Introduction
Abdominal pain is one of the most common yet complex complaints in medicine. Whether sudden or persistent, localized or generalized, understanding the cause of acute abdominal pain requires anatomical insight, clinical skill, and swift action in emergencies.
What is Acute Abdominal Pain?
- Pain that arises suddenly in the abdomen and lasts hours to a few days
- Can signal anything from indigestion to life-threatening emergencies
- Referred pain can complicate diagnosis
Key Principles of Evaluation
- Full history (onset, character, duration, radiation, severity)
- Consider patient age, sex, comorbidities
- Repeated examinations may be key
- Look for red flags: shock, guarding, rigidity
Anatomical Region-wise Causes of Pain
1. Right Upper Quadrant (RUQ) Pain
- Hepatitis, hepatic tumour, abscess
- Biliary causes: biliary colic, cholecystitis, cholangitis
- Renal causes: pyelonephritis, renal colic, infarction
- Referred pain: retrocecal appendicitis, right lower lobe pneumonia
2. Epigastric Pain
- Peptic ulcer disease: gastric or duodenal
- Pancreatitis
- Oesophagitis, reflux, hiatus hernia
- Gastritis
3. Left Upper Quadrant (LUQ) Pain
- Splenic infarction or rupture
- Pancreatitis
- Pyelonephritis, renal colic
- Left lower lobe pneumonia
4. Right Iliac Fossa (RIF) Pain
- Appendicitis
- Meckel’s diverticulitis
- Crohn’s disease
- Renal colic, UTI
- Gynecological: ovarian cyst, ectopic pregnancy, salpingitis
5. Left Iliac Fossa (LIF) Pain
- Diverticulitis
- Sigmoid volvulus
- Colitis
- Gynecological causes
6. Central Abdominal Pain
- Aortic aneurysm (AAA)
- Meckel’s diverticulum
- Intussusception
- Crohn’s disease, enteritis, infarction, obstruction
7. Suprapubic Pain
- UTI, cystitis
- Pelvic appendicitis
- Diverticulitis
- Gynecological: ovarian cyst, fibroids, ectopic pregnancy
Types of Pain and Their Significance
| Pain Type | Suggests |
|---|---|
| Visceral (colicky) | Hollow organ stretch (gallbladder, ureter) |
| Somatic (sharp) | Peritonitis, inflammation (appendicitis) |
| Referred pain | Shared neural pathways (e.g., pneumonia mimicking RUQ pain) |
Red Flags in Acute Abdominal Pain
- Sudden, severe, generalized pain (e.g., perforation, ischemia)
- Rigid or board-like abdomen
- Rebound tenderness
- Guarding, fever, hypotension
- Shock symptoms (tachycardia, low BP)
Physical Examination
- Inspection: distension, scars, movement
- Palpation: superficial and deep tenderness, masses
- Rebound tenderness: sign of peritoneal irritation
- Guarding and rigidity
- Percussion and auscultation: listen for bowel sounds, organomegaly
Important Diagnostic Features
- RUQ pain with fever = cholecystitis
- Epigastric pain radiating to back = pancreatitis
- RIF pain with rebound and guarding = appendicitis
- Sudden LUQ pain after trauma = splenic rupture
- Colicky central pain with vomiting = obstruction
- Sudden tearing central pain = AAA
Key Investigations
| Test | Use |
|---|---|
| FBC | Infection, anemia |
| LFTs | Hepatobiliary pathology |
| Amylase/Lipase | Pancreatitis |
| β-HCG | Rule out ectopic pregnancy |
| Urinalysis (MSU) | UTI, stones |
| ECG | Rule out cardiac referred pain |
| Chest X-ray | Free air (perforation), pneumonia |
| Abdominal X-ray | Obstruction, ileus, perforation |
| Ultrasound | Gallbladder, appendix, gynecological issues |
| CT scan | Best for AAA, diverticulitis, trauma, abscess |
| OGD | If gastric ulcer or PUD suspected |
| Diagnostic laparoscopy | For uncertain diagnosis, especially in women |
Management of Acute Abdominal Pain
Initial Resuscitation
- ABC, IV access, fluids
- Pain relief (but don’t mask signs early)
- Avoid antibiotics until diagnosis clear
Observation
- 24-hour monitoring for subtle conditions (e.g., appendicitis)
- Repeat exams crucial
Surgical Referral
- Suspected appendicitis, perforation, ectopic pregnancy, ischemia
- Laparoscopy/laparotomy as needed
Medical Management
- Pancreatitis: IV fluids, NPO, monitoring
- UTI: antibiotics
- PUD: PPI + H. pylori treatment
- Colitis: supportive or specific antimicrobial
FAQs About Acute Abdominal Pain
What is the most common cause of acute abdominal pain?
Appendicitis is among the most common surgical causes.
How can I tell if abdominal pain is serious?
Severe, persistent pain with vomiting, fever, or guarding requires urgent evaluation.
Is CT scan better than ultrasound for abdominal pain?
CT gives more detail but is usually reserved for unclear or severe cases.
When should I go to the ER for abdominal pain?
If pain is sudden, severe, worsening, or associated with red flag symptoms.
Can abdominal pain be referred from other organs?
Yes—lungs, heart, and kidneys can all refer pain to the abdomen.
Conclusion
Acute abdominal pain can range from a benign stomach upset to a surgical emergency. A systematic approach—guided by pain location, type, associated symptoms, and timely investigations—is critical to making an accurate diagnosis and saving lives.
