Differential Diagnosis for RUQ Abdominal Pain

The differential diagnosis for right upper quadrant (RUQ) abdominal pain can be categorized based on the likelihood and potential impact of missing the diagnosis. Here's a structured approach:

• Single Most Likely Diagnosis

  • Gallbladder Disease (Cholecystitis or Cholelithiasis): This is often the most common cause of RUQ pain, especially in females over 40 years old. The pain is typically postprandial, worsening after fatty meals, and may radiate to the right shoulder.

• Other Likely Diagnoses

  • Peptic Ulcer Disease: Both gastric and duodenal ulcers can cause RUQ pain, often related to food intake and relieved by antacids or food.
  • Hepatitis: Viral, alcoholic, or drug-induced hepatitis can cause RUQ pain, jaundice, and elevated liver enzymes.
  • Pyelonephritis or Kidney Stones: While more commonly associated with flank pain, pyelonephritis or kidney stones can radiate pain to the RUQ, especially if the right kidney is involved.
  • Right Lower Lobe Pneumonia: Referred pain from the right lower lobe of the lung can cause RUQ abdominal pain due to the shared innervation of the diaphragm.

• Do Not Miss Diagnoses

  • Appendicitis (with an atypical presentation): Although appendicitis typically presents with right lower quadrant pain, an retrocecal appendix can cause RUQ pain.
  • Hepatic Abscess or Infected Liver Cyst: These conditions can present with RUQ pain, fever, and jaundice, requiring urgent drainage.
  • Cholangitis: Infection of the biliary tree can cause severe RUQ pain, jaundice, and sepsis, necessitating prompt antibiotic treatment and possible intervention.
  • Aortic Dissection: While rare, aortic dissection can cause severe, tearing pain that may radiate to the RUQ and is a medical emergency.

• Rare Diagnoses

  • Hepatocellular Carcinoma: A rare cause of RUQ pain, often associated with a palpable mass and elevated alpha-fetoprotein levels.
  • Intrahepatic Duct Stones: Stones within the intrahepatic bile ducts can cause recurrent RUQ pain and jaundice.
  • Fitz-Hugh-Curtis Syndrome: A rare condition where pelvic inflammatory disease causes adhesions between the liver and abdominal wall, leading to RUQ pain.
  • Diaphragmatic Irritation (from a subphrenic abscess or hematoma): Can cause RUQ pain due to irritation of the diaphragm.