What causes referred pain from the right upper quadrant (RUQ) to the left upper quadrant (LUQ)?

From the Guidelines

Referred pain from the right upper quadrant (RUQ) to the left upper quadrant (LUQ) of the abdomen is typically caused by disorders affecting organs that cross the midline or have bilateral innervation, with pancreatitis being a common cause, as noted in studies such as 1. The most common causes of referred pain from the RUQ to the LUQ include:

• Pancreatitis, where inflammation of the pancreas can present as pain radiating from the RUQ to the LUQ
• Biliary disease like gallstones or cholecystitis, where pain may refer across the abdomen due to shared nerve pathways
• Subdiaphragmatic irritation from conditions like pneumonia or pleurisy
• Vascular issues such as aortic aneurysms or dissections, which may present with bilateral upper quadrant pain This phenomenon occurs because of the complex innervation of abdominal organs, where sensory nerve fibers from different regions converge on the same pathways in the spinal cord, causing the brain to misinterpret the origin of pain signals, as discussed in 1 and 1. When evaluating such pain, clinicians should consider the patient's complete clinical picture, including other symptoms like fever, nausea, or jaundice, to determine the underlying cause, as recommended in 1 and 1. It is essential to note that the diagnosis of acute cholecystitis, a common cause of RUQ pain, can be challenging, and imaging studies like ultrasound and CT scans play a crucial role in establishing the diagnosis, as highlighted in 1 and 1.

From the Research

Referred Pain from Right Upper Quadrant (RUQ) to Left Upper Quadrant (LUQ)

• The phenomenon of referred pain from the RUQ to the LUQ can be attributed to various causes, including complications of acute cholecystitis, such as perforation 2.
• In some cases, the pain may radiate from the RUQ to the LUQ, as seen in a patient with choledocholithiasis, where the pain was initially localized to the right upper quadrant and then radiated to the left upper quadrant 3.
• The exact mechanism of referred pain is not fully understood, but it is thought to be related to the shared innervation of the abdominal organs 4.
• Ultrasound and CT scans are commonly used to diagnose the causes of RUQ pain, but they may not always detect the underlying cause of referred pain 5.
• In some cases, rare conditions such as Lemmel syndrome, which involves a periampullary duodenal diverticulum compressing the common bile duct, may cause referred pain from the RUQ to the LUQ 6.

Possible Causes of Referred Pain

• Complications of acute cholecystitis, such as perforation 2
• Choledocholithiasis 3
• Other causes of RUQ pain, such as hepatic, pancreatic, adrenal, renal, gastrointestinal, vascular, and thoracic diseases 4
• Rare conditions, such as Lemmel syndrome 6

Diagnostic Approaches

• Ultrasound and CT scans are commonly used to diagnose the causes of RUQ pain 5
• MRI and MRCP may be used to confirm the diagnosis of choledocholithiasis and other conditions 6
• Endoscopic retrograde cholangiopancreatography (ERCP) may be used to diagnose and treat choledocholithiasis and other conditions 3, 6