More than 20 % of emergency abdominal surgery is performed for intestinal obstruction and of these small bowel obstructions outweigh colonic obstructions by a 3 a 1 margin [3]. Across all ages, adhesions and hernias remain the two most common causes of small bowel obstruction and this has remained remarkably constant over time since a review from well over 100 years ago to a more recent review document that these are the two dominant etiologies of bowel obstruction [3]. In a geriatric patient, the three most common sources of intestinal obstruction are postoperative adhesions with the highest prevalence seen following colorectal and pelvic operations, incarcerated or strangulated hernias, and neoplasms. Bowel obstruction in the elderly is a very serious condition since it must be remembered that greater than half the deaths in obstructed patients occur after the age of 65. In accordance with an aging population, the peak age of patients undergoing operation for intestinal obstructions has risen to the seventh decade [4]. In light of the fact that over 30 % of our population will be over the age of 65 by the year 2030, it is very likely that an even larger percentage of patients requiring admission and intervention for intestinal obstruction will be of advanced age.

Other causes of small intestinal obstruction in the elderly that are less common but must be considered include small bowel tumors, both primary and secondary from metastatic melanoma or direct invasion from colon cancers, Crohn’s disease, volvulus, intussusception, internal hernia, bezoar formation, strictures, and gallstone ileus. While primary small bowel tumors only make up approximately 5 % of all gastrointestinal neoplasms, intestinal obstruction is the most frequent presenting sign of a host of neoplastic processes including small bowel lymphomas, stromal tumors, carcinoid tumors, adenocarcinomas, and metastases [5]. Gallstone ileus resulting from cholecystoenteric fistula and subsequent stone impaction in the terminal ileum is a particularly interesting etiology that almost exclusively presents in the elderly population and accounts for 1–4 % of mechanical intestinal obstructions [6]. Patients that suffer from gallstone ileus also tend to be debilitated and have significant comorbidities and diagnosis can be challenging. Small bowel obstruction in the elderly patient with no prior history of surgery and no hernias should raise the possibility of gallstone ileus or malignant obstruction, but the finding of air in the biliary tree is pathognomonic of gallstone ileus.

Colonic obstructions are significantly more prevalent in elderly patients rather than younger patients. In developing nations, where the dietary intake of crude fiber is very high, colonic volvulus and specifically sigmoid volvulus is a major etiology of large bowel obstructions. Many years ago this was also true in the United States but now colonic tumors are by far the most common etiology of large bowel obstruction followed by inflammation from repeated episodes of diverticulitis, ischemic stricture, and incarcerated hernias. The sigmoid colon is the most frequent location of obstructing colon cancers, and in general the likelihood of a cancer-causing obstruction increases as its location moves distally. Other important causes of large bowel obstruction include the functional, nonmechanical etiologies that are generally pertinent only to those of advanced age with significant debilitation, namely, colonic pseudo-obstruction, also known as Ogilvie’s syndrome. The approach to treatment of colonic dysfunction is very different from that of mechanical causes of obstruction and will be discussed later in detail. Lastly, in the elderly population constipation and stool impaction are not trivial causes of colonic obstruction and must be considered in the differential diagnosis.

Patients with intestinal obstruction pose significant diagnostic challenges due to the varied nature of how the patient presents. In order to create a systematic approach to the patient with suspected obstruction, all signs and symptoms of obstruction should be considered separately. The most specific symptom of bowel obstruction is a prolonged period without bowel function, namely, a complete cessation of the production of flatus or stool. Every effort should be made when obtaining a history of present illness to determine from the patient or family members when the last signs of bowel function occurred and also to gather an estimate of how often the patient’s bowel function normally occurs as in the elderly this can be quite variable. Additional commonly reported symptoms include abdominal pain that is colicky in nature but that can progress to more diffuse, severe, and constant pain, which is typically accompanied by nausea and emesis. Depending on the location of the obstruction, the emesis can range from minimal, as with proximal obstructions, to voluminous as seen with distal pathology. In the case of gastric volvulus, there can be severe retching but almost little or no production of vomitus. More distal obstructions tend to produce large emesis since in addition to whatever food or fluid has been consumed, the proximal gastrointestinal tract makes several liters of secretions when the summation of gastric, biliary, duodenal, and pancreatic secretions are considered and contribute to the amount of emesis. Feculent emesis due to long-standing pooling and bacterial overgrowth of intestinal contents proximal to an obstruction is not an unusual finding. Cheadle’s review on “The importance of early diagnosis of small bowel obstruction” found abdominal pain and vomiting to be the most commonly noted symptoms in 92 and 82 % of patients, respectively, in a review of 3,000 patients presenting with bowel obstruction [7]. There are also several less-specific symptoms frequently reported that are likely related to dehydration and lack of nutritional intake associated with obstruction including fatigue, general malaise, and weakness.

Abdominal tenderness and distention are the two most commonly noted and classical physical findings of intestinal obstruction. In multiple investigations and reviews, it is unclear which of these two findings is more commonly present, but regardless they are each seen in greater than half of patients with obstruction [7]. Distention though tends to be less noticeable in more proximal obstructions such as gastric volvulus, gastric outlet obstruction, duodenal obstruction, and jejunal obstruction, while more distal obstructions such as small bowel obstruction due to adhesions or hernias involving the ileum, cecal volvulus, colonic masses, and colonic pseudo-obstruction can lead to marked and impressive distention due to large volumes of air and fluid that can accumulate in the gastrointestinal tract. Abdominal tenderness implies irritation of the peritoneal surfaces and in the initial stages is usually due to the apposition of a dilated viscus against the peritoneum.

While it is difficult to quantify, it is important to evaluate the degree of the presenting symptoms and signs to aid in determining what surgical process is occurring. Patients with partial obstructions often report a decrease in their stool production or frequency or that they have recently developed intermittent loose stools and do not report total and prolonged obstipation as is more commonly reported by patients with complete obstructions. Patients with partial obstructions tend to present with relapsing and remitting degrees of tolerance of oral intake or that they have altered their diet to take mainly liquids as they feel this does not lead to as much abdominal pain as taking solid food. Conversely patients with strangulated intestinal obstruction with resulting ischemic bowel that requires urgent surgical intervention tend to present with greater degrees of abdominal tenderness and even peritonitis. While all patients should be assessed carefully, it is true that peritoneal signs such as abdominal guarding and rebound tenderness have been shown to be present in less than 50 % of patients with small bowel obstruction and are also of limited sensitivity and specificity in detecting strangulation [8, 9]. While nonspecific, the general appearance of patients harboring ischemic intestine from obstruction is often ominous and patients can appear in significant distress and discomfort, as well as appear diaphoretic.

Unfortunately there is no set of symptoms, signs, or any criteria that can be utilized to determine the presence of nonviable bowel due to obstruction, but presenting vital signs may yield important clues. Tachycardia can be due to dehydration and hypovolemia related to obstruction, pain, or marked inflammation and cytokine release from ischemic intestine. Fever can also be an ominous vital sign derangement, but much like tachycardia it has been shown in multiple reviews to have no significant correlation to the presence of nonviable intestine. As mentioned above, the entire presentation of the patient with suspected intestinal obstruction including symptoms and signs needs to be assimilated to establish a differential diagnosis that includes intestinal obstruction and to determine the degree of surgical urgency of an obstruction. This is reflected in Stewardson’s 1978 hallmark review of the records of 238 patients with small bowel obstruction; the 4 “classical” findings of leukocytosis, tachycardia, fever, and localized tenderness were examined, and when none were present patients could be safely managed nonoperatively initially without significant morbidity or mortality [10].