Differential Diagnosis for RUQ Pain

The differential diagnosis for right upper quadrant (RUQ) pain can be categorized into several groups based on the likelihood and potential impact of missing the diagnosis.

• Single Most Likely Diagnosis

  • Gallbladder Disease (Cholecystitis or Cholelithiasis): This is often the first consideration for RUQ pain due to the high prevalence of gallstones and the frequency with which they cause symptoms in this area. The pain is typically colicky, radiates to the right shoulder, and is exacerbated by fatty meals.

• Other Likely Diagnoses

  • Peptic Ulcer Disease: Both gastric and duodenal ulcers can cause RUQ pain, especially if the ulcer is located in the duodenum. The pain is often described as burning and can be relieved by eating or worsened by hunger.
  • Hepatitis: Inflammation of the liver can cause RUQ pain, and it may be accompanied by jaundice, fatigue, and loss of appetite. Viral hepatitis, drug-induced hepatitis, and alcoholic hepatitis are common causes.
  • Pyelonephritis or Kidney Stones: While these conditions primarily affect the kidneys, they can cause pain that radiates to the RUQ, especially if the right kidney is involved. The pain is often severe and can be accompanied by urinary symptoms.

• Do Not Miss Diagnoses

  • Appendicitis (with an atypical presentation): Although appendicitis typically presents with pain in the lower right quadrant, an inflamed appendix can sometimes cause pain in the RUQ, especially if it is retrocecal. Missing this diagnosis can lead to perforation and severe complications.
  • Hepatic Abscess or Infected Liver Cyst: These conditions can cause severe RUQ pain and are life-threatening if not promptly treated. They often present with fever, jaundice, and significant illness.
  • Cholangitis: Infection of the bile ducts can cause RUQ pain, jaundice, and fever. It is a medical emergency due to the risk of sepsis.

• Rare Diagnoses

  • Liver Tumors (Primary or Metastatic): While not common, liver tumors can cause RUQ pain, especially if they are large or involve the liver capsule.
  • Right Pneumonia or Pleurisy: Inflammation of the lung or pleura in the right upper lobe can cause RUQ pain that worsens with deep breathing or coughing.
  • Diaphragmatic Irritation (from a subphrenic abscess, for example): Conditions that irritate the diaphragm can cause RUQ pain, often accompanied by shoulder pain due to referred pain via the phrenic nerve.