Evaluation of the elderly patient with abdominal pain can be difficult, time-consuming, and fraught with potential missteps . As the population continues to age, the utilization of CT imaging in elderly patients presenting to the ED becomes increasingly important . CT provides a global perspective of the gut, mesenteries, omenta, peritoneum, and retroperitoneum, uninhibited by the presence of bowel gas and fat .
Obtaining a careful medical history and performing a clinical examination are the initial diagnostic steps for patients with acute abdominal pain. On the basis of the results of this clinical evaluation and laboratory investigations, the clinician considered imaging examinations to help establish the correct diagnosis. Findings after using erect abdominal X-ray and abdominal ultrasound were inconclusive, and CT was mandatory for diagnosing the etiology of gastrointestinal pain in the studied cases.
In the current study, acute abdominal pain due to intestinal causes in 42 patients (84%) was more common than due to gastric causes in 8 patients (16%). This is matching with Gardner et al.  among their study on elderly patients with acute abdominal pain which found that intestinal causes (SBO, diverticulitis, appendicitis, bowel ischemia, and colonic obstruction) were the predominant causes of acute abdominal pain.
In the current study, regarding gastric causes of acute abdominal pain in geriatric patients, gastric obstruction was noted in 8 patients (62.5%), while gastric perforation was seen in 3 patients (37.5%); perforated PUD was the main cause of gastric perforation followed by gastric carcinoma. This is in agreement with Hainaux et al.  who reported that the perforation of gasteroduodenal ulcer is much common than perforated gastric carcinoma. Chang et al.  reported that the incidence of peptic ulcer disease is increasing in the elderly owing in part to the increasing availability and use of aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) with high risk of developing complications as perforation.
Based on MDCT findings, intestinal obstruction was the most common intestinal etiology of acute abdominal pain among these geriatric patients which represented 71.4% of intestinal causes followed by acute inflammatory conditions (28.6%), intestinal perforation (23.8%), and acute vascular etiologies (11.9%). Only one patient had colo-cholecystic fistula (2.4%). This is matching with the study done by Pinto et al.  among the elderly patients presented with acute abdominal pain that found bowel obstruction was the commonest etiology followed by inflammatory, perforation, and vascular etiologies.
In the present study, small bowel obstruction more commonly occurred (66.7%) with proximally dilated small bowel loops than large bowel obstruction (33.3%) with proximally dilated large bowel loops. This is in agreement with Gardner et al.  and Hendrickson et al.’s  studies among elderly patients that small bowel obstruction was more common than large bowel obstruction, and Jackson et al.  noted that in patients with intestinal obstruction, the bowel loops are seen dilated proximal to the site of obstruction and decompressed distally.
In the current study, external hernias were the most common causes of small bowel obstruction. This is different from the study of Henry et al.  among the elderly patients that found the main causes for small intestinal obstruction were adhesions followed by hernia. Meanwhile, Hendrickson et al.  reported that hernias are extremely important to recognize in the elderly because this group has a high rate of strangulation and bowel infarction. This difference might be explained as hernias are common among the geriatric population because of loss of strength of the abdominal wall which was seen in 5 cases of the current study as well as majority of the studied patients with small bowel obstruction did not undergo previous abdominal operations; therefore, they did not have a risk for obstruction due to postoperative adhesions; only two patients had adhesions due to prior abdominal surgeries with consequent small bowel obstruction.
In the present study, primary colonic tumors were the most common causes of large bowel obstruction, 5 out of 10 cases of large bowel obstruction (LBO) were due to colonic tumors followed by fecal impaction in 3 cases and sigmoid volvulus in 2 cases. This is matching with Scott et al.  and Lyon et al.  who reported that primary colonic tumor was the most common etiology of LBO in the elderly. On CT basis, tumors showed asymmetrical focal heterogeneous enhancement. This is relatively coping with Sheikh et al.’s  study among bowel diseases that found marked asymmetrical wall thickening and focal bowel wall involvement with heterogeneous enhancement in neoplastic diseases.
In the current study, mechanical bowel obstruction (86.7%) was due to various causes as external hernias, colonic tumors, gall stone ileus, fecal impaction, sigmoid volvulus, postoperative adhesions, intussusception, active Crohn’s disease, phytobezoar, and bowel hematoma; 4 cases were diagnosed by MDCT as gall stone ileus. Similarly, Morano et al.  and Scott et al.  reported that gallstone ileus, which is rare in the general population, is more common in the elderly and can lead to short bowel obstruction (SBO). Maddu et al.  reported that incidence of fecal impaction is increased with age particularly in institutionalized elderly patients and constituted 12% of intestinal obstruction in Henry et al.’s  study among elderly patients.
In the present study, inflammatory etiology represented 28.6% of intestinal causes of acute abdominal pain among the studied patients; most of them were acute diverticulitis and acute appendicitis with subsequent complications which occurred in 66.7% of inflammatory conditions. This is more or less similar to the study done on the elderly patients by Pinto et al.  that found intestinal inflammatory causes of acute abdominal pain to represent 21.8%; Chang et al.  and Storm-Dickerson  both stated that complications of acute diverticulitis and acute appendicitis are more frequent in the elderly.
In the current study, intestinal perforation due to inflammatory causes was more common than due to neoplastic causes. Launay-Savary et al.  reported that colonic perforation in the elderly is most often secondary to complications of diverticular disease, while colonic perforations secondary to cancer are rare. Detection of pneumoperitoneum is of paramount importance for the timely diagnosis of gastrointestinal tract perforation. In the present study, pneumoperitoneum was detected in 7 patients (14%), and 2 out of 7 showed leakage of the oral contrast material on MDCT, surgically proving gastrointestinal tract perforation. This is typically matching with Maniatis et al.’s  report that extraluminal air or extravasation of the oral contrast medium is considered to be the direct sign of GI perforation.
Acute intestinal ischemia was seen as vascular etiology of acute abdominal pain among the studied elderly patients; end-stage irreversible ischemic insults were seen in 3 patients (6%) with occlusive arterial, and venous changes showed pneumatosis intestinalis and coupled with mural non-enhancement correlated with final surgical findings. Only one patient showing reversible bowel ischemia as a sequel to SMV occlusive changes showed diminished bowel enhancement. This is matched with Treyaud et al.’s  findings that stated pneumatosis intestinalis as commonly seen in irreversible ischemic mural changes. Also, presence of portal venous gas is highly diagnostic to ischemic changes, and this in parallel to Millet et al.  who indicate that bowel ischemia was uncommon in elderly patients as an etiology of acute abdominal pain.
One of the main advantages of contrast-based CT studies is assessment of the supplying vessel abnormalities. Patients with suspected vascular insults gain the main benefit. This is matching with the study of Florim et al.  which reported that acute arterial thrombi and emboli may appear as obvious low-attenuation filling defects on contrast-enhanced CT in the SMA lumen and reported that low-attenuation filling defect on contrast-enhanced CT of the superior mesenteric vein has higher specificity values in venous acute mesenteric ischemia. Florim et al.  also reported portomesenteric venous gas as less common but more specific finding of acute bowel ischemia, being present in 3–14% of cases.
Spontaneous intramural bowel hematoma was detected in one elderly patient in the current study with excessive anticoagulant intake, presented with acute abdominal pain. Samie et al.  stated the incidence of spontaneous intramural small bowel hematoma secondary to anticoagulant therapy is predicted to further increase as a result of the wide use of long-term anticoagulation in an aging population.
Summation of the current MDCT findings was correlated with the final diagnosis, whether confirmed by surgical intervention, histopathological examination, or good response to medical treatment. There was only one misdiagnosis; a hypothesized acute diverticulitis and associated colonic wall thickening was highly suspicious for cancer. In this case, the patient underwent further colonoscopy examination, and the following histology excluded cancer. So MDCT has a very high sensitivity of 98% and positive predictive value of 100% in diagnosing the causative pathological condition of acute gastrointestinal pain in these geriatric patients. This is in parallel to Reginelli et al.  who stated that the usefulness of CT in the diagnosis and management of acute gastrointestinal emergencies is well established and confirmed by the results of their study, in which the CT diagnosis correlated with the final diagnosis in very high rate, and Chang et al.  reported that with its proven ability to diagnose a wide variety of conditions, CT remains the diagnostic modality of choice for imaging the acute abdomen in the elderly.