The radiologic evaluation of gross cecal distension: emphasis on cecal ileus

Assessment of predictors of response to neostigmine for acute colonic pseudo-obstruction

OBJECTIVE

Acute colonic pseudoobstruction (ACPO) most commonly develops after surgery, with narcotic administration, or in association with severe illness. Most cases resolve with conservative management. Colonoscopic decompression may be required in patients failing to respond to conservative treatment. Neostigmine has been proposed as an effective treatment for ACPO as an alternative to colonoscopic decompression. We sought to identify factors associated with spontaneous resolution of ACPO and to identify variables associated with a response to i.v. administration of neostigmine for the treatment of ACPO.

METHODS

Retrospective analysis of Mayo Clinic's diagnostic index revealed all patients who developed ACPO between July, 1999 and September, 2001 at the Mayo Clinic Medical Center. We separately analyzed those patients who did not resolve ACPO with conservative management and to whom i.v. neostigmine was administered. Patient records were abstracted for demographic data, etiology of ACPO, management, and response to treatment.

RESULTS

A total of 151 patients were identified with ACPO between July, 1999 and September, 2001; 117 patients (77%) had spontaneous resolution of symptoms. Of the 34 "nonresolvers," 18 patients received neostigmine, whereas 16 did not receive neostigmine. Of those 16 patients, 11 required colonoscopic decompression, two underwent surgery, and three died of underlying illness. "Spontaneous resolvers" were less likely to be taking narcotics (59% vs 74%, p = 0.08). Of the 16 nonresolvers who did not receive neostigmine, only one had a contraindication to neostigmine use. Of the 18 patients that who received neostigmine, 16 patients (89%) had prompt evacuation (<30 min) of flatus or stool. Sustained clinical response to neostigmine was noted in 11 of 18 (61%); the remaining seven patients (39%) required colonoscopic decompression or surgery for recurrent or persistent colonic dilation. Neostigmine-responders were more likely to be older (mean age, 76 yr vs 54 yr, p = 0.03), than nonresponders. Preneostigmine cecal diameter did not differ significantly between responders (median, 12 cm) and nonresponders (median, 13 cm), p = 0.9. Median time to resolution of ACPO in spontaneous resolvers was 4 days compared to 2 days in patients responding to neostigmine; p = 0.038.

CONCLUSIONS

Most patients with ACPO respond to conservative treatment. Female gender and older age are associated with a response to neostigmine in those patients who do not respond to conservative management. Neostigmine appears to be under-used in patients with ACPO who do not have a true contraindication to its use.

Cecal perforation in thermal injury: case report and review of the literature

Gastrointestinal complications in burn patients include ileus, constipation, hemorrhage from ulcerations, ischemic bowel, and rarely, perforations. Patients with hypotensive episodes and sepsis are at risk for developing ischemic bowel disease. There have been three reports in the literature of cecal perforation in burn patients. We present an additional case and review of the literature.

Controlled transperitoneal percutaneous cecostomy as a therapeutic alternative to the endoscopic decompression for Ogilvie's syndrome

Acute colonic pseudo-obstruction, the so-called Ogilvie's syndrome, results in massive colonic dilation without mechanical obstruction. In most cases, a conservative treatment with or without endoscopic decompression is sufficient. In rare cases of relapses or failures, a cecostomy has to be performed. A surgical cecostomy is associated with high morbidity and mortality. However, a percutaneous cecostomy could be an interesting alternative treatment. We report the case of a 67-yr-old male with colonic pseudoobstruction for which both the conservative and the endoscopic treatments were unsuccessful. A percutaneous cecostomy was performed, and for the first time in this indication, a transperitoneal access was used with the help of nylon T-fasteners.

Gastrointestinal problems in the chronically critically ill patient

In summary, a variety of gastrointestinal processes may occur in the chronically critically ill patient population, usually as consequence of the primary systemic process. The clinical presentation is frequently nonclassic and there often is a substantial delay in diagnosis, resulting in increased morbidity and mortality.

Neostigmine infusion: new standard of care for acute colonic pseudo-obstruction?

This study was designed to assess the efficacy of i.v. infusion of neostigmine in patients with acute colonic pseudo-obstruction, which was defined as colonic distention with a cecal diameter of at least 10 cm on plain radiographs and no radiographic evidence of mechanical obstruction. Patients who failed to respond to conventional management (nothing by mouth, nasogastric suction, postural changes, i.v. fluids, electrolyte replacement, and discontinuation of any drugs that affect colonic motility) for 24 h were included in the study. Those with bradycardia (heart rate <60/min), hypotension (systolic blood pressure <90 mm Hg), active bronchospasm, clinical or radiographic evidence of perforation, history of partial colonic resection, active gastrointestinal bleeding, pregnancy, or serum creatinine >3 mg/dL were excluded. Twenty patients were included in this prospective, randomized, double-blind, placebo-controlled study. Eleven patients received neostigmine 2.0 mg i.v. over 3-5 min with electrocardiographic monitoring, and 10 received placebo. Patients were evaluated for immediate clinical response (passage of flatus or stools associated with decreased abdominal distention within 30 min) and sustained response with decreased abdominal girth and reduced colonic dilation on radiographs 3 h after infusion. Ten patients in the neostigmine group had an immediate clinical response (median time, 4 min) compared to none in the placebo group (p<0.001). Three patients in the neostigmine group (27%) and eight in the placebo group (80%) failed to show sustained improvement 3 h after infusion (p = 0.04). Eight patients (one-neostigmine; seven-placebo) who failed to respond received open-label treatment with neostigmine. Seven patients responded; one patient from the placebo group failed and eventually required colonic resection. In conclusion, from a total of 18 patients treated with neostigmine, 17 (94%) had immediate clinical response, and 16 (89%) did not have recurrent colonic dilation. The most common side effect was crampy abdominal pain reported in 13 patients, although usually mild (nine). Symptomatic bradycardia requiring atropine occurred in two patients. Two patients in the neostigmine group died, but death was felt not to be related to acute colonic pseudo-obstruction or its treatment.

Megacolon: Acute, Toxic, and Chronic

Megacolon refers to cecal dilatation above the dimension of 12 cm and above 6.5 cm of the sigmoid colon, measured at the pelvic brim. Dilatation of the colon can be broadly categorized into three clinical entities: In acute megacolon (Ogilvie's syndrome), colonic dilatation is attributed to a sympathetically mediated reflex response to a number of serious medical or surgical conditions in elderly patients. The initial tasks are to exclude mechanical obstruction (with a hypaque enema), to discontinue enabling medications, and to correct metabolic disturbances. Dilatation of the cecum to greater than 12 cm diameter is a cause for grave concern. The rectum should be decompressed with an indwelling tube and tap water enemas. Intravenous neostigmine is generally effective and safe for patients with colonic distention unresponsive to such conservative therapies. Endoscopic decompression is necessary for patients who do not respond to, or relapse after neostigmine, or in whom neostigmine is contraindicated. Signs of peritonitis may imply colonic perforation, and surgery will be needed, often on an emergent basis. Toxic megacolon is secondary to an identifiable inflammation of the colon. Therapy is directed toward specific treatment for the underlying disorder, inflammatory bowel disease, or infectious colitis. Bowel rest and close monitoring of the clinical status is vital. Colectomy may be needed under emergency circumstances. Chronic megacolon may be congenital (due to Hirschsprung's disease) or may represent the end-stage of any form of refractory constipation (slow transit constipation or pelvic floor dysfunction). The initial treatment for Hirschsprung's disease is surgery, while pelvic floor dysfunction and encopresis respond to biofeedback therapy. In chronic idiopathic megacolon, medical measures, such as colonic evacuation with enemas, fiber supplementation, and laxatives may suffice. If severe motor dysfunction is confined to the colon, a subtotal colectomy with an ileorectal anastomosis, or an ileostomy may occasionally be necessary.

Radiographic changes after colonoscopic decompression for acute pseudo-obstruction

PURPOSE

Colonoscopy has been the principal tool for decompression in acute colonic pseudo-obstruction, known as Ogilvie's syndrome. The objectives of this study were to determine the immediate effect of colonoscopy on the cecal diameter (measured on supine radiographs) and to delineate possible correlations in the diameters of dilated segments of the colon.

METHODS

The charts and radiographs of 24 patients who had colonoscopic decompression for acute colonic pseudo-obstruction between 1992 and 1997 at the San Diego Veterans Affairs Medical Center and the University of California, San Diego Hospitals were reviewed. We measured cecal, transverse, descending, and sigmoid colon diameters on serial radiographs up to the point of clinical resolution.

RESULTS

Mean +/- standard deviation cecal diameter change (between initial and post-decompression films) was -2+/-3.4 cm at four hours and -2.2+/-3.3 cm one day after decompression. On the daily radiographs between colonoscopic decompression and clinical resolution, there was a close correlation between the diameter of the cecum and that of the transverse colon (P<0.05). There was no correlation between the cecal diameter and that of the descending or sigmoid colon.

CONCLUSIONS

Colonoscopic decompression only causes a small decrease in cecal size in the patient with acute colonic pseudo-obstruction. Dilation patterns of the cecum and transverse colon are significantly correlated in acute colonic pseudo-obstruction. This correlation provides additional support to the contention that the same pathophysiology affects these two segments of the colon.

Neostigmine for the treatment of acute colonic pseudo-obstruction

BACKGROUND

Acute colonic pseudo-obstruction -- that is, massive dilation of the colon without mechanical obstruction -- may develop after surgery or severe illness. Although it may resolve with conservative therapy, colonoscopic decompression is sometimes needed to prevent ischemia and perforation of the bowel. Uncontrolled studies have suggested that neostigmine, may be an effective treatment.

METHODS

We studied 21 patients with acute colonic pseudo-obstruction. All had abdominal distention and radiographic evidence of colonic dilation, with a cecal diameter of at least 10 cm, and had had no response to at least 24 hours of conservative treatment. We randomly assigned 11 to receive 2.0 mg of neostigmine intravenously and 10 to receive intravenous saline. A physician who was unaware of the patients' treatment assignments recorded clinical response (defined as prompt evacuation of flatus or stool and a reduction in abdominal distention), abdominal circumference, and measurements of the colon on radiographs. Patients who had no response to the initial injection were eligible to receive open-label neostigmine three hours later.

RESULTS

Ten of the 11 patients who received neostigmine had prompt colonic decompression, as compared with none of the 10 patients who received placebo (P<0.001). The median time to response was 4 minutes (range, 3 to 30). Seven patients in the placebo group and the one patient in the neostigmine group without an initial response received open-label neostigmine; all had colonic decompression. Two patients who had an initial response to neostigmine required colonoscopic decompression for recurrence of colonic distention; one eventually underwent subtotal colectomy. Side effects of neostigmine included abdominal pain, excess salivation, and vomiting. Symptomatic bradycardia developed in two patients and was treated with atropine.

CONCLUSIONS

In patients with acute colonic pseudo-obstruction who have not had a response to conservative therapy, treatment with neostigmine rapidly decompresses the colon.

Management and causes of acute large-bowel obstruction

Acute LBO has many possible causes. In the United States, the most common cause is colorectal carcinoma. Mechanical obstruction should be differentiated from pseudo-obstruction by contrast enema or colonoscopy because the treatments differ. The high postoperative mortality and morbidity of LBO compared with elective resection are explained by the multiple associated pathophysiologic changes of obstruction. Management of this condition requires careful assessment, awareness, and expertise in the current modalities of treatment. Gangrene and perforation should be avoided because they limit treatment options and are associated with an increase in mortality. We prefer, in most instances, to perform a single-stage procedure, which has the advantages of reduced hospital stay (and cost) and avoidance of a stoma. However, the appropriate treatment needs to be tailored to the individual situation. Recent developments in nonoperative decompressing procedures may demonstrate advantages in the future.

Ogilvie's syndrome: colonoscopic decompression and analysis of predisposing factors

Forty-eight cases of Ogilvie's syndrome, colonic pseudo-obstruction, presenting between 1983 and 1989 were retrospectively reviewed to assess the results of colonoscopic decompression and to identify potential etiologic factors. Three patients had spontaneous resolution with medical treatment. Forty-five patients required 60 colonoscopic decompressions: 38 (84 percent) were successfully treated using colonoscopy; five (11 percent) required an operation; and two died within 48 hours of colonoscopy from medical causes. No complications or deaths were the result of colonoscopy. Twenty-nine patients (64 percent) were successfully treated with a single colonoscopy. One-third of patients required serial decompressions. Average cecal diameter in patients with successful colonoscopic decompression was 12.4 cm but was larger for patients requiring more than one colonoscopy (13.3 cm) and for those who failed colonoscopic therapy (13.4 cm). The spine or retroperitoneum had been traumatized or manipulated in 52 percent of patients. Patients with Ogilvie's syndrome were being treated with narcotics (56 percent), H-2 blockers (52 percent), phenothiazines (42 percent), calcium-channel blockers (27 percent), steroids (23 percent), tricyclic antidepressants (15 percent), and epidural analgesics (6 percent) at diagnosis. Electrolyte abnormalities included hypocalcemia (63 percent), hyponatremia (38 percent), hypokalemia (29 percent), hypomagnesemia (21 percent), and hypophosphatemia (19 percent). Colonoscopic decompression in Ogilvie's syndrome is safe and effective management. Multiple pharmacologic and metabolic factors, as well as spinal and retroperitoneal trauma, appear to alter autonomic regulation of colonic function, resulting in colonic pseudo-obstruction.

True and false large bowel obstruction

Acute large bowel obstruction can be the result of mechanical causes (such as colorectal cancer) or motility disturbances, the latter being termed colonic pseudo-obstruction. Whatever the aetiology, the pathophysiology of large bowel obstruction has clinical significance. Changes in motility augmented by increased colonic blood flow may play a role in dissemination of tumour cells and/or bacteria. Intravascular fluid depletion, especially shortly after intestinal decompression, has important haemodynamic implications. The diagnosis is often confirmed on plain abdominal X-ray, but water-soluble contrast studies are important in distinguishing a mechanical obstruction (which almost always requires an operation) from a pseudo-obstruction (which can usually be managed without surgery). Mortality and morbidity may be reduced by optimization of the patient's condition both before and after the operation using intensive care facilities and by careful timing of surgery. The surgical management of malignant large bowel obstruction is best directed by a senior surgeon. For tumours up to and including the splenic flexure, an extended right hemicolectomy is advisable since it offers adequate removal of the tumour and allows an immediate safe ileocolic anastomosis. More distal tumours should be resected if possible, and there is much to recommend on-table irrigation and immediate anastomosis, although a colostomy with a mucous fistula or Hartmann's procedure still have a place. Endoscopic diagnosis and decompression enables definitive surgery to be undertaken electively and several techniques are being evaluated. Non-operative reduction of sigmoid volvulus by rigid or flexible endoscopy is achieved with high success rates, but is not recommended for caecal volvulus. Resection is usually necessary in both to prevent recurrence. Mortality of colonic volvulus is closely related to bowel viability. Uncomplicated colonic pseudo-obstruction may be managed medically or by endoscopic decompression. It often occurs in association with systemic medical conditions, which need to be treated vigorously. Surgery is indicated if there are signs of impending or frank perforation, or if non-operative measures fail.

Cecal volvulus

A review of 561 cases of cecal volvulus that were published between 1959 and 1989 along with 7 new cases, was performed to characterize the clinical and laboratory profile and to evaluate the various surgical options in treating this life-threatening condition. The age and sex distribution of these patients have changed over the years and shifted toward older patients (mean, 53 years) and female predominance (female:male ratio, 1.4:1). The clinical presentation was usually of distal closed-loop small bowel obstruction. Forty-six percent of the plain abdominal radiographs were suspected for cecal volvulus, but only 17 percent were diagnostic. Barium enema had a high rate of accuracy (88 percent) and was associated with minimal complications. True volvulus was 6 times more common than bascule, and gangrenous cecum was found in 20 percent of cases. Detorsion alone and cecopexy had almost similar complications, mortality, and recurrence rates (15, 10, and 13 percent, respectively), whereas, resection, which was performed primarily for gangrenous cecum, had higher rates. However, the highest rates of complications (52 percent), mortality (22 percent), and recurrence (14 percent) were noticed after cecostomy. These data suggest that resection should be reserved for patients with necrotic cecum and that detorsion is sufficient for patients with viable cecum. Cecostomy should be abandoned.

CT-guided percutaneous catheter cecostomy

A patient with pseudomembranous colitis is described in whom a percutaneous cecostomy was performed using computed tomographic guidance. Several lines of evidence indicate the safety of this approach, and clinical circumstances are suggested in which the procedure may have potential therapeutic benefit.

Complications of endoscopic gastrostomy: pneumoperitoneum and volvulus of the colon

Pneumoperitoneum caused by percutaneous gastrostomy usually follows a benign clinical course, but led to progressive volvulus of the ileocolic segment in the patient described here. This article explains relationships between pneumoperitoneum after surgical or endoscopic procedures and volvulus involving the intraperitoneally mobile intestinal loops.

Acute colonic pseudo-obstruction (Ogilvie's syndrome). Presentation of 14 of our own cases and analysis of 1027 cases reported in the literature

In addition to the presentation of 14 of our own patients, this study analyzes 1027 cases with acute colonic pseudo-obstruction reported in the literature from 1948 to 1987. Principal associated diseases are cardiopulmonary insufficiencies, postoperative conditions, and systemic disorders. The syndrome is related to a disturbance of colonic autonomic innervation resulting in gross dilatation of the cecum and the right hemicolon. Therapeutic measures include conservative management, colonoscopic decompression, and surgical procedures. The latter have been associated with high morbidity and mortality. Our data support a nonoperative approach to this condition, including conservative measures and colonoscopic decompression as the initial therapy of choice with few complications and high efficacy.