Introduction: Norovirus infection with necrotizing enterocolitis has so far been reported as a specific tropism of the small bowel in premature newborns.
Case presentation: Three cases of premature newborns presenting with extensive isolated colonic ischemia due to norovirus infection are reported.Patient 1 was a Caucasian girl with a gestational age of 29+2 weeks. She had sudden onset of abdominal distension on the 30th day of life. Radiological signs of colonic pneumatosis were present 48 hours before perforation and stool analysis was positive for norovirus. On the 34th day, free air was detected on plain abdominal X-ray. At laparotomy, stenosis, necrosis and perforations involved the whole colon. The patient underwent ileostomy. A large colon resection and ileosigmoid anastomosis were done 3 months later.Patient 2 was a Caucasian boy with a gestational age of 28+3 weeks. On the 19th day, bloody stools with abdominal distension appeared. Stool analysis resulted positive for norovirus. A plain abdominal X-ray showed distended bowel loops. Antibiotic treatment was started. On the 32nd day due to the progressive deterioration of clinical conditions and the appearance of colic pneumatosis, a laparotomy was performed. Severe damage of the transverse colon and multiple areas of necrosis were found. Terminal ileostomy was performed. Six months later surgery consisted of mid-transverse colon resection as far as the splenic flexure, colocolic anastomosis and closure of ileostomy.Patient 3 was a Caucasian boy with a gestational age of 30 weeks. On the 44th day bloody-mucous stools appeared and stool analysis was positive for norovirus infection. Even with institution of antibiotic therapy clinical abdominal radiologic signs of colonic pneumatosis of the upper right quadrant were found. At the 70th day an explorative laparotomy showed dilated bowel loops and stenotic right colon and ileostomy was mandatory. Partial colectomy was later necessary and ileocolic anastomosis was performed.
Conclusion: We hypothesize that norovirus infection may be responsible for severe, distinctive colonic lesions, even in premature newborn infants.