Superior mesenteric artery syndrome in a pediatric patient: A rare case report and literature review

Abstract

Introduction and importance

Superior mesenteric artery (SMA) syndrome, or aorto-mesenteric clamp syndrome, is a rare condition where the third portion of the duodenum is compressed between the aorta and the superior mesenteric artery. This syndrome often affects adolescents and young adults, with predisposing factors including significant weight loss, anatomical variations, and spinal deformities. Early diagnosis and intervention are critical for managing symptoms and preventing complications.

Case presentation

A 14-year-old girl with a history of mitral insufficiency presented with persistent postprandial vomiting over four years. Despite minimal weight loss and stable vital signs, imaging studies revealed significant gastric and duodenal dilation, with a reduced aorto-mesenteric angle and distance, confirming SMA syndrome. Due to the chronicity of her symptoms, surgical intervention in the form of a gastrojejunostomy was performed, bypassing the compressed duodenal segment.

Discussion

SMA syndrome is characterized by a reduced aorto-mesenteric angle and narrowing of the aorto-mesenteric distance, which can lead to duodenal compression. Risk factors include rapid weight loss and certain anatomical variations. Diagnosis relies on imaging, particularly CT angiography and gastroduodenal transit studies. While conservative management is the initial approach, up to 75 % of patients require surgical intervention. Various surgical techniques, including gastrojejunostomy, have been successful in providing symptomatic relief and improving quality of life.

Conclusion

SMA syndrome should be considered in patients with chronic postprandial vomiting, particularly when conservative measures fail. Early diagnosis through imaging is essential, and surgical treatment, such as gastrojejunostomy, can offer significant symptom relief and improve patient outcomes in refractory cases.

Highlights

• •Superior mesenteric artery (SMA) syndrome is a rare condition characterized by duodenal compression between the aorta and the superior mesenteric artery, leading to symptoms such as chronic postprandial vomiting and weight loss.
• •Diagnosis of SMA syndrome relies heavily on imaging, particularly computed tomography angiography (CTA) and gastroduodenal transit studies, to confirm the reduced aorto-mesenteric angle and distance.
• •Conservative management, including nutritional support and postural adjustments, is the first approach, but surgical intervention is often necessary for refractory cases to provide symptom relief and improve quality of life.
• •This case highlights the successful use of gastrojejunostomy in a pediatric patient, leading to the resolution of symptoms and significant improvement in weight gain and overall health.

1. Introduction

The mesenteric clamp syndrome, also known as superior mesenteric artery (SMA) syndrome, is a rare condition characterized by compression of the third portion of the duodenum between the superior mesenteric artery anteriorly and the aortovertebral plane posteriorly [[1], [2], [3]]. Epidemiologically, this syndrome is infrequently encountered, primarily affecting adolescents and young adults, although cases have been reported across various age groups [4]. Individuals who have undergone rapid weight loss are particularly susceptible [2]. This condition is often multifactorial, with predisposing factors including significant weight loss, lumbar spine deformities, and anatomical variations such as a short ligament of Treitz and low insertion of the SMA on the aorta [2,5]. Here, we present a case of aorto-mesenteric clamp syndrome in an infant, examining the etiopathogenic mechanisms, diagnostic approaches, and therapeutic options. This case report has been prepared in line with the SCARE criteria [6].

2. Case presentation

A 14-year-old girl with a history of mitral insufficiency managed with beta-blocker therapy was referred to our service for persistent late postprandial vomiting over the past four years. Her vomiting episodes, occurring one to two hours after meals, were non-bilious and non-bloody but had progressively worsened, affecting her dietary intake and overall quality of life. Despite her symptoms, she maintained a stable condition with minimal recent weight loss.

On examination, the patient appeared lean, weighing 45 kg with a height of 161 cm, yielding a body mass index (BMI) of 17.3 kg/m², which is on the lower end of the scale for her age. Vital signs were stable, and she showed no signs of dehydration or hemodynamic compromise. Her abdomen was soft and non-distended, with no tenderness, palpable masses, or visible peristaltic waves. Bowel sounds were normal.

Laboratory tests showed mild normochromic normocytic anemia with hemoglobin slightly below the normal range. Electrolyte levels, including sodium, potassium, calcium, and magnesium, were normal, as were her renal and liver function tests. The absence of electrolyte imbalance and dehydration suggested adequate compensation despite chronic vomiting.

A gastroduodenal transit study with Gastrografin revealed significant dilation of the stomach, the first and second portions of the duodenum, and the proximal third portion (D3) of the duodenum. The contrast medium halted abruptly at the level of D3, indicating obstruction (Fig. 1). Computed tomography angiography (CTA) further confirmed narrowing of the aorto-mesenteric angle to 10° and a reduced aorto-mesenteric distance, demonstrating compression of the third part of the duodenum by the superior mesenteric artery (SMA) against the aorta (Fig. 2). These findings were consistent with superior mesenteric artery (SMA) syndrome.

Fig. 1.

Gastrografin study showing dilation of the stomach and duodenum, with contrast medium halted at the obstructed D3 (yellow arrow).

Fig. 2.

CTA showing compression of the third duodenal portion by the superior mesenteric artery (yellow arrow).

Due to the chronicity and severity of symptoms, conservative management was deemed unlikely to succeed, so surgical intervention was recommended. The patient underwent laparoscopic side-to-side gastrojejunostomy anterior to the mesocolon, bypassing the compressed duodenal segment. The procedure was performed without complications.

Postoperatively, the patient showed significant improvement, with complete resolution of vomiting and tolerance of oral intake by postoperative day 3. She was discharged in stable condition on postoperative day 5. At a three-month follow-up, she had gained 3 kg, was asymptomatic, and was able to maintain a normal diet without restrictions.

This case underscores the importance of considering SMA syndrome in cases of chronic postprandial vomiting and highlights the effectiveness of surgical intervention in severe cases.

3. Discussion

This syndrome, known by various names—including superior mesenteric artery (SMA) syndrome, cast syndrome, Wilkie's syndrome, and chronic duodenal ileus—results from the compression of the third portion of the duodenum between the aorta and the superior mesenteric artery [7,8]. Aorto-mesenteric clamp syndrome is rare, with a reported prevalence between 0.013 % and 0.78 % [4,9]. It occurs more frequently in young females and does not appear to be associated with any specific racial or ethnic predispositions [4].

Pathophysiologically, the syndrome is characterized by a reduced aorto-mesenteric angle, typically <20°, and a narrowed aorto-mesenteric distance of <8 mm [1,10]. Normally, the adipose tissue surrounding the origin of the SMA maintains this angle, protecting the duodenum from compression; a reduction in this fat pad can therefore predispose the duodenum to external compression [2,11].

Key risk factors include rapid weight loss, growth spurts without corresponding weight gain, and certain anatomical variations [2,10]. Weight loss or malnutrition reduces perimesenteric fat, thereby narrowing the aorto-mesenteric space [1,2]. Additionally, lumbar spine deformities such as hyperlordosis, or spinal changes following trauma or surgery, can further exacerbate the syndrome by altering aortic positioning [3,10]. Anatomical factors like a low origin of the SMA on the aorta or a short ligament of Treitz may also contribute to the risk of compression [[10], [11], [12]].

In this case, no anatomical anomalies were noted, suggesting a primary form of SMA syndrome that may be related to a genetic or familial predisposition. Clinically, aorto-mesenteric clamp syndrome should be suspected in patients with recurrent upper intestinal obstruction presenting with symptoms such as postprandial vomiting (which can be bilious or food-related), epigastric distension, weight loss, and nutritional deficiencies [7,10,11]. Diagnostically, differentiating this syndrome from other causes of duodenal obstruction can be challenging, so imaging plays a crucial role [2,10]. A gastroduodenal transit study often reveals dilation of the stomach and proximal duodenum, while contrast-enhanced abdominal CT remains the gold standard, allowing measurement of both the aorto-mesenteric angle and distance [9,12,13]. Typical findings in SMA syndrome include upstream dilation of the duodenum and a reduced aorto-mesenteric angle (<15°) and distance (<8 mm), as opposed to normal values of 45°-60° for the angle and 10–28 mm for the distance [4,7,14].

Prognosis for SMA syndrome is generally favorable with timely and appropriate management [10]. However, delayed diagnosis and treatment can lead to severe complications, including electrolyte imbalances, respiratory distress, and, in extreme cases, gastric perforation [7,10]. Our patient presented with a chronic form of the syndrome without acute complications. Initial management typically includes conservative measures, such as nasogastric decompression, correction of electrolyte imbalances, and nutritional support, with postural adjustments (such as left lateral decubitus positioning) potentially providing symptomatic relief in approximately half of cases [2,5,10].

Surgical intervention is considered when conservative measures fail, which occurs in up to 75 % of patients with this syndrome [2,5,7]. Various surgical options include the division of the ligament of Treitz and duodenojejunostomy, with retro-mesenteric transposition of the duodenum often preferred in pediatric patients to avoid an anastomosis, though duodenojejunostomy can be performed later if necessary [5,7,10]. In our case, due to the chronic nature of the patient's condition and limited response to medical management, we opted for surgical intervention, performing a gastrojejunostomy. This procedure, which can be performed laparoscopically or via laparotomy, provides an alternative pathway for gastric emptying and generally yields positive outcomes, as demonstrated by our patient's resolution of vomiting and weight gain during follow-up [2,7]. Surgical success rates for SMA syndrome vary, with duodenojejunostomy and gastrojejunostomy showing favorable outcomes in 80–90 % of cases [5]. Laparoscopic approaches offer quicker recovery and fewer complications [3,5]. The choice of surgery depends on symptom severity and response to conservative treatment, with gastrojejunostomy yielding positive results in our case [5]. In summary, while conservative management remains the initial approach for SMA syndrome, surgical intervention offers an effective solution for patients with chronic or refractory symptoms [2,12].

Our case report highlights the successful management of a chronic form of SMA syndrome in a young female patient, contributing to the literature by emphasizing the role of surgical intervention in refractory cases. Unlike many reported cases associated with rapid weight loss or anatomical abnormalities, our patient presented without these common risk factors, suggesting a primary form of SMA syndrome potentially linked to an underlying predisposition. Additionally, the use of laparoscopic gastrojejunostomy as a definitive treatment underscores its efficacy in achieving symptom resolution and weight gain, further differentiating our case. This underscores the importance of individualized treatment approaches in managing this rare but impactful condition.

4. Conclusion

In conclusion, this case underscores the importance of recognizing superior mesenteric artery (SMA) syndrome as a potential cause of chronic postprandial vomiting and weight loss [2,13]. Although rare, SMA syndrome significantly impacts patient quality of life due to duodenal compression [9,10]. Early diagnosis through imaging, especially CT, is crucial for assessing the aorto-mesenteric angle and distance [3]. While conservative management is the first approach, persistent cases may require surgical intervention [7]. Our patient's successful gastrojejunostomy highlights the effectiveness of surgical treatment in achieving symptom resolution and weight gain, reinforcing surgery as a viable option for refractory SMA syndrome cases.

CRediT authorship contribution statement

• Hanene Guelmami and Nabil Haloui contributed to manuscript writing and editing, and data collection;

• Ahmed Omry and Wael Ferjaoui contributed to data analysis;

• Hager Behi and Med Bachir Khalifa contributed to conceptualization and supervision;

• All authors have read and approved the final manuscript.

Patient consent

Written informed consent was obtained from the patient for the publication of this case report and its accompanying images. A copy of the written consent is available for the Editor-in-Chief of this journal to review upon request.

Ethical approval

Ethical approval is not applicable/waived at our institution.

Guarantor

Dr. Ahmed Omry.

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Declaration of Generative AI and AI-assisted technologies in the writing process

AI tools were not used for the elaboration of the manuscript.

Funding

This research did not receive funding from any specific grant provided by public, commercial, or not-for-profit organizations.

Declaration of competing interest

No conflicts of interest.