You are in: eMedicine Specialties > Pediatrics: Surgery > General Surgery Small Left Colon SyndromeArticle Last Updated: May 26, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Erik Skarsgard, MD, Associate Professor of Surgery, Division of Pediatric Surgery, University of British Columbia, Children's and Women's Health Center of British Columbia Erik Skarsgard is a member of the following medical societies: American Academy of Pediatrics, American College of Surgeons, American Pediatric Surgical Association, and Royal College of Physicians and Surgeons of Canada Coauthor(s): Geoffrey Blair, MD, Clinical Professor of Pediatric General Surgery, Department of Pediatric Surgery, University of British Columbia; Head, British Columbia's Children's Hospital Editors: Robert Kelly, MD, Chairman, Department of Surgery, Departments of Surgery and Pediatrics, Children's Hospital of the King's Daughters; Associate Professor, Eastern Virginia Medical School; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Deborah F Billmire, MD, Associate Professor, Department of Surgery, Indiana University Medical Center; H Biemann Othersen Jr, MD, Professor of Surgery and Pediatrics, Emeritus Head, Division of Pediatric Surgery, Medical University of South Carolina; Harsh Grewal, MD, FACS, FAAP, Professor of Surgery and Pediatrics, Temple University School of Medicine; Chief, Section of Pediatric Surgery, Temple University Children's Medical Center Author and Editor Disclosure Synonyms and related keywords: small left colon syndrome, neonatal small left colon syndrome, NSLCS INTRODUCTIONSection 2 of 12
  Intestinal obstruction is one of the most frequent reasons for obtaining surgical consultation in newborns. Distal intestinal obstruction of the newborn may be anatomic (eg, imperforate anus, colonic atresia, colonic stenosis) or functional. Most cases of functional colonic obstruction are caused by Hirschsprung disease; however, a subset of term or near-term babies experience colonic obstruction with a characteristic caliber reduction in the sigmoid and descending colon unrelated to meconium inspissation or aganglionosis. This condition, which has a frequent association with maternal gestational diabetes mellitus and seldom requires surgical intervention, is termed the neonatal small left colon syndrome (NSLCS). History of the ProcedureIn 1974, Davis coined the term small left colon syndrome in his initial description of 20 infants with colonic obstruction not caused by a meconium plug or Hirschsprung disease. In all patients, a contrast enema demonstrated a narrowed descending and sigmoid colon, with a caliber transition at the splenic flexure, and of these, 17 patients experienced immediate and complete resolution of obstruction without operation. Although Davis observed that 8 of the 20 infants were born to mothers with diabetes mellitus, he hypothesized that the apparent dysmotility syndrome was determined neurogenically. In 1975, Philippart et al reported 8 patients with a similar clinical and radiographic presentation, all born to mothers treated for gestational diabetes mellitus with either insulin or oral hypoglycemic agents. In 4 of 8 cases, resolution of obstruction after contrast enema was uncomplicated. One patient presented with a cecal perforation requiring emergency operation, one patient underwent operation for suspected Hirschsprung disease (which was subsequently disproved by biopsy), and 2 patients required a delayed operation—one for persistent obstruction and the other for sudden distension and cecal perforation occurring after institution of oral feedings. Philippart et al speculated on the effects that neonatal hypoglycemia have on intestinal motility via activation of the autonomic nervous system and through stimulated glucagon release. They also identified a small group of patients who developed late complications and advocated close surveillance for the minority who did not respond promptly to decompressive enemas. ProblemNSLCS is an uncommon cause of neonatal intestinal obstruction characterized by an abrupt intestinal caliber transition at or near the splenic flexure and associated, in approximately half of cases, with a maternal history of gestational diabetes mellitus. FrequencyThe frequency with which NSLCS occurs is difficult to estimate because the entire subject literature contains only case reports and a few case series. In one institution's review of consecutive suction rectal biopsies performed in 456 pediatric patients (median age of 13 d) for symptoms of constipation, abdominal distension, and bloody stools, 61 cases of Hirschsprung disease (13%) were identified. The remaining cases included 7 neonates who had a clinical and radiologic picture consistent with NSLCS. In this study cohort, the incidence of symptoms of distal intestinal obstruction and/or enterocolitis is 1.5% (Schofield, 1991). EtiologyAlthough the precise cause of this form of neonatal intestinal obstruction, which has a typical radiologic picture but is distinctly unusual, is unknown, a number of theories have been proposed, which include neural, humoral, and drug-induced etiologic mechanisms. In 1974, Davis et al reported the association of NSLCS with abnormalities of intestinal neurohistology. Their initial report described increased numbers of immature small ganglion cells in the myenteric plexus (in both the narrowed and dilated portions of the colon) in 4 of 20 patients with NSLCS. They compared the histology from NSLCS patients to that from control subjects, including infants of diabetic mothers without colon changes, premature infants, and term infants. They concluded that the hypercellularity observed in the NSLCS specimens most closely resembled the histology observed in the colons of premature infants. Despite this conclusion, they did not provide gestational age data on the patients; therefore, at least some of them assumably were premature. In 1991, Schofield and Yunis reported an association in 7 patients with clinical and radiographic NSLCS and suction rectal biopsy histology demonstrating intestinal neuronal dysplasia (IND). In all 7 cases, the biopsies, which were stained with hematoxylin and eosin (H and E) and acetylcholinesterase (AChE), demonstrated an increase in the number of AChE-stained fibers in the mucosa and increased submucosal ganglia or large ganglia. These changes are also observed with prematurity, and because most of the infants with NSLCS in this report were indeed premature, gestational age seems to have had a confounding effect on the biopsy results. In a 1975 report, Philippart et al focused on humoral and autonomic nervous system changes, which occur in response to neonatal hypoglycemia in developing a mechanistic explanation. Glucagon release and sympathoadrenal stimulation are typical in vivo responses to hypoglycemia, and both result in blood glucose stabilization through hepatic gluconeogenesis and glycogenolysis. Along with several effects on the gastrointestinal tract, glucagon release is known to decrease motility in the jejunum and left colon. Hypoglycemia also stimulates sympathetic and parasympathetic arms of the autonomic nervous system. Maximal vagal (parasympathetic) stimulation results in increased motility in its area of distribution, which ends at the splenic flexure, whereas sympathetic stimulation results in diminished motility. Therefore, a composite effect of glucagon release with sympathetic and parasympathetic nervous system stimulation would hypothetically be an overall diminution in intestinal motility, with a functional block in the colon beyond the splenic flexure. Philippart et al point out that precipitants other than hypoglycemia (eg, stress) may mediate the same changes through similar mechanisms, thereby explaining the phenomenon when it occurs in the absence of maternal diabetes mellitus (Philippart, 1975). Other possible contributors to intestinal hypomotility include maternal drugs used during the third trimester that cross the placenta and affect the fetus. This concept is supported by the report of 2 cases of NSLCS in infants born to mothers using psychotropic drugs with known anticholinergic effects and the recognized association between hypermagnesemia (in infants born to eclamptic mothers treated with magnesium sulfate) and hypomotility conditions. Although earlier reports of neonatal colonic obstruction undoubtedly included cases of NSLCS in the spectrum of obstructive conditions referred to as meconium plug syndrome, obstruction in NSLCS is not typically associated with the presence of a mucus or meconium plug in the distal constricted segment. No analytical abnormality has been reported in the meconium of infants with NSLCS, with the exception of a single case report of an infant with cystic fibrosis who presented with a meconium ileus–like obstruction at the splenic flexure with distal microcolon. In contrast, the meconium in meconium plug syndrome is reported to have an elevated protein content with altered enzymatic activity, suggesting that the obstruction is caused by an immobile luminal obturator rather than mural constriction and diminished peristalsis. ClinicalThe clinical features of infants described in all English language case series of NSLCS are summarized in the Table. Most are born at or near term and are of normal birth weight. Approximately 50% have a history of maternal diabetes mellitus, and other maternal comorbidities (usually eclampsia), which contribute to neonatal stress, may exist. All patients do not pass meconium within the first 24 hours of life, and they all develop abdominal distension with bilious vomiting or nasogastric aspirates. A small number of infants develop progressive distension leading to perforation, typically in the cecum, within the first 24-36 hours of life. Clinical Features of Infants Described in All English Language Case Series of NSLCS
*Death was due to an unrelated cause. †Seven out of 14 (50%) underwent colostomy for incorrect diagnosis of Hirschsprung disease. INDICATIONSSection 3 of 12
As discussed in the sections that follow, the indications for operation in NSLCS include intestinal perforation and failure of resolution of obstruction following contrast enema administration RELEVANT ANATOMYSection 4 of 12
The neonatal colon is the anatomy relevant to this discussion. CONTRAINDICATIONSSection 5 of 12
No absolute contraindications to surgery for NSLCS exist. Remember that the diagnosis of NSLCS is not definitive until Hirschsprung disease has been excluded by rectal biopsy; therefore, any surgical procedure must take into account this diagnostic similarity. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Other Tests
Diagnostic Procedures
TREATMENTSection 7 of 12
Medical therapyAs for any newborn with intestinal obstruction, the first priority of treatment should include resuscitation, such as intravenous fluids, nasogastric decompression, and intravenous antibiotics (if clinically indicated). Once plain film abdominal radiography has demonstrated a distal obstruction without pneumoperitoneum, the infant should undergo contrast enema. Fortunately, for most patients with NSLCS, the contrast enema is not only diagnostic of the condition, but also therapeutic. The vast majority of infants experience spontaneous passage of meconium after the examination, their abdominal distension resolves, and soon after, enteral feedings can be introduced cautiously and advanced carefully. As noted above, excluding other diagnoses, even if the infant has the expected clinical response to a contrast enema, is important; thus, a suction rectal biopsy and workup for cystic fibrosis are always indicated. Surgical therapySurgery is reserved for infants with intestinal perforation or for those in whom obstruction is refractory or recurrent, despite appropriate conservative measures.
COMPLICATIONSSection 8 of 12
Refractory or recurrent obstruction After the diagnosis of NSLCS has been adequately established, the need for surgical intervention seems unlikely. Historically, most operations have been performed because of a mistaken diagnosis of Hirschsprung disease, although Philippart et al reported 2 patients who required delayed operations and did not have aganglionosis; one patient developed recurrent obstruction after initial successful enema decompression and required transition zone colostomy, while the other developed an obstruction with cecal perforation 6 days after institution of oral feedings (Philippart, 1975). OUTCOME AND PROGNOSISSection 9 of 12
Most infants respond completely to contrast enema decompression and are able to progress quite rapidly to full enteral feedings. A number of patients who have undergone follow-up examinations of their colon have demonstrated normalization of caliber within a few weeks. In a 1975 report, Philippart et al warned of the small number of patients who experience delayed complication, either recurrent or persistent obstruction or delayed perforation, mandating close surveillance during the first week or 2 of life. FUTURE AND CONTROVERSIESSection 10 of 12
Apart from more definitive understanding of the pathophysiology of this condition, currently, no real areas of controversy exist regarding the treatment of NSLCS. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Small Left Colon Syndrome excerpt Article Last Updated: May 26, 2006 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
