Differential Diagnosis for Right Upper Quadrant Pain

The patient's history of poor adherence to synthroid and previous appendectomy at 13 years old is considered in the differential diagnosis for right upper quadrant (RUQ) pain. The differential diagnoses are categorized as follows:

• Single Most Likely Diagnosis
  • Cholecystitis or gallstones: The patient's RUQ pain could be related to gallbladder disease, which is a common cause of RUQ pain. Poor adherence to synthroid may contribute to increased risk of gallstones due to potential hypothyroidism-related changes in lipid metabolism.
• Other Likely Diagnoses
  • Hepatitis: Although less common, hepatitis can cause RUQ pain and should be considered, especially if the patient has a history of liver disease or risk factors for hepatitis.
  • Peptic ulcer disease: The patient's RUQ pain could be referred pain from a peptic ulcer, which is a common cause of abdominal pain.
  • Right kidney stone or pyelonephritis: These conditions can cause severe RUQ pain and should be considered in the differential diagnosis.
• Do Not Miss Diagnoses
  • Liver abscess or tumor: Although rare, a liver abscess or tumor can cause RUQ pain and would be a critical diagnosis to miss.
  • Budd-Chiari syndrome: This rare condition, caused by hepatic vein thrombosis, can present with RUQ pain and would be catastrophic if missed.
  • Pulmonary embolism: Although the pain is in the RUQ, a pulmonary embolism can refer pain to this area and is a critical diagnosis to consider.
• Rare Diagnoses
  • Fitz-Hugh-Curtis syndrome: This rare condition, caused by Neisseria gonorrhoeae or Chlamydia trachomatis, can cause RUQ pain and should be considered in patients with risk factors for sexually transmitted infections.
  • Right adrenal gland tumor or hemorrhage: These rare conditions can cause RUQ pain and would be an unusual diagnosis to consider.