Pancreas divisum is a common congenital anatomical variation of the pancreas, an organ located behind the stomach that produces digestive enzymes and hormones. This variation involves an unusual drainage pattern of pancreatic fluids. Many individuals with pancreas divisum remain asymptomatic.
Anatomy and Development of Pancreas Divisum
The pancreas typically functions by producing digestive enzymes that flow into the small intestine through a system of ducts. In normal anatomy, the main pancreatic duct, known as the duct of Wirsung, merges with the common bile duct and drains into the duodenum (the first part of the small intestine) through a common opening called the major duodenal papilla. An accessory pancreatic duct, or duct of Santorini, may also be present, typically connecting to the minor duodenal papilla.
During fetal development, the pancreas forms from two separate embryonic components: a ventral bud and a dorsal bud, each possessing its own duct. Around the seventh or eighth week of gestation, these two buds and their ducts normally fuse together to form a single, unified pancreas with a single main pancreatic duct. Pancreas divisum occurs when this fusion process fails to complete, meaning the ventral and dorsal pancreatic ducts remain separate.
As a result of this non-fusion, the larger portion of the pancreas, derived from the dorsal bud, drains predominantly through the smaller accessory duct into the minor duodenal papilla. The smaller part of the pancreas, originating from the ventral bud, continues to drain through its duct into the major duodenal papilla. Since this is a developmental anomaly, pancreas divisum is a congenital condition.
Symptoms and Associated Conditions
In some cases, symptoms can develop because the minor papilla, responsible for draining the larger dorsal pancreatic duct, may be too narrow or small to effectively handle the volume of pancreatic fluid. This can create a “bottleneck” effect, leading to impaired drainage and increased pressure within the dorsal pancreatic duct.
The primary condition associated with symptomatic pancreas divisum is recurrent acute pancreatitis. When pancreatic enzymes, which are normally activated in the small intestine, back up into the pancreas due to inadequate drainage, they can prematurely activate and begin to digest the pancreatic tissue itself, leading to inflammation. Symptoms of acute pancreatitis typically include severe pain in the upper abdomen, which may spread to the back, along with nausea and vomiting. Other indicators can include fever, a rapid heart rate, or tenderness in the abdominal area.
Diagnosis and Treatment Approaches
Pancreas divisum is frequently identified incidentally when medical imaging is performed for other reasons. Imaging techniques like CT scans or standard MRI scans can sometimes reveal this anatomical variation. Magnetic Resonance Cholangiopancreatography (MRCP) is considered the primary non-invasive diagnostic tool, as it provides detailed images of the pancreatic duct system. Using secretin during an MRCP can enhance visualization by stimulating pancreatic fluid production, making the ducts more apparent.
Endoscopic Retrograde Cholangiopancreatography (ERCP) is another accurate diagnostic method that can confirm the non-fusion of ducts, though it is more invasive than MRCP. Endoscopic ultrasound (EUS) also offers detailed imaging of the pancreatic ductal system and can aid in diagnosis.
Treatment for pancreas divisum is typically reserved for individuals who experience symptoms or complications, such as recurrent pancreatitis. For those with mild or no symptoms, conservative management is often recommended, focusing on observation, pain relief, and dietary adjustments like consuming low-fat meals. Pancreatic enzyme supplements may also be prescribed in some cases.
When symptoms are present, particularly recurrent pancreatitis, endoscopic therapy is often the first-line intervention. Endoscopic sphincterotomy of the minor papilla is a common procedure performed during an ERCP. This involves enlarging the opening of the minor papilla to improve the drainage of pancreatic fluids and prevent enzyme backup. Sometimes, a small tube called a stent is placed to help keep the opening clear. Recent studies, however, suggest that minor papilla sphincterotomy may not consistently reduce the risk of acute pancreatitis in all patients with pancreas divisum and recurrent pancreatitis. If endoscopic treatments are unsuccessful, surgical options, such as minor papilla sphincteroplasty or pancreaticojejunostomy, may be considered as a last resort to improve fluid flow and reduce inflammation.