What is the treatment of necrotizing enterocolitis (NEC)?

Treatment of Necrotizing Enterocolitis

Necrotizing enterocolitis requires immediate bowel rest with nasogastric decompression, aggressive intravenous fluid resuscitation, and broad-spectrum antibiotics covering gram-positive, gram-negative, and anaerobic organisms, with the first-line regimen being ampicillin plus gentamicin, adding metronidazole for surgical cases. 1

Initial Stabilization and Supportive Care

Upon diagnosis of NEC, immediately implement the following measures:

• Make the patient NPO (nothing by mouth) and insert a nasogastric tube for bowel decompression to reduce intestinal distension and prevent further ischemic injury 1
• Initiate aggressive intravenous fluid resuscitation to address the hemodynamic instability that commonly accompanies NEC, as these neonates can rapidly develop septic shock 1
• Monitor hemodynamics closely with serial vital signs and laboratory assessments for thrombocytopenia, neutropenia, and metabolic acidosis, which indicate disease severity 1

Antibiotic Therapy

First-Line Regimen

The standard empiric antibiotic regimen is ampicillin plus gentamicin, which has been shown effective in decreasing mortality and preventing clinical deterioration in NEC 1, 2. This combination provides coverage against the most common pathogens involved in NEC.

When to Add Anaerobic Coverage

Add metronidazole to the ampicillin-gentamicin regimen in the following situations:

• Surgical NEC (when operative intervention is required) 1, 2
• Clinical deterioration despite initial therapy 1
• Evidence of bowel perforation or extensive necrosis 1

The evidence does not support routine addition of metronidazole for all cases of medical NEC, as ampicillin and gentamicin alone are effective for non-surgical cases 2.

Alternative Regimens

If the above regimen is not suitable, alternative first-line options include:

• Ampicillin, cefotaxime, and metronidazole 1
• Meropenem as monotherapy (provides broad-spectrum coverage including anaerobes) 1

Special Circumstances

Substitute vancomycin for ampicillin if there is suspected MRSA or ampicillin-resistant enterococcal infection based on local resistance patterns or prior cultures 1

Add fluconazole or amphotericin B if fungal infection is suspected, particularly in extremely low birth weight infants (<1000g) with risk factors for invasive candidiasis 1

Duration of Antibiotic Therapy

Continue antibiotics until clinical improvement is evident, typically when the neonate demonstrates:

• Decreased abdominal distension 3
• Resolution of bloody stools 3
• Improved hemodynamic parameters 3
• Normalization of laboratory values (white blood cell count, platelet count) 3

Research suggests that post-operative antibiotic courses can be abbreviated, with some centers using as little as 2 days post-operatively without adverse outcomes 4.

Surgical Intervention

Urgent or emergent surgery is indicated when:

• Pneumoperitoneum or evidence of bowel perforation is present on imaging 1
• Clinical deterioration occurs despite maximal medical therapy (worsening acidosis, persistent hypotension, progressive abdominal distension) 1
• Persistent gastrointestinal bleeding despite correction of coagulopathy 3

Surgical Options

The surgical approach includes:

• Laparotomy with resection of all necrotic bowel and creation of ostomies (preferred in most cases) 1
• Primary anastomosis may be considered in select stable patients, though this carries higher risk in severely compromised neonates 3
• Peritoneal drainage as a temporizing measure in extremely unstable very low birth weight neonates 1

Obtain intraoperative Gram stains and cultures to guide subsequent antimicrobial therapy adjustments 1

Nutritional Management

Maintain bowel rest (NPO status) during the acute phase until clinical improvement is documented and abdominal examination normalizes 1

Total parenteral nutrition (TPN) should be initiated to provide nutritional support during the prolonged period of bowel rest, which typically lasts 7-14 days or longer depending on disease severity 5

Common Pitfalls to Avoid

Do not use anticholinergic, antidiarrheal, or opioid agents as they may aggravate ileus and mask clinical deterioration 6, 3

Avoid delaying surgical consultation when there are signs of perforation or clinical deterioration, as failure to remove necrotic bowel in these severely immunocompromised patients is often fatal 3

Do not use overly broad antibiotic regimens empirically (such as adding metronidazole to all cases) without indication, as no regimen has proven superior to ampicillin-gentamicin for medical NEC 2, 4

Monitoring Response to Treatment

Serial abdominal examinations every 4-6 hours are essential to detect progression requiring surgical intervention 3. Look specifically for:

• Worsening abdominal distension or rigidity 1
• Development of abdominal wall erythema or crepitus 1
• Increasing bloody stools 1
• Deteriorating vital signs or laboratory parameters 1

Prognosis

Survival rate is approximately 95% when NEC does not involve the entire bowel, but mortality increases dramatically to 40-90% when pan-intestinal involvement occurs 1. Nonoperative management is successful in approximately 70% of cases 1.