Differential Diagnosis for Left Upper Quadrant Pain

Single Most Likely Diagnosis

• Gastroesophageal Reflux Disease (GERD): This condition is a common cause of left upper quadrant pain due to the reflux of stomach acid into the esophagus, leading to inflammation and discomfort.
• Peptic Ulcer Disease: Ulcers in the stomach or duodenum can cause pain in the left upper quadrant, especially if the ulcer is located near the stomach.

Other Likely Diagnoses

• Gastritis: Inflammation of the stomach lining can cause left upper quadrant pain, often accompanied by nausea, vomiting, and loss of appetite.
• Pancreatitis: Although pancreatitis typically causes mid-abdominal pain, it can radiate to the left upper quadrant, especially if the tail of the pancreas is involved.
• Splenomegaly: Enlargement of the spleen can cause left upper quadrant pain due to stretching of the splenic capsule or pressure on adjacent structures.
• Left Kidney Stone or Pyelonephritis: Although kidney stones or infections typically cause flank pain, they can radiate to the left upper quadrant in some cases.

Do Not Miss Diagnoses

• Myocardial Infarction: Cardiac ischemia can cause referred pain in the left upper quadrant, especially if the inferior wall of the heart is involved.
• Pulmonary Embolism: A pulmonary embolism can cause sudden onset of left upper quadrant pain if the embolism is located in the left lower lobe of the lung.
• Aortic Dissection: A tear in the aorta can cause severe, tearing pain that radiates to the left upper quadrant.
• Spleen Rupture: A ruptured spleen is a life-threatening condition that requires immediate attention, often presenting with severe left upper quadrant pain and hemodynamic instability.

Rare Diagnoses

• Left Diaphragmatic Hernia: A hernia through the diaphragm can cause left upper quadrant pain, especially if abdominal contents herniate into the thoracic cavity.
• Gastric Cancer: Although rare, gastric cancer can cause left upper quadrant pain, often accompanied by weight loss, nausea, and vomiting.
• Splenic Infarction: Infarction of the spleen can cause left upper quadrant pain, often due to embolic events or vasculitis.
• Left Adrenal Gland Pathology: Tumors or infections of the left adrenal gland can cause left upper quadrant pain, often accompanied by systemic symptoms such as fever or weight loss.