Differential Diagnosis for Chronic Abdominal Pain
Gastrointestinal Causes
The differential diagnosis for chronic abdominal pain is extensive and must be systematically organized by organ system, with functional disorders considered only after organic pathology is confidently excluded. 1
Upper Gastrointestinal
- Chronic pancreatitis - most common pancreatic cause of chronic left upper quadrant pain 2
- Peptic ulcer disease - frequently misdiagnosed and overtreated in primary care 3
- Gastritis and gastroesophageal reflux disease 4
- Gastric malignancy - must be excluded in patients with alarm features 1
Hepatobiliary
- Chronic cholecystitis - right upper quadrant predominance 5
- Biliary dyskinesia 4
- Hepatic pathology including chronic hepatitis and cirrhosis 6
Small and Large Intestine
- Crohn's disease - particularly when isolated to small bowel; capsule endoscopy warranted in patients without strictures when suspected 5
- Diverticulitis - though more common in left lower quadrant, can cause left upper quadrant pain 2
- Small bowel obstruction - partial or intermittent 5
- Celiac disease - diagnosed by endoscopy with duodenal biopsies, not capsule endoscopy 5
- Mesenteric ischemia - consider in patients with diffuse pain and vascular risk factors 5, 6
- Colorectal malignancy 4
Functional Disorders
- Irritable bowel syndrome - diagnosis of exclusion after organic pathology confidently ruled out 5, 1
- Functional dyspepsia 4
- Centrally mediated abdominal pain syndrome (formerly chronic functional abdominal pain) 4
Genitourinary Causes
- Nephrolithiasis - can cause chronic left upper quadrant pain 2
- Chronic pyelonephritis 6
- Renal malignancy 4
- Endometriosis - in women of reproductive age 4
- Chronic pelvic inflammatory disease 5
- Ovarian pathology including cysts and malignancy 4
Abdominal Wall and Musculoskeletal
- Chronic abdominal wall pain (CAWP) - a common yet frequently overlooked cause affecting middle-aged adults, more prevalent in women (4:1 ratio), diagnosed by Carnett's sign and response to trigger point injection 7, 3
- Hernia - including incisional, ventral, and inguinal 4
- Rectus sheath hematoma 7
- Myofascial pain syndrome 4
Splenic Pathology
Vascular Causes
- Chronic mesenteric ischemia - consider when lactate and D-dimer elevated, though these lack specificity 6, 8
- Abdominal aortic aneurysm - must be excluded as life-threatening 2
- Median arcuate ligament syndrome 4
Metabolic and Systemic
- Diabetic radiculopathy 4
- Porphyria - rare but important consideration 4
- Familial Mediterranean fever 4
- Lead poisoning 4
- Abdominal migraine 4
Infectious and Inflammatory
- Chronic intra-abdominal abscess 5
- Tuberculosis - particularly in immunocompromised patients 8
- Parasitic infections 4
Critical Diagnostic Approach
The primary role is to differentiate organic disease from functional disorders through systematic evaluation, not exhaustive testing. 1
Key Pitfalls to Avoid
- Failing to diagnose chronic abdominal wall pain - this condition is frequently missed despite being common, leading to extensive unnecessary workup with estimated annual costs exceeding $1,100 before diagnosis 7, 3
- Ordering capsule endoscopy for chronic pain without inflammatory markers - diagnostic yield is only 21.4% in patients negative for biomarkers versus 66.7% in those positive 5
- Repetitive testing after functional diagnosis established - once functional pain is diagnosed, avoid repeated investigations and refer for psychological support 1
- Missing pregnancy in reproductive-age women - always obtain β-hCG before imaging 6, 8
When Imaging Is Indicated
- CT abdomen/pelvis with IV contrast is first-line when diagnosis unclear or alarm features present, changing diagnosis in 51% and management in 25% of cases 5, 2
- Ultrasonography for right upper quadrant pain and suspected hepatobiliary disease 5, 6
- CT enterography for suspected Crohn's disease 5
- Plain radiography has limited diagnostic value and should not be routinely ordered 5, 6