wednesday april 7, 2010 nicole withrow necrotizing enterocolitis
TRANSCRIPT
WEDNESDAY APRIL 7 , 2010NICOLE WITHROW
Necrotizing Enterocolitis
Definition
NEC is an acute inflammatory disease of the gastrointestinal mucosa
Characterized by mucosal or even deeper intestinal necrosis
Most common GI emergency in neonatesThe condition is commonly complicated by perforation
Resulting in the outflow of intestinal contents into the abdominal cavity
Although the etiology is unknown, three factors appear to play an important role in the development of NEC Intestinal ischemia, colonization by pathogenic bacteria, and
enteral feedings
Generalized signs of NEC
These signs may be indicative of sepsis:
HypotoniaDecreased activityPallorDecreased oxygen
saturationDecreased perfusionTemperature
instability
Recurrent apnea and bradycardia
Respiratory distressMetabolic acidosisOliguriaCyanosis
Gastrointestinal signs of NEC
Abdominal distentionDecreased bowel soundsFeeding intoleranceIncreasing or bile-stained residual gastric
aspirates Vomiting (bile or blood)Grossly bloody stoolsAbdominal tendernessErythema (redness) of the abdominal wall
Abdominal Distention
One of the later and more obvious gastrointestinal signs of NEC
Bowel perforation and therefore leakage of gastrointestinal contents into the abdominal cavity may cause severe abdominal distention such as this…
Frequency
NEC occurs in about 1%to 5% of newborns in NICUsOutbreaks seem to follow an epidemic pattern within
nurseries, suggesting an infectious etiology, although a specific causative organism has not been isolated
Extremely premature infants (1000 g) are particularly vulnerable, with reported mortality rates of 40-100%
The mortality rate ranges from 10% to more than 50% in infants who weigh less than 1500 g, depending on the severity of disease, compared with a mortality rate of 0-20% in babies who weigh more than 2500 g
Sepsis occurs in 33% of infants which may also lead to death
Risk factors for developing NEC
Preterm birth remains the most prominent risk factor in development of NEC In the preterm infant the development of NEC may be delayed for up to 30 days The onset of NEC in the term infant usually occurs earlier, 4 to 10 days after birth
Lowered oxygen levels or birth asphyxia during delivery Lack of oxygen leading to intestinal ischemia and eventually necrosis
Infants with polycythemia Increased amounts of RBCs may thicken blood and therefore hinder transportation of
oxygen to the intestines Race
Some studies indicate a higher frequency of NEC in African-American neonates than Caucasian neonates
Congenital heart disease Poor systemic perfusion due to circulatory insufficiency Patent ductus arteriosus (ductus arteriosus fails to close normally resulting in
abnormal blood flow between aorta and pulmonary artery) Treatment for this condition includes the medication Indomethacin which is related to the
development of NEC due to decreased intestinal perfusion
Risk factors for developing NEC
“Breast milk contains many factors such as immunoglobulins, particularly IgA, lymphocytes and macrophages (mediate inflammatory response) that potentially mature the intestinal barrier and may prevent the occurrence of NEC”
(Barlow B, Santuli T, Heird W, et al. An experimental study of acute necrotizing enterocolitis-the importance of breast milk. J Pediatric Surg. 1984, 9:587)
Some studies indicate that infants are at a higher risk for developing NEC if they are formula-fed due to the condition being less common among breast-fed infants…
Diagnosing NEC
NEC is confirmed by radiographic examination which may reveal:
Bowel loop distentionPneumatosis intestinalis (gas in the bowel
wall)Pneumoperitoneum (gas in the abdominal
cavity), portal venous air, or a combination of these findings Pneumatosis intestinalis, pneumoperitoneum, and
portal venous air are caused by gas produced by the bacteria that invades the wall of the intestines and escapes into the peritoneum and portal system when perforation occurs
Bowel Loop Distention
Radiographic examination reveals bowel loop distention
Diagnosing NEC
Laboratory evaluation:Complete blood cell count with differential, coagulation
studies, ABG analysis, serum electrolyte levels, and blood culture
The white blood cell count may be either increased or decreased In response to bacterial colonization
The platelet count and coagulation studies may be abnormal Thrombocytopenia (low platelet count) and disseminated
intravascular coagulation Electrolyte levels may be abnormal, with leaking capillary
beds and fluid shifts with the infection Hyponatremia
Treatment
Discontinue enteral feedingsAdminister NGT attached to intermittent
suction To provide gastric decompression (relieve pressure)
Parenteral therapy Fluid resuscitation (to support circulation) TPN (usually for 14-21 days while intestine heals)
Systemic antibiotic therapy Also institute infection control and proper hand
washingPossible surgery
Dependent on severity
Surgery
Surgery should be considered for an infant with NEC whose clinical and laboratory condition worsens despite nonsurgical support
Extensive involvement may necessitate surgical intervention and establishment of an ileostomy, jejunostomy, or colostomy
Surgical intervention is needed in < 25% of infantsIndications for surgery include:
Intestinal perforation (pneumoperitoneum) Signs of peritonitis (absent bowel sounds, tenderness or erythema
and edema of the abdominal wall) Purulent material aspirated from the peritoneal cavity by
paracentesis
Necrotizing Enterocolitis
An example of necrotic intestinal tissue requiring surgery…
Combination liver and small bowel transplantation may also be necessary for severely affected infants who have also acquired life-threatening hyperalimentation hepatitis
http://www.youtube.com/watch?v=f13bhv7d9gw
Further Complications
Some conditions resulting from this disease in surviving infants include short-bowel syndrome, narrowing of the colon with obstruction, fat malabsorption, and failure to thrive secondary to intestinal dysfunction
Preventing NEC
Corticosteroid administration Promotion of intestinal maturity
Human milk is thought to provide some degree of protection Use of Indomethacin used during pregnancy (medication
relaxes uterine smooth muscle) may cause adverse reactionsUmbilical catheters, if required, should be placed below the
renal arteries May cause intravascular clotting or possibly perforate walls and enter
pericardial space, may increase risk of infectionPolycythemia should be treated promptlyPossibly delaying feedings for several days to weeks in
premature infants while providing TPN Recent evidence suggests that probiotics (ex: Bifidus infantis,
Lactobacillus acidophilus) may help prevent NEC
Case Study
L.J. a 36-week SGA African-American infant is admitted into the NICU and begins receiving enteral feedings. The infant’s pulse and respirations are periodically low and the infant has been placed on a warming bed. A diaper change reveals an absence of urinary voiding but also a small amount of grossly bloody stool. The nurse assesses for bowel sounds and hears none and also notices a slightly rounded abdomen.
What are some of the evident risk factors?What signs and symptoms in this case may be indicative of
NEC?How might the residual gastric aspirates of this infant look?What interventions would follow a diagnosis of NEC?
Case Study
Risk factors: 36-week SGA (prematurity) African-American Receiving enteral feedings
Signs and symptoms in this case: Pulse and respirations are
periodically low Warming bed (temperature
instability) Absence of urinary voiding
(oliguria) Grossly bloody stool Lack of bowel sounds Slightly rounded abdomen
(abdominal distention)
How might the residual gastric aspirates of this infant look?: Bile-stained
What interventions would follow a diagnosis of NEC? Discontinue enteral feedings Administer NGT attached to
intermittent suction Parenteral therapy
Fluid resuscitation (to support circulation)
TPN (usually for 14-21 days while intestine heals)
Systemic antibiotic therapy Also institute infection
control and proper hand washing
Most likely surgery
Questions?
Resources
Bakewell-Sachs, S., Medoff-Cooper, B., Escobar, G., Silber, J., & Lorch, S. (2009). Infant functional status: the timing of physiologic maturation of premature infants. Pediatrics, 123(5), e878-86
Cakmak Celik, F., Aygun, C., & Cetinoglu, E. (2009). Does early enteral feeding of very low birth weight infants increase the risk of necrotizing enterocolitis?. European Journal of Clinical Nutrition, 63(4), 580-584.
Ladd, N., & Ngo, T. (2009). Pharmacology notes. The use of probiotics in the prevention of necrotizing enterocolitis in preterm infants. Baylor University Medical Center Proceedings, 22(3), 287-291.
Perry, Shannon, Hockenberry, Marilyn, Lowdermilk, Deitra, & Wilson, David. (2009). Maternal child nursing care. Mosby, 731-732.
Pickard, S., Feinstein, J., Popat, R., Huang, L., & Dutta, S. (2009). Short- and long-term outcomes of necrotizing enterocolitis in infants with congenital heart disease. Pediatrics, 123(5), e901-6.
Thompson, A., & Bizzarro, M. (2008). Necrotizing enterocolitis in newborns: pathogenesis, prevention and management. Drugs, 68(9), 1227-1238.