Elderly Woman With Acute Abdominal Pain

A 92-year-old woman presents with sharp abdominal pain of 1 day's duration, accompanied by 1 episode of emesis. The pain is neither relieved nor exacerbated by food ingestion. The patient has chronic mild dyspepsia, with a distant history of peptic ulcer disease; congestive heart failure; and chronic obstructive pulmonary disease.

Blood pressure is 140/70 mm Hg; temperature, 36.9°C (98.5°F); heart rate, 56 beats per minute; and respiration rate, 12 breaths per minute. Mild epigastric abdominal pain, without rebound or guarding, is noted on deep palpation. Bowel sounds are normal. Results of a complete blood cell count, basic metabolic panel, and liver function tests are all within normal limits.

Images from an upper GI endoscopy are shown here. Which of the following best explains the clinical and endoscopic findings?

• Acquired double-channel pylorus
• Congenital double-channel pylorus
• Gastric intramural diverticulum
• Gastroduodenal Crohn disease
• Cameron ulcer

(Answer on next page.)

Acquired double-channel pylorus

An upper GI endoscopy reveals a normal esophagus and 2 channels from the stomach (Figure); the lower channel originates from the normal pylorus in the duodenal cap. The duodenum can be visualized by passing the endoscope through either opening.

DOUBLE-CHANNEL PYLORUS: AN OVERVIEW
Double-channel pylorus has been reported in 0.02% to 0.4% of the population; in the majority of cases it is an acquired defect secondary to peptic ulcer disease.¹ Most accessory channels extend from the lesser curvature of the gastric antrum to the superior aspect of the duodenal bulb. An ulcer that originates in either of the 2 structures may cause adhesion formation, and continued erosion eventually results in a gastroduodenal fistula.

Making the diagnosis. The diagnosis of acquired double-channel pylorus is largely based on imaging, although the defect may be mistaken for polyps, tumors, or large mucosal folds on double-contrast radiography. The interpretation of endoscopic findings is more straightforward. Diagnosis requires observation of an accessory opening near the pylorus that lacks normal peristalsis and through which the duodenal bulb can be accessed-as demonstrated in this case.

Treatment. Most patients with an acquired double-channel pylorus can be treated medically with intensive anti-ulcer therapy, although poor healing of ulcers is observed in these patients. Ulcerogenic medications, such as corticosteroids and NSAIDs, may substantially contribute to the pathogenesis of acquired double-channel pylorus and prevent recovery. This is particularly relevant in patients who have comorbid conditions, such as diabetes and chronic renal failure, that impair mucosal protective mechanisms. Triple therapy may help reduce overall symptoms and ulcer recurrence in patients infected with Helicobacter pylori; however, long-term follow-up has shown that these effects are not significant.

A common site of ulcer recurrence is the septum dividing the 2 channels, where bile reflux may occur and predispose the area to further ulceration. In patients with recurrent or severe persistent ulceration, distal gastrectomy may be considered.

DIFFERENTIAL DIAGNOSIS
Congenital double-channel pylorus is rare (about 8.3% of reported cases of double-channel pylorus).² To be deemed congenital, the accessory channel must meet certain criteria, including presence in early childhood and containment of mucosa, lamina propria, and muscularis mucosae. This patient's age and her history of chronic dyspepsia and peptic ulcer disease strongly suggested an acquired double-channel pylorus.

Gastric diverticula (the rarest of all GI diverticula) are observed in 0.02% of autopsies; fewer than 25% are termed "intramural."³ Intramural gastric diverticulum is most commonly prepyloric and is actually a pseudo-diverticulum formed by the herniation of mucosa or submucosa through a muscular defect that is usually secondary to peptic ulcer disease, malignancy, or trauma. Symptoms, if present, may consist of epigastric or lower chest pain, indigestion, and nonbilious emesis. On contrast radiography, an intramural gastric diverticulum appears as a well-defined, movable pouch, frequently with an air-fluid level; it is occasionally associated with delayed emptying. Endoscopy reveals a well-defined opening with a clear terminus on probing. Although consistent with this patient's history of chronic dyspepsia and peptic ulcer disease, intramural gastric diverticulum was ruled out because of the passage of the endoscope through the accessory opening to the duodenum. Gastroduodenal Crohn disease (GCD) is a rare form of Crohn disease that most frequently involves the gastric antrum, duodenal bulb, and duodenal loop. The diagnosis may be established by findings on gastric or duodenal biopsy of noncaseating granulomatous inflammation or, in the setting of documented Crohn disease elsewhere in the GI tract, by findings on radiography or upper endoscopy of diffuse gastric or duodenal inflammation.⁴ Double-contrast radiography may show "cobblestoning" (or mucosal nodularity), ulceration, pseudo-diverticular formation of stenosis, or the ram horn sign-a funnel-like contour from the gastric antrum to duodenal bulb, which is pathognomonic for GCD. Upper endoscopy may reveal macroscopically normal mucosa or friable or nodular mucosa with variable degrees of ulceration. Giant ulcers near the pylorus have been reported in several cases, and duodenal fistulae have also been identified. GCD was unlikely in this patient because of its rarity and the lack of a medical history suggestive of Crohn disease.

Cameron ulcer, first described by Cameron and Higgins⁵ in 1986, is a linear gastric erosion that develops within a hiatal hernia-which was absent in this patient. The Cameron ulcer is seen in about 5% of hiatal hernias viewed endoscopically.⁶ It is thought to arise from the mechanical trauma engendered by diaphragmatic contraction or from ischemia. Frequently associated with chronic anemia, a Cameron ulcer may become a source of acute hemorrhage.

 

References:

REFERENCES:
1. Hu TH, Tsai TL, Hsu CC, et al. Clinical characteristics of double pylorus. Gastrointest Endosc. 2001;54:464-470.
2. Archampong EQ, Blanchard RJ, Boult I. Double-channel pylorus: congenital or acquired. Can J Surg. 1981;24:537-539.
3. Jeyarajah R, Hartford W. Diverticula of the hypopharynx, esophagus, stomach, jejunum, and ileum. In: Feldman M, Friedman LS, Sleisenger MH, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 7th ed. New York: Saunders; 2002:363-364.
4. van Hogezand RA, Witte AM, Veenendaal RA, et al. Proximal Crohn's disease: review of the clinicopathologic features and therapy. Inflamm Bowel Dis. 2001;7:328-337.
5. Cameron AJ, Higgins JA. Linear gastric erosion. A lesion associated with large diaphragmatic hernia and chronic blood loss anemia. Gastroenterology. 1986;91: 338-342.
6. Lin CC, Chen TH, Ho WC, Chen TY. Endoscopic treatment of a Cameron lesion presenting as life-threatening gastrointestinal hemorrhage. J Clin Gastroenterol. 2001;33:423-424.