Journal of Dr. NTR University of Health Sciences

REVIEW ARTICLE
Year
: 2016  |  Volume : 5  |  Issue : 3  |  Page : 165--168

Reversed Z-shaped anomaly of main pancreatic duct as a cause of recurrent acute pancreatitis: A review


Amarnath Kadimella, Thirunavukkarasu Sampath, Varaprasada Rao Gudi 
 Department of Surgical Gastroenterology, Narayana Medical College and Hospital, Nellore, Andhra Pradesh, India

Correspondence Address:
Amarnath Kadimella
Department of Surgical Gastroenterology, Narayana Medical College and Hospital, Nellore, Andhra Pradesh
India

Abstract

Idiopathic pancreatitis comprises of around 20% cases of acute pancreatitis. We report a case with reversed Z-type main pancreatic duct, a very rare and unusual anomaly of the main pancreatic duct as a cause for idiopathic acute pancreatitis. A review of literature showed it is one of the significant causes for idiopathic recurrent acute pancreatitis. Meandering main pancreatic duct (MMPD) comprises loop type and reversed Z-type main pancreatic ducts. These are found more frequently in idiopathic recurrent acute pancreatitis than in the community.



How to cite this article:
Kadimella A, Sampath T, Gudi VR. Reversed Z-shaped anomaly of main pancreatic duct as a cause of recurrent acute pancreatitis: A review.J NTR Univ Health Sci 2016;5:165-168


How to cite this URL:
Kadimella A, Sampath T, Gudi VR. Reversed Z-shaped anomaly of main pancreatic duct as a cause of recurrent acute pancreatitis: A review. J NTR Univ Health Sci [serial online] 2016 [cited 2020 Aug 9 ];5:165-168
Available from: http://www.jdrntruhs.org/text.asp?2016/5/3/165/191846


Full Text

 Introduction



Recurrent acute pancreatitis is a clinical entity largely associated with pancreatic ductal obstruction.[1] Pancreatitis is associated with several morphological anomalies such as anomalous pancreatic biliary junction [2] pancreatic divisum.[3],[4],[5],[6] Approximately 20-30% cases of acute pancreatitis remain idiopathic.

There are other variants of pancreatic ductal anomalies that are yet to be proven as causes of recurrent acute pancreatitis; one such group of variant is meandering main pancreatic duct (MMPD). On review of literature, there are no cases of MMPD associated with recurrent acute pancreatitis reported in Indian medical literature.

The main pancreatic duct normally has obtuse angled curves from tail to the major ampulla. However, occasionally, the ventral duct in the head of the pancreas has abnormal curvature with localized spiral or hair pin curve on magnetic resonance cholangio pancreaticogram (MRCP) or endoscopic retrograde cholangiopancreatography (ERCP). They produce ductal hypertension and cause the onset of idiopathic pancreatitis. Mechanical obstruction theory such as that of pancreatic divisum is not postulated as a pathophysiology.[7],[8],[9] Even though, in a study of 504 patients by Gonoi et al.[10] on MMPD, one single case of MMPD was associated with ductal dilatation.

We present here, a case of recurrent acute pancreatitis with reversed Z-type anatomic variant and proximal ductal dilatation.

 Case Details



A 37-year-old male presented with pain in the abdomen radiating to the back since 5 days. It was of a continuous type not associated with food intake or any periodicity. He had nausea and intermittent hiccups. He was not a known alcoholic, smoker, or a drug abuser. There was no history of trauma. He had three similar episodes of epigastric pain radiating to the back, associated with hyperamylasemia that was treated conservatively as acute pancreatitis. The first attack of pain was at the age of 7 years and the other attacks at the age of 27 years.

The patient's serum Amylase was 6,800 IU (Normal <220 IU) and serum Lipase was 920 IU (Normal <60 IU). Ultra sonogram did not reveal any gall stones or common bile duct sludge. On investigating the etiology serum triglycerides, serum calcium and parathyroid hormone levels were normal. We ordered MRCP to know the cause for his recurrent acute pancreatitis to rule out any congenital ductal anomalies such as pancreatic divisum or annular pancreas.

 Mrcp



Main Pancreatic Duct (MPD) was abnormally curved in the head (reversed Z-type anatomic variant) of the pancreas [Figure 1]. Side branches were additionally prominent and they were draining into the MPD. A well-defined collection, measuring 2.7 cm × 1.2 cm was seen in the region of proximal body [Figure 2]. MPD was prominent, measuring 4.3 mm in the head of the pancreas. There were no calcifications or strictures seen in the pancreas.{Figure 1}{Figure 2}

He was managed conservatively by keeping nil oral, intravenous fluids, analgesics, and oxygen support. During the course of treatment, the patient developed increasing abdominal pain, tachycardia, and fever. On contrast-enhanced computed tomography (CECT) [Figure 3], the fluid collection has been infected with a size measuring 6.5 cm × 4.5 cm. In view of persistence, tachycardia, and fever, pigtail drainage was done and fluid collection drained. The patient clinically improved and was discharged. On a 2 month follow-up, there were no further episodes of pain or fever.{Figure 3}

 Discussion



MMPD comprises two types of anatomical defects, one is reversed Z-type as in our case and the other is loop type as shown in [Figure 4]. Review of literature showed only one study by the Tokyo University comparing idiopathic recurrent acute pancreatitis patients having meandering pancreatic duct anomaly and general community having similar anatomical abnormality with no symptoms.{Figure 4}

MMPD was reported in 2.2% of the population in a community-based study of 504 subjects against 2.6% for pancreatic divisum in the same study.[10] In our center, out of 322 MRCPs, this was the first of the two cases of MMPD. The other patient had a loop variant with no evidence of pancreatitis. In a large study by Gonoi et al.,[10] a 40% association of MMPD with idiopathic recurrent acute pancreatitis was found, but in our center it was the only case associated with pancreatitis out of 16 idiopathic recurrent pancreatitis cases.

According to the Tokyo university study,[10] the results of univariate analysis revealed a significant positive association of MMPD to the onset of pancreatitis [P = 0.0002; OR, 4.01 {95% confidence interval (CI), 1.92-6.11}] and recurrent acute pancreatitis [P < 0.0001; OR, 26.2 (95% CI, 22.2-30.2)]. Positive association of loop/reversed Z-type to the onset of Recurrent Acute Pancreatitis (RAP) was detected as well [P = 0.0006/0.0009; OR, 21.6/18.5 (95% CI, 15.9-27.3/12.9-24.0)] respectively.

The etiology of MMPD is unknown and the mechanism by which MMPD was associated with RAP is not yet established.[10] A single case of reversed Z-type accompanied by Wirsungocele, is reported which may support the mechanical obstruction theory.[11] In our patient as well, MMPD was associated with prominent MPD (4.3 mm) and side branches in favor of obstruction theory. But the Tokyo study [10] concluded that there was neither MPD or dorsal duct dilatation nor pancreatic gland atrophy in MMPD pancreatitis, suggesting mechanical obstruction theory less conceivable.

Pancreatitis in patients with MMPD and idiopathic acute pancreatitis was possibly less severe and localized in the head of the pancreas than pancreatitis in patients without MMPD, however, no significant statistical analysis was available due to insufficient number of data.[10] But in our case, the pancreatitis was not localized to the head, it additionally involved the body, the tail, and it was severe unlike the Tokyo University study.

Although the study revealed that there is significant association of MMPD and recurrent acute pancreatitis but in the general population, having MMPD have no signs of pancreatitis, suggesting that this anomaly behaves similar to other pancreatic ductal anomaly, pancreatic divisum where only 5-10% of patients become symptomatic with pancreatitis.[10]

MRCP is the accurate study to diagnose MMPD. Heavily T2-weighted MRCP images are helpful in picking up the anomaly. Although MMPD cannulation is less successful due to bends in the MPD, the role of ERCP as therapeutic or diagnostic procedure is not standardized due to insufficient data.[10]

At present, the management of the patients with MMPD having recurrent acute pancreatitis is similar to the pancreatitis of other causes because there are no specific treatment protocols made, such as pancreatic divisum, because the pathophysiology of causing pancreatitis in MMPD patients is unknown due to rarity of this anomaly.

 Conclusion



MMPD is a rare variation of the pancreatic ductal anatomy and it is found relatively common in patients with idiopathic recurrent acute pancreatitis. The management protocol does not change from acute pancreatitis of other causes. In conclusion, MMPD may be considered as a relevant factor to the onset of idiopathic recurrent acute pancreatitis. But still, the pathophysiology and outcome is unclear in view of limited number of reports published. Consensus can be arrived only when more reports will be available in the future.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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