Chronic pancreatitis: This condition can cause dilation of the pancreatic duct and common bile duct due to inflammation and scarring of the pancreas, leading to obstructive symptoms like constipation.

Pancreatic cancer: A tumor in the pancreas can obstruct the pancreatic duct and common bile duct, causing dilation and leading to symptoms such as constipation, weight loss, and abdominal pain.
Choledocholithiasis: Gallstones in the common bile duct can cause obstruction, leading to dilation of the duct and potentially causing constipation due to the resulting biliary colic and intestinal dysmotility.
Sphincter of Oddi dysfunction: Abnormal function of the sphincter of Oddi, which controls the flow of bile and pancreatic juice into the intestine, can cause dilation of the pancreatic duct and common bile duct, leading to symptoms like constipation.

Pancreatic adenocarcinoma with metastasis: Although less likely, missing a diagnosis of pancreatic cancer with metastasis could be deadly, as it requires prompt and aggressive treatment.
Ampullary cancer: A tumor at the ampulla of Vater, where the pancreatic and bile ducts empty into the intestine, can cause obstructive symptoms and dilation of the ducts, with potentially severe consequences if left untreated.

Congenital anomalies of the pancreas or biliary tree: Rare congenital conditions, such as pancreatic divisum or choledochal cysts, can cause dilation of the pancreatic duct and common bile duct, leading to symptoms like constipation.
Parasitic infections: Certain parasitic infections, such as ascaris or clonorchis, can cause biliary obstruction and dilation, although this is relatively rare in most populations.