|Year : 2014 | Volume
| Issue : 3 | Page : 223-225
Superior mesenteric artery syndrome and nutcracker phenomenon
Awwad Alenezy1, Al Dhafeeri Obaid2, Abeer Al Qattan2, Ahmed Hamad3
1 Department of Family and Community Medicine, Northern Border University, Arar, Saudi Arabia
2 Department of Radiology, Dammam Medical Complex, Dammam, Saudi Arabia
3 Department of Medicine, Faculty of Medicine, Northern Border University, Arar, Saudi Arabia
|Date of Web Publication||11-Oct-2014|
Department of Medicine, Faculty of Medicine, Northern Border University, P.O.Box No. 1321, Arar, Zip Code 91431
The superior mesenteric artery (SMA) syndrome is a rare cause of proximal intestinal obstruction in which the third part of the duodenum is compressed between SMA and the aorta due to narrowing in aortomesenteric angle. High index of suspicion, in the presence of known risk factors, is the key to early diagnosis. We describe a case of SMA syndrome in a 17-year-old boy who admitted with a long history of abdominal pain and intermittent vomiting. The computed tomography (CT) features were diagnostic of SMA syndrome. The CT also showed partial compression of the left renal vein by SMA with more proximal dilatation (nutcracker phenomenon). He received conservative medical treatment, with a favorable outcome. Our case is unique in that two rare syndromes which rarely coexist found together in our patient.
ملخص البحث :
تعتبر متلازمة الشريان المساريقي العلوي من الأسباب النادرة للانسداد المعوي. يصف الباحثون حالة لهذه المتلازمة لدى مراهق في السابعة عشرة من عمره تم تنويمه بالمستشفى لمعاناته من الم مزمن في البطن والقئ المتقطع. وضحت الأشعة المقطعية ضغطًا جزئيًا للوريد الكلوي الأيسر. تلقى المريض علاجًا محافظًا ناجحًا. تعتبر هذه الحالة فريدة لأنها جمعت متلازمتين قل ما يوجدان سويًا في مريض واحد.
Keywords: Abdominal pain, intestinal obstruction, superior mesenteric artery syndrome
|How to cite this article:|
Alenezy A, Obaid AD, Qattan AA, Hamad A. Superior mesenteric artery syndrome and nutcracker phenomenon. Saudi J Med Med Sci 2014;2:223-5
|How to cite this URL:|
Alenezy A, Obaid AD, Qattan AA, Hamad A. Superior mesenteric artery syndrome and nutcracker phenomenon. Saudi J Med Med Sci [serial online] 2014 [cited 2020 Jun 2];2:223-5. Available from: http://www.sjmms.net/text.asp?2014/2/3/223/142587
| Introduction|| |
Superior mesenteric artery (SMA) syndrome is a form of upper intestinal obstruction due to vascular compression of the third portion of duodenum, which passes between the SMA and the abdominal aorta and spine.  A variety of gastrointestinal (GI) symptoms, including nausea, vomiting, postprandial abdominal pain and weight loss, may develop.  Nutcracker phenomenon (NCP) is characterized by impeded outflow from the left renal vein (LRV) into the inferior vena cava (IVC) due to extrinsic LRV compression.  Diagnosis is based on clinical suspicion with radiologic confirmation.  We report a case of (SMA) and NCP in patient with a long history of abdominal pain and intermittent vomiting.
| Case report|| |
A 17-year-old boy was presented to our emergency department with a long history of abdominal pain and intermittent vomiting. He weighed only 45.9 kg. There was no past history of medical or surgical disease. Psychological assessment was unremarkable. Physical examination on admission revealed very thin (body mass index = 16.9 kg/m 2 ), dehydrated patient with mild tenderness at epigastric area, otherwise no other abnormalities. Laboratory tests including complete blood count, urine analysis, electrolytes, hepatic, and renal function test were normal apart from mild anemia (Hgb: 11.7 g/dL).
Abdominal radiograph was obtained, which showed markedly distended, fluid filled stomach. Computed tomography (CT) scan of the abdomen and pelvis was performed with intravenous and oral contrast. This showed remarkable dilatation of the stomach and proximal duodenum with narrowing of the third part of the duodenum between the SMA and aorta. The distance between the SMA and abdominal aorta at the level where the duodenum was crossing was reduced to 4.1 mm [Figure 1]. The Sagittal reconstruction of contrast enhanced CT showed a marked narrowing of the aortomesenteric angle to 16° compatible with the diagnosis of SMA syndrome [Figure 2]. The patient was also noted to have partial compression of the LRV by SMA with more proximal dilatation (NCP), but no collaterals veins were identified [Figure 3].
|Figure 1: Coronal multiplanar reformatted image showing typical imaging findings include pronounced dilatation of the stomach and proximal duodenum with vertical linear compression defect in the transverse duodenum, overlying the spine|
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|Figure 2: Sagittal CT with contrast shows narrow angle formed by the SMA and the aorta. There was very little mesenteric fat|
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|Figure 3: CT scan showing Left renal vein entrapment between SMA and abdominal aorta resulting in dilated proximal left renal vein|
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Conservative management was started and included fluid and electrolytes replacement and nasogastric tube decompression. The patient condition was improved and discharged from the hospital on good condition. Two weeks after discharge, the patient was seen in the clinic and he was asymptomatic, with no significant weight gain was demonstrated.
| Discussion|| |
The SMA syndrome is characterized by vascular compression of the third portion of the duodenum within aortomesenteric compartment due to narrowing of the angle between SMA and aorta to 10-22 (normal 45-65). 
Nutcracker phenomenon, also known as LRV entrapment, is characterized by impeded outflow from the LRV into the IVC due to extrinsic LRV compression, often accompanied by demonstrable lateral (hilar) dilatation and medial (mesoaortic) narrowing. 
Very rarely, SMA syndrome and NCP may coexist. 
There are many predisposing conditions like depletion of retroperitoneal fat (e.g., rapid severe weight loss, catabolic state such as cancer and burns, severe injury leading to prolonged bed rest, or dietary disorder such as anorexia nervosa or malabsorption), anatomic/congenital anomalies (such as an abnormally high and fixed position of the ligament of Treitz, or an unusually low origin of the SMA), exaggerated lumbar lordosis and the use of a body cast in the treatment of scoliosis or vertebral fractures. 
Postprandial epigastric pain, nausea, vomiting, anorexia, and weight loss are the main clinical presentations. Symptoms can be acute or chronic, or with intermittent exacerbation. Usually the pain relieved in prone, knee-chest or left lateral decubitus position. 
Best diagnostic clue is dilated first and second portions of the duodenum with abrupt change in caliber distally as it crosses spine as well as vertical linear compression defect in transverse portion of duodenum overlying spine.  Confirmation of the diagnosis of the SMA syndrome is usually by radiological means, such as upper GI series or contrast CT scanning. Fluoroscopically (upper GI serious); can reveal constant dilatation of the proximal duodenum with a delay in the passage of contrast distally. The presence of a vertical linear extrinsic pressure defect in the third part of the duodenum is characteristic.  Thin slice contrast enhanced CT with reformat in the sagittal plane to see aorta and SMA is one of the best imaging tool. The main CT findings are beak like compression of the third part of the duodenum between SMA and aorta, aorto-SMA angle <22-25 in the sagittal plane (42.8% sensitivity and 100% specificity) and the aorta-SMA distance <8 mm (normal 10-20 mm) (100% sensitivity and specificity). ,
Abdominal ultrasonography may be helpful in measuring the angle of the SMA and the aortomesenteric distance. When combined with endoscopy, this may offer an alternative way to diagnose SMA syndrome in children to avoid other tests with a risk of radiation exposure. 
Conservative management is usually the first line treatment in all patients with SMA syndrome. This includes nutritional supplementation with decompression of the stomach via a nasogastric tube. Weight gain, by increasing fat deposition in the mesentery, appears to be an important factor in preventing further episodes of SMA syndrome. 
Surgery is indicated when the conservative treatment fails or if the case is severe or chronic.  Several surgical procedures have been described in the literature. Options for surgery include a duodenojejunostomy or gastrojejunostomy to bypass the obstruction or a duodenal derotation procedure to alter the aortomesenteric angle and place the third and fourth portions of the duodenum to the right of the SMA. Laparoscopic duodenojejunostomy gives the same results as open surgery with all the advantages of a minimally invasive procedure.  Duodenojejunostomy provides the best results. 
The outcome of the disease is excellent if it is diagnosed early and if the patient receives appropriate therapy. 
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[Figure 1], [Figure 2], [Figure 3]