Differential Diagnosis for Right Upper Quadrant Pain and Right Shoulder Pain

• Single Most Likely Diagnosis
  • Cholecystitis: This is the most likely diagnosis due to the referred pain to the right shoulder, which is a common presentation of gallbladder inflammation. The pain is often sharp and constant, and may worsen after eating fatty foods.
• Other Likely Diagnoses
  • Biliary colic: This condition occurs when the gallbladder contracts in response to a gallstone blocking the cystic duct, causing severe pain in the right upper quadrant that may radiate to the right shoulder.
  • Peptic ulcer disease: Although the pain is typically in the epigastric region, it can sometimes radiate to the right upper quadrant and be referred to the right shoulder.
  • Hepatitis: Inflammation of the liver can cause right upper quadrant pain that may be referred to the right shoulder, especially if the liver is enlarged.
• Do Not Miss Diagnoses
  • Myocardial infarction: Although less common, myocardial infarction can present with atypical symptoms, including right upper quadrant and shoulder pain, especially in women or diabetic patients.
  • Pneumonia (right lower lobe): Referred pain from the diaphragm can cause right shoulder pain, and if the pneumonia is severe, it can also cause right upper quadrant pain.
  • Pulmonary embolism: A large pulmonary embolism can cause referred pain to the right shoulder and upper quadrant, especially if it involves the right lower lobe.
• Rare Diagnoses
  • Fitz-Hugh-Curtis syndrome: A rare condition characterized by inflammation of the liver capsule and adjacent peritoneal surfaces, often due to pelvic inflammatory disease, which can cause right upper quadrant pain and referred pain to the right shoulder.
  • Diaphragmatic irritation (e.g., from a subphrenic abscess): Inflammation or irritation of the diaphragm can cause referred pain to the right shoulder and upper quadrant.