Anorexia Nervosa and Superior Mesenteric Artery Syndrome

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Anorexia nervosa (AN) is an eating disorder with signs and symptoms of severe weight loss, restrictive eating, and fear of weight gain. While not everyone with AN is severely underweight, many individuals with this disorder experience drastic weight loss.

Severe weight loss in AN is dangerous because it can lead to additional health complications, such as Superior Mesenteric Artery Syndrome (SMAS), which can hinder AN recovery.

Superior Mesenteric Artery Syndrome (SMAS)

SMAS is a condition where substantial weight loss causes the fat pad surrounding the superior mesenteric artery (SMA) in the digestive tract to shrink.^1,2,3 This fat pad is an important part of the body because it holds the SMA in place away from the small intestine. When this fat pad shrinks, the SMA moves and the small intestine becomes squeezed between it and the aorta (i.e., main blood vessel of the body). This squeezing narrows the small intestine and prevents food in the stomach from entering it. This intestinal blockage causes great abdominal discomfort for individuals with SMAS during and after eating.

Signs and symptoms of SMAS vary across individuals but often include nausea, abdominal pain, vomiting, and weight loss.^1,2,3

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Anorexia Nervosa and Superior Mesenteric Artery Syndrome (SMAS)

Because SMAS and AN have similar symptoms (e.g., abdominal pain; weight loss) and SMAS is considered rare, SMAS is often overlooked in people with AN.

A case study involving a 26 year old woman with a history of AN demonstrates how easy it is for a health care professional (HCP) to overlook SMAS in a patient with AN.⁴ In this example, the woman was rapidly losing weight (i.e., 17 pounds) two months after she attended residential treatment for AN; she was also experiencing nausea, vomiting, feelings of "fullness", and malnutrition. Her rapid weight loss and symptoms led to three trips to the emergency room in one month. On her third trip to the emergency room the patient's doctors attempted to insert a feeding tube into her stomach. It was during this attempt that the doctors noticed the patient's intestines were unusually narrow. An ultrasound revealed that this patient had SMAS.

Treating Superior Mesenteric Artery Syndrome (SMAS)

SMAS is treated using inpatient medical management and, in severe cases, surgery.^1,2,3 Patients with SMAS are first given small meals and oral supplements to facilitate weight gain. If a patient is unable to eat, nutritional support via a feeding tube might be used. Additional approaches for treating SMAS include changing the patient's posture and providing the patient with medication (e.g., antidepressants) to reduce related symptoms (e.g., depression). If SMAS doesn't improve using these approaches, the patient might need surgery to reposition the SMA and "reopen" the small intestine.

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It is important that patients with SMAS aren't pushed to consume too many calories too quickly, as this can cause refeeding syndrome.^1,2 Refeeding syndrome is a temporary condition where malnourished individuals experience dramatic shifts in electrolytes and fluids after consuming too many calories too quickly. Though temporary, refeeding syndrome is a serious medical complication that can result in heart failure or death.

Treating Superior Mesenteric Artery Syndrome (SMAS) in People with Anorexia Nervosa

SMAS in people with AN adds an additional complexity to treating AN.⁴ People with AN who develop SMAS might refuse meals or continue to lose weight, making it appear that they are resistant to AN treatment. Because patients with AN are unlikely to know if they have SMAS, these individuals might find it difficult to explain why they aren't gaining weight.

Unfortunately, health care professionals (HCPs), especially those inexperienced with AN, can hold negative views of people with AN.⁵ These negative opinions might become aggravated by SMAS, as SMAS hinders weight gain and recovery. HCPs unfamiliar with SMAS in AN might label a patient with both disorders hopeless and assume that the patient doesn't "want" to recover. This negative attitude towards the patient's recovery process might discourage the patient and their caregivers from seeing recovery as possible.

Conclusions

Currently, just 68% of individuals with AN will maintain recovery two decades after treatment.⁶ The low recovery rate for AN is due to the disorder's complexity — AN isn't a simple disorder with a simple recovery process. People with AN can develop severe medical complications, like SMAS, that can make maintaining recovery difficult.

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Health care professionals (HCPs) treating patients with AN should, therefore, have specialized knowledge regarding medical complications related to AN, like SMAS, so that they can approach the AN recovery process effectively and compassionately. One way to do this is to improve AN related training and educational materials for HCPs. Currently, medical students receive very little education about eating disorders during their training, which could be contributing to the high rate of AN relapse.⁷