Gastrointestinal ileus is defined as a pathologic reduction or absence of intestinal peristalsis. Postoperative ileus is common after surgery in all age groups [88], but elderly patients are particularly sensitive to disturbances in intestinal motility [72]. The pathophysiology of ileus is multifactorial, owing primarily to neurogenic, inflammatory, and enteroendocrine factors [89]. Risk factors for the this condition include advanced age, extensive bowel manipulation, narcotic-type analgesics, and general anesthesia [90]. Furthermore, the intestines are susceptible to age-related neuronal degeneration, placing the geriatric patient at profound risk of prolonged ileus [10, 70, 71].

Signs and symptoms of ileus include lack of flatus, abdominal distention, nausea, and emesis. Postoperative ileus is most pronounced within the large bowel; therefore, flatus is a common sign indicating return of bowel function. Peristalsis within the small intestine and stomach returns to normal within the first postoperative day, but colonic peristalsis may be stunted upward for 72 h [91].

Postoperative ileus is a clinical diagnosis, and its management is largely supportive. Bowel rest and fluid resuscitation are the mainstay of therapy until bowel function returns spontaneously. Nasogastric decompression is theorized to mitigate the risk of aspiration pneumonia in patients with recurrent emesis, though this fact remains debated. Early ambulation is often implemented under the notion that physical motion may stimulate intestinal motility. Minimizing the use of narcotic medications may also accelerate the return of bowel function.

Alvimopan (Entereg), a peripherally acting mu-receptor antagonist, is the only FDA-approved medication for accelerated return of bowel function [92]. Since opioid medications impede gastrointestinal motility, in theory, peripheral opioid receptor blockade should have the reverse effect. Many studies have analyzed the efficacy of alvimopan on bowel function, with varying results. One multicenter, phase III trial found significantly accelerated return of bowel function and shorter hospital length of stay (LOS) with the use of alvimopan in patients undergoing major abdominal surgery [93]. A separate trial in urologic patients also found significantly decreased hospital LOS, as well as reduced cost per admission [94]. In patients undergoing laparoscopic gastrointestinal surgery, alvimopan reduced the risk of postoperative ileus by 75 %, though there was no significant effect on overall LOS [95]. Colorectal surgical patients benefited highly from alvimopan, with faster return of bowel function, lower incidence of postoperative ileus, shorter hospital LOS, and reduced cost [96]. Further trials may elucidate the optimal use of this promising medication.

Acute intestinal pseudo-obstruction, or Ogilvie syndrome, is an acute-onset, massive colonic dilation in the absence of mechanical obstruction. It is a severe form of gastrointestinal ileus limited to the large bowel. Its pathophysiology is multifactorial and primarily attributed to enteric dysautonomia [97]. Risk factors for Ogilvie syndrome include advanced age (>60 years), trauma, abdominal surgery, orthopedic surgery, severe medical illness, metabolic derangements, and use of narcotic medications [98]. Thus, like ileus, geriatric trauma victims are at significant risk for developing this condition.

The most feared complication of Ogilvie syndrome is bowel perforation. Once intraluminal pressure exceeds capillary perfusion pressure, the colon is at risk of venous congestion, with resultant tissue ischemia, bowel perforation, intra-abdominal sepsis, and, possibly, death. With timely diagnosis and treatment, mortality rates are less than 20 %. However, this increases to greater than 40 % with delayed recognition and bowel perforation [98]. Therefore, early diagnosis is crucial to patient survival.

Initial evaluation with abdominal X-ray will reveal massive dilation of the colon. Cross-sectional CT imaging can confirm the diagnosis and, more importantly, rule-out secondary causes of obstruction.

Management of Ogilvie syndrome is similar to that of ileus. This includes bowel rest, nasogastric decompression, fluid resuscitation, correction of electrolyte imbalances, and minimizing use of narcotic medications. When cecal diameter reaches 12 cm, the risk of bowel ischemia increases markedly, necessitating chemical or mechanical decompression [99]. Neostigmine, a potent parasympathomimetic drug, stimulates intestinal motility and quickly decompresses the colon [100]. Because geriatric patients are prone to neostigmine-induced arrhythmias, including bradycardia, cardiac telemetry is advised prior to administration [101]. Symptomatic bradycardia is treated with atropine [102]. If neostigmine is ineffective or contraindicated, then endoscopic decompression is warranted [103]. Any evidence of peritonitis or bowel perforation requires surgical exploration.

Gastrointestinal diseases, such as hemorrhage and motility disorders are much more prevalent among the elderly. Each of these conditions carries significantly higher rates of morbidity and mortality in the older adult. Timely diagnosis and proper management are critical to good outcomes.