A 3 week old infant is bought into your ED late at night. She is febrile and looks incredibly unwell. Her parents report a 36 hour history of increasing vomiting and poor oral intake. She has not had a wet nappy for 12 hours or so and the parents now report a fever of 39.5*C.
She was born at 39 weeks gestation following an unremarkable pregnancy and delivery. They were only in hospital for 2 days as everything was going so well…..
When you approach this child in resus, you immediately identify that she is in a whole world of trouble. She is flat and listless, tachypnoeic at 70/min (with moderate work of breathing) and tachycardic at 204 bpm. Her capillary return is 5-6 seconds and her skin is mottled. Her abdomen is quite obviously distended.
Amongst the flurry of activity at the bedside the following x-ray is taken….
Based on the clinical picture above, we were left with a few differentials including;
- Sepsis, sepsis, sepsis…
- Pyloric stenosis
- ‘something nasty in the belly’…
There are a number of things going on in this xray….
- a healing left-sided clavicle fracture, with callous formation.
- small right pneumothorax.
- intestinal dilatation. nasogastric tube insitu.
- pneumatosis intestinalis.
- portal vein gas.
These xray findings were almost diagnostic of necrotising enterocolitis ….
Necrotising Enterocolitis (NEC).
The most common gastrointestinal emergency in neonates and the most common cause of intestinal perforation occurring in the neonatal period. It is a condition of intestinal necrosis in previously well infants and whilst it is predominately a disease of prematurity & most cases occur whilst the child is in the NICU, up to 10% of cases occur in full term infants. As today’s child-delivery practices change (home-births, very early discharges from labour wards – some as early as 4 hours) this is potentially a problem that can make its way into the Emergency Department.
The exact pathophysiologic mechanism behind NEC remains unknown, but appears multifactorial. The primary event may be inflammation or injury to the intestinal wall, which begins in the mucosa and then extends transmurally. The distal ileum and proximal colon are more commonly affected, and the involvement may be continuous or patchy.
Risk factors include;
- Prematurity (90% of cases)
- Aggressive enteral feeding
- Birth-related hypoxic or ischaemic insults (including congenital heart disease)
- Infectious causes
The development of NEC is closely related to gestational age; * 24-28 weeks: NEC w/in 2-4 weeks of life. * 29-32 weeks: NEC w/in 1-3 weeks of life. * Full term infants: NEC in 1st week of life.
The classic symptoms are that of food intolerance (poor feeding) and vomiting (either bilious or non-bilious). Examination may reveal palpable loops of bowel (oedematous & distended with air), as well as erythema & discolouration of the abdominal wall. Other symptoms and signs include; haematemesis, PR bleeding, shock and apnoea.
NEC is commonly divided into three stages: 1) Early or suspected NEC [food intolerance, vomiting, ileus] 2) Definite NEC [confirmed on radiograph w/ intestinal dilatation & pneumatosis intestinalis] 3) Advanced disease [perforation, marked abdo distension, metabolic acidosis, DIC & shock]
- Stage I:
- Loss of normal, symmetric bowel pattern.
- Dilated loops of bowel (a non-specific finding)
- Variable degrees of dilatation
- Stage II:
- Intramural air (“pneumatosis intestinalis”)
- Present in ~ 75% of cases
- Intramural air (“pneumatosis intestinalis”)
- Other / later signs:
- Portal vein gas (10-30% of cases)
- Gas in gastric wall (“pneumatosis gastralis”)
Ultrasound & barium enema have proven helpful, however are not going to be of assistance in the ED.
** an example of pneumatosis intestinalis, courtesy of Wikipedia **
- Gastro-oesophageal reflux (constant small volume)
- Pyloric Stenosis (progressive from 2-3 weeks of age, then projectile)
- Inflammatory/Infective conditions [sepsis, meningitis, gastroenteritis…]
- Metabolic [congenital adrenal hyperplasia, DKA]
- Other [occult trauma, intracranial mass, ingestion…]
- Basic principles of ABCD… including standard indications for intubation/mechanical ventilation.
- Keep ‘nil by mouth’. Place gastric tube for decompression.
- IV access w/ aggressive fluid resuscitation.
- Potential for significant third-spacing of fluid.
- Refractory shock is common and inotropes may be needed.
- Maintenance fluid should contain dextrose.
- Correct electrolytes
- Broad-spectrum antibiotic coverage (usually ampicillin/gentamicin is appropriate for neonates).
- Covers differential of sepsis plus potential bowel perforation.
- Urgent consultation with a Paediatric Surgeon.
- High rates of surgical intervention required.
- Only 50-75% of patients w/ perforation will have free gas on x-ray.
- Rosenʼs Emergency Medicine. Concepts and Clinical Approach. 7th Edition
- Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th Edition.