Differential Diagnosis of Left Upper Quadrant Pain

The differential diagnosis for left upper quadrant pain can be organized into the following categories:

• Single Most Likely Diagnosis
  • Gastritis or peptic ulcer disease: This is often the most common cause of left upper quadrant pain, as the stomach is located in this region and inflammation or ulcers can cause significant discomfort.
• Other Likely Diagnoses
  • Gastroesophageal reflux disease (GERD): Similar to gastritis, GERD can cause pain in the left upper quadrant due to the reflux of stomach acid into the esophagus.
  • Pancreatitis: Although the pancreas is located in the midline, pancreatic inflammation can radiate to the left upper quadrant, causing pain.
  • Splenic infarction or rupture: The spleen is located in the left upper quadrant, and any damage to it can cause severe pain.
  • Left kidney stone or pyelonephritis: The left kidney is also located in this region, and conditions affecting it can cause left upper quadrant pain.
• Do Not Miss Diagnoses
  • Aortic dissection: Although less common, aortic dissection can cause severe, tearing pain that radiates to the left upper quadrant and is a medical emergency.
  • Pulmonary embolism: If the embolism affects the left lung, it can cause referred pain to the left upper quadrant.
  • Cardiac ischemia or myocardial infarction: In some cases, cardiac conditions can cause referred pain to the left upper quadrant.
• Rare Diagnoses
  • Diaphragmatic rupture or hernia: These conditions can cause left upper quadrant pain due to the proximity of the diaphragm to this region.
  • Left adrenal gland pathology: Tumors or bleeding in the left adrenal gland can cause left upper quadrant pain, although this is relatively rare.
  • Intercostal muscle strain or rib fracture: Injury to the muscles or bones in the left upper quadrant can cause pain in this region.