Loyola researchers identify risk factor for life-threatening disease in preemies
Many premature infants suffer a life-threatening bowel infection called necrotizing enterocolitis (NEC).
Researchers at Loyola University Health System have identified a marker to identify those at risk for the infection, enabling doctors to employ early preventive strategies. These findings were published in the latest issue of the Journal of Pediatric Surgery.
“This information will allow us to better care for these premature infants,” said Jonathan Muraskas, MD, study investigator and co-medical director of Loyola’s neonatal ICU. “Simple changes to blood transfusion practices, feeding patterns and treatment of these infants may significantly reduce the incidence of NEC.”
NEC is the most common serious gastrointestinal disorder among preterm newborns. It affects up to 10 percent of extremely low birth weight infants and has a mortality rate of nearly 30 percent. There is no known cause for the disease, yet researchers believe it may result from a combination of decreased blood flow to the bowel, feeding patterns, infection, mechanical injury or abnormal immune response.
NEC occurs when the lining of the intestinal wall dies and tissue falls off. Most cases of NEC are mild to moderate and can be successfully treated with antibiotics. But in severe cases, a hole can develop in the intestine, allowing bacteria to leak into the abdomen causing a life-threatening infection.
Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) medical/surgical emergency occurring in neonates. An acute inflammatory disease with a multifactorial and controversial etiology, the condition is characterized by variable damage to the intestinal tract ranging from mucosal injury to full-thickness necrosis and perforation.
Necrotizing enterocolitis represents a significant clinical problem and affects close to 10% of infants who weigh less than 1500 g, with mortality rates of 50% or more depending on severity. Although it is more common in premature infants, it can also be observed in term and near-term babies. (See Epidemiology and Prognosis.)
NEC most commonly affects the terminal ileum and the proximal ascending colon. However, varying degrees of NEC can affect any segment of the small intestine or colon. The entire bowel may be involved and may be irreversibly damaged.
Numerous, vague reports in 19th-century literature report described infants who died from peritonitis in the first few weeks of life. The first half of the 20th century brought more reports of peritonitis with ileal perforation due to what was called infectious enteritis. In 1953, Scmid and Quaiser called this condition newborn NEC. The first clear report of NEC did not appear until 1964, when Berdon from the New York Babies Hospital described the clinical and radiographic findings of 21 infants with the disease.
As neonatal intensive care has progressed an d as premature newborns have come to survive long enough for the disease to develop, the incidence of NEC in neonatal intensive care units (NICUs) has increased. NEC remains one of the most challenging diseases confronted by pediatric surgeons. It likely represents a spectrum of diseases with variable causes and manifestations, and surgical care must therefore be individualized.
NEC typically occurs in the second to third week of life in the infant who is premature and has been formula fed. Although various clinical and radiographic signs and symptoms are used to make the diagnosis, the classic clinical triad consists of abdominal distension, bloody stools, and pneumatosis intestinalis. Occasionally, signs and symptoms include temperature instability, lethargy, or other nonspecific findings of sepsis.
This study evaluated 177 infants born at less than 32 weeks’ gestation and/or babies, who were less than 3 pounds, 3 ounces. Blood samples were collected from these infants within 72 hours of birth and weekly for four weeks to measure reticulated platelets (RP) and intestinal alkaline phosphatase (iAP). Of the 177 infants, 15 (8.5 percent) developed NEC. Of these, 93 percent had low RP levels and 60 percent had high iAP. Those infants with low RP levels were significantly more likely to develop NEC while those with high iAP showed a similar trend.
“Decreased reticulated platelets serve as a sensitive indicator for NEC onset,” Dr. Muraskas said. “Further research also may find that infants with elevated iAP levels may be at risk for this serious illness.”
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This study was conducted in collaboration with Richard Kampanatkosol, MD, Tricia Thomson, MD, Phillip DeChristopher, MD, Sherri Yong, MD, and Walter Jeske, PhD from Loyola University Health System; Omar Habeeb, MD, from Hutt Valley District Health Board, in Wellington, New Zealand; Loretto Glynn, MD, from Ann and Robert H. Lurie Children’s Hospital at Cadence Health; and Akhil Maheshwari, MD from University of Illinois at Chicago.
Etiology and Risk Factors
Overall, NEC affects one in 2,000 to 4,000 births, or between 1% and 5% of neonatal intensive care unit admissions. The disease occurs in nearly 10% of premature infants but is rare in full term infants. Although the exact cause of NEC is still unknown, there are many theories to explain why NEC affects mainly premature infants. The only consistent observations made in infants who develop NEC are the presence of prematurity and formula feeding. The premature infant has immature lungs and immature intestines. Therefore, any decrease in oxygen delivery to the intestines, because the lungs cannot oxygenate the blood adequately, will damage the lining of the intestinal wall. This damage to the bowel wall will allow bacteria that normally live inside the intestine to invade the wall of the intestine and cause local infection and inflammation (NEC) that can eventually lead to rupture or perforation of the intestine.
Loyola has one of the premier neonatal ICUs in the Midwest. It has cared for more than 25,000 babies and holds the Guinness World Record for the smallest surviving baby (9.2 ounces).
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Nora Dudley
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Loyola University Health System