurologic care when worsening clinical exam and/or hepatic encephalopathy grades III and IV:

  • Invasive intracranial pressure (ICP) monitoring can be considered, but there is risk of bleeding and lack of evidence it improves survival.

    • Mannitol and/or hypertonic saline may be used for acutely elevated ICP

    • CPP goal range 40 to 60 mmHg depending on age

  • Target PaCO₂ 35 to 40 mmHg using mechanical ventilation.

  • Active cooling to keep temperature <37.5°

• Monitor for infections. If antibiotics are indicated, consider using ceftriaxone due to its ability to protect astrocyte glutamate transporters.

• Therapies for specific etiologies:

  • Acetaminophen toxicity: N-acetyl cysteine

  • Autoimmune causes: steroids

  • Herpes simplex virus: acyclovir

  • Hepatitis B: lamivudine

  • Wilson's disease: chelation, plasmapheresis

  • HLH: steroids, chemotherapy

  • Gestational alloimmune liver disease/neonatal hemochromatosis: IVIG, exchange transfusion

  • Tyrosinemia type 1: nitisinone (NTBC)

• Liver transplant

  • Treatment with liver transplant is a multidisciplinary decision. There are no existing standardized indications for liver transplant for pediatric acute liver failure (see Chapter 67).

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INDICATIONS FOR LIVER TRANSPLANT

• Biliary atresia often following the Kasai procedure

• Metabolic diseases

  • Alpha-1-antitrypsin deficiency

  • Tyrosinemia

  • Wilson's disease

  • Urea cycle defects

  • Hemochromatosis

  • Glycogen storage disease

• Fulminant hepatic failure (see Chapter 66)

  • Infection

  • Toxin

  • Drug ingestion

• Hepatic malignancy

• Chronic liver disease

• End-stage liver disease

CONTRAINDICATIONS FOR LIVER TRANSPLANT

• Absolute contraindications

  • Unresectable hepatic malignant tumor

  • Uncontrollable extrahepatic sepsis

  • Neurologic devastation (arrived by consensus, as stage IV hepatic encephalopathy can mask brain death)

• Relative contraindications

  • Acceptable alternative medical therapy

  • Expected suboptimal outcome

  • Impairment of other organ systems that would compromise function of the graft

  • Major systemic infection

  • Cancer with a high postsurgical recurrence rate

OPERATIVE TECHNIQUE

• Recipient hepatectomy phase

• Anhepatic phase

• Reperfusion phase

  • Arterial anastomoses

  • Biliary reconstruction

  • Hemostasis

TYPES OF TRANSPLANTS

• Reduced size graft

• Split liver graft

• Living related donor transplantation

POSTOPERATIVE MANAGEMENT

RESPIRATORY MANAGEMENT

• Most pediatric patients will return from the operating room intubated and mechanically ventilated.

• The goal should be to extubate as quickly as medically possible, generally within 48 hours.

• Factors that determine extubation readiness for all patients include ventilatory parameters, sedation and analgesia requirements, and hemodynamics.

• Extubation is often delayed until the 12-hour assessment of graft function.

• Prolonged ventilation increases the risk of nosocomial infection and ventilator-associated pneumonia.

• Age and nutritional status play a role in extubation readiness, as does the transplant type.

• Pleural effusion is common, and the right side is more frequently affected. These effusions can generally be managed with diuretics and fluid restriction and rarely require pleurocentesis and drainage.

• Atelectasis is a common problem, especially in young children, and contributes to respiratory distress and difficulty weaning from mechanical ventilation.

• Diaphragmatic dysfunction is associated with prolonged ventilatory requirement and prolonged PICU stay and may require diaphragmatic plication.

• Monitoring includes oxygen saturation, capnography, and arterial blood gas analysis (Table 67-1).

CARDIOVASCULAR MANAGEMENT

• Patients should be monitored with invasive and noninvasive blood pressure monitoring and central venous pressure monitoring, as well as heart rate monitoring (Table 67-1).

• Hemodynamic instability in the early postoperative period is contributed to by acid–base status, fluid status, and bleeding issues.

• A small percentage of patients will have evidence of bacterial translocation intraoperatively (taking down an old Roux-en-Y, manipulating bowel) and present with a sepsis-like picture.

• Maintaining good flow to the liver is paramount, and hypotension must be avoided at all costs.

• Following liver transplantation, children frequently have hypertension requiring medical control.

• Hypertension results from pain, side effects of immunosuppression (steroids), or volume overload.

• Hypertension can be particularly dangerous in post-transplant patients due to coagulopathy and thrombocytopenia, and vigilance for hemorrhagic stroke is indicated.

• Calcium channel blockers such as nicardipine and amlodipine are often considered first-line agents in the treatment of acute hypertension in the immediate post-transplant period.

FLUID, ELECTROLYTE, AND ACID–BASE STATUS

• It is important to follow fluid status and electrolytes closely in the postoperative period. Key electrolytes and metabolites to follow post-transplant are serum glucose, pH, and serum phosphorous (Table 67-1).

• Postoperatively, patients are often fluid overloaded due to intraoperative fluid administration. Monitoring should include urine output as well as total fluids in and total fluids out.

• In the child with significant ascites and increased Jackson-Pratt (JP) drainage post-transplant, there may be an associated decrease in urine output.

• Maintaining euvolemia is best accomplished by fluid replacement strategies matching JP drainage with cc/cc fluid replacement intravenously.

• Drainage from the abdominal drains should be measured hourly. This can be an early indicator of intra-abdominal bleeding, coagulopathy, or issues with vascular anastomoses.

GASTROINTESTINAL ASSESSMENT OF GRAFT FUNCTION

• It is imperative to monitor and assess graft quality and function.

• Follow laboratory markers, including pH, glucose, coagulation studies, phosphorous, bilirubin, and transaminases (Table 67-1).

• Issues with graft function are often related to the degree of ischemia-reperfusion during the transplant procedure and blood flow in general postoperatively.

• Ultrasound with Doppler is generally performed in the first 12 hours post-transplant.

• Biliary complications are the most common technical complication after liver transplantation and range from early anastomotic leaks to late obstruction.

• The serum biochemical abnormalities associated with biliary system complications include an elevated bilirubin level and changes in canalicular enzyme levels of alkaline phosphatase and γ-glutamyl transferase (GGT).

• Ultrasonography is not as reliable in assessing biliary pathology.

• Follow coagulation studies closely and replace JP abdominal fluid drainage with fresh frozen plasma if the international normalized ratio (INR) is >1.7. With an INR of <1.7, replacement can be with 5% albumin or lactated Ringer's (LR) depending on the acid–base status of the patient.

• An elevated INR is indicative of poor graft function or an ongoing consumptive process, is consistent with bleeding, and is the first clue that the patient may require re-exploration.

• In these cases, stop all anticoagulation interventions and support with blood products until a surgical problem is clearly defined.

NEUROLOGIC MANAGEMENT

• It is important to assess and reassess neurologic function in the postoperative period.

• Drugs with prolonged half-lives, hepatic metabolism, or a propensity for delirium should be used cautiously. Benzodiazepine administration is avoided.

• Most neurologic complications are related to (1) the degree of pretransplantation encephalopathy or (2) the post-transplant metabolic abnormalities caused by immunosuppressive agents, most notably the calcineurin inhibitors (CNIs).

• Neurologic complications following pediatric liver transplant include seizures, encephalopathy, posterior reversible encephalopathy syndrome (PRES), and headache.

• Seizures are the most common neurologic complication and occur in up to 30% of children following transplant. Causes of seizures include hypoglycemia, electrolyte abnormalities, and high levels of CNI, as well as ischemic or hemorrhagic stroke and infection.

• Neuroimaging should be obtained to rule out intracerebral hemorrhage in any patient with a new-onset seizure or altered mental status.

• CNI-related neurotoxicity occurs in approximately 25% of liver transplant recipients. Many are dose related, and treatment includes reducing or completely discontinuing the suspected offending agent. In some cases, substitution of one CNI by another is all that is needed.

• Primary graft nonfunction causes cerebral edema and increased intracranial pressure, often requiring intracranial pressure monitoring to manage and maintain cerebral perfusion pressure. The treatment is to replace the nonfunctioning liver.

• Electroencephalogram and transcutaneous Doppler studies are valuable to differentiate cerebral edema from encephalopathy from drug effect, especially when prognosis is a factor in determining retransplant candidacy.

• If there are concerns for brain death, a nuclear medicine scan for brain perfusion may be the only study to differentiate hepatic encephalopathy (+ flow) from brain death (− flow).

IMMUNOSUPPRESSION

• The immune system recognizes the graft as foreign and begins a destructive immune response mediated principally by T lymphocytes.

• In order to avoid graft destruction, immunosuppressive drugs must be administered.

• Most patients, regardless of age, will begin maintenance immunosuppressive therapy with a triple drug regimen consisting of a CNI, an antiproliferative agent, and steroids (Table 67-2).

• The goal is to minimize CNI exposure and facilitate early steroid withdrawal, thereby preventing the long-term toxicities: abnormal growth development, steroid-induced osteoporosis and post-transplant lymphoproliferative disease.

ANTICOAGULATION (TABLE 67-2)

• All patients receive one dose of vitamin K immediately upon arrival to the PICU post-transplant.

• All patients are candidates for low-dose heparin infusion. This is viewed as prophylactic dosing, and patients are started on a 10 units heparin/hour regardless of weight. The goal of this therapy is not to alter the partial thromboplastin time (PTT), but rather to prevent small clot formation in critical vessels.

• Patients who are identified by transplant surgery as being at high risk for vascular thrombosis will receive treatment-dose heparin infusion. In these patients the therapeutic goal will be to increase the PTT by 1.5 to 2.0 times normal.

• Prior to the initiation of the heparin drip, the following criteria must be met: prothrombin time <25 seconds (INR = 2.1), no obvious evidence of bleeding, and platelet count must be >20,000/mm³.

• Heparin therapy should be discontinued 24 hours after antiplatelet therapy with aspirin has begun and with approval from transplant surgery.

• Aspirin is started on postoperative day #3 as long as the following criteria are met: platelet count ≥20,000, no anticipated procedures requiring adequate platelet function, approval from the transplant team. The duration of aspirin therapy is intended to be 6 months.

• The transplant team may request that the patient be placed on a prostaglandin drip (alprostadil) to reduce vascular resistance and improve blood flow to the liver graft.

• Patients receiving a split liver graft from a deceased donor, patients receiving grafts from marginal donors, patients with rapidly climbing liver enzymes, or patients with a suboptimal intraoperative course (i.e., prolonged ischemia time, poor perfusion) are candidates for alprostadil therapy.

• Alprostadil has potent vasodilatory and antiplatelet effects in addition to its cytoprotective and immunomodulatory properties. These beneficial qualities modulate ischemic reperfusion injury and minimize the risk of primary nonfunction of the graft in the early post-transplant period.

• The duration of therapy is intended to be 3 to 5 days or until AST/ALT normalize.

INFECTION PREVENTION (TABLE 67-2)

• All patients are placed on empiric antibiotics for at least 48 hours after transplantation.

• Ampicillin and cefotaxime are the standard antibiotics for patients with normal renal function.

• All patients receive Pneumocystis jiroveci pneumonia (PCP) prophylaxis with sulfamethoxazole-trimethoprim for 1 year post-transplant unless contraindicated.

• All patients receive Candida prophylaxis for prevention of oral thrush with nystatin for 3 months post-transplant.

• Select patients will receive antiviral prophylaxis for cytomegalovirus (CMV) with ganciclovir based on the transplant recipient's age, CMV serologic status at the time of transplant, and the donor's CMV serologic status.

• Patients who are retransplanted and those who have been treated with antithymocyte globulin are considered high risk for acquiring CMV disease and should be treated with antivirals for a total of 3 months.

NUTRITION

• Nutrition in the post-transplant patient is critically important.

• For the child who is well nourished preoperatively, the transition is easier. Frequently the patient's preoperative profile includes malnutrition, preexisting ascites, and edema.

• For the first 3 to 5 days postoperatively, the patient is treated like a surgical abdomen patient.

• Enteral calories begin once there are bowel sounds, flatus, and no evidence of ileus.

• In a liver transplant, a choledochojejunostomy is performed to allow for bile drainage. In a patient who has had a previous Kasai procedure, they will already have had a choledochojejunostomy with a Roux-en-Y loop, so this does not need to be created.

• A child with an existing choledochojejunostomy with a Roux-en-Y loop can be fed when they meet postsurgical criteria on postoperative day #3, whereas a fresh choledochojejunostomy with a new Roux-en-Y loop cannot be fed until postoperative day #5 as per the surgical team.

• The liver is essential for the digestion and absorption of protein, fat, and carbohydrate as well as the fat-soluble vitamins (A, D, E, and K). The transplant child also needs supplementation with iron, zinc, calcium, and magnesium.

POST-TRANSPLANT COMPLICATIONS

• Postoperative complications usually present with a nonspecific combination of cholestasis, rising hepatocellular enzyme levels, fever, lethargy, and anorexia.

• Early complications include

  • Primary nonfunction

  • “Small for size” syndrome

  • Technical complications

  • Vascular thrombosis

  • Biliary leak

  • Rejection

  • Infection

• Late complications include

  • Infection

  • Rejection

  • Hypertension

  • Renal dysfunction

  • Lymphoproliferative disease

PRIMARY NONFUNCTION

• The lack of graft functional recovery can be seen in the first hours following transplantation, with high lactate levels, increasing prothrombin time and partial thromboplastin time, rapidly rising liver enzyme levels, bleeding, vasoplegia, progressive renal and multisystem failure, and encephalopathy.

• It is the most common cause of early graft loss. Biopsy reveals histologic evidence of hepatocyte necrosis in the absence of any vascular compromise.

• The only treatment is emergent retransplantation.

• A possible cause is hyperacute rejection.

• With improved donor selection and management, operative techniques, reducing cold ischemia times, and newer preservative solutions, the risk of primary nonfunction has decreased but remains around 5%.

• Patients with initial dysfunction, also known as primary graft dysfunction, might recover with support, but those who progress to show evidence of extrahepatic complications as listed earlier must be considered as having primary nonfunction and listed for retransplantation.

VASCULAR COMPLICATIONS

• Hepatic artery thrombosis is the most common vascular complication. The incidence in children ranges between 5% and 20%.

• It may present as acute liver failure, biliary fistula, or enzyme elevation.

• Hepatic artery thrombosis is associated with small-size donors and presents with massive graft necrosis and graft loss.

• Hepatic artery thrombosis occurs in children three to four times more frequently than in adult transplant patients and usually within the first 30 days after transplantation.

• Late thromboses can manifest with biliary complications.

• Hepatic artery thrombosis and biliary complications are correlated because the blood supply of the biliary tract is exclusively arterial. Diagnosis is made based on an absence of flow using Doppler ultrasound.

• Surgical exploration and thrombectomy may be required.

• Anticoagulation or antiplatelet agents are often used to help.

• Portal vein thrombosis is less frequent than hepatic artery thrombosis, occurring in 4% to 15% of recipients and is more frequent in children transplanted for biliary atresia.

• The incidence of vascular thrombosis is related to vessel size

• Presentation includes elevation in liver enzymes, portal hypertension, and encephalopathy.

• Diagnosis is also made by Doppler ultrasound.

• Thrombectomy is often required.

• Prevention includes anticoagulation and avoidance of hemoconcentration.

BILIARY COMPLICATIONS

• Biliary complications occur in approximately 8% to 30% of pediatric liver transplant recipients.

• In the early postoperative period, the presence of bile-like fluid in the abdominal drains is strongly suggestive of a bile leak.

• Ultrasound evidence of intrahepatic biliary ducts dilatation, elevated alkaline phosphatase, and gamma-glutamyl transferase (GGT) suggest biliary stricture. Patients may require dilation and internal stenting.

REJECTION

• Acute cellular rejection is very common, and about 20% to 50% of patients develop at least one episode of acute rejection in the first few weeks after liver transplant, with about 45% of patients developing at least one episode of rejection within 6 months of transplant.

• Clinical signs include fever, irritability, malaise, and leukocytosis.

• Increases in GGT, bilirubin, and/or transaminases after transplant in a stable patient may be the first sign of rejection.

• Histologic biopsy evaluation of the liver is essential for making the diagnosis of rejection.

• Treatment involves pulse steroids and adjustment in immunosuppression.

• Based on the severity of the rejection, the patient receives additional treatments, which could range from an increase in the baseline immunosuppressive regimen to the administration of steroid boluses and the addition of other drugs to the maintenance therapy, or the administration of antilymphocyte antibodies in case of resistance to the primary line of therapy.

INFECTION

• Infectious complications now represent the most common source of morbidity and mortality following transplantation. This includes sepsis, nosocomial infection, and opportunistic infection.

• About 38% of patients develop serious bacterial or fungal infections <30 days and 14% have serious viral infections <15 months after liver transplant.

• The risk of infection in liver transplant recipients is determined by the intensity of exposure to infectious agents (hospital or community sources) and the overall immunosuppression level.

• In the first few weeks, bacterial pathogens are more common offending organisms with gram negative bacteria, enterococci or staphylococci.

• Fungal infections are also frequent, with the most common agent being Candida albicans.

• Fungal infection most often occurs in high-risk patients, requiring multiple operative procedures, retransplantation, hemodialysis, or multiple antibiotic courses.

• Viral infections occur later, with cytomegalovirus (CMV) being the most common viral infectious agent. Epstein-Barr virus (EBV) infection occurs in the first year after transplant.

• The risk of developing either CMV or EBV infection is influenced by the preoperative serologic status of the transplant donor and recipient.

• Most young children are EBV seronegative at the time of transplant, and during primary exposure to EBV, significant immunosuppression increases the risk of post-transplant lymphoproliferative disease (PTLD).

• Risk factors for PTLD include young age at transplant (less than 2), primary EBV infection, and at least one episode of rejection.

• The incidence of PTLD is decreasing in pediatric liver transplant recipients due to improved immunosuppression regimens.

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