Massive Gastric Dilatation and Multi-Organ Ischemia Due to Superior Mesenteric Artery Syndrome: A Rare Case Report

Background

Superior mesenteric artery (SMA) syndrome, also known as Cast or Wilkie’s syndrome, is defined as a proximal intestinal obstruction in the third duodenal portion caused by the SMA and aorta [1–3]. The cause of this anatomic obstruction is said to be due to the loss of intra-abdominal fat. The prevalence of SMA syndrome is estimated at 0.013–0.3% and is quite rare [2]. Symptoms include chronic anorexia, nausea, vomiting, and postprandial abdominal pain. Physical examination findings include abdominal stretching, tenderness in the upper abdomen on deep palpation, and high-pitched bowel sounds, but the findings are usually vague and less specific [1]. Therefore, the diagnosis is difficult to make on clinical grounds alone and is based on radiological findings, especially CT findings [1], but the diagnosis of SMA syndrome can be delayed due to its rarity and its nonspecific symptoms, which can lead to serious complications. Here, we present the case of a patient with multi-organ ischemia, which was caused by acute gastric dilatation (AGD) due to SMA syndrome. The abdominal aorta and portal vein were compressed by the dilated stomach and duodenum.

Case Report

An 83-year-old Japanese man presented to the emergency department with primary concerns of dull intermittent lower abdominal pain, which had started at noon the day before the visit. Despite earlier improvement, the dull abdominal pain worsened on the day of the visit, prompting the visit to the hospital.

The patient weighed 39 kg and was 170 cm in height. His medical history included type 2 diabetes mellitus, hypertension, gastric ulcer, prostatic hypertrophy, hiatal hernia, and esophageal squamous cell cancer treated by endoscopic submucosal dissection. His medications included 10 mg cilnidipine and 0.2 mg tamsulosin hydrochloride. He had a history of smoking (about 5–10 pack-years) but was not smoking at the time of admission. He had no history of alcohol intake. Vital signs at presentation were as follows: blood pressure, 149/94 mmHg; pulse, 57 beats per minute; temperature, 36.6°C; respiratory rate, 12 breaths/minute; and peripheral capillary oxygen saturation, 95%. Although the abdomen was slightly distended, the intestinal peristaltic sounds were normal and abdominal pain and tenderness had been resolved without analgesia before admission. Blood tests showed a mild inflammatory response (leukocyte count, 10 800/µL; C-reactive protein, 0.41 mg/dL) and elevated serum amylase (217 U/L), and abdominal X-ray showed gastric air. Based on the mild inflammatory response and the resolution of pain, the examining physician concluded that the abdominal pain was due to intestinal peristalsis and allowed the patient to return home without medical treatment.

However, the following day, the dull abdominal pain reappeared and the patient developed labored breathing. During the few minutes while his family was preparing to take him to the hospital, his level of consciousness declined to the point that he stopped responding to verbal and tactile stimuli and emergency medical assistance was requested. At the time of contact with the emergency medical service, the blood pressure could not be measured and the patient began to engage in mandibular breathing. Therefore, he was transported to our hospital with ventilator support using a bag-valve mask.

On arrival at the hospital, the patient was in shock, with a pulse of 120 beats per minute, and no palpable blood pressure was detected. His abdomen was distended (Figure 1). Severe body movements, such as twisting of limbs or trunk, obstructed treatment and examination, and it was considered that continuous bag-valve-mask ventilation would further contribute to the abdominal distention. Therefore, 50 mg rocuronium was intravenously administered as a muscle relaxant and oral tracheal intubation was performed. At the same time, a gastric tube was inserted and fixed 50 cm from the nasal cavity, without discharge of gastric contents. Arterial blood gas analysis indicated severe lactic acidosis based on the following results: pH, 7.089; pCO2, 49.1 mmHg; pO2, 546 mmHg; HCO3–, 14.8 mmol/L; and lactate, 13.6 mmol/L. Blood tests showed worsening inflammatory response (leukocyte count, 13 900/µL; C-reactive protein, 2.74 mg/dL), impaired renal function (blood urea nitrogen, 54 mg/dL; serum creatinine, 3.6 mg/dL), and elevated levels of serum amylase (1318 U/L) and lipase (2140 U/L). Intestinal ischemia was considered based on the abdominal findings and the elevated lactate level, and plain computed tomography (CT) was performed because of severe impairment of renal function. The plain CT showed dilatation extending from the stomach to the middle of the third portion of the duodenum (Figure 2A) and stenosis of the SMA (Figure 2B). Additionally, the inserted gastric tube was stuck at the level of the gastric cardia. Based on the CT findings, the patient was diagnosed with SMA syndrome and gastric tube advancement for decompression was planned. However, the gastric tube could not be inserted manually or with the use of a guidewire, and the patient was referred to a gastroenterologist for endoscopic gastric tube insertion.

Endoscopic examination revealed mechanical obstruction in the gastric cardia (Figure 3A). The gastric tube could not be advanced to pass through the cardia despite use of the endoscope. First, a guidewire was passed through, which allowed the gastric tube to be placed in the stomach. The drainage from the gastric tube was more than 700 mL. Evaluation immediately after the insertion revealed a pale gastric mucosa, suggesting ischemia (Figure 3B). The pale mucosa became red-tinted after decompression, indicating slight relief of ischemia. However, the blood pressure gradually declined after insertion of the gastric tube; therefore, the patient was admitted to the Intensive Care Unit (ICU) and administered noradrenaline (0.4 μg/kg/min) continuously.

In the ICU, he had prolonged hypotension and was treated with vasopressin (0.2 U/min). Additionally, he was given hydrocortisone sodium succinate (200 mg) for critical illness-related corticosteroid insufficiency. He also became anuric and was placed on continuous hemodiafiltration. Six hours after ICU admission, the patient was transfused with concentrated red blood cells (4 packs) because of progressive anemia due to bloody bowel discharge. The systolic and mean blood pressures were maintained above 110 and 75 mmHg, respectively, by vasopressors and blood transfusion; however, the serum lactate levels did not improve (Figure 4). Additionally, liver enzymes and creatine kinase were prominently elevated (aspartate transaminase, 2869 U/L; alanine transaminase, 1398 U/L; lactate dehydrogenase, 3428 U/L; creatine kinase, 4693 U/L). The next day, contrast-enhanced CT, which was performed to evaluate organ ischemia, showed contrast-free areas in almost all gastrointestinal, renal, hepatic, splenic, and pancreatic tracts, including the gastric wall (Figure 5). These findings indicated necrosis or infarction in the stomach, duodenum, small and large intestines, kidneys, spleen, liver, and pancreas. However, the celiac artery, SMA, and bilateral renal arteries were enhanced by contrast. Therefore, the dilated stomach was considered to directly compress and obstruct the abdominal aorta and portal vein, leading to multi-organ ischemia rather than thromboembolism. Based on the clinical and imaging findings, surgery was not considered a feasible option and additional treatment was not possible. After discussion with the family, the patient was administered best supportive care. Thereafter, his blood pressure gradually decreased, and he died due to multi-organ ischemia on the second day of hospitalization.

The XXX University Ethics Committee approved this study [details blinded for peer review]. The patient and his family provided written informed consent for publication of this case report and accompanying images.

Discussion

In AGD, the gastric wall rapidly loses tension, and the gastric lumen fills with gas and secretions, leading to rapid expansion even in the absence of an organic cause of obstruction in the stomach or duodenum. Although the boundaries are not clearly defined, massive AGD is defined as a distended stomach occupying the right and left abdominal cavities and extending from the diaphragm to the pelvis [4]. Massive AGD is caused by decreased gastric motility and stagnation of gastric contents due to sympathetic nerve stimulation. Excessive distention promotes parasympathetic paralysis, leading to a further reduction in gastric motility as well as dilatation [5]. AGD can be caused by a variety of medications, central nervous system disorders, and postoperative conditions, including SMA syndrome.

SMA syndrome is believed to be caused by a decrease in fat in the superior mesentery between the abdominal aorta and the superior mesenteric artery, which results in a narrowing of the space between the aorta and the superior mesentery and compression of the duodenal 3rd portion [1]. Causes of fat loss in the superior mesentery that trigger SMA syndrome include malignancy, malabsorption syndrome, trauma, spinal injury, and anorexia nervosa [1]. Differentiation of SMA syndrome includes giant duodenal disease, paralytic ileus, recurrent cholestatic pancreatitis, dermatomyositis, SLE, amyloidosis, muscle tension dystrophy, and rare causes of decreased peristalsis such as chronic idiopathic intestinal pseudo-obstruction [6]. Various imaging studies have been used to differentiate SMA syndrome. Upper-gastrointestinal radiography, which has been the mainstay of diagnosis of SMA syndrome, is said to be diagnostic for findings of contrast loss in the third part of the duodenum just to the right of the midline, delayed emptying of the stomach and duodenum, dilatation of the first and second parts of the duodenum, and reciprocal patterns of peristaltic waves in the proximal third of the duodenum [7]. Magnetic resonance enterography (MRE) has been performed at the institution of Giuseppe Cicero et al for SMA syndrome due to Crohn’s disease and is useful for detecting anatomic abnormalities of the small intestine in Crohn’s disease and its dysfunction [8]. However, it is difficult to perform fluoroscopy in cases of circulatory failure such as the present case. Recently, CT imaging has become the criterion standard for diagnosis because it provides anatomic information such as the distance and angle between the supra-aortic mesentery, the mechanism of occlusion, and the amount of retroperitoneal fat. The normal distance between the aorta and SMA is 10–28 mm, and the angle between the 2 structures is 38–65° [6]. In SMA syndrome, the distance between the aorta and SMA is reduced to <10 mm and the angle is below 25° [2,3]. In fact, a distance of 8 mm or less (100% sensitivity and specificity) and an angle of 22° or less (42.8% sensitivity and 100% specificity) between the aorta and SMA are used as diagnostic criteria for SMA syndrome [9]. However, Siva P Raman’s study cautions against using this measure alone diagnostically, reporting that asymmetric dilation of the left renal vein caused by compression of the SMA and aorta is an important finding to prove that duodenal compression is not coincidental, and that 3D reconstruction is useful for this purpose [10].

In the present case, the patient was diagnosed with SMA syndrome based on CT images showing obstruction extending from the stomach to the third portion of the duodenum and a distance of 4 mm and an angle of 10° between the aorta and the SMA (Figures 2B, 6). Because no 3D reconstruction was performed in our patient, asymmetric dilation of the left vein was not confirmed. However, since the angle between the aorta and SMA was improved to 35° on the contrast-enhanced CT image after decompression (Figure 7), the compression of the duodenum by the SMA and aorta was not considered accidental, and a diagnosis of SMA syndrome was made. The patient had a low body weight for an adult male and was later found to have experienced significant weight loss in the last few years, according to his family. There was no evidence of recurrent esophageal cancer, and weight loss, the cause of which was unknown, was considered to have triggered SMA syndrome. In some cases, the diagnosis of SMA syndrome is delayed due to nonspecific symptoms and physical findings, leading to serious complications and even death from shock, gastric necrosis, or perforation [11–13]. Although the case presented here did not exhibit electrolyte abnormalities or gastric perforation, we speculate that AGD due to SMA syndrome compressed the abdominal aorta, leading to ischemia in multiple organs. In fact, studies have reported some cases in which the mesenteric root was compressed between the dilated stomach and the duodenum due to SMA syndrome, which resulted in impaired portal blood flow and intestinal congestion, and other cases in which the liver and kidneys became congested along with the intestinal tract [3,13]. In the present case, ischemia of organs along the gastrointestinal tract, including the stomach, spleen, liver, and kidneys, based on liver enzyme and creatine kinase levels, led to the suspicion of occlusion of nutrient vessels of the gastrointestinal tract. Evaluation with imaging was difficult, and plain CT was performed at admission, whereas contrast-enhanced CT was only performed 24 h later. Both the plain and contrast-enhanced CT studies revealed that the abdominal aorta, celiac artery, and SMA were completely compressed by the stomach and that the portal vein was slightly compressed by the dilated stomach and duodenum (Figure 8A). Additionally, the renal artery could not be identified in the initial plain CT images, whereas the contrast-enhanced CT images performed after decompression revealed enhancement of the renal artery along with the celiac artery, SMA, and portal vein (Figure 8B). In summary, although the blood flow resumed after decompression at the time of contrast-enhanced CT scanning, multiple ischemic findings persisted in the images. Therefore, the plain and contrast-enhanced CT findings suggested that the SMA syndrome caused gastric and duodenal dilatation and compression of the abdominal aorta and portal vein, leading to ischemia.

Treatment of SMA syndrome usually begins conservatively, including placement of a nasogastric tube. However, surgery is indicated in cases where conservative treatment is ineffective, weight loss progresses, and the disease becomes prolonged, or complications such as peptic ulcer or pancreatitis due to bile reflux develop. Emergency surgery is indicated for patients in whom gastric necrosis is suspected or drainage is difficult and gastric necrosis is likely to progress [1,2,5]. In the present case, decompression was initially chosen as the conservative treatment considering the patient’s general condition. However, the gastric cardia was mechanically obstructed by an excessively dilated stomach. Although recurrence of esophageal cancer was considered as the possible cause of mechanical obstruction, no obvious stenosis or recurrence was noted during upper-endoscopy performed 3 months prior to the patient’s visit for AGD. Bravender et al reported that a 22-year-old woman with anorexia nervosa developed AGD due to overeating and the massive gastric dilation changed the gastroesophageal junction so that the distal esophagus was horizontal and that this change created a unidirectional valve that prevented the reflux of gastric contents [14]. However, Bravender et al reported that gastric tube insertion in patients with AGD was easy. In contrast, in the present case, the gastric tube was endoscopically inserted after manual insertion proved difficult because of the mechanical obstruction. Therefore, endoscopy allowed the observation of the obstruction in the cardia due to gastric dilatation. This is the first study to report endoscopic findings of mechanical obstruction of the cardia caused by gastric dilatation, suggesting the utility of this diagnostic approach. Additionally, the gastric mucosa could be endoscopically evaluated in the present case. Ischemia of the gastric wall occurs when the intragastric pressure exceeds 20 cmH2O. Evaluation of the gastric mucosa is important since necrosis of the mucosa occurs first [4]. Therefore, endoscopic gastric tube placement for decompression in patients with gastric dilatation may be useful both for treatment by providing decompression and for diagnosis by allowing mucosal evaluation. However, in the present case, the blood flow was restored immediately after decompression, although the ischemia in the gastric mucosa was present at the time of gastric tube insertion. Therefore, we chose to continue conservative treatment instead of surgical intervention. Considering the extensive gastric necrosis observed in subsequent CT studies, endoscopic evaluation of the mucosa only once might have underestimated the clinical status.

Conclusions

Here, we presented a case of AGD caused by SMA syndrome, which resulted in death due to progressive multi-organ ischemia. To the best of our knowledge, this is the first case in which massive giant gastric dilatation due to SMA syndrome caused hepatic, renal, and splenic infarction as well as ischemia of the large and small intestines, in addition to ischemia of the stomach. Gastric dilatation due to SMA syndrome requires early decompression. However, a massively dilated stomach can hinder gastric tube insertion. In such cases, endoscopic gastric tube insertion can be useful to evaluate the gastric mucosa. In addition, endoscopic reevaluation of the gastric mucosa may be needed at a later time. Given the rarity of SMA syndrome with extensive ischemia and infarction, clinicians should remain vigilant for its potential complications.