Gastrointestinal Endoscopy

Anupam Singh

Randall S. Pellish

Wahid Y. Wassef

Gastrointestinal (GI) endoscopy has evolved into an essential diagnostic and therapeutic tool for the treatment of critically ill patients in the new millennium. Innovations in the field continue to emerge. This chapter reviews general aspects of current indications and contraindications, provides an update of emerging technologies, and concludes by discussing potential future directions in the field.

Indications

The indications for GI endoscopy in the intensive care unit (ICU) are summarized in Table 13.1 and are divided into those for (a) evaluation of the upper GI tract (esophagus, stomach, and duodenum); (b) evaluation of the pancreaticobiliary tract; (c) evaluation of the mid-GI tract (jejunum and ileum); and (d) evaluation of the lower GI tract (colon and rectum).

Evaluation of the Upper Gastrointestinal Tract

Common indications for evaluation of the upper GI tract in the ICU include, but are not limited to, upper GI bleeding (UGIB), caustic or foreign body ingestion, and placement of feeding tubes. Evaluation of the GI tract in ICU patients with clinically insignificant bleeding or chronic GI complaints should generally be postponed until their medical/surgical illnesses improve. One exception in this group of patients is if anticoagulation or thrombolytic therapy is being contemplated.

Upper Gastrointestinal Bleeding

With an estimated 300,000 admissions annually, acute UGIB is one of the most common medical emergencies [1]. It is defined as the presence of melena, hematemesis, or blood in the nasogastric (NG) aspirate. Studies have shown improved outcomes with urgent endoscopic management in critically ill patients with hemodynamic instability or continuing transfusion requirements [2,3]. Urgent evaluation allows differentiation between nonvariceal (peptic ulcer, esophagitis, Mallory–Weiss tear, and angiodysplasia) and variceal lesions (esophageal or gastric varices), therefore promoting targeted therapy [4,5]. Furthermore, urgent evaluation allows the identification and stratification of stigmata of bleeding, promoting appropriate triage and risk stratification. Finally, urgent evaluation allows the early identification of patients who may require surgical or radiologic intervention [6,7].

Foreign Body Ingestions

Foreign body ingestions (FBI) can be divided into two groups: (i) food impactions and (ii) caustic ingestion. Food impactions constitute the majority of FBI. Although most will pass spontaneously, endoscopic removal will be needed for 10% to 20% of cases, and 1% of patients will ultimately require surgery [8]. Evaluation is crucial to determine the underlying cause of the obstruction (strictures, rings, and carcinoma). Although caustic ingestions constitute only a small number of FBI, they are frequently life threatening, especially when they occur intentionally in adults, and warrant endoscopic evaluation to prognosticate and triage this group of patients [9].

Feeding Tubes

Enteral nutrition improves outcomes in critically ill patients and is preferred over parenteral nutrition in patients with a functional GI tract [10]. Although nasoenteric and oroenteric feeding tubes may be used for short-term enteral nutrition, these tubes are felt to carry a higher risk of aspiration, displacement, and sinus infections than endoscopically placed percutaneous tubes. Percutaneous endoscopic gastrostomy (PEG) [11] is appropriate for most patients in the ICU when there is a reversible disease process likely to require more than 4 weeks of enteral nutrition (e.g., neurologic injury,
tracheostomy, and neoplasms of the upper aerodigestive tract) [12]. PEG with jejunostomy tube and direct percutaneous endoscopic jejunostomy (PEJ) tubes are appropriate for select patients in the ICU with high risk of aspiration. This includes patients with severe gastroesophageal reflux disease and those with gastroparesis. Enteral feeding beyond the ligament of Treitz with a nasojejunal tube or a jejunostomy tube has been demonstrated to be beneficial in patients with necrotizing pancreatitis. Occasionally, endoscopic gastrostomies or jejunostomies may be indicated for decompression in patients with GI obstruction [13]. Although these procedures are technically simple and can be performed at the bedside under moderate sedation, the risks and benefits should always be weighed carefully in this critically ill group of patients [14].

Table 13.1 Indications for Gastrointestinal (GI) Endoscopy

Upper GI endoscopy
   Upper GI bleeding (variceal or nonvariceal)
   Caustic or foreign body ingestion
   Placement of feeding or drainage tubes
Endoscopic retrograde cholangiopancreatography
   Severe gallstone pancreatitis
   Severe cholangitis
   Bile leak
Lower GI endoscopy
   Lower GI bleeding
   Decompression of nontoxic megacolon or sigmoid volvulus
   Unexplained diarrhea in the immunocompromised (graft vs. host disease and cytomegalovirus infection)

Evaluation of the Pancreaticobiliary Tract

The indications for evaluation of the pancreaticobiliary tract by endoscopic retrograde cholangiopancreatography (ERCP) in critically ill patients are described in detail in Chapter 97 and only briefly discussed here. Indications include biliary tract obstruction by gallstones [15,16,17], pancreatic duct leaks, and bile duct leaks (generally a postoperative or traumatic complication) [18,19,20]. ERCP with sphincterotomy and/or stenting is the treatment of choice. When conventional ERCP is unsuccessful, the recent introduction of miniature endoscopes (cholangioscopes or pancreatic scopes) with direct endoscopic visualization into these ductal systems has proved to be beneficial through the use of advanced techniques such as electrohydraulic lithotripsy (EHL), laser lithotripsy, and glue [21]. Unfortunately, this technique is limited by its lack of availability at all centers and the great deal of experience that is needed for its proper use.

Figure 13.1. Normal jejunal image as seen by video capsule endoscope (VCE).

Figure 13.2. Tumor seen in proximal jejunum during double-balloon enteroscopy (DBE). (Courtesy: David Cave, MD: Professor of Medicine, University of Massachusetts Medical School.)

Evaluation of the Mid-Gastrointestinal Tract (Jejunum and Ileum)

Persistent, obscure GI bleeding is the most common indication for evaluation of this portion of the GI tract. Although this area of the GI tract had been difficult to evaluate in the past, this is no longer the case. The advent of the wireless video capsule endoscope (VCE), the double-balloon endoscope (DBE), and the spiral endoscope has made this area of the GI tract easily accessible. VCE is usually the first test performed to look for possible sites of bleeding in the jejunum and ileum (Fig. 13.1). If bleeding or lesions are identified, the DBE (Fig. 13.2) or the spiral endoscope (Fig. 13.3) would be used to implement therapy.

Figure 13.3. Bleeding seen in jejunum during spiral endoscopy. (Courtesy: David Cave, MD: Professor of Medicine, University of Massachusetts Medical School.)

Figure 13.4. A: X-ray showing cecal volvulus. (Courtesy: Milliam Kataoka, MD, Radiology Fellow, UMass Memorial Medical Center.) B: CT scan showing cecal volvulus. (Courtesy: Milliam, MD, Radiology Fellow, UMass Memorial Medical Center.)

Evaluation of the Lower Gastrointestinal Tract

Colonoscopic evaluation is urgently needed in ICU patients in cases of severe lower GI bleeding (LGIB), acute colonic distention, and at times for the evaluation of infection (Cytomegalovirus [CMV] and Clostridium difficile) in the immunocompromised patients [22,23].

Severe LGIB is predominantly a disease of the elderly. It is defined as bleeding from a source distal to the ligament of Treitz for less than 3 days [24]. Common causes include, but are not limited to, diverticular bleeding, ischemic colitis, and vascular abnormalities (arteriovenous malformations, AVMs). However, as many as 11% of patients initially suspected to have an LGIB are ultimately found to have a UGIB [25]. Therefore, UGIB sources should always be considered first in patients with LGIB, particularly in patients with unstable hemodynamics. Once an upper GI source has been excluded, colonoscopy should be performed to evaluate the lower GI tract and administer appropriate therapy. Although urgent colonoscopy within 24 to 48 hours has shown to decrease the length of hospital stay [26] and endoscopic intervention is often successful, 80% to 85% of LGIBs stop spontaneously [27]. If the bleeding is severe or a source cannot be identified at colonoscopy, a technetium (TC)-99m red blood cell scan with or without angiography should be considered [28].

Acute Colonic Distention

This condition can be caused by acute colonic obstruction or acute colonic pseudo-obstruction. Acute colonic obstruction can be caused by neoplasms, diverticular disease, and volvulus [29]. Volvulus (Fig. 13.4A and B) is a “closed-loop obstruction” and is considered an emergency because unlike the other causes of colonic obstruction, it can rapidly deteriorate from obstruction to ischemia, perforation, and death. However, if identified and treated early, it can be reversed. Acute colonic pseudo-obstruction is a syndrome of massive dilation of the colon without mechanical obstruction that develops in hospitalized patients with serious underlying medical and surgical conditions due to impaired colonic motility. Increasing age, cecal diameter, delay in decompression, and status of the bowel significantly influence mortality, which is approximately 40% when ischemia or perforation is present. Evaluation of the markedly distended colon in the ICU setting involves excluding mechanical obstruction and other causes of toxic megacolon, such as C. difficile infection, and assessing for signs of ischemia and perforation. The risk of colonic perforation in acute colonic pseudo-obstruction increases when cecal diameter exceeds 12 cm and when the distention has been present for greater than 6 days [30].

Only gold members can continue reading. Log In or Register to continue