Interventional endoscopy

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CHAPTER 7 Interventional endoscopy

7.1 Stricture dilation

Summary

1 Clinical and endoscopic assessment

1.1 Esophageal strictures

3 Endoscopic techniques

3.1 General principles

3.1.1 Dilation using bougies

3.1.2 Dilation using balloons

3.2 Esophageal strictures

3.3 Achalasia

3.5 Small intestinal/colonic strictures

7.2 Emergency endoscopy in benign gastrointestinal obstruction

Summary

Information about the emergency management of gastroduodenal or colonic obstruction due to stricture or malignancy can be found in Chapter 7.3.

1 Volvulus

1.1 Gastric volvulus

Gastric volvulus is a rare, potentially life-threatening entity that occurs when the stomach twists upon itself (Fig. 1). By definition, gastric volvulus is rotation of the entire or part of the stomach more than 180°. It is supra-diaphragmatic and associated with a paraesophageal or a mixed diaphragmatic hernia in two-thirds of the cases, and is subdiaphragmatic in the remaining one third. The volvulus is organoaxial in 60% of cases where the axis passes through the gastroesophageal and gastropyloric junctions, and mesenteroaxial in 40% of cases where the axis bisects the lesser and greater curvatures.

Gastric volvulus can present as: (1) transient event with mild short-lived upper abdominal symptoms; (2) chronic volvulus with mild and non-specific symptoms such as dysphagia, hiccups, early satiety, bloating, heartburn, and upper abdominal discomfort, with symptoms being worse after meals; or (3) acute gastric volvulus which presents with sudden onset of severe pain in the upper abdomen or lower chest and unproductive retching. Some patients present with Borchardt’s triad of pain, unproductive retching, and the inability to pass a nasogastric tube.

Although strangulation is more common in organoaxial volvulus, it only occurs in 5–28% of these cases due to the rich blood supply of the stomach. Mesenteroaxial volvulus usually causes incomplete obstruction that may be intermittent in nature.

If gastric volvulus is associated with a diaphragmatic hernia, physical examination may reveal evidence of the stomach in the left chest. Chest X-ray will reveal a gas-filled viscus in the chest. The diagnosis is usually confirmed with a barium upper gastrointestinal study. Upper endoscopy will show twisting of gastric folds at the point of torsion.

Acute gastric volvulus carries a high mortality risk if not recognized early. Early diagnosis and surgical correction remain the mainstays of therapy. Nonetheless, gastroenterologists still play a crucial role in the diagnosis and management of acute and chronic gastric volvulus.

1.2 Colonic volvulus

Colonic volvulus is the third most frequent cause of large bowel obstruction after neoplasms and diverticulitis. Whereas colonic neoplasms and diverticulitis usually result in an open-loop obstruction where the lumen is occluded at a single point along the bowel segment, colonic volvulus occurs when a colonic segment becomes twisted on its mesenteric axis and occludes both ends of the bowel segment resulting in a closed-loop obstruction (Fig. 4). The mesentery gets trapped and the blood supply to the bowel segment becomes strangulated, potentially leading to gut ischemia, necrosis and perforation. Delay in diagnosis and decompression compromises viability of the bowel and is a major cause of mortality.

The sigmoid colon (Fig. 4) and cecum (Fig. 5) are the most frequent sites of colonic volvulus, accounting for 75% and 22% of all cases, respectively. Patients with acute colonic volvulus present most commonly with acute abdominal distension and may have other non-specific symptoms of abdominal pain, nausea, vomiting, and constipation. The diagnosis of colonic volvulus can be made with plain abdominal films (supine and upright) or water-soluble contrast enemas in 85% of the cases.

Acute colonic volvulus should be managed on an emergent basis. Patients with colonic necrosis/perforation should be managed surgically. A more conservative approach with an initial attempt at endoscopic detorsion and decompression can be followed in more stable patients (Fig. 6). The benefits of such a strategy are:

Colonic segmental resection and primary anastomosis is considered the treatment modality of choice of colonic volvulus after successful endoscopic detorsion. Non-resectional techniques such as colonopexy and colonostomy carry a substantial risk of recurrence, but may be considered in high-risk patients.

2 Acute colonic pseudo-obstruction

Acute colonic pseudo-obstruction, also known as Ogilvie’s syndrome, is a disorder characterized by massive colonic dilation in the absence of colon obstruction. This definition excludes toxic colitis, which occurs in the setting of severe colitis secondary to inflammatory bowel disease or infection. It occurs most often in the setting of surgery and severe medical illnesses, and thus is a disorder of institutionalized patients. Acute colonic pseudo-obstruction is believed to result from autonomic imbalance with suppressed large bowel parasympathetic tone. This results in decreased colonic motility, accumulation of gas and fluid in the colon, increased intraluminal pressure, colonic distension and rising wall tension. Wall tension is highest in the cecum where the colonic diameter is the largest. This may result in the impediment of cecal capillary circulation and lead to ischemia, gangrene, and subsequent perforation. Plain abdominal radiographs show diffuse dilatation of the colon. A cutoff in the colonic gas is often seen at the hepatic flexure, splenic flexure, or sigmoid region with minimal air distal to the cutoff (collapsed left colon). Unlike toxic colitis, preserved haustral markings, smooth inner colonic contour, and thin colonic wall are present. In contrast to mechanical obstruction, air fluid levels are absent and distension is gaseous (Figs 7, 8). Water-soluble contrast enema is usually needed to rule out a true mechanical obstruction.

Therapy of acute colonic pseudo-obstruction can be divided into conservative treatment and active interventions. Conservative measures should be tried for 24–48 h, after which the condition usually resolves in most patients (at least in 75% of cases). Active interventions should be implemented if the disease progresses or does not respond to conservative measures.

Active interventions, including treatment with neostigmine and/or colonoscopic decompression, should be considered in patients who do not respond to a maximum of 48 h of conservative therapy, those with extreme abdominal pain, and those with cecal diameter >12 cm.

Neostigmine, an anticholinesterase parasympathomimetic agent, is usually the first medical agent tried in patients who do not have any contraindications to its use.

Colonoscopic decompression with placement of decompression tube should be performed in patients who fail neostigmine treatment.

Box 3 Facts about colonoscopic decompression in patients with acute colonic pseudo-obstruction

Patients who fail medical and endoscopic treatment and those with signs of colonic perforation/necrosis should be treated surgically with cecostomy or colectomy. Figure 9 illustrates an algorithm suggested by the ASGE for treating patients with ACPO.

7.3 Esophageal, duodenal and colorectal stenting

Summary

Introduction

Advances in interventional endoscopy over the last two decades have made an immense impact on clinical care. One such advance is the endoscopic placement of stents for the treatment and palliation of benign and malignant strictures involving the esophagus, duodenum, and colorectal regions of the gastrointestinal tract.

Esophageal cancer is one of the most lethal malignancies in the Western world. The incidence of esophageal cancer is rising at a faster rate as compared to any other GI cancer, and fewer than 50% of cases are curable and the 5-year survival rate is only 5–10%. For these reasons, palliative treatment of esophageal cancer remains an essential part of its management. Palliative esophageal surgery is associated with unacceptably high morbidity and mortality; it has largely been replaced by chemoradiation, brachytherapy, and/or endoscopic therapy. Among the available endoscopic techniques, endoluminal stenting is the most commonly employed because of its efficacy and wide availability.

Tumors involving the gastric outlet or the duodenum cause symptoms and signs of gastric outlet obstruction. Neoplasms that most commonly result in gastric outlet obstruction include pancreatic cancer, gastric cancer, carcinoid tumor, and metastases from other primary malignancies. Multiple studies have shown that palliative stent placement for unresectable tumors, as compared with palliative surgery, is more efficacious, cost-effective, and is associated with less morbidity and mortality.

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