Understanding Hourglass Syndrome: Causes, Symptoms, and Diagnosis


Hourglass syndrome, medically known as Superior Mesenteric Artery Syndrome (SMAS), is a rare and potentially serious condition characterized by compression of the duodenum (the first part of the small intestine) between two major blood vessels in the abdomen. This compression can lead to a range of gastrointestinal symptoms and requires careful medical evaluation and management.

Causes of Hourglass Syndrome

Hourglass syndrome typically occurs due to anatomical variations and changes in the angle between the abdominal aorta and the superior mesenteric artery. Some common causes include:

  1. Reduced Mesenteric Angle: A smaller-than-normal angle between the abdominal aorta and the superior mesenteric artery can lead to compression of the duodenum, particularly when there is a decrease in the mesenteric fat pad that normally cushions these structures.
  2. Rapid Weight Loss: Severe weight loss, whether due to surgery, trauma, eating disorders, or other causes, can reduce the protective cushion of fat around the duodenum, making it more susceptible to compression.
  3. Spinal Deformities or Surgical Interventions: Conditions such as scoliosis or kyphosis, or surgeries that alter the anatomical position of the spine and abdominal organs, may contribute to changes in the mesenteric angle and increase the risk of duodenal compression.

Symptoms of Hourglass Syndrome

The symptoms of hourglass syndrome can vary but often include:

  • Severe Abdominal Pain: Particularly after eating, due to obstruction and distension of the duodenum.
  • Nausea and Vomiting: Resulting from impaired digestion and food passage through the narrowed duodenal segment.
  • Bloating and Fullness: Feeling of abdominal bloating and discomfort, especially after meals.
  • Weight Loss: Due to reduced food intake and malabsorption caused by digestive disturbances.
  • Difficulty Swallowing: Some individuals may experience dysphagia (difficulty swallowing) due to compression near the esophagus.

Diagnosis of Hourglass Syndrome

Diagnosing hourglass syndrome involves a combination of clinical evaluation, imaging studies, and exclusion of other possible causes of gastrointestinal symptoms. Diagnostic approaches may include:

  1. Medical History and Physical Examination: The healthcare provider will review the patient’s symptoms, medical history, and perform a thorough physical examination to assess abdominal tenderness and signs of digestive distress.
  2. Imaging Studies: Imaging techniques such as abdominal ultrasound, computed tomography (CT) scan, or magnetic resonance imaging (MRI) may be used to visualize the anatomy of the abdomen and identify any structural abnormalities, including the compression of the duodenum between the abdominal aorta and superior mesenteric artery.
  3. Upper Endoscopy (Esophagogastroduodenoscopy, EGD): In some cases, an EGD procedure may be performed to directly visualize the duodenal anatomy and assess for any signs of obstruction or narrowing.
  4. Barium Swallow Study: This diagnostic test involves swallowing a contrast material (barium) that coats the inside of the digestive tract and allows for detailed X-ray imaging of the esophagus, stomach, and duodenum to detect any structural abnormalities or narrowing.

Treatment and Management Options

Management of hourglass syndrome depends on the severity of symptoms and underlying causes identified through diagnostic evaluation. Treatment approaches may include:

  1. Conservative Management: Initially, conservative measures such as dietary modifications (small, frequent meals), nutritional support to manage weight loss, and addressing any underlying conditions contributing to duodenal compression may be recommended.
  2. Nutritional Counseling: Working with a registered dietitian to ensure adequate nutrient intake and optimize digestive function, especially in cases of severe weight loss.
  3. Surgical Intervention: In more severe or persistent cases of hourglass syndrome, surgical options such as duodenojejunostomy (surgical bypass of the duodenal obstruction) may be considered to relieve duodenal compression and improve gastrointestinal function.
  4. Lifestyle Modifications: Avoiding rapid weight loss, maintaining a healthy body weight, and practicing proper posture and body mechanics to reduce the risk of anatomical changes that could contribute to duodenal compression.


Hourglass syndrome, or Superior Mesenteric Artery Syndrome (SMAS), is a rare but serious condition characterized by compression of the duodenum between the abdominal aorta and the superior mesenteric artery. It can lead to significant gastrointestinal symptoms such as abdominal pain, nausea, vomiting, and weight loss. Early recognition, accurate diagnosis, and appropriate management are essential to alleviate symptoms and prevent complications associated with this condition. If you or someone you know is experiencing symptoms suggestive of hourglass syndrome, seeking prompt medical evaluation and treatment from qualified healthcare professionals is crucial for effective management and improved quality of life.

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