Intestinal pain: causes, warning signs, diagnosis and treatment

Bowel pain is not a distinct disease, but a complaint that can accompany both relatively harmless functional disorders and severe inflammatory, infectious, obstructive, and vascular diseases. The most common clinical scenarios include irritable bowel syndrome, infectious gastroenteritis and colitis, Crohn's disease, ulcerative colitis, diverticular disease, celiac disease, intestinal obstruction, and, less commonly, intestinal ischemia. [1]

For a doctor, it's not just the pain itself and its intensity that are important, but also the entire context: its location, how it started, whether it's associated with bowel movements, eating, stress, bloating, diarrhea, constipation, blood in the stool, weight loss, or nighttime awakenings. It's the combination of these details that allows one to differentiate a functional problem from inflammation, infection, diverticulitis, or intestinal obstruction.

Current guidelines emphasize that not all patients with bowel pain require the same extensive testing. If the complaints fit the typical picture of irritable bowel syndrome and there are no alarming signs, a positive diagnosis can be made, rather than relying on endless exclusion of all possible diseases. [2]

At the same time, it's important to remember that "intestinal" pain, as perceived by the patient, does not always originate from the intestines. Acute appendicitis, urolithiasis, urinary tract infections, pelvic pathology, pain of muscular-ligamentous origin, and even some extra-abdominal conditions can mimic an intestinal source of pain. [3]

The duration of the symptom is of particular importance. Acute abdominal pain is generally considered to be pain lasting less than 7 days and requires the primary exclusion of urgent causes, whereas chronic or recurrent pain more often directs the search toward functional disorders, inflammatory bowel disease, celiac disease, chronic diverticular disease, and other long-term conditions. [4]

Table 1. How the nature of pain helps narrow down the causes

The nature of pain and accompanying symptoms	The most likely search directions
Recurring pain associated with bowel movements, changes in stool frequency or form	Irritable bowel syndrome
Constant severe pain in the lower left abdomen, fever, tenderness on palpation	Acute diverticulitis
Pain along with diarrhea, blood in stool, weight loss, night symptoms	Inflammatory bowel disease, colitis
Cramping pain, bloating, vomiting, lack of stool and gas	Intestinal obstruction
Bloating, chronic diarrhea, nutritional deficiencies, weight loss	Celiac disease, malabsorption syndrome
Pain after an infection or due to stress without warning signs	Post-infectious or functional disorder

The table is compiled based on clinical features described in guidelines for irritable bowel syndrome, diverticular disease, inflammatory bowel disease, celiac disease, and intestinal obstruction. [5]

The main causes of intestinal pain

Irritable bowel syndrome remains the most common cause of recurrent intestinal pain without structural damage to the intestine. It is characterized by recurring abdominal pain, pain associated with bowel movements, and changes in bowel habits, while a standard examination reveals no visible organic damage to the digestive tract. This is not an "imaginary" problem, but a disorder of the interaction between the intestine and the nervous system, which can significantly impair quality of life. [6]

The second major cause is infection and the consequences of a previous infection. In cases of acute abdominal pain, gastroenteritis remains one of the most common reasons for seeking medical attention, and after some intestinal infections, symptoms can persist longer due to post-infectious functional disorders or temporary disruption of the digestion of certain carbohydrates. Therefore, questions about recent diarrhea, fever, travel, water and food quality, and contact with sick people are important. [7]

Inflammatory bowel diseases, primarily Crohn's disease and ulcerative colitis, constitute a separate category. They are characterized by abdominal pain, chronic diarrhea, weight loss, anemia, weakness, and, in ulcerative colitis, often rectal bleeding. These diseases require not only symptomatic treatment, but also long-term monitoring and assessment of inflammatory activity using biomarkers, endoscopy, and imaging techniques. [8]

Diverticular disease, and especially acute diverticulitis, often causes constant rather than intermittent pain, often in the lower left abdomen, sometimes accompanied by fever, bowel changes, and localized tenderness. If complications develop, abscesses, perforations, peritonitis, and intestinal obstruction are possible. Therefore, with typical diverticulitis, it is important not to limit yourself to "home observation" but to assess the risk of complications. [9]

Celiac disease is another cause of chronic intestinal pain and bloating, especially when the pain is associated with chronic diarrhea, nutritional deficiencies, weight loss, anemia, or extraintestinal manifestations. The diagnosis cannot be made solely based on how one feels after giving up bread: serological tests and, usually, a small intestinal biopsy are required for confirmation, and the examination should be performed while on a gluten-containing diet. [10]

The most dangerous causes are intestinal obstruction and intestinal ischemia. Obstruction is characterized by pain, vomiting, bloating, and the inability to pass stool or gas. Ischemia is characterized by sudden pain associated with disruption of the intestinal blood supply, with the risk of rapid progression to necrosis. These conditions are considered emergencies and require immediate hospitalization. [11]

Finally, not all lower abdominal pain indicates bowel disease. When assessing a patient, one must always consider appendicitis, urological pathology, pelvic pain, gynecological causes, abdominal wall pain, and even some extra-abdominal diseases. The less typical the clinical presentation, the more important a broad differential diagnosis is. [12]

Table 2. Main causes of intestinal pain and their clinical clues

Group of reasons	What usually brings to mind her
Functional disorders	The pain is associated with defecation and stool, and there are no alarming signs.
Infectious processes	Acute onset, diarrhea, fever, epidemiological history
Inflammatory bowel disease	Blood in the stool, chronic diarrhea, weight loss, anemia
Diverticular disease	Constant local pain, usually in the lower left abdomen, sometimes fever
Celiac disease and malabsorption	Bloating, chronic diarrhea, deficiencies, weight loss
Obstructive and vascular causes	Severe pain, bloating, vomiting, stool and gas retention, rapid deterioration
Non-intestinal mimics	Atypical localization, urinary, pelvic, extra-abdominal symptoms

The table is based on materials from the National Institute of Diabetes and Digestive and Kidney Diseases in the USA, guidelines from the National Institute for Health and Care Excellence in the UK and a review of acute abdominal pain in adults. [13]

When does intestinal pain become dangerous?

The first and most important warning sign is sudden or severe pain, especially if it develops rapidly or is accompanied by abdominal muscle tension, rigidity, repeated vomiting, severe weakness, or presyncope. This suggests perforation, ischemia, severe obstruction, or another surgical emergency. [14]

The second major set of warning signs relates to blood and inflammation. Blood in the stool, black stool, fever, severe localized tenderness, night pain, rapid weight loss, and anemia shift the patient from probable functional pain to a group where inflammatory bowel disease, infectious colitis, ischemia, tumor, or complicated diverticulitis should be actively sought.

A combination of pain, bloating, vomiting, and failure to pass gas or stool deserves special mention. This is a classic set of symptoms that raises suspicion of intestinal obstruction, especially in people following abdominal surgery, hernias, tumors, or Crohn's disease. In this situation, waiting at home is dangerous. [15]

Persistent pain in the left lower abdomen with fever, tenderness, and sometimes a palpable mass or significant distension requires evaluation for complicated diverticulitis and often same-day hospitalization. This is no longer a scenario where prolonged self-medication with antispasmodics and diet without an examination is acceptable. [16]

In elderly patients and those with vascular risk factors, severe pain with rapid deterioration of general condition should be of particular concern, as the risk of intestinal ischemia is higher in this group. Guidelines for emergency surgery emphasize that delay in this area increases the risk of intestinal necrosis and severe outcomes. [17]

Table 3. Warning signs of intestinal pain

An alarming sign	What needs to be excluded first
Sudden, very severe pain	Perforation, ischemia, acute surgical abdomen
Blood in stool or black stool	Colitis, ischemia, tumor, bleeding
Fever and local tenderness	Diverticulitis, infectious colitis, complicated inflammation
Nighttime symptoms, weight loss, anemia	Inflammatory bowel disease, tumor, malabsorption
Bloating, vomiting, lack of gas and stool	Intestinal obstruction
Rapid deterioration in an elderly patient	Vascular catastrophe, severe obstruction, peritonitis

The table is based on the irritable bowel syndrome, diverticulitis, acute abdominal pain in adults, and bowel ischemia guidelines.[18]

Diagnostics

Diagnosis begins not with a laboratory or CT scan, but with a thorough interview and examination. It is necessary to clarify the duration of pain, its precise location, the nature of the stool, its relationship with defecation and food, episodes of fever, recent infections, abdominal surgery, use of nonsteroidal anti-inflammatory drugs, weight loss, and a family history of inflammatory bowel disease or colorectal cancer. [19]

If the clinical picture is consistent with irritable bowel syndrome and there are no alarming signs, a modern approach allows for a positive diagnosis based on symptoms. In this situation, targeted rather than random testing is essential. In cases with diarrhea, evaluation of fecal C-reactive protein and calprotectin is recommended to differentiate between a functional disorder and inflammatory bowel disease. [20]

If pain is accompanied by bloating, chronic diarrhea, weight loss, or deficiencies, celiac disease should be evaluated. Serological tests are used initially, primarily IgA antibodies to tissue transglutaminase, and if IgA deficiency is suspected, additional IgG tests are used. If serology is positive, the diagnosis is confirmed by endoscopy with duodenal biopsy. A key rule: the examination should be conducted while gluten is being consumed. [21]

Colonoscopy is important, but it's not a universal answer to every intestinal pain. Guidelines recommend against routinely performing it on young patients with typical irritable bowel syndrome without warning signs. However, if there is blood in the stool, anemia, weight loss, or suspected inflammatory bowel disease, tumor, or diverticular bleeding, endoscopy becomes crucial. [22]

Imaging is required when there is a risk of complicated pathology. In acute diverticulitis with suspected abscess or complications, contrast-enhanced CT is recommended. Intestinal obstruction and vascular accidents also require urgent imaging and surgical evaluation. [23]

When inflammatory bowel disease is suspected, diagnosis typically involves a combination of laboratory markers of inflammation, endoscopy, and imaging techniques. New European guidelines emphasize the importance of a comprehensive approach, rather than relying solely on a single test or patient complaints. [24]

Table 4. Step-by-step diagnostic approach

Step	What is being assessed	Why is this necessary?
1	Pain history and physical examination	Distinguish between likely functional and potentially dangerous causes
2	Complete blood count, inflammation markers, basic biochemistry	Look for signs of inflammation, anemia, dehydration, complications
3	Fecal calprotectin for suspected functional pain with diarrhea	Distinguish between irritable bowel syndrome and inflammatory bowel disease
4	Serology for celiac disease	To identify immune damage to the small intestine
5	Colonoscopy according to indications	Confirm inflammatory bowel disease, exclude bleeding, tumor, and other organic matter
6	Computed tomography or other imaging as indicated	Confirm diverticulitis, obstruction, complications, ischemia

The table is based on guidelines for irritable bowel syndrome, celiac disease, diverticulitis, inflammatory bowel disease, and a review of acute abdominal pain in adults.[25]

Treatment

Treatment for intestinal pain should always be specific to the underlying cause. The same symptom may require completely different approaches: from dietary modification and stress management for functional disorders to immunoinflammatory therapy for Crohn's disease, a strict gluten-free diet for celiac disease, or emergency surgery for obstruction and ischemia. Therefore, the main principle is not to "numb the pain," but to understand its source. [26]

If the presentation is consistent with irritable bowel syndrome, treatment typically involves patient education, symptom diary maintenance, dietary modification, and tailoring fiber and medications to the dominant stool pattern. American guidelines support a time-limited trial diet with a reduction in fermentable short-chain carbohydrates and the use of soluble fiber rather than crude insoluble fiber. The approach should be individualized, as different patients respond to different dietary triggers. [27]

Probiotics should not be automatically prescribed as a "must-have" treatment for bloating and distension. The American Gastroenterological Association specifically states that probiotics should not be used routinely for the treatment of bloating and abdominal distension. If a patient has pelvic floor dysfunction, biofeedback may be helpful. [28]

For celiac disease, the mainstay of treatment is a strict, lifelong gluten-free diet under the guidance of a nutritionist. This is not a short-term "gluten-free" regimen, but a permanent strategy that helps reduce symptoms and promote healing of the small intestinal mucosa. Without a confirmed diagnosis, switching to such a diet early is undesirable, as it can complicate subsequent testing. [29]

For diverticulitis, treatment depends on its severity. Some patients with uncomplicated cases can be treated at home, while severe, complicated cases, or those with a high risk of complications require hospitalization. Not all patients with diverticulitis require antibiotics, and for pain relief in this condition, the National Institute of Diabetes and Digestive and Kidney Diseases (NID) recommends that doctors prefer antispasmodics or acetaminophen over nonsteroidal anti-inflammatory drugs (NSAIDs), as the latter increase the risk of complications. [30]

In inflammatory bowel disease, treatment is determined by the activity and extent of inflammation and includes anti-inflammatory, immunomodulatory, and biological approaches, and sometimes surgical treatment of complications. Prolonged self-medication without a confirmed diagnosis is particularly dangerous here, as delayed therapy increases the risk of intestinal damage and systemic complications. [31]

Intestinal obstruction and ischemia are treated in a hospital setting. For obstruction, the basic principles of non-surgical management include complete bowel rest, gastric decompression with a catheter, and intravenous fluid and electrolyte replacement. If these are ineffective or there are signs of ischemia, strangulation, or peritonitis, surgery is required. Intestinal ischemia requires the most rapid restoration of blood flow and assessment of intestinal viability. [32]

The work doesn't end after pain relief. For functional pain, the response to diet and lifestyle is assessed; for celiac disease, dietary adherence and serology; for diverticulitis, the risk of recurrence and complications; and for inflammatory bowel disease, the inflammatory activity and the need for monitoring. Otherwise, temporary relief may be followed by a recurrence or missed serious illness. [33]

Table 5. Treatment principles depending on the cause

Cause	Basic approach
Irritable bowel syndrome	Individualized nutritional adjustments, soluble fiber, time-limited diet with reduction of fermentable short-chain carbohydrates, symptomatic medications
Bloating with functional pain	Don't rely on routine probiotics; if necessary, look for pelvic floor dysfunction
Celiac disease	A strict lifelong gluten-free diet under the supervision of a specialist
Diverticulitis	Severity assessment: some uncomplicated cases can be treated at home, while complicated cases require hospitalization.
Inflammatory bowel disease	Anti-inflammatory and immunomodulatory therapy according to the disease profile
Intestinal obstruction	Inpatient stay, decompression, intravenous fluids, surgery as indicated
Intestinal ischemia	Emergency vascular and surgical tactics

The table is based on the recommendations of the American College of Gastroenterology, the Gastroenterological Association of the United States, the National Institute of Diabetes and Digestive and Kidney Diseases of the United States, and the guidelines of the World Society of Emergency Surgery. [34]

Prevention and prognosis

Prevention depends on the cause, but for diverticular disease, general lifestyle measures have been shown to be important: a diet high in fiber, reduced red meat intake, regular physical activity, smoking cessation, and maintaining a healthy weight. These measures do not guarantee complete protection, but they are associated with a reduced risk of diverticulitis. [35]

For functional bowel pain, relapse prevention typically revolves around recognizing your triggers, maintaining a regular diet, adjusting fiber intake, and discussing targeted dietary restrictions with a specialist. What's important isn't the "strictest diet," but one that truly reduces symptoms and doesn't create deficiencies. [36]

The prognosis also varies. Irritable bowel syndrome often has a chronic and intermittent course, but does not result in visible intestinal destruction. Celiac disease is usually well controlled with strict adherence to a gluten-free diet. Inflammatory bowel disease requires long-term monitoring, and the prognosis for obstruction and ischemia depends largely on prompt recognition and treatment. [37]

The main prognostic error is dismissing any recurring intestinal pain as "just a spasm." If the pain becomes new, more severe, more frequent, begins to wake you at night, is accompanied by blood, vomiting, weight loss, or persistent bloating, the algorithm should shift from observation to active diagnosis.

FAQ

Can intestinal pain be "nervous"?
Yes. In irritable bowel syndrome, pain is associated with a disruption in the interaction between the intestines and the nervous system, not with visible damage to the intestinal wall. However, this conclusion is only valid after assessing warning signs and other causes. [38]

Does everyone need a colonoscopy for these complaints?
No. Routine colonoscopy is not recommended for young patients with typical irritable bowel syndrome without warning signs. It is indicated for the following reasons: blood in the stool, anemia, weight loss, suspected inflammatory bowel disease, tumor, or diverticular bleeding. [39]

What tests are particularly important if celiac disease is suspected?
The first step is serology, primarily antibodies to tissue transglutaminase (ITG) of the immunoglobulin A class, followed by a total IgA assessment and additional tests if necessary. If serology is positive, endoscopy with a duodenal biopsy is usually required. [40]

Do probiotics help with bloating and abdominal pain?
Not in all cases. According to a recent expert review by the American Gastroenterological Association, probiotics should not be used routinely to treat bloating and abdominal distension. [41]

When should you call an ambulance?
In case of sudden, very severe pain, blood in the stool or black stool, repeated vomiting, severe bloating, inability to pass gas or stool, fever with localized severe pain, as well as a rapid deterioration in the condition of an elderly person. [42]

Is it possible to simply eliminate gluten first and see if it improves?
This isn't recommended without a confirmed diagnosis, as a gluten-free diet can distort the results of subsequent celiac disease tests. Test first, then diet. [43]

Key points from experts

Expert	Regalia	Practical thesis
Brian I. Lacy	MD, PhD, FACG, Professor of Medicine, Gastroenterologist, Mayo Clinic	The typical presentation of irritable bowel syndrome requires a positive clinical diagnosis rather than an endless array of tests; in the case of diarrhea, calprotectin and C-reactive protein are advisable, while colonoscopy without alarming signs is not indicated for everyone.
Alberto Rubio Tapia	MD, Director of the Celiac Disease Program at the Cleveland Clinic	Suspected celiac disease should be confirmed in stages: first serology, then biopsy; examination is carried out against the background of gluten consumption
Anne F. Peary	MD, MS, CSc, board-certified gastroenterologist and clinical researcher, diverticular disease specialist	Diverticulitis requires stratification by severity: some uncomplicated cases can be managed without mandatory antibiotics, but complicated forms require imaging and inpatient management.

The table is compiled based on expert profiles and associated clinical guidelines. [44]