I. Overview
Neonatal necrotizing small intestinal colitis (NEC) is an acquired disease in which diffuse or localized necrosis of the small intestine and colon occurs due to ischemia and hypoxia caused by damage to the intestinal mucosa from various causes. The main symptoms are abdominal distention and blood in stool, characterized by necrosis of the intestinal mucosa and even deep intestinal layers, most often in the distal ileum and proximal colon, and the small intestine is rarely involved, characterized by cystic gas accumulation in part of the intestinal wall on abdominal X-ray.
Etiology
1.Inadequate blood supply to the intestine
Such as neonatal asphyxia, pulmonary hyaline membrane disease, umbilical artery cannulation, erythrocytosis, hypotension, shock, etc.
2, dietary factors
Such as hypertonic milk or hypertonic drug solution can damage intestinal mucosa, nutrients in food facilitate bacterial growth and carbohydrate fermentation to produce hydrogen.
3.Bacterial infection
Such as Escherichia coli, Klebsiella, Pseudomonas aeruginosa, Salmonella, Clostridium difficile and other overgrowth, invade the intestinal mucosa causing damage, or cause sepsis and infectious toxic shock aggravate the intestinal damage.
Third, the clinical manifestations
Male infants more than female infants, mainly disseminated cases, no obvious seasonality, normal meconium after birth, often within 2-3 weeks after birth, with a peak of 2-10 days, in the neonatal diarrhea epidemic NEC can also be a small epidemic, no gender, age and seasonal differences in the epidemic.
1. Abdominal distension and diminished bowel sounds
The child first has delayed gastric emptying and gastric retention, followed by abdominal distention. In mild cases, there is only abdominal distention, but in severe cases, the symptoms rapidly worsen, with abdominal distention like a drum and diminished or even absent bowel sounds.
2.Vomiting
Children often vomit, and the vomit may be coffee-like or bile-like, some children do not vomit, but the stomach can be pumped with coffee or bile-like gastric contents.
3. Diarrhea and bloody stools
At the beginning, the stool is watery, ranging from 5 to 6 times a day to more than 10 times a day, and after 1 to 2 days, the stool is bloody, which can be fresh blood, jam-like or black.
4. Systemic symptoms
Children with NEC often have poor response, atrophy, refusal to eat, pale or blue-gray face, cold extremities, shock, acidosis, jaundice aggravation, preterm infants are prone to recurrent apnea, slowed heart rhythm, normal body temperature or hypothermia, or temperature does not rise.
IV. Examination
1.Peripheral blood picture
Increase in white blood cell count, left shift of classification nucleus, decrease in platelets.
2.Blood gas analysis and electrolyte measurement
It can understand the degree of electrolyte disorder and acidosis, and guide the treatment of fluid and intravenous nutrition solution.
3.Fecal examination
Dark appearance, positive occult blood, microscopic examination with variable number of white blood cells and red blood cells, stool bacterial culture with Escherichia coli, Klebsiella and Pseudomonas aeruginosa are common.
4.Blood culture
If the bacterial culture is consistent with the fecal culture, it is meaningful to diagnose the etiology of NEC.
5.Abdominal X-ray examination
X-ray plain film showing partial cystic pneumatosis of the intestinal wall is of great value for the diagnosis of NEC, and it is important to follow up the examination several times to observe the dynamic changes.
V. Diagnosis
In children with risk factors for this disease, a more definite diagnosis can be made once the relevant clinical manifestations and X-ray examination changes occur.
VI. Treatment
Treatment is based on fasting, maintaining water-electrolyte and acid-base balance, supplying nutrition and symptomatic treatment. In recent years, the prognosis of this disease has been greatly improved due to the wide application of total intravenous nutrition and strengthening of supportive therapy.
1.Fasting
(1) Fasting time Once the diagnosis is confirmed, fasting should be immediate, 5-10 days in mild cases, 10-15 days or longer in severe cases. Give gastrointestinal decompression when abdominal distension is obvious.
(2) Criteria for resumption of feeding Abdominal distension disappears, fecal occult blood turns negative, abdominal X-ray is normal, and general condition improves significantly. If the child has symptoms such as abdominal distension and vomiting again after feeding, fasting is required again.
(3) Feeding food When starting to feed, try to feed 5% sugar water first, after 2-3 times if there is no vomiting and abdominal distension, you can change to dilute milk, breast milk is the best, do not use hypertonic milk.
2, intravenous replenishment of fluids and maintenance of nutrition
During fasting, intravenous fluid must be replenished to maintain water-electrolyte and acid-base balance and supply nutrition.
(1)Fluid volume The total daily fluid volume is 100~150ml/kg according to the age of the day.
(2) Caloric value: 209.2kJ/kg (50kcal/kg) per day at the beginning of the disease, gradually increasing to 418.4~502.1kJ/kg (100~120kcal/kg) later. Of which 40% to 50% is provided by carbohydrates, 45% to 50% is provided by fat, and 10% to 15% is provided by amino acids.
(3) Carbohydrates are generally infused intravenously around glucose.
(4) Protein The main purpose of amino acid infusion is to facilitate protein synthesis under the premise of ensuring calories.
(5) Fat The infusion of 10% fat milk injection is commonly used.
(6) Electrolytes Blood electrolyte concentration should be monitored and adjusted at any time.
(7) Various trace elements and vitamins
3. Anti-infection
Commonly used ampicillin and butylamine kanamycin, also can choose antibiotics according to culture allergy.
4.Symptomatic treatment
In addition to 2:1 sodium-containing solution, plasma, albumin and 10% low molecular dextrose can also be used for volume expansion.
5.Surgical treatment indications
Intestinal perforation, peritonitis signs and symptoms are obvious, the abdominal wall is obviously red and swollen or by medical treatment is ineffective, surgery should be performed.