What is Pancreas divisum?
Pancreas divisum is a congenital anomaly, which affects the anatomy of the pancreas. In patients diagnosed with this condition, the pancreatic duct is not formed as a single structure – instead, there are two distinct pancreatic ducts (dorsal and ventral). This condition has been found in association with the adenoma of the lower papilla.
As it is one of the most common variation of pancreatic duct formation, it should come as no surprise that this condition is present in 4-10% of the general population. The prevalence identified through imaging studies (particularly through MRCP - magnetic resonance cholangiopancreatography) is of 9%, while the one related to autopsies is of 14%.
According to the specialists, there are three main types of pancreas divisum. Type 1 (classic) is the one in which the pancreatic ducts present no connection at all (70% of the cases). Type 2 (absent ventral duct) is the one in which the minor papilla is solely responsible for the drainage of the pancreas, while the major papilla handles the drainage of the bile duct (20-25% of the cases). Type 3 (functional) is the one in which an inadequate or incomplete connection is present between the two pancreatic ducts (5% of the cases).
Studies have shown that the patients who suffer from both pancreas divisum and pancreatitis are of young age, rare consumers of alcohol and often times women. Such patients also present a higher risk for recurrent acute pancreatic attacks.
Symptoms
In the majority of the patients who present pancreas divisum, there are no obvious symptoms (asymptomatic condition). Such structural abnormalities are often identified upon performing an autopsy. When the patients do present symptoms, these generally include: nausea, vomiting and chronic abdominal pain. Acute and chronic pancreatitis can develop as a result of pancreas divisum.
In general, suffers of idiopathic pancreatitis might present such structural abnormalities. It is possible that the pancreatic divisum leads to the appearance of santorinicele, which is actually a cystic dilatation that occurs at the level of the distal dorsal duct. This modification appears in the close vicinity of the minor papilla.
If the pancreas is drained through the minor papilla, inadequacy might characterize the actual drainage process. The abnormalities can lead to obstruction, which is mainly responsible for the chronic abdominal pain. In general, both the obstruction and the pancreatitis appear in patients of adult age.
Causes
As the embryo starts to form, there are two pancreatic ducts that appear along the development (dorsal and ventral). In a healthy fetus, the pancreatic ducts are going to fuse into one single structure (this happens in 90% of the cases). In 10% of the cases, the pancreatic ducts do not fuse, which leads to the condition known as pancreas divisum.
During the fetal period, the dorsal duct is responsible for draining the majority of the pancreas, with the said duct opening into the minor papilla. On the other hand, the ventral duct is responsible for the drainage of the minority of the pancreas, opening into the major papilla. Upon reaching adult age, the ventral duct is responsible for the drainage of 70% of the pancreas. If the two ducts fail to fuse together, the dorsal duct will handle the task of draining the majority of the pancreas, opening up into the minor papilla.
Recent studies have suggested that pancreatic divisum might have a genetic component, with genetic mutations being identified in multiple patients. However, no clear association has been made between genetic markers and the appearance of pancreas divisum.
Diagnosis
These are the most common methods used for the diagnosis of pancreas divisum:
Physical examination
- In general, the abdominal examination does not reveal any abnormal findings
- If the patient suffers from an episode of pancreatitis, the palpation of the abdomen might elicit tenderness in the epigastric area and a palpable pseudocyst
Imaging studies
- MRCP (magnetic resonance cholangiopancreatography)
- Standard method of investigation upon suspecting pancreas divisum – evaluation of the pancreatic duct
- Key imaging features include:
- The dorsal duct continues with the Santorini duct, draining into the minor papilla
- The ventral duct does not communicate with the dorsal one; instead, it joins the respective duct at the level of the distal bile duct, entering the major papilla
- Non-invasive alternative to ERCP
- ERCP (endoscopic retrograde cholangiopancreatography) – this investigation can cause pancreatitis attacks (traditional method of diagnosis)
- Both of these tests can be used to identify the presence of two distinct pancreatic ducts
- Endoscopic ultrasound – this investigation can be performed without having to worry about pancreatitis attacks (no such risks have been identified)
- Additional imaging studies (CT, MRI) – generally used for the confirmation of the diagnosis; these investigations can be useful in identifying the dilatation of the dorsal duct, as well as the changes that have occurred with chronic pancreatitis.
Blood testing
- Amylase and lipase levels
- Leukocytes
- Creatinine
The differential diagnosis can be made with the following conditions: acute pancreatitis, chronic abdominal pain of other causes, gallstones, chronic pancreatitis, hyperamylasemia, pancreatic cancer and sphincter of Oddi dysfunction.
Treatment
If the individual does not present any symptoms, then no treatment is required. For the patients who present symptoms, these are the most used treatment approaches:
Symptomatic treatment
- Analgesic medication
- Intravenous hydration
Sphincterotomy
- Surgical intervention that involves the cutting of the minor papilla
- The purpose of the surgery is to enlarge the existing opening and also for the normal flow of the pancreatic enzymes
- During the surgical intervention, it is normal that a stent is placed at the level of the duct (prevents the closing of the duct, thus reducing the risk of blockage)
- Balloon dilatation – this can be used to treat associated strictures
- Surgical risks or complications include pancreatitis, kidney failure and failure to survive.
Prognosis
In the situation of patients who are asymptomatic, the prognosis of pancreas divisum is excellent. When it comes to symptomatic patients, these present the same risks as the ones who are diagnosed with pancreatitis. It is important to understand that these patients present high recurrence risks for pancreatitis, despite the different treatment approaches.