Management of Small Intestinal Obstruction due to Superior Mesenteric Artery (SMA) Syndrome
Initial management of SMA syndrome (Wilkie's syndrome) should include conservative treatment with nasogastric decompression, fluid resuscitation, and nutritional support, with surgical intervention reserved for cases refractory to medical management. 1, 2
Diagnosis and Initial Assessment
- CT scan with intravenous contrast is the preferred diagnostic imaging technique for SMA syndrome, with superior diagnostic accuracy (>90%) compared to conventional radiography 1
- Upper gastrointestinal radiography remains the primary means of diagnosis in pediatric populations 3
- Laboratory tests should include complete blood count, C-reactive protein, lactate, electrolytes, BUN/creatinine, and coagulation profile to assess for complications 1
- Physical examination findings typically include abdominal distension, tympany to percussion, and high-pitched bowel sounds 4
Conservative Management
- Non-operative management should be the initial approach for SMA syndrome unless there are signs of peritonitis, strangulation, or bowel ischemia 5, 1
- Key components include:
- Nil per os (NPO) status 5
- Nasogastric tube decompression to relieve vomiting and abdominal distension 5, 6
- Intravenous fluid resuscitation with correction of electrolyte abnormalities 5, 1
- Nutritional support, potentially via nasojejunal or gastrojejunal feeding tube placed distal to the obstruction 6
- Positioning the patient in prone or left lateral decubitus position to reduce duodenal compression 2
- Conservative management is effective in approximately 70-90% of patients with intestinal obstruction 5, 1
- Duration of non-operative management should typically be limited to 72 hours if no improvement is seen 5
Nutritional Management
- Nutritional assessment is crucial, including measuring height, weight, BMI, and percentage weight loss 5
- For patients who cannot tolerate oral intake, enteral nutrition via nasojejunal or gastrojejunal tube placed distal to the obstruction is preferred 6
- If enteral feeding fails due to abdominal distension or pain, parenteral nutrition support may be necessary 5
- Monitor for vitamin and mineral deficiencies, particularly iron, vitamin B12, and fat-soluble vitamins 5
Indications for Surgical Intervention
- Failure of conservative management after an adequate trial (typically 72 hours) 5, 2
- Signs of peritonitis, strangulation, or intestinal ischemia 5, 1
- Persistent symptoms despite adequate decompression 5
- Chronic, recurrent symptoms with significant impact on quality of life 2
Surgical Options
- Laparoscopic duodenojejunostomy is the procedure of choice for SMA syndrome refractory to medical management 2
- Alternative procedures include:
- Strong's procedure (division of the ligament of Treitz with mobilization of the duodenum)
- Gastrojejunostomy (less preferred due to potential for continued duodenal distension)
- Laparoscopic approach offers advantages of less extensive adhesion formation, earlier return of bowel movements, and reduced post-operative pain 5
Post-operative Management
- Regular nutritional assessment and support is essential 5
- Monitor for common complications including dehydration with kidney injury, electrolyte disturbances, malnutrition, and aspiration 5, 1
- Gradual reintroduction of oral intake as tolerated 2
Special Considerations
- Pediatric patients with neurological injury and spastic quadriparesis may be at higher risk for SMA syndrome 6
- Weight loss is not necessary for SMA syndrome development in children 3
- Expected outcome with appropriate management is excellent in pediatric populations 3
Pitfalls to Avoid
- Delaying surgical intervention when conservative management fails after 72 hours 5
- Failing to provide adequate nutritional support during conservative management 5
- Using antiemetics that increase gastrointestinal motility in patients with complete obstruction 1
- Overlooking SMA syndrome as a potential cause of intestinal obstruction, particularly in patients with recent weight loss or prolonged recumbency 6