Clinical Pearl Series Edited from Yale-G First Aid: Crush USMLE Step 2CK & Step 3 by Yale Gong, MD, Sr. Medical Advisor at www.medicine.net (Copyrighted)

 Abdominal pain is a very common symptom. Most patients have a benign and/or self-limited cause, and the initial goal and challenge is to identify those patients with a serious etiology that may require urgent intervention. A detailed history and focused physical examination (P/E) are important for most differential diagnosis, which may require further evaluation with laboratory testing and/or imaging.

Important differentiations of abdominal pain by clinical features are summarized below.

Summary: Brief Differentiations of Abdominal Pain

I. Left Upper Quadrant (LUQ)

Gastritis: LUQ or epigastric pain or discomfort, heartburn, nausea, vomiting, and hematemesis.                                                        

Gastric ulcer: LUQ or epigastric pain or discomfort associated with food intake.                                                                                  

Others: splenic rupture, infarct, abscess; splenomegaly; IBS (splenic flexure syndrome).

II. (Middle) Epigastrium

Acute pancreatitis: Acute, persistent upper abdominal pain radiating to the back; usually after big meals/alcohol.                                

Chronic pancreatitis: Chronic epigastric pain radiating to the back; associated with pancreatic insufficiency.                                             

Peptic ulcer disease: Epigastric pain or discomfort; occasionally localized to one side.                                                                              

GERD: Epigastric pain associated with heartburn, regurgitation, and dysphagia.                                                                                

Gastritis/gastropathy: Abdominal discomfort/pain, heartburn, nausea, vomiting, and hematemesis; may have history of ingestion of alcohol or NSAIDs.                                                                    

Functional dyspepsia: The presence of one or more of the following: postprandial fullness, early satiation, epigastric pain, or burning; no evidence of structural disease.                                                            

Gastroparesis: Nausea, vomiting, abdominal pain, early satiety, postprandial fullness, and bloating. Most causes are idiopathic, diabetic, or postsurgical.

III. Right Upper Quadrant (RUQ)

Biliary colic: Intense, dull pain located in the RUQ or epigastrium; associated with nausea, vomiting, and diaphoresis; usually lasting > 30 min and alleviated within 1 hour; generally benign P/E results.     

Acute cholecystitis: Prolonged (> 4 hours) RUQ or epigastric pain typically following fatty foods; fever. Patients will have abdominal guarding and Murphy's sign.                                                           

Acute cholangitis: Triad of fever, jaundice, RUQ pain; may have atypical presentation in older or immuno-suppressed patients.                                                                                                   

Sphincter of Oddi dysfunction: RUQ pain similar to other biliary type pain without other apparent causes.                                    

Acute hepatitis: Dull RUQ pain with fatigue, malaise, nausea, vomiting, and anorexia; +/- jaundice, dark urine, and light-colored stools. Causes include hepatitis A, alcohol, and drug-induction.

Perihepatitis (Fitz-Hugh-Curtis syndrome): RUQ pain with a pleuritic condition; pain may radiate to the right shoulder; aminotransferases are usually normal or only slightly elevated.  

Budd-Chiari syndrome: Fever, abdominal pain and distention (from ascites), lower extremity edema, jaundice, gastrointestinal bleeding, and/or hepatic encephalopathy.                                                    

Portal vein thrombosis: RUQ pain, dyspepsia, or gastrointestinal bleeding; most commonly associated with cirrhosis.                        

Others: duodenal ulcer (perforation), hepatic abscess.

IV. Right Lower Quadrant (RLQ)

Appendicitis: Initial periumbilical pain that radiates to the right lower quadrant; associated with anorexia, nausea, and vomiting.

Cecal diverticulitis: Constant RLQ pain and low fever for several days; may have nausea and vomiting but no lower GI bleeding.                

Others: ectopic pregnancy, ovarian torsion.

V. Left Lower Quadrant (LLQ)

(Sigmoid) diverticulitis: Constant LLQ pain and low fever for several days; may have palpable sigmoid mass but no lower GI bleeding. 

(Sigmoid) diverticulosis: LLQ colicky pain and relieved by defecation; may also have typical painless rectal bleeding or hematochezia (melena).                                                                                     

Others: sigmoid volvulus, ectopic pregnancy, ovarian torsion.

VI. Lower Abdomen (left or right)

Infectious colitis: Diarrhea and associated abdominal pain +/- fever. Clostridium difficile infection can show acute abdomen and peritoneal signs in the setting of perforation and fulminant colitis.

Nephrolithiasis: Usually mild to severe flank pain (left or right); may have back or abdominal pain.                                                      

Ectopic pregnancy: Triad of amenorrhea, unilateral lower abdominal pain, and spotting vaginal bleeding (1-2 weeks after last menstrual period--LMP).

Others: twisted/ruptured ovary cyst, endometriosis, intestinal obstruction, abdominal abscess.