Small Intestinal Obstruction Flashcards
What are causes of small intestinal obstruction in children?
Small intestinal obstruction in children can have a wide range of etiologies.
Neonatal intestinal obstructions are often related to specific gastrointestinal pathology such as intestinal atresias, meconium ileus, meconium plug syndrome, small left colon syndrome, Hirschsprung disease, anorectal malformation, necrotizing enterocolitis, malrotation with midgut volvulus, incarcerated inguinal hernia, anterior abdominal wall defects and more.
In older children, intestinal obstruction are also seen in the setting of intussusception, vitelline duct remnants, perforated appendicitis, malrotation with or without midgut volvulus, foreign bodies, tumors and more.
How common is adhesive small bowel obstruction (ASBO) in the pediatric population?
Overall, ASBO occurs in 1–6% of children following abdominal surgery [1].
Which patients are at the highest risk for developing ASBO?
High rates of ASBO have been reported after the following index operations: ileostomy formation and closure (25%), Ladd procedure for malrotation (24%), and nephrectomy for Wilm׳s tumor (8.9%) [1, 2].
Younger patients who have undergone index operation during infancy are also at higher risk (13%), particularly within two years of the initial operation [3].
Which patients are at lowest risk for developing ASBO?
The rate of ASBO is <1% in patients who have undergone appendectomy but may
be more common in patients with perforated appendicitis [1].
How do patients with ASBO present?
Patients commonly present with anorexia, crampy abdominal pain, emesis, and obstipation. Lethargy, significant abdominal distension and constant abdominal pain are late findings.
What are the clinical signs and symptoms of bowel ischemia?
The signs and symptoms of bowel ischemia can be difficult to determine in the pediatric population.
Peritonitis is an obvious sign. Other indicators are fever, tachycardia and an elevated white blood cell count and lactic acidosis on labora- tory work-up.
What are radiologic findings of small bowel obstruction on abdominal plain films?
Two-view plain radiographs should be obtained in all patients with suspected ASBO. Dilated loops of small bowel, presence of air-fluid levels, bowel wall thickening and lack of colonic or rectal air may be seen on X-ray. Paucity of bowel gas can also be seen and may be a more worrisome finding.
What are the radiologic signs and symptoms of bowel ischemia?
On plain film pneumoperitoneum is a clear indication of perforation likely secondary to bowel ischemia.
Other concerning findings include bowel wall thickening, pneumatosis intestinalis and portal venous gas. On computed tomography (CT) scan, free peritoneal fluid is also concerning for bowel ischemia [1].
What other imaging modalities aid in the diagnosis of ASBO?
The diagnosis of small bowel obstruction (SBO) can often be made by history, physical examination, and abdominal plain films only. CT scan has a sensitivity of 87–92% in diagnosing SBO and can be useful in determining the site and cause of obstruction in children.
However, risks of ionizing radiation and possible need for sedation preclude routine use of CT in children [1].
Administration of oral water-soluble contrast can be used as a diagnostic tool and as a way to predict potential failure of non-operative management.
It may have therapeutic effects in non-operative resolution of ASBO in children [4].
When is CT indicated in pediatric patients suspected of having an ASBO?
CT scan can be useful in identifying high grade obstruction with signs of bowel ischemia; however, it is most useful for clinical decision-making when used to differentiate benign from worrisome pneumatosis intestinalis beyond infancy.
Additionally, CT can help differentiate ileus versus SBO in children with concern for concomitant intra-abdominal abscess (for example in the post-appendectomy patient). CT images can then be used to aid in the drainage of these abscesses [1].
Can CT scan be used to predict failure of non-operative management in children?
CT findings associated with the need for an operation have been describe in adults, including lack of fecalization of the small bowel, free intraperitoneal fluid, mesenteric edema and the presence of a transition point [1].
However, this has not been specifically studied in children, and CT scan should be used judiciously in children.
When should water soluble contrast studies be used?
Children undergoing trial of non-operative management may benefit from upper gastrointestinal series with water-soluble contrast.
Delayed plain films are per- formed at 10 and 24 hours.
These studies should be performed on initial presentation, if they are to be used, in order to limit delay in surgical intervention.
Failure of contrast to reach the colon within 24 hours predicts failure of non-operative management and surgical exploration should then be considered.
Oral administration of water-soluble contrast may improve success rate of non-operative management of ASBO in children [4].
Which patients with ASBO should undergo trial of non-operative management?
Children presenting with clinical signs and symptoms of small bowel obstruction who have undergone previous abdominal operation and do not have any of the following: signs of bowel ischemia, hemodynamic compromise or evidence of end-organ distress.
Those with bowel ischemia, perforation, sepsis, and severe physiologic disruption should undergo prompt surgical exploration after appropriate resuscitative measures.
What does non-operative management of ASBO consist of?
Initial fluid resuscitation is imperative in all children with SBO.
Standard non-operative treatment of ASBO includes bowel rest, nasogastric tube decompression with a large diameter sump tube, intravenous fluid replacement and correction of electrolyte abnormalities.
An abdominal plain film is the initial imaging
modality of choice when SBO is suspected in children.
Serial abdominal examinations should be performed, ideally by the same examiner.
Analgesics should be administered as needed.
When treating pediatric patients with ASBO non-operatively, how is their progress monitored?
Strict monitoring of patient fluid status, urine output and daily nasogastric tube output is imperative.
Serial abdominal exams should be performed.
Water-soluble contrast administration can be used to determine progress of contrast to the colon, predicting successful non-operative management with 96% sensitivity and 98% specificity [4].
If nasogastric tube output does not significantly decrease within 24–48 hours, the abdominal exam worsens, or there are aberrant changes in vital signs, prompt surgical exploration is warranted.
