What should I do if I have lower abdominal pain?

Management of Lower Abdominal Pain

For acute lower abdominal pain with fever and leukocytosis, obtain CT abdomen and pelvis with IV contrast as the initial imaging study, as it provides the highest diagnostic accuracy (sensitivity 85.7-100%, specificity 94.8-100%) for identifying surgical emergencies like appendicitis and alternative diagnoses. 1

Initial Diagnostic Approach Based on Location and Patient Demographics

Right Lower Quadrant Pain

• CT abdomen and pelvis with IV contrast is the preferred initial test for most patients with suspected appendicitis, achieving sensitivities of 85.7-100% and specificities of 94.8-100%. 1
• The use of preoperative CT reduces negative appendectomy rates from 16.7% (clinical evaluation alone) to 8.7%. 1
• For premenopausal women with suspected gynecologic pathology, start with pelvic/transvaginal ultrasound before proceeding to CT. 2
• Ultrasound alone for appendicitis has lower sensitivity (51.8-87.1%) and may miss the appendix in 27.7-45% of cases. 1

Left Lower Quadrant Pain

• CT abdomen and pelvis with contrast is the preferred initial imaging for suspected diverticulitis, as it detects complications like perforation, abscess, or fistula and identifies alternative diagnoses. 2
• Plain radiography has limited sensitivity and is not useful as an initial test. 2
• For premenopausal women, consider pelvic/transvaginal ultrasound first if gynecologic pathology is suspected. 2

Management of Chronic or Functional Abdominal Pain

First-Line Treatments

• Antispasmodics (hyoscine butylbromide or dicyclomine) are first-line for pain relief, particularly when triggered by eating or bowel spasms. 3
• Peppermint oil ranks third in efficacy for abdominal pain relief in network meta-analyses. 1
• Implement dietary modifications: eliminate lactose, alcohol, and high-osmolar supplements; eat frequent small meals of easily digestible foods (bananas, rice, applesauce, toast). 3
• Start soluble fiber (ispaghula) at 3-4g/day, gradually increasing to avoid bloating; avoid insoluble fiber like wheat bran. 3

Second-Line Neuromodulators for Persistent Pain

• Tricyclic antidepressants (TCAs) rank first for abdominal pain relief and should be the first choice for neuromodulation. 1
• Start amitriptyline 10mg once daily at bedtime, titrating slowly to 30-50mg based on response. 3
• TCAs work through central pain modulation and may cause constipation, which can be beneficial in diarrhea-predominant conditions. 1
• SSRIs are less effective for direct pain reduction but may help global symptoms and should be used if mood disorders are present or TCAs are not tolerated. 1
• SNRIs are useful alternatives, particularly in patients with psychological comorbidity, though evidence in abdominal pain is limited. 1

Condition-Specific Pharmacotherapy

For IBS with Constipation:

• Linaclotide 290 mcg once daily ranks first for abdominal pain reduction. 1
• Tenapanor 50 mg twice daily ranks second. 1

For IBS with Diarrhea:

• Ramosetron 2.5 mcg daily ranks first (available only in Asia). 1
• Alosetron 1 mg twice daily ranks third. 1
• Rifaximin is not superior to placebo for pain specifically. 1
• Eluxadoline is effective but contraindicated in patients with prior cholecystectomy, sphincter of Oddi problems, alcohol dependence, pancreatitis, or severe liver impairment. 1

Critical Pitfalls to Avoid

• Never use opioids for chronic abdominal pain—they cause addiction and paradoxically amplify pain sensitivity through central mechanisms. 3
• Do not dismiss pain as "not real" when inflammation resolves; explain that allodynia (innocuous stimuli perceived as painful) and hyperalgesia (exaggerated pain response) are real neurobiological phenomena requiring different treatment approaches. 1
• Recognize that central sensitization can maintain pain even without ongoing peripheral stimulation, requiring neuromodulators and brain-gut behavioral therapies rather than continued anti-inflammatory treatment. 1
• Ultrasound may miss non-gynecologic causes of left lower quadrant pain that CT would detect. 2

When to Suspect Abdominal Wall Pain

• If pain is chronic, unremitting, unrelated to eating or bowel function, but related to posture (lying, sitting, standing), suspect abdominal wall origin. 4
• Perform Carnett's sign: if tenderness is unchanged or increased when abdominal muscles are tensed, the abdominal wall is the likely source. 4
• Inject local anesthetic with or without corticosteroid into the trigger point for both diagnosis and treatment. 4

Multidisciplinary Approach for Refractory Pain

• Patients at highest risk for chronic pain include those with history of chronic pain, early-life trauma, catastrophizing, pre-existing anxiety/depression, or prior negative pain experiences. 1
• Baseline therapy includes breathing techniques and low-dose TCAs or SNRIs managed by gastroenterologists. 1
• For limited response, add cognitive behavioral therapy (best for patients with insight into thought-pain relationships) or gut-directed hypnotherapy (best for visceral hypersensitivity, unless severe PTSD is present). 1
• Defer choice of psychological therapy modality to mental health professionals with chronic pain experience. 1

Special Consideration: GLP-1 Agonist-Related Pain

• For patients on semaglutide with new abdominal pain, obtain CBC, CMP, and serum amylase/lipase to evaluate for pancreatitis. 5
• Consider CT scan to rule out pancreatitis, bowel perforation, portal vein thrombosis, or ischemic colitis. 5
• For confirmed pancreatitis, permanently discontinue semaglutide. 5
• For mild symptoms without pancreatitis, temporarily discontinue and provide supportive care; consider antispasmodics or low-dose TCAs for visceral pain. 5