Talk:Superior mesenteric artery syndrome

2014 Revisions
Due to some recent findings in research, I felt it was time to make some revisions to this page. I'm new to this, but I figured I should post my proposed changes on here before I saved them in order to get feedback. Here it goes:

Superior mesenteric artery (SMA) syndrome is a rare, potentially life-threatening gastro-vascular disorder characterized by a compression of the third portion of the duodenum by the abdominal aorta (AA) and the overlying superior mesenteric artery. The syndrome is typically caused by an angle of 6°-25° between the AA and the SMA, in comparison to the normal range of 38°-56°, due to a lack of retroperitoneal and visceral fat (mesenteric fat). In addition, the aortomesenteric distance is 2-8 millimeters, as opposed to the typical 10-20. However, a narrow SMA angle alone is not enough to make a diagnoses, because patients with a low BMI, most notably children, have been known to have a narrow SMA angle with no symptoms of SMA Syndrome.

SMA syndrome was first described in 1861 by Carl Freiherr von Rokitansky in victims at autopsy, but remained pathologically undefined until 1927 when Wilkie published the first comprehensive series of 75 patients. According to a 1956 study, only .3% of patients referred for a barium meal study fit this diagnosis, making it one of the rarest gastrointestinal disorders known to medical science. Recognition of SMA syndrome as a distinct clinical entity is controversial, due in part to its possible confusion with a number of other conditions, though it is now widely acknowledged.

SMA syndrome is also known as Wilkie's syndrome, cast syndrome, mesenteric root syndrome, chronic duodenal ileus and intermittent arterio-mesenteric occlusion. It is distinct from Nutcracker syndrome, which is the entrapment of the left renal vein between the AA and the SMA, although it is possible to be diagnosed with both conditions.

I altered some of the wording to make it less dramatic and to reflect the current data better, added a sentence about the possibility of a narrow mesenteric angle without SMAS symptoms (cited a journal article), altered the sentence about SMAS' distinction as a clinical entity to better match the source, and added a bit about the possibility of having both SMAS and nutcracker syndrome (cited a journal article). I also removed the sentence about the 1 in 3 mortality rate due to its controversy, and I think it would be best to expand upon the controversy in the mortality section rather than the intro. Firielusa (talk) 19:13, 18 September 2014 (UTC) I corrected some of my terminology from "mesenteric angle" to "SMA angle." Firielusa (talk) 18:56, 19 September 2014 (UTC) I replaced the source for the .3% prevalence to a source that contains the original data, and modified the sentence to more closely match the source. Firielusa (talk) 05:29, 23 September 2014 (UTC)


 * You are spreading false info! As a SMAS warrior, Im so disgusted at you. How dare you mimimize this rare disease. 2603:6000:C0F0:83C0:95C0:2AA0:2A92:8D72 (talk) 03:01, 1 March 2024 (UTC)

Here are my proposed revisions to the Symptoms section:

-- Symptoms --

Symptoms include early satiety, nausea, vomiting, extreme "stabbing" postprandial abdominal pain (due to both the duodenal compression and the compensatory reversed peristalsis), abdominal distention/distortion, eructation, external hypersensitivity or tenderness of the abdominal area, diarrhea, reflux, and heartburn. In infants, feeding difficulties and poor weight gain are also frequent symptoms. In some cases of SMA Syndrome, severe malnutrition accompanying spontaneous wasting may occur. This, in turn, increases the duodenal compression, spurring a vicious cycle. "Food fear" is a common development among patients 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 (pressure applied 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 supine (face up) position.

I added diarrhea, reflux, and heartburn as symptoms, and altered the wording of the sentence about severe malnutrition and wasting to indicate that it does not apply to all patients. I also added the prone position to the list of common helpful positions, and changed the wording to indicate that positioning may not help all patients. Firielusa (talk) 19:39, 19 September 2014 (UTC) I added feeding difficulty and poor weight gain as symptoms in infants, source cited. Firielusa (talk) 04:37, 12 October 2014 (UTC)

Here are my proposed revisions to the causes section:

-- Causes --

Retroperitoneal fat and lymphatic tissue normally serve as a cushion for the duodenum, protecting it from compression by the SMA. SMA syndrome can thus be triggered by any condition involving an insubstantial cushion and narrow mesenteric angle. SMA Syndrome can present in two forms: chronic/congenital or acute/induced.

Patients with the chronic, congenital form of SMA syndrome predominantly have a lengthy or even lifelong history of abdominal complaints with intermittent exacerbations depending on the degree of duodenal compression. Risk factors include anatomic characteristics such as: aesthenic (very thin or "lanky") body build, an unusually high insertion of the duodenum at the ligament of Treitz, a particularly low origin of the SMA, or intestinal malrotation around an axis formed by the SMA. Predisposition is easily aggravated by any of the following: poor motility of the digestive tract, retroperitional tumors, loss of appetite, malabsorption, cachexia, exaggerated lumbar lordosis, visceroptosis, abdominal wall laxity, peritoneal adhesions, abdominal trauma, rapid linear adolescent growth spurt, weight loss, starvation, catabolic states (as with cancer and burns), and history of neurological injury.

The acute form of SMA Syndrome develops rapidly after traumatic incidents that forcibly hyper-extend the SMA across the duodenum, inducing the obstruction, or severe, rapid weight loss for any reason. Causes include prolonged supine bed rest (as with the application of body casts), spinal cord injury, scoliosis, scoliosis surgery, left nephrectomy, ileo-anal pouch surgery , or eating disorder. However, while SMA Syndrome can be caused by, or mimic, an eating disorder, distinguishing the two conditions is extremely important, as misdiagnosis in this situation can be dangerous.

I added history of neurological injury as a risk factor. I also added severe, rapid weight loss as a cause of the acute form of SMAS, and added ileo-anal pouch surgery and eating disorders as potential causes, with an amendment mentioning the dangers of misdiagnosing an SMAS patient with an eating disorder. Sources cited for everything. Firielusa (talk) 04:28, 20 September 2014 (UTC)


 * MORE FALSE INFO!!!! body type, shape. Weight,bmi have all been proven not to be true!!!
 * Stop the false info. Listen to REAL SMAS warriors on how aweful this syndrom is and comes in all shapes and sizes! The non profit SMAS is also spreading this false info! ENOUGH IS ENOUGH! 2603:6000:C0F0:83C0:95C0:2AA0:2A92:8D72 (talk) 03:05, 1 March 2024 (UTC)

Here are my proposed changes to the Epidemiology section:

--Epidemiology--

SMA syndrome is extremely rare, evident in only 0.3% of upper-gastrointestinal-tract barium studies. However, unfamiliarity with this condition in the medical community coupled with its intermittent and nonspecific symptomatology probably results in its underdiagnosis.

As the syndrome often involves a lack of essential fat, more than half of those diagnosed are underweight, sometimes to the point of sickliness and emaciation; however the syndrome also occurs in people with a normal BMI. 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 are 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.

American actor, director, producer, and writer Christopher Reeve suffered from the acute form of SMA syndrome as a result of spinal cord injury.

I updated source about the prevalence of SMAS to one containing the original data. I also made a lot of changes to the second paragraph based on the findings of the article "Superior mesenteric artery syndrome: Where do we stand today?" which is the biggest, most recent study on SMAS I have found, and should have the best data on epidemiology. I left in the same basic categories, but changed the info to match the source. Firielusa (talk) 19:55, 23 September 2014 (UTC)


 * Where do you stand?? FALSE INFO THATS OUT OF DATE! 2603:6000:C0F0:83C0:95C0:2AA0:2A92:8D72 (talk) 03:07, 1 March 2024 (UTC)

Here are my proposed revisions for the mortality section:

--Mortality--

Delay in the diagnosis of SMA syndrome can result in fatal catabolysis (advanced malnutrition), dehydration, electrolyte abnormalities, hypokalemia, acute gastric rupture or intestinal perforation (from prolonged mesenteric ischemia), gastric distention, spontaneous upper gastrointestinal bleeding, hypovolemic shock, or aspiration pneumonia.

A 1-in-3 mortality rate for Superior Mesenteric Artery syndrome has been reported by a small number of sources. 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 and one in 2012 looking at 80 cases, show mortality rates of 0% and 6.3% , respectively. The expected outcome for SMA syndrome treatment is generally considered to be excellent.

I removed oliguria as a complication as it is generally a symptom of dehydration, which is listed. I also changed gastrectasia to gastric distention (a more common term for the same thing), and removed sentence about sudden cardiovascular collapse as I cannot find more than a passing mention of this in the literature, which is not enough to back it up. I also added the paragraph about the mortality rate being likely unreliable and the outcome of SMAS treatment generally being good, citing two recent and fairly extensive studies. I'm currently looking for a way to cite the same source multiple times without it appearing as a new entry in the bibliography. Firielusa (talk) 04:03, 25 September 2014 (UTC) I updated several of the references throughout my proposed changes to consolidate multiple citations of the same article. Firielusa (talk) 17:28, 26 September 2014 (UTC) Corrected the doi on Althobity citation Firielusa (talk) 17:32, 26 September 2014 (UTC)

As I am still waiting for access to some of the sources used in the diagnosis section, I will add revisions to that section later.

Later: Here are my revisions to the diagnosis section: --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 gastrointestinal tract including upper endoscopy, colonoscopy, and evaluation for various malabsorptive, ulcerative and inflammatory instestinal conditions with a higher diagnostic frequency. Diagnosis may follow x-ray examination revealing duodenal dilation followed by abrupt constriction proximal to the overlying SMA, as well as a delay in transit of four to six hours through the gastroduodenal region. Standard diagnostic exams include abdominal and pelvic computed tomography (CT) scan with oral and IV contrast, upper gastrointestinal series (UGI), and, for equivocal cases, hypotonic duodenography. In addition, vascular imaging studies such as ultrasound and contrast angiography may be used to indicate increased bloodflow velocity through the SMA or a narrowed SMA angle.

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. However, the reason for the persistence of gastrointestinal symptoms even after surgical correction in some cases has been recently traced to the remaining prominence of reversed peristalsis in contrast to direct peristalsis.

Since females between the ages of 10 and 30 are most frequently afflicted, 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 in its chronic form. Patients in the earlier stages of chronic 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. Eating disorder treatment protocols involving forced refeeding and behavioral therapy are noted to have poor outcomes with individuals suffering from SMA syndrome.

I took out the part about increased bloodflow through the SMA causing cardiovascular collapse since the source doesn't back it up and I haven't found any others that do. I also added "in some cases" to the part about reverse peristalis after surgery since it may not apply to all cases. Firielusa (talk) 17:59, 11 October 2014 (UTC)

For now, here are my proposed revisions to the treatment section:

--Treatment--

SMA syndrome can present in acute, acquired form (e.g. abruptly emerging within an inpatient stay following scoliosis surgery) as well as chronic form (i.e. developing throughout the course of a lifetime and advancing due to environmental triggers, life changes, or other illnesses). At least 70% of cases can typically be treated with medical treatment, while the rest require surgical treatment.

Medical treatment should be attempted first in all cases, except for cases where emergency surgery is necessary upon presentation. A six-week trial of medical treatment is recommended in pediatric cases. The goal of medical treatment for SMA Syndrome is resolution of underlying conditions and weight gain. Medical treatment may involve nasogastric tube placement for duodenal and gastric decompression, mobilization into the prone or left lateral decubitus position, the reversal or removal of the precipitating factor with proper nutrition and replacement of fluid and electrolytes, either by surgically inserted jejunal feeding tube, nasogastric intubation, or peripherally inserted central catheter (PICC line) administering total parenteral nutrition (TPN). Pro-motility agents such as metoclopramide may also be beneficial. Symptoms typically improve after restoration of weight, except when reversed peristalsis persists, or if regained fat refuses to accumulate within the mesenteric angle. Most patients seem to benefit from nutritional support with hyperalimentation irrespective of disease history.

If medical treatment fails, or is not feasible due to severe illness, surgical intervention is required. The most common operation for SMA syndrome, duodenojejunostomy, was first proposed in 1907 by Bloodgood. Performed as either an open surgery or laparoscopically, duodenojejunostomy involves the creation of an anastomosis between the duodenum and the jejunum, bypassing the compression caused by the AA and the SMA. Less common surgical treatments for SMA syndrome include Roux-en-Y duodenojejunostomy, gastrojejunostomy, anterior transposition of the third portion of the duodenum, intestinal derotation, division of the ligament of Treitz(Strong's operation), and transposition of the SMA. Both transposition of the SMA and lysis of the duodenal suspensory muscle have the advantage that it does not involve the creation of an intestinal anastomosis.

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.

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.

I replaced the sentence about a difference of treatment between chronic and acute cases and replaced it with the sentence about the 70% success rate as that seems to apply to all causes of SMAS (sources cited). I edited the first sentence of the second paragraph to match the literature, specifically citing BiankWerlin. I clarified the description of medical treatment by stating the goal of medical treatment and arranging the possible treatments into a more logical paragraph. I also added the sentence about the recommended six-week trial period for medical treatment (source cited). I edited the first sentence in the paragraph about surgical treatment to include failure of medical treatment or severe illness but not chronic illness, since chronic illness has been shown to respond to medical treatment in some cases. I also added transposition of the SMA as a surgical option (source cited). Firielusa (talk) 02:43, 30 September 2014 (UTC) I added the part about treating SMAS in patients who have other life-threatening conditions plus sources.Firielusa (talk) 18:44, 11 October 2014 (UTC)

discovery
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5133654/ says it was in 1842? Rogerdpack (talk) 10:43, 18 February 2017 (UTC)