Indian Pediatrics 2003; 40:349-351 

Pneumatosis Coli - A benign Form of Necrotising Enterocolitis

Necrotising enterocolitis (NEC) is the most common acquired gastrointestinal emergency in neonates. Presence of pneumatosis intestinalis is taken as evidence of definite NEC. A distinctive but rare form of NEC called ‘pneumatosis coli’ has been described, presenting with gross blood in stools and minimal or absent local and systemic signs. Radio-graph characteristically reveal isolated colonic pneumatosis without small bowel involvement. Pneumatosis coli has a more benign course compared with definite NEC. Total parenteral nutrition, antibiotics, an appropriate duration ’off feeds’ and close observation remain the corner stones of therapy assuring a benign course.

Key words: Necrotising enterocolitis, Neonates, Pneumatosis.

Necrotising enterocolitis (NEC) is the most common acquired gastrointestinal emergency in the newborn(1). Presence of pneumatosis intestinalis is taken as evidence of definite (stage 2) NEC(2). Extensive pneumatosis suggests extensive injury to long segments of gut with a higher mortality and medical management usually fails in upto 20% of cases(3). The location of pneumatosis is however important. A distinctive but rare form of NEC called ‘pneumatosis coli’ has been described(4-6), presenting with gross blood in stools and minimal or absent local and systemic signs. Radiographs, character-istically reveal isolated colonic pneumatosis without small bowel involvement. This form of colonic disease is recognized as a benign variety of NEC carrying a favorable prog-nosis and responds to medical management without sequelae.

Case Report

A preterm male neonate, first of the twins with a birth weight of 2080 grams (<10th centile) was born to a primigravida caucasian mother at 35 weeks of gestation by emer-gency cesarean section for fetal distress. Apgar scores were 8 and 9 at 1 and 5 minutes respectively with a cord pH of 7.2, PaCO2 44.7 mmHg, BE-10.5 and no resuscitation was required. There was no respiratory distress and gavage feeds with preterm formula (60 mL/kg/day) were started from 2 hours of age. Feeds were discontinued at 36 hours of age following a large gastric aspirate. By 48 hours he was lethargic and had bile and blood stained gastric aspirates and abdominal distension. Radiograph (Fig. 1) revealed intramural gas in the colon with no small bowel distension remaining unchanged over the next 48 hours. C-reactive protein was elevated (102 mg/L) associated with thrombocytopenia (platelet count 23,000) and a normal white cell count. Blood culture was negative at the end of 48 hours. Treatment was initiated with vancomycin, gentamicin and metronidazole. Marked clinical improve-ment occurred over the next 48 hours, with resolution of abdominal distension and blood/bile aspirates. Following 7 days of total parenteral nutrition, enteral feeds (expressed breast milk) were gradually reintroduced, reaching full feeds by day 16. The subsequent course was uneventful and the infant was discharged home on day 42 with a weight of 2745 grams. The second twin, a female, was discordant in growth with a birth weight of 1395 grams (<10th centile), had an uneventful stay in the nursery and was discharged at a weight of 1920 grams.

Fig.1. Abdominal radiograph demonstrating pneumatosis in the colon without small intestinal involvement

Discussion

Pneumatosis coli as an entity without small bowel distension, and minimal or absent local and systemic signs representing a milder form of NEC was first reported in English literature in 1975 by Richmond and Mikity(4). Subsequently, Leonidas and Hall(5) and Hoehn et al.(6) reported similar cases of isolated colonic involvement with NEC. All these infants (n = 13) did have risk factors for NEC, but of a lesser severity. Their gestational age and birth weight ranged from 28 to 39 weeks and 875 grams to 3395 grams respectively and the initial clinical course was unremarkable. Except for three of the thirteen, all had 5-minute Apgar scores greater than 7 and four infants were growth retarded. All the infants in their series had mild systemic manifestations, slight to moderate abdominal distension, gastric residuals and grossly bloody stools. None required surgical intervention and recovered within 2-3 days. Pneumatosis was confined to the colon and was predominantly circular, indicating a submucosal rather than sub-serosal location. Similar to these reports, our case did have risk factors for NEC, but of a lesser severity, was small for gestational age, had grossly bloody stools, had diffuse pneumatosis limited to the colon and an uneventful recovery.

Pathophysiology of pneumatosis coli is poorly understood. The consistent finding in NEC is ischemic necrosis, which most commonly affects the terminal ileum and proximal colon, watershed areas of superior mesenteric arterial supply(7). Ischemia - reperfusion injury is quite possible in the colon given its extensive extra and intramural plexus of collateral vessels, and the presence of aldehyde oxidase as a rich source of oxygen free radicals. The junction (Griffith’s point) between the distal branches of the superior and inferior mesenteric arteries supplying the colon is the watershed area most susceptible to ischemia(8). Selective vascular compromise in this area possibly due to regional differences in autoregulation may explain isolated colonic involvement. The colonic mucosa has low baseline oxygen requirements and lacks hairpin vascular architecture responsible for a countercurrent shunting of oxygen. The combination of these two factors may explain the rarity and benign course of pneumatosis coli.

Pneumatosis coli can be regarded as a subform of neonatal intestinal disease with a more benign course as compared to classical NEC. Total parenteral nutrition, antibiotics, an appropriate duration ‘off feeds’ and close observation remain the corner stones of therapy assuring a benign course.

Contributors: JNT searched the literature and wrote the manuscript. SKP conceived the study and helped in drafting. KG revised the manuscript. JNT shall act as the guarantor for the paper.

Funding: None.

Competing interests: None stated.

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