Postprandial Pain at the Costal Arch with Tenderness on Palpation

Most Likely Differential Diagnoses

1. Biliary Colic / Acute Cholecystitis (Right costal arch — most common)

• Gallstones are a leading cause of postprandial upper abdominal pain
• Fatty meals trigger gallbladder contraction → stone obstructs the cystic duct → pain
• Classic features: right upper quadrant / right costal margin pain, often radiating to the right shoulder or back, nausea, vomiting
• Murphy's sign: pain and inspiratory arrest on deep palpation under the right costal margin (highly suggestive of cholecystitis)
• Rigidity/guarding on touch indicates inflammation or peritoneal irritation
• Workup: Ultrasound abdomen, liver function tests, CBC

2. Peptic Ulcer Disease (Gastric or Duodenal Ulcer) (Epigastric / costal area)

• According to Harrison's Principles of Internal Medicine (p. 8915), epigastric tenderness is the most frequent finding, and pain may be found to the right of the midline in ~20% of patients
• Duodenal ulcer pain classically improves with eating, then returns 2–3 hours later; gastric ulcer pain may worsen with eating
• Associated with H. pylori infection or NSAID use
• Workup: upper endoscopy (gold standard), H. pylori testing

3. Liver Disease / Hepatitis (Right costal arch)

• Per Harrison's (p. 9303), right-upper-quadrant discomfort ("liver pain") arises from stretching of Glisson's capsule and is marked by tenderness over the liver area
• Can be caused by acute hepatitis (viral, alcoholic, drug-induced), liver abscess, or congestion
• Hardness on palpation may reflect an enlarged liver (hepatomegaly)
• Workup: LFTs, viral hepatitis panel, abdominal ultrasound

4. Splenic Pathology (Left costal arch)

• Splenomegaly (enlarged spleen) causes left costal margin pain/fullness after meals
• The stomach fills → presses against the spleen → pain
• Causes include infections (EBV/mono), portal hypertension, hematologic disorders
• Workup: ultrasound, CBC with differential

5. Gastritis / Functional Dyspepsia

• Inflammation of the gastric mucosa causing postprandial epigastric discomfort
• Less likely to cause significant rigidity on touch
• H. pylori, NSAIDs, alcohol are common triggers

6. Pancreatitis (Epigastric, radiates to back)

• Epigastric pain worsening after eating, sometimes with board-like rigidity in severe cases
• Associated with nausea, vomiting
• Workup: serum lipase/amylase, CT abdomen

Red Flag Symptoms — Seek Urgent Care if Present

Recommended Initial Workup

1. Abdominal ultrasound — first-line for gallstones, liver/spleen assessment
2. Blood tests: CBC, LFTs (ALT, AST, bilirubin, ALP), serum lipase, H. pylori antigen
3. Upper endoscopy if peptic ulcer disease suspected
4. CT abdomen/pelvis if diagnosis remains unclear or red flags are present