Superior mesenteric artery syndrome

In some cases of SMA syndrome, severe malnutrition accompanying spontaneous wasting may occur.^[7] This, in turn, increases the duodenal compression, which worsens the underlying cause, creating a cycle of worsening symptoms.^[8]

Fear of eating is commonly seen among those with the chronic form of SMA syndrome. For many, symptoms are partially relieved when in the left lateral decubitus or knee-to-chest position, or in the prone (face down) position. A Hayes maneuver, which corresponds to applying pressure below the umbilicus in cephalad and dorsal direction, elevates the root of the SMA, also slightly easing the constriction. Symptoms can be aggravated when leaning to the right or taking a face up position.^[7]

Causes

The acute form of SMA syndrome develops rapidly after traumatic incidents that forcibly hyper-extend the SMA across the duodenum, inducing the obstruction, or sudden weight loss for any reason. Causes include prolonged supine bed rest, scoliosis surgery, left nephrectomy, ileo-anal pouch surgery.^[citation needed]

SMA syndrome is usually difficult to differentiate with anorexia nervosa.^[12] Patients with SMA syndrome can be hindered restoring weight in those with anorexia nervosa.^[13]

Diagnosis

Diagnosis is very difficult, and usually one of exclusion. SMA syndrome is thus considered only after patients have undergone an extensive evaluation of their

Despite multiple case reports, there has been controversy surrounding the diagnosis and even the existence of SMA syndrome since symptoms do not always correlate well with radiologic findings, and may not always improve following surgical correction.[16] However, the reason for the persistence of gastrointestinal symptoms even after surgical correction in some cases has been traced to the remaining prominence of reversed peristalsis in contrast to direct peristalsis.^[17]

Since females between the ages of 10 and 30 are most frequently affected, it is not uncommon for physicians to initially and incorrectly assume that emaciation is a choice of the patient instead of a consequence of SMA syndrome. Patients in the earlier stages of SMA syndrome often remain unaware that they are ill until substantial damage to their health is done, since they may attempt to adapt to the condition by gradually decreasing their food intake or naturally gravitating toward a lighter and more digestible diet.^{[citation needed]}

• 
  Upper gastrointestinal series showing extreme duodenal dilation (white arrow) abruptly preceding constriction by the SMA.
• Ultrasound showing SMA syndrome^[18]
• 
  Ultrasound showing SMA syndrome^[18]
• 
  A diagram of a healthy mesenteric angle.
• 
  A diagram of a compressed duodenum due to a reduced mesenteric angle.

Treatment

SMA syndrome can present in

The possible persistence of symptoms after surgical bypass can be traced to the remaining prominence of reversed peristalsis in contrast to direct peristalsis, although the precipitating factor (the duodenal compression) has been bypassed or relieved. Reversed peristalsis has been shown to respond to duodenal circular drainage—a complex and invasive open surgical procedure originally implemented and performed in China.^[17]

In some cases, SMA syndrome may occur alongside a serious, life-threatening condition such as cancer or AIDS. Even in these cases, though, treatment of the SMA syndrome can lead to a reduction in symptoms and an increased quality of life.^[25][26]

Prognosis

Delay in the diagnosis of SMA syndrome can result in fatal

A 1-in-3 mortality rate for Superior Mesenteric Artery syndrome has been quoted by a small number of sources.^[28] However, after extensive research, original data establishing this mortality rate has not been found, indicating that the number is likely to be unreliable. While research establishing an official mortality rate may not exist, two recent studies of SMA syndrome patients, one published in 2006 looking at 22 cases^[11] and one in 2012 looking at 80 cases,^[19] show mortality rates of 0%^[11] and 6.3%,^[19] respectively. According to the doctors in one of these studies, the expected outcome for SMA syndrome treatment is generally considered to be excellent.^[11]

Epidemiology

According to a 1956 study, only 0.3% of patients referred for an upper-gastrointestinal-tract barium studies fit this diagnosis, and is thus a rare disease.^[29] Recognition of SMA syndrome as a distinct clinical entity is controversial, due in part to its possible confusion with a number of other conditions,^[30] though it is now widely acknowledged.^[1] However, unfamiliarity with this condition in the medical community coupled with its intermittent and nonspecific symptomatology probably results in its underdiagnosis.^[26]

As the syndrome involves a lack of essential fat, more than half of those diagnosed are underweight, sometimes to the point of sickliness and emaciation. Females are impacted more often than males, and while the syndrome can occur at any age, it is most frequently diagnosed in early adulthood. The most common co-morbid conditions include mental and behavioral disorders including eating disorders and depression, infectious diseases including tuberculosis and acute gastroenteritis, and nervous system diseases including muscular dystrophy, Parkinson's disease, and cerebral palsy.^[19]

History

SMA syndrome was first described in 1861 by

American actor, director, producer, and writer Christopher Reeve had the acute form of SMA syndrome as a result of spinal cord injury.^{[citation needed]} Former model Lisa Brown died in 2017 due to her SMAS after her insurance denied the potentially life saving surgery she needed. Her initial surgery failed causing her to require an intestinal transplant that was expected to cost up to $1 million leading her insurance to deny it. She planned her own funeral. ^{[32] [33]}

Non-profit

In 2017 the only US non-profit began distributing grants to those with SMAS. They are registered to the IRS under the name Superior Mesenteric Artery Syndrome Research, Awareness and Support, but also work under the DBA of SMAS Patient Assistance. They offer several resources on their website smasyndrome.com and their Facebook business page. SMAS Patient assistance works to disprove inaccurate information, educate on better diagnostic testing, and more successful surgeries such as Duodenal Deroation with LADDS. ^{[citation needed]}

See also

References