Biliary disease, primarily gallstone-related conditions like cholecystitis, is the most commonly identified cause of acute abdominal pain in adults over 65, though bowel obstruction and diverticular disease follow closely behind. The answer shifts depending on whether you are asking about emergency department visits, surgical emergencies, or chronic complaints, and this ambiguity is itself revealing. Abdominal pain in older adults is a different clinical animal than in younger people, with blunted symptoms, atypical presentations, and a wider net of possible diagnoses that can make pinpointing the cause genuinely difficult.
Biliary Disease Leads the List
When researchers look at what actually sends older adults to the emergency department with acute belly pain, gallstone-related problems consistently top the charts. A study of geriatric patients presenting to the emergency department with acute abdominal pain found that biliary diseases and pancreatitis were the most common causes of acute abdomen in this age group.1PubMed Central. Causes of acute abdomen, preferred imaging methods, and prognoses in geriatric patients presenting to the emergency department with abdominal pain Acute cholecystitis, the inflamed gallbladder that typically results from a gallstone blocking the cystic duct, is one of the most common conditions requiring emergency surgery in the elderly.2PubMed Central. Acute Cholecystitis in Very Elderly Patients: Disease Management, Outcomes, and Risk Factors for Complications
Why gallstones become so prevalent with age comes down to decades of bile chemistry slowly shifting. The gallbladder concentrates bile less efficiently as you get older, and cholesterol saturation in the bile increases over time. The result is that gallstones quietly accumulate. Many older adults have had gallstones for years without knowing it. The trouble starts when a stone lodges in the wrong spot, causing sudden pain in the upper right abdomen, often with nausea and sometimes fever. In younger patients, this presentation is usually textbook. In older adults, the pain can be vague or even absent, which is a problem we will come back to.
Diverticular Disease and Its Complications
While biliary disease is the most common acute cause, diverticular disease is arguably the most common underlying structural problem in the older gut. Diverticula, the small pouches that bulge outward through the colon wall, are present in roughly two-thirds of people aged 65 and older.3PubMed. Diverticular disease in the elderly Most people with diverticula never know they have them. The pouches sit there quietly and cause no symptoms at all. But somewhere between one in ten and one in four people who have diverticula will eventually develop diverticulitis, which is the infection or inflammation of one or more of those pouches.3PubMed. Diverticular disease in the elderly
Diverticulitis typically announces itself with left-lower-quadrant pain, fever, and changes in bowel habits. In mild cases, antibiotics and a temporary change in diet are enough. But older adults are at higher risk for severe diverticulitis, and predictive factors for a complicated course include advanced age, obesity, and a weakened immune system.3PubMed. Diverticular disease in the elderly Severe cases can lead to abscess formation, perforation, or strictures that partially block the colon. Because so many older adults harbor diverticula, even a low complication rate translates into a large absolute number of people affected.
Bowel Obstruction as a Surgical Emergency
When the question shifts from “most common cause of abdominal pain” to “most common reason for emergency abdominal surgery,” the answer changes. Bowel obstruction is the leading cause of emergency surgery in older adults, with a higher proportion of colonic obstructions compared to younger patients, driven in particular by obstructive colorectal cancer and sigmoid volvulus.4PubMed Central. CT of acute abdomen in the elderly In a large CT-based study, bowel obstruction accounted for about 9% of diagnoses in patients scanned for acute abdominal pain.5PubMed. Acute abdominal pain: diagnostic impact of immediate CT scanning
Bowel obstruction in older adults is particularly dangerous because the causes tend to be more serious than in younger patients. In a younger person, a small-bowel obstruction is often caused by adhesions from a prior surgery and may resolve without an operation. In an older patient, colonic obstruction from a tumor or a twisted segment of sigmoid colon often requires surgical intervention. The time between symptom onset and hospital admission is a strong predictor of death in these cases.6PubMed Central. Mortality associated with emergency abdominal surgery in the elderly That means delays in seeking care, which are common in older adults for reasons discussed below, can turn a treatable problem into a fatal one.
Constipation and Fecal Impaction
Not every cause of abdominal pain in older adults is dramatic. Constipation is probably the single most under-discussed source of chronic abdominal discomfort in this age group. The basic motility of the gut does not change much with aging on its own, but constipation and fecal incontinence do become significantly more prevalent with age. When constipation becomes severe and prolonged, the result can be fecal impaction, a hardened mass of stool that cannot pass. Fecal impaction is a common cause of lower gastrointestinal tract obstruction, trailing only strictures from diverticulitis and colon cancer.7PubMed Central. Fecal impaction: a cause for concern?
The issue is compounded by the medications many older adults take. Opioid pain medications, certain blood pressure drugs, iron supplements, and anticholinergic medications all slow the bowel. Add in reduced physical activity, lower fluid intake, and a diet that may lack fiber, and the setup for chronic constipation is nearly universal in some institutional settings like nursing homes. In rare but alarming cases, chronic constipation in older adults can progress to stercoral perforation, where the pressure of impacted stool actually ruptures the colon wall. This is an uncommon but potentially fatal complication that predominantly affects elderly individuals.8PubMed Central. Sigmoid colon perforation presumed to be stercoral in origin in an elderly patient with chronic constipation: a case report
Why Abdominal Pain Looks Different in Older Adults
One of the most important things to understand about abdominal pain in older adults is that it frequently does not look the way you would expect. Aging changes how the body perceives and communicates pain. Older patients with diseases of visceral organs are much more likely than younger adults to present atypically, and the absence of pain has been documented in conditions as serious as heart attacks, perforated ulcers, and collapsed lungs. This is not a minor clinical footnote. It means that by the time an older person feels enough pain to seek help, the underlying problem may be significantly more advanced than it would be in a younger person presenting with the same disease.
The reasons for this blunted pain response are not fully understood, but they appear to involve changes in how the nerves lining the abdominal organs detect and transmit pain signals. The practical consequence is that older adults with genuinely dangerous surgical conditions, like a perforated appendix or a strangulated hernia, may walk in complaining of mild discomfort rather than the severe pain a younger person would report. This is why clinicians who work in emergency medicine learn to treat even moderate abdominal pain in an older patient as potentially serious. The severity of the pain does not reliably track with the severity of the disease.
Appendicitis in Older Adults
Appendicitis is often thought of as a young person’s disease, but it occurs across all ages and is particularly treacherous in older adults. The challenge is that classic appendicitis symptoms, sharp pain starting near the navel and migrating to the lower right abdomen, often do not appear in older patients. Many present with vague, diffuse abdominal pain that does not point clearly to the appendix. More than half of elderly patients with appendicitis had been experiencing symptoms for more than two days before hospital admission, and most cases were found to be perforated by the time of operation, with abscesses present in more than a third of patients.9JAMA Surgery. Outcome of Elderly Patients With Appendicitis: Effect of Computed Tomography and Laparoscopy
A separate study found that the appendix was perforated in about 41% of elderly appendicitis patients, with the delay between symptom onset and hospital arrival being the single most important risk factor for perforation.10PubMed Central. Acute appendicitis in the elderly: risk factors for perforation Compare that to younger adults, where perforation rates at the time of surgery are substantially lower. The combination of atypical symptoms and delayed care means that appendicitis in older adults has a much higher complication rate and a higher mortality rate than in younger patients. It is one of the clearest illustrations of why the same disease can be much more dangerous in an aging body.
When the Problem Is Not in the Abdomen at All
One of the trickiest aspects of evaluating abdominal pain in older adults is that the source of pain may not be in the abdomen. The heart, lungs, and even the spine can produce pain that is felt in the belly. For older adults with significant atherosclerosis, vascular problems like aortic dissection or acute myocardial infarction are real considerations when someone walks in complaining of abdominal pain. These are among the deadliest diagnoses that can hide behind what initially looks like a stomach problem.11PubMed Central. Abdominal emergencies in the geriatric patient
Heart attacks deserve special attention here. A heart attack can present with upper abdominal pain, nausea, and vomiting and nothing else, particularly in older adults, women, and people with diabetes. Abdominal pain accompanied by a normal initial electrocardiogram can mask an underlying heart attack, and when that cardiac origin is missed, the results can be fatal.12Journal of Anesthesia & Pain Medicine. Massive Myocardial Infarction Presenting With Abdominal Pain and Non-Specific ECG Findings: A Fatal Case Report Pneumonia and pulmonary embolism can also trigger abdominal symptoms, as can referred pain from the hips or genitourinary system. This means that a thorough evaluation of abdominal pain in an older adult often includes an ECG, chest imaging, and blood work looking well beyond the gut.
Medications as a Hidden Cause
The average older adult takes multiple prescription medications, and several common drug classes can cause or contribute to abdominal pain. Non-steroidal anti-inflammatory drugs like ibuprofen and naproxen are among the most commonly prescribed pain medications, and they are well known for causing gastrointestinal problems, including stomach ulcers and bleeding.13PubMed Central. A Comprehensive Review of Non-Steroidal Anti-Inflammatory Drug Use in The Elderly In an older adult whose stomach lining is already thinning with age, even short courses of these drugs can trigger erosions or full-blown ulcers.
Beyond NSAIDs, opioid painkillers slow the bowel and contribute to the constipation and impaction discussed earlier. Blood thinners like warfarin and the newer direct oral anticoagulants can cause bleeding in the gut or, less commonly, a rectus sheath hematoma, which is a collection of blood in the abdominal wall muscles that can mimic an intra-abdominal emergency. Metformin, a widely prescribed diabetes medication, causes abdominal cramping and diarrhea in a meaningful fraction of users. Iron supplements are notorious for causing constipation and dark, tarry stools. When an older adult presents with new abdominal pain, one of the first questions a clinician should ask is what medications they are taking and whether anything has changed recently.
How CT Scanning Changed the Diagnostic Picture
Computed tomography has become the backbone of diagnosing acute abdominal pain. CT is considered the primary imaging technique for acute abdominal pain because it provides an accurate and reproducible diagnosis, and its findings have a marked effect on treatment decisions. The one notable exception is suspected acute cholecystitis, where ultrasound is the preferred first-line imaging study.14PubMed. Imaging patients with acute abdominal pain
In a large study of over 2,200 patients who underwent CT for acute abdominal pain, the scan produced a correct diagnosis in about 97% of cases.5PubMed. Acute abdominal pain: diagnostic impact of immediate CT scanning That study also gives a useful snapshot of what causes acute abdominal pain across all ages: the single largest category, at about 44%, was “nonspecific abdominal pain,” meaning the CT did not find a clear surgical or medical cause. Appendicitis came next at roughly 16%, followed by bowel obstruction, diverticulitis, urological causes, pancreatitis, and gallstone disease. In older adults specifically, the mix shifts toward more bowel obstruction, more biliary disease, and more vascular catastrophes compared to younger patients.
The value of CT scanning is especially high in older adults because the physical exam is less reliable. With blunted pain responses and a higher prevalence of cognitive impairment that can make it hard for patients to describe their symptoms precisely, the clinician is often navigating with incomplete information. A CT scan can reveal an inflamed gallbladder, a bowel obstruction, free air from a perforation, or an aortic aneurysm before the clinical picture has fully declared itself. For older adults with acute abdominal pain, there is a strong argument that imaging early rather than waiting and watching improves outcomes.
Mesenteric Ischemia and Abdominal Aortic Aneurysm
Some causes of abdominal pain in older adults are uncommon but carry an extremely high mortality rate, and missing them is catastrophic. Mesenteric ischemia occurs when the blood supply to the intestines is suddenly cut off, usually by a blood clot. The classic description is “pain out of proportion to exam,” meaning the patient is in severe distress but the abdomen feels relatively soft and non-tender on physical examination. By the time the bowel begins to die and signs become more obvious, the window for effective treatment has often closed. Mesenteric ischemia and abdominal aortic aneurysm are among the deadliest causes of abdominal pain in the elderly.11PubMed Central. Abdominal emergencies in the geriatric patient
Abdominal aortic aneurysm, an abnormal ballooning of the body’s largest artery, can rupture without warning. When it does, the patient may feel sudden severe back or abdominal pain, and the situation becomes a race against time. Many ruptured aneurysms are fatal before the patient reaches the operating room. Screening programs using ultrasound have helped identify some of these aneurysms before they rupture, but the condition remains a concern particularly in older men with a history of smoking. These vascular emergencies are worth knowing about not because they are common, but because they are the diagnoses where a few hours of delay can mean the difference between life and death.
Why Delays Are So Dangerous in This Age Group
A recurring theme across nearly every cause of abdominal pain in older adults is the danger of delay. The interval between symptom onset and hospital admission is a significant predictor of death after emergency abdominal surgery in the elderly.6PubMed Central. Mortality associated with emergency abdominal surgery in the elderly Older adults delay seeking care for several overlapping reasons. Pain perception is blunted, so the early warning system is weaker. Older adults may attribute symptoms to “something I ate” or dismiss them as part of normal aging. People living alone may not have someone who notices they look unwell. Those with cognitive impairment may struggle to communicate what they are feeling or may not recognize the significance of new symptoms.
The result is that abdominal emergencies in older adults are consistently diagnosed later, are more advanced at the time of treatment, and carry a higher mortality rate than the same conditions in younger patients. This is not inevitable. Knowing that abdominal pain in an older adult deserves prompt medical attention, even when it seems mild, can change outcomes. If you are caring for an older family member and they mention stomach pain that is new, persistent, or accompanied by vomiting, fever, or a change in bowel habits, that warrants a call to their doctor or a trip to the emergency room sooner rather than later. The wait-and-see approach that works well for a 30-year-old with a stomachache is a poor strategy for someone in their 70s or 80s.
Rectus Sheath Hematoma and Other Mimics
Not every cause of abdominal pain originates from an organ inside the abdominal cavity. Rectus sheath hematoma, a bleeding event within the muscles of the abdominal wall, is an uncommon but real cause of acute abdominal pain that can mimic a wide variety of intra-abdominal disorders, frequently leading to delayed treatment or even unnecessary surgery. It is particularly relevant in older adults who take blood-thinning medications, where even minor strain or a coughing fit can trigger bleeding into the abdominal wall musculature. The condition is usually diagnosed on CT and managed without surgery, but the initial presentation can be alarming and confusing.
Herpes zoster, or shingles, can also produce abdominal pain before the characteristic rash appears. When the virus reactivates along nerves that supply the abdominal wall, the resulting pain can precede the visible skin lesions by days, leading to investigations for an intra-abdominal cause that is not there. In older adults with unexplained abdominal wall pain, particularly if it follows a band-like distribution on one side, shingles should be on the list of possibilities. These non-organ sources of pain are easy to miss when the reflex is to look inside the abdomen, and recognizing them can spare patients unnecessary imaging, procedures, and worry.