Minimal weight loss related to a short fasting period causes superior mesenteric artery syndrome in a patient with amyotrophic lateral sclerosis: A case report

INTRODUCTION: Superior mesenteric artery syndrome (SMAS) is rare cause of small bowel obstruction and is characterized by an extrinsic vascular compression of the duodenum. The most common cause of SMAS is known as rapid and significant weight loss. PATIENT CONCERNS: A 61-year-old man who was diagnosed with amyotrophic lateral sclerosis and maintained a stable diet before admission. When the patient re-started feeding by gastrostomy tube after 5 days of therapeutic fasting due to gastric ulcer caused by gastrostomy tube irritation, he presented postprandial vomiting, abdominal distention, and tachycardia. Since fasting, his weight has been reduced by about 3 kg. DIAGNOSIS: Based on clinical symptoms and radiological findings, diagnose of SMAS was finally made. Abdomen computed tomography confirmed decreased aortomesenteric distance and tubography confirmed gastric and proximal duodenum distension above the compressed part. INTERVENTIONS: We performed jejunal tube insertion and the amount of feeding through the jejunal tube was gradually increased while maintaining parenteral nutrition. OUTCOMES: The presenting symptoms of the patient gradually improved. Follow-up abdomen computed tomography and tubography showed improvement in duodenal narrowing and stomach distension. CONCLUSION: SMAS should be considered when there is an abrupt observation of symptom of gastrointestinal obstruction in patients with predisposing condition such as a low body weight, even if the weight loss is relatively small.