This study aimed to evaluate the clinical and radiologic findings suggestive of spontaneous intestinal perforation (SIP) in extremely-low-birth-weight infants (ELBWIs) with persistent gasless abdomen, and to investigate the usefulness of abdominal ultrasonography for the diagnosis of SIP.
In total, 22 infants with birth weights less than 1,000 g who showed persistent gasless abdomen on simple abdominal radiography were included. Perinatal, neonatal, and perioperative clinical findings were retrospectively reviewed, and the risk factors for intestinal perforation were evaluated. Abdominal sonographic findings suggestive of intestinal perforation were also identified, and postoperative short-term outcomes were evaluated.
In total, eight of the 22 infants (36.4%) with gasless abdomen had SIP. The number of infants with patent ductus arteriosus who were treated with intravenous ibuprofen or indomethacin was significantly higher in the SIP group than in the non-SIP group (
Intestinal perforation may occur in ELBWIs with gasless abdomen. As intramural echogenicity and extraluminal echogenic materials on abdominal ultrasonography are indicative of SIP, this technique could be useful for diagnosing SIP.
Gasless abdomen has been defined as a state of scanty or invisible intestinal gas on simple abdominal radiography [
SIP is a common complication observed in ELBWIs with birth weight less than 1,000 g, and it has been described as a distinct clinical entity that differs from necrotizing enterocolitis (NEC), in terms of both clinical and histologic presentation [
Given that the delayed treatment of SIP in ELBWIs owing to difficulty in early diagnosis may increase the likelihood of subsequent dismal outcomes, a more careful clinical and radiologic assessment is required if the gasless abdomen is persistently observed in these infants [
Thus, in this study, we intended to evaluate the clinical and radiologic findings for early diagnosis of SIP in ELBWIs with persistent gasless abdomen, and to determine the risk factors associated with SIP. We also aimed to evaluate the usefulness of abdominal ultrasonography for the diagnosis of SIP in ELBWIs with gasless abdomen.
This study included 22 ELBWIs with birth weight less than 1,000 g, whose simple abdominal radiography showed persistently gasless abdomen lasting for more than 3 days (
Abdominal ultrasonography was conducted in infants who showed gasless abdomen on simple abdominal radiography for at least 3 consecutive days or in infants with clinical symptoms suggestive of meconium peritonitis or intestinal perforation, such as gray or bluish abdominal discoloration and/or free air on simple abdominal radiography. Abdominal ultrasonography was performed in the NICU, and the findings were evaluated by a pediatric radiologist.
Statistical analysis was performed using SPSS version 23.0 (IBM Co., Armonk, NY, USA). Variables were compared between the SIP and non-SIP groups using the independent
In total, eight of the 22 infants (36.4%) with gasless abdomen on simple abdominal radiography had SIP. Mean gestational age and mean birth weight did not significantly differ between infants without and with SIP (25.0±1.0 weeks vs. 23.9±1.6 weeks, 793.6±143.9 g vs. 743.8±166.6 g, respectively;
Trophic feedings before onset of gasless abdomen were performed in seven (50.0%) and five infants (62.5%) of the non-SIP and SIP groups, respectively (
Ages at which gasless abdomen was detected on simple abdominal radiography were 5.9±4.7 and 7.3±3.2 days of life in the non-SIP and SIP groups, respectively (
All infants with SIP had isolated focal intestinal perforations surrounded by a normal-appearing bowel (100%). Perforation occurred in the terminal ileum in five infants (62.5%); in the proximal ileum, in one infant (12.5%); in the transverse colon, in one infant (12.5%); and in the cecum, in one infant (12.5%). None of the surgical specimens were compatible with the gross or microscopic features of NEC. Primary peritoneal drainage was performed in three infants (37.5%), and primary laparotomy with resection of perforated segments of the intestine was performed in five infants (62.5%). All three infants treated with primary peritoneal drainage required salvage laparotomy. Four infants (50%; one who underwent primary peritoneal drainage [33.3%] and three who underwent primary laparotomy [60.0%]) died at 0, 4, 6, and 12 days after operation (
This study showed the clinical and radiological findings associated with SIP occurring in ELBWIs with persistent gasless abdomen on simple abdominal radiography. PDA treated with intravenous ibuprofen or indomethacin might be regarded as a significant risk factor associated with SIP in ELBWIs with gasless abdomen. Pneumoperitoneum was found in only one of the eight infants (12.5%) with SIP on simple abdominal radiography; abdominal ultrasonography in the non-SIP group showed ascites or focal fluid collection in three infants; the other findings were mostly unremarkable. Meanwhile, abdominal ultrasonography of infants in the SIP group exclusively showed findings suggestive of intestinal perforation such as intramural echogenicity (75.0%), echogenic extramural material (50.0%) and ascites (50%), with or without bowel wall thickening (50.0%). Thus, this study suggested that abdominal ultrasound might help detect intestinal perforation when SIP is suspected in ELBWIs with gasless abdomen.
Several causes of SIP in extremely premature infants have been suggested. Multifocal partial or complete defects of musculature in the intestinal muscular layer have been frequently observed in the histologic findings of SIP [
SIP of the newborn occurs primarily in ELBWIs with an incidence of approximately 3% in this specific population [
In general, infants with SIP have no typical symptoms or signs of NEC, such as abdominal distension, abdominal rigidity, tenderness, abdominal wall edema, or erythema [
Previous studies have reported that abdominal ultrasonography may be a very useful tool for diagnosis of SIP [
Treatment options for SIP in ELBWIs are primary laparotomy with resection or primary peritoneal drainage [
This study has several limitations. First, this study was conducted retrospectively in a single center, and included only a small number of ELBWIs with persistent gasless abdomen on abdominal radiography. Thus, the exact incidence and prognosis of SIP in ELBWIs with gasless abdomen could not be predicted. Second, because the clinical and radiologic findings suggestive of SIP in ELBWIs in this study would be non-specific and might present in other gastrointestinal disorders, such as NEC, the results indicating that these clinical findings may be associated with intestinal perforation in ELBWIs with gasless abdomen should be interpreted with caution. However, despite the above limitations, the findings of abdominal ultrasonography in this study such as extraluminal echogenic materials and intraluminal echogenicity may be helpful for early detection of a slowly progressive intestinal perforation in ELBWIs with gasless abdomen.
In conclusion, this study showed that SIP could commonly occur in ELBWIs who show persistent gasless abdomen on simple abdominal radiography, and gray or bluish discoloration of the abdomen suggestive of meconium peritonitis was frequently observed in infants with SIP. Moreover, this study showed that abdominal ultrasound could be a highly useful for the diagnosis of SIP.
No potential conflict of interest relevant to this article was reported.
Gasless abdomen on simple abdominal radiography supine (A) and cross-table lateral (B) views show gasless or scanty gas abdomen.
Abdominal ultrasonographic findings suggestive of intestinal perforation in extremely low-birthweight infants with gasless abdomen on simple abdominal radiography. (A) Fluid collection with heterogenous echogenecities is observed in the extraluminal space (short arrow). (B) Bowel wall thickening (short arrow) and increased intramural echogenicity (arrowheads) are observed. (C) Two tiny echogenic air bubbles are observed in the extraluminal space (long arrows).
Perinatal and Neonatal Characteristics of Enrolled Infants
Characteristic | Infants without SIP (n=14) | Infants with SIP (n=8) | |
---|---|---|---|
Gestational age (wk) | 25.0±1.0 | 23.9±1.6 | 0.062 |
Birth weight (g) | 793.6±143.9 | 743.8±166.6 | 0.469 |
Twin birth | 2 (14.3) | 4 (50.0) | 0.070 |
PROM | 3 (21.4) | 3 (37.5) | 0.416 |
Cesarean section | 8 (57.1) | 3 (37.5) | 0.375 |
SGA | 0 | 0 | - |
Preeclampsia | 1 (7.1) | 0 (0.0) | |
Maternal diabetes | 1 (7.1) | 1 (12.5) | 0.674 |
Antenatal corticosteroid, complete | 4 (28.6) | 1 (12.5) | 0.387 |
RDS treated with surfactant | 12 (85.7) | 7 (87.5) | 0.907 |
PDA treated with IV ibuprofen or indomethacin | 6 (42.9) | 7 (87.5) | 0.040 |
BPD | 5 (35.7) | 2 (25.0) | 0.887 |
Postnatal dexamethasone for BPD | 4 (28.6) | 2 (25.0) | 0.865 |
Inotropic for hypotension | 8 (57.1) | 7 (87.5) | 0.070 |
Hydrocortisone for hypotension | 0 | 1 (12.5) | 0.176 |
IVH grade ≥3 | 2 (14.3) | 4 (50.0) | 0.070 |
Periventricular leukomalacia | 1 (7.1) | 0 | 0.439 |
ROP stage ≥3 | 4 (28.6) | 0 | 0.095 |
Sepsis during gasless abdomen | 2 (14.3) | 2 (25.0) | 0.240 |
Death, in-hospital | 6 (42.9) | 4 (50.0) | 0.746 |
Age of death (d) | 29.3±26.7 | 16.6±10.9 | 0.404 |
Duration of hospital stay (d) | 82.3±52.8 | 85.7±79.7 | 0.915 |
Values are expressed as mean±standard deviation or number (%).
Abbreviations: SIP, spontaneous intestinal perforation; PROM, premature rupture of membrane; SGA, small for gestational age, RDS, respiratory distress syndrome; PDA, patent ductus arteriosus; IV, intravenous; BPD bronchopulmonary dysplasia; IVH, intraventricular hemorrhage; ROP, retinopathy of prematurity.
Perioperative Feeding History and Clinical Findings Suggestive of Intestinal Perforation
Variable | Infants without SIP (n=14) | Infants with SIP (n=8) | |
---|---|---|---|
Feeding before gasless abdomen | |||
Trophic feeding | 7 (50.0) | 5 (62.5) | 0.571 |
Brest milk feeding | 6 (42.9) | 5 (62.5) | 0.375 |
Age of start of trophic feeding (d) | 3.2±4.0 | 4.5±4.2 | 0.720 |
Clinical findings suggestive of perforation | |||
Greenish or red gastric residue | 2 (14.3) | 5 (62.5) | 0.020 |
Abdominal distension | 2 (14.3) | 5 (62.5) | 0.020 |
Decreased bowel sound | 4 (28.6) | 8 (100) | 0.001 |
Gray or bluish discoloration of abdomen | 2 (14.3) | 6 (75.0) | 0.004 |
Age of perforation (d) | - | 11.6±4.4 | - |
Values are expressed as number (%) or mean±standard deviation.
Abbreviation: SIP, spontaneous intestinal perforation.
Radiologic Findings Suggestive of Spontaneous Intestinal Perforation
Variable | Infants without SIP (n=14) | Infants with SIP (n=8) | |
---|---|---|---|
Simple abdominal radiography | |||
Age of onset of gasless abdomen (d) | 5.9±4.7 | 7.3±3.2 | 0.605 |
Duration of gasless abdomen (d) | 8.7±6.8 | 8.3±5.4 | 0.807 |
Pneumoperitoneum | 0 | 1 (12.5) | 0.176 |
Abdominal ultrasonography | |||
Bowel wall thickening | 0 | 4 (50.0) | 0.008 |
Intramural echogenicity | 0 | 6 (75.0) | 0.001 |
Extra-luminal echogenic material | 0 | 4 (50.0) | 0.008 |
Ascites or intra-abdominal focal fluid collection | 3 (21.4) | 4 (50.0) | 0.311 |
Values are expressed as mean±standard deviation or number (%).
Abbreviation: SIP, spontaneous intestinal perforation.
Operative Findings and Postoperative Outcomes
Variable | Perforation (n=8) |
---|---|
Focal intestinal perforation | 8 (100) |
Perforation site | |
Terminal ileum | 5 (62.5) |
Proximal ileum | 1 (12.5) |
Cecum | 1 (12.5) |
Transverse colon | 1 (12.5) |
Surgical intervention | |
Primary peritoneal drainage followed by salvage laparotomy | 3 (37.5) |
Primary laparotomy with resection | 5 (62.5) |
Postoperative death | 4 (50.0) |
Primary peritoneal drainage | 1/3 (33.3) |
Primary laparotomy with resection | 3/5 (60.0) |
Values are expressed as number (%).