Differential Diagnosis for Right Upper Quadrant Abdominal Pain

The patient presents with right upper quadrant abdominal pain that radiates to the right shoulder tip, worsens when lying on the side of the pain, and hurts with deep breathing. These symptoms, combined with the patient being on the progesterone-only pill (POP) and experiencing breakthrough bleeding, guide the differential diagnosis.

• Single Most Likely Diagnosis

  • Biliary Colic or Cholecystitis: The pain's location and radiation to the shoulder, along with exacerbation by deep breathing and positional changes, are classic for gallbladder pathology. The use of POP can increase the risk of gallstones due to its effect on bile composition.

• Other Likely Diagnoses

  • Peptic Ulcer Disease: Although less likely given the specific radiation to the shoulder and worsening with breathing, peptic ulcers can cause upper abdominal pain and can be exacerbated by certain positions.
  • Hepatic Pathology: Conditions like hepatitis or liver abscess could cause right upper quadrant pain but might not fully explain the radiation to the shoulder or the specific exacerbating factors mentioned.
  • Right Lower Lobe Pneumonia: Referred pain from the diaphragm due to a lower lobe pneumonia could cause shoulder pain and worsen with deep breathing, but the primary location of pain would be expected to be more thoracic.

• Do Not Miss Diagnoses

  • Pulmonary Embolism: Although the primary symptom is abdominal pain, a pulmonary embolism can cause sudden onset of chest pain that worsens with deep breathing (pleuritic chest pain), and in rare cases, can refer pain to the abdomen.
  • Myocardial Infarction: Less common in younger individuals but can present atypically, especially in women, with pain referred to the abdomen.
  • Ruptured Hepatic Adenoma: Associated with the use of hormonal contraceptives, a ruptured hepatic adenoma can cause severe abdominal pain and is a medical emergency.

• Rare Diagnoses

  • Fitz-Hugh-Curtis Syndrome: A rare condition involving inflammation of the liver capsule and adjacent peritoneal surfaces, often due to pelvic inflammatory disease, which can cause right upper quadrant pain radiating to the shoulder.
  • Diaphragmatic Irritation from Other Causes: Such as a diaphragmatic hernia or diaphragmatic eventration, which could cause referred pain to the shoulder and worsen with breathing.