Overview
Definition:
Feeding intolerance refers to a range of gastrointestinal symptoms that occur when an infant is unable to adequately digest or absorb nutrients from enteral feeds, leading to discomfort and poor feed tolerance
Necrotizing enterocolitis (NEC) is a severe, life-threatening inflammatory condition of the gastrointestinal tract, primarily affecting preterm neonates, characterized by intestinal ischemia, inflammation, and often necrosis
NEC represents a critical, advanced stage of feeding intolerance.
Epidemiology:
Feeding intolerance is common in neonates, especially premature infants and those with medical conditions affecting the GI tract
NEC affects approximately 1-4% of all NICU admissions and up to 10% of very low birth weight infants
incidence is inversely related to gestational age.
Clinical Significance:
Distinguishing between simple feeding intolerance and early signs of NEC is crucial for timely intervention, preventing progression to severe disease, surgical complications, and mortality
Accurate abdominal examination and judicious use of imaging are paramount in this differentiation for DNB and NEET SS aspirants.
Clinical Presentation
Symptoms:
Feeding intolerance: Poor feeding, vomiting (non-bilious or bilious), abdominal distension, increased gastric residuals, altered stool pattern (constipation or looser stools)
NEC: Emesis (often bilious), significant abdominal distension and erythema, abdominal tenderness, lethargy, apnea, bradycardia, temperature instability, bloody stools (gross or occult), intestinal perforation signs.
Signs:
Feeding intolerance: Mild to moderate abdominal distension, increased bowel sounds or absent bowel sounds, palpable stool in colon
NEC: Severe abdominal distension with tense abdomen, visible bowel loops (rigidity), abdominal wall erythema/discoloration, significant tenderness to palpation, absent bowel sounds, shock, peritonitis signs (rebound tenderness, guarding) in advanced stages
Vital sign instability is more pronounced in NEC.
Diagnostic Criteria:
Modified Bell staging criteria are widely used for NEC: Stage I (suspected NEC): Non-specific symptoms, abdominal distension, positive stool guaiac
Stage II (definite NEC): Stage I findings plus abdominal tenderness, absent bowel sounds, and/or mild GI bleeding
Stage IIA: Pneumatosis intestinalis on X-ray
Stage IIB: As IIA plus abdominal tenderness and absent bowel sounds
Stage III (advanced NEC): Stage II findings plus abdominal wall erythema/discoloration, abdominal rigidity, shock, apnea/bradycardia
Stage IIIA: Pneumatosis intestinalis and/or portal venous gas
Stage IIIB: Intestinal perforation.
Diagnostic Approach
History Taking:
Detailed history of gestation, birth weight, feeding method (oral, NG/OG), type of feed (breast milk, formula), volume, progression, presence of previous GI issues, prior abdominal surgeries, and any recent changes in clinical status
Focus on onset and progression of abdominal symptoms, emesis character (bilious is a red flag), stool characteristics, and systemic signs like apnea or lethargy.
Physical Examination:
Systematic abdominal examination in a neonate: 1
Inspection: Distension, erythema, visible distended bowel loops, umbilical anomalies
2
Auscultation: Bowel sounds (normal, hyperactive, hypoactive, absent)
3
Palpation: Assess for tenderness (diffuse vs
localized), guarding, rigidity, masses, hepatosplenomegaly
Note: Palpation should be gentle to avoid exacerbating injury
Assess vital signs (heart rate, respiratory rate, blood pressure, temperature) and overall infant demeanor (lethargic, irritable).
Investigations:
Laboratory: Complete blood count (leukocytosis or leukopenia, thrombocytopenia), electrolytes, BUN, creatinine, blood gas analysis (metabolic acidosis), CRP
Imaging: Abdominal X-ray (plain film) is the cornerstone
Initial views: supine and cross-table lateral
Supine view: General distension, dilated loops, altered gas pattern
Cross-table lateral: Free air under the diaphragm (pneumoperitoneum - indicative of perforation), air in the falciform ligament
Other findings: "Doughnut sign" (dilated bowel loop with thickened wall), intramural gas (pneumatosis intestinalis), portal venous gas (bad prognostic sign)
Ultrasound: Can be useful for detecting free fluid, pneumoperitoneum, and bowel wall thickening, especially in unstable infants where X-ray positioning is difficult
CT scan: Rarely used in neonates due to radiation but may be helpful in select cases for complex anatomy or abscess evaluation
Stool studies: Guaiac test for occult blood, stool culture if sepsis suspected.
Differential Diagnosis:
Other causes of abdominal distension and poor feeding intolerance in neonates include: Small bowel obstruction (e.g., malrotation with volvulus, intussusception, atresia), sepsis, milk protein intolerance, ileus secondary to other conditions (e.g., congenital heart disease), urinary tract infection, gastroparesis, chylous ascites.
Management
Initial Management:
For suspected feeding intolerance or early NEC: NPO (nil per os) status immediately
Gastric decompression via nasogastric or orogastric tube (low intermittent suction)
Intravenous fluids for hydration and electrolyte correction
Broad-spectrum antibiotics are initiated if NEC is suspected or confirmed
Close monitoring of vital signs, abdominal girth, and clinical status.
Medical Management:
For definite NEC (Bell Stage II and III): Continued NPO and gastric decompression
Aggressive intravenous fluid resuscitation
Broad-spectrum antibiotics targeting Gram-positive, Gram-negative, and anaerobic organisms (e.g., ampicillin, gentamicin, metronidazole)
Nutritional support via parenteral nutrition (TPN) once feeds are stopped
Hematological support (transfusion of packed red blood cells, platelets, fresh frozen plasma) as indicated by laboratory findings and clinical status
Close monitoring for signs of peritonitis or perforation.
Surgical Management:
Surgical intervention is indicated for: Intestinal perforation (pneumoperitoneum on X-ray, free air on ultrasound), peritonitis (abdominal rigidity, worsening distension, hemodynamic instability), clinical deterioration despite maximal medical management, or localized disease (e.g., focal necrosis)
Options include laparotomy with intestinal resection and diversion (stoma) or creation of a stoma without resection if possible, or peritoneal drainage (less common).
Supportive Care:
Continuous cardiorespiratory monitoring
Mechanical ventilation may be required for respiratory distress or apnea
Strict input/output charting
Regular abdominal girth measurements and assessment for distension or changes in skin color
Pain management
Kangaroo care and parental involvement
Close collaboration between neonatologists, pediatric surgeons, and nursing staff.
Complications
Early Complications:
Intestinal perforation, peritonitis, sepsis, shock, disseminated intravascular coagulation (DIC), bowel strictures, short bowel syndrome, recurrence of NEC, abdominal wall dehiscence if surgery performed.
Late Complications:
Chronic malnutrition, failure to thrive, neurodevelopmental deficits, recurrent bowel obstructions due to adhesions or strictures, cholestatic liver disease from prolonged TPN, surgical site hernias, psychological impact on infant and family.
Prevention Strategies:
Promotion of breastfeeding, judicious use of antibiotics in neonates, slow and cautious advancement of enteral feeds, particularly in preterm infants, use of probiotics, avoiding unnecessary instrumentation of the GI tract, prompt recognition and management of feeding intolerance.
Key Points
Exam Focus:
Differentiate between simple feeding intolerance (mild distension, increased residuals) and NEC (bilious vomiting, abdominal tenderness, distension with erythema, systemic signs)
Recognize key imaging findings: dilated loops, pneumatosis intestinalis, portal venous gas, and crucially, pneumoperitoneum indicating perforation
Bell staging criteria are essential.
Clinical Pearls:
Always perform serial abdominal examinations
Bilious emesis is a critical sign that warrants immediate attention
Palpate the abdomen gently
tenderness and rigidity are hallmarks of serious pathology
A truly distended, firm, and tender abdomen in a neonate is an emergency
Early consultation with surgery is vital if NEC is suspected.
Common Mistakes:
Delaying NPO and gastric decompression when feeding intolerance worsens or NEC is suspected
Underestimating the significance of bilious vomiting
Inadequate fluid resuscitation and electrolyte management
Misinterpreting ambiguous X-ray findings
Not considering early surgical consultation for suspected perforation or peritonitis
Aggressive feeding advancement in at-risk neonates.