Necrotizing enterocolitis (NEC) is an inflammatory disease of the gastrointestinal mucosa. The signs of NEC are nonspecific. Some generalized signs include:

Choice A rationale Hypertension is not a typical sign; often, hypotension occurs due to sepsis or shock. Absence of apnea is incorrect; apnea (cessation of breathing) is a common, generalized sign of serious illness in neonates, including NEC, reflecting central nervous system compromise or sepsis. Ruddy skin color is the opposite of the pallor or mottling often seen due to poor peripheral perfusion associated with septic shock in NEC. Choice B rationale A scaphoid abdomen suggests a sunken appearance, whereas NEC typically causes abdominal distention due to intestinal gas accumulation and paralytic ileus. No residual with feedings is an atypical finding; often, increased gastric residuals are observed due to decreased peristalsis. Increased urinary output is contrary to the oliguria often seen in infants with NEC due to third spacing or shock, indicating poor renal perfusion. Choice C rationale Hypertonia (increased muscle tone) is generally not an initial sign; neonates with severe systemic illness often exhibit lethargy and hypotonia. Tachycardia is a common response to systemic inflammation or shock. Metabolic alkalosis is incorrect; the typical finding is metabolic acidosis due to poor tissue perfusion leading to anaerobic metabolism and lactic acid production, often compounded by fluid loss. Choice D rationale Abdominal distention results from gas accumulation and paralytic ileus caused by inflammation and mucosal damage. Temperature instability (either hypothermia or fever) is a generalized sign of neonatal sepsis, which is a frequent precursor or complication of NEC, reflecting a dysfunctional thermoregulatory system. Grossly bloody stools occur due to intestinal mucosal necrosis and sloughing, a hallmark of advanced NEC, indicating capillary bleeding.