miércoles, 15 de mayo de 2019

Types of Volvulus

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By Dr. Damien Jonas Wilson, MDReviewed by Susha Cheriyedath, M.Sc.

Volvulus, derived from the Latin term volvere, is a subtype of abnormal gastrointestinal (GI) rotation.

In volvulus, a loop of intestines is twisted at a point along the mesentery that is attached to the GI tract.

Volvulus may result in bowel obstruction, which is a medical emergency, because not only is there blockage, but there is compromised vascular supply to the gut as well.

There are 4 primary mesenteries found within the abdomen. As a result of the 4 main types of mesenteries, there are 4 corresponding primary types of volvulus: gastric, midgut, cecal, and sigmoid volvuli.

Gastric Volvulus

Gastric volvulus (GV) occurs when the stomach twists at least 180 degrees around its mesentery, leading to obstruction of the bowel. Patients with GV may present with what is known as Borchardt’s triad.

The triad signs are sudden and severe epigastric pain, uncontrollable making of vomiting noises without actually vomiting, and the impossibility of passing a nasogastric tube through to the gut.

There are two subtypes of GV:

Organo-axial volvulus (OAV-GV)

Almost 70% of cases associated with OAV-GV will be found in adults and it tends to occur after traumatic events or hernia of the para-esophageal area.

The stomach rotates along its long axis in OAV-GV (i.e. along the path between the pylorus and the cardia).

OAV-GV is usually symptomatic when the rotation is more than 180 degrees and causes ischemia in addition to obstruction.

Mesentero-axial volvulus (MAV-GV)

MAV-GV tends to occur more frequently in children as opposed to adults and is the rotation of the stomach along its short axis (i.e. along the path perpendicular to OAV-GV axis or the pathway between the lesser and greater curvatures of the stomach).

The management of GV may involve an emergency laparotomy, insertion of gastrostomy percutaneous tube, and where applicable, hernia and diaphragmatic damage repair.

The surgery aims to primarily reduce the degree of twisting and prevent any chances of recurrence while taking care of factors that create a predisposition.

Midgut Volvulus

Nine out of every 10 midgut volvuli (MV) occur within the first year of life.

The newborn appears clinically fine for a period of time before developing the condition, which presents with sudden bilious vomiting.

Additionally, the abdomen becomes tender as it fills with fluid that accumulates within the bowel lumen and this is followed by inflammation of the peritoneum and shock.

Patients with MV typically have a corkscrew sign visible on fluoroscopic contrast examination, which is a spiral appearance of the bowel.

Other imaging techniques such as ultrasound and CT show a whirlpool sign, which is used to denote the twisting of the bowel on itself.

A Ladd surgical procedure is done to treat MV.

This procedure entails dividing Ladd’s bands (tissue that creates an attachment between the cecum and the abdominal wall), widening the mesentery of the small intestines, removal of the appendix and proper placing of the colon and cecum.

Cecal Volvulus

Cecal volvuli (CV) tend to occur most frequently between the 3rd and 6th decades of life and account for less than 10% of all intestinal volvuli.

They are predominantly associated with two predisposing factors: lack of thorough peritoneal fixation and fulcrums such as abdominal masses or adhesions.

Patients with CV tend to have distended abdomens in addition to vomiting and colicky abdominal pain.

Nearly half of the patients with CV tend to have a cecum that is abnormally rotated in an axial plane while the remainder have a cecum that inverts in addition to twisting.

Treating CV may involve laparotomy (incision through the abdominal wall), hemicolectomy (removal of part of the colon), or cecostomy (opening of the cecum through the abdominal wall).

Sigmoidal Volvulus

Sigmoidal volvulus (SV) account for nearly 60% of volvuli involving the large bowel.

These patients often have abdominal bloating, constipation, and nausea that may or may not be accompanied by vomiting.

SV is thought to be associated with neurological pathologies such as multiple sclerosis and Parkinson’s disease. Causes of SV are many.

These include the South American Chagas disease, laxative use, and diets rich in fiber. Like in MV, a whirlpool sign is also seen in SV on imaging.

In addition to the whirlpool sign, a coffee bean sign may be seen on the abdominal X-ray, which looks like an inner tube that is bent. The insertion of a rectal tube has been shown to be successful in treating SV in the majority of cases.