Endoscopic ultrasound imaging of pancreatic duct ascariasis

Ascaris lumbricoides infestation is endemic in tropical countries. Most infections by A. lumbricoides are asymptomatic, but they can produce a wide spectrum of manifestations including hepatobiliary and pancreatic complications. Pancreatic ascariasis is a rare entity. In a study of 500 patients with hepatobiliary and pancreatic disease due to A. lumbricoides infection, only seven had pancreatic ascariasis [1], and there are few case reports of ascariasis-induced acute pancreatitis [2]. Mechanisms of acute pancreatitis associated with ascariasis include invasion of the pancreatic duct, the ampullary orifice, and both the common bile duct and the pancreatic duct [3].

Idiopathic pancreatitis is diagnosed when clinical, laboratory, and conventional radiologic methods do not provide a clear etiology for the episode. In the past, endoscopic retrograde cholangiopancreatography (ERCP) has been the imaging test of choice for evaluation of idiopathic recurrent acute pancreatitis, whereas now endoscopic ultrasonography (EUS) and magnetic resonance cholangiopancreatography (MRCP) are advocated as safer options [4]. However, EUS should be considered as the first investigation for evaluation of idiopathic pancreatitis [5].

A 30-year-old man presented with idiopathic recurrent acute pancreatitis that had been occurring in the previous 8 months. Abdominal ultrasonography showed a bulky pancreas and MRCP findings were normal. Linear EUS was performed for evaluation of idiopathic recurrent acute pancreatitis. The pancreas was enlarged and hypoechoic, suggestive of acute pancreatitis. EUS revealed linear, nonshadowing, echogenic strips in a dilated pancreatic duct ([Fig. 1 a], [Fig. 1 b] and [Video 1]). An ascaris worm was seen as a linear shadow with two hyperechoic linear echogenic strips on either side of the longitudinal anechoic lumen ([Fig. 1 c]). Side-viewing endoscopy showed two worms in the duodenal lumen with one extruding from the papilla. The worms were removed with a biopsy forceps ([Fig. 2]). They were 29 cm and 22 cm in length ([Fig. 3]) and identified as A. lumbricoides. The patient underwent deworming with albendazole and was followed up for 6 months with no further episodes of acute pancreatitis.

Fig. 1 Endoscopic ultrasonography (EUS) was done for investigation of idiopathic recurrent acute pancreatitis in a 30-year-old man. a A linear echogenic shadow was seen in the pancreatic duct within the head of the pancreas. b EUS from the duodenal bulb demonstrated the ascaris worm in the head of the pancreas. c EUS from the descending duodenum showed a linear shadow with two hyperechoic linear echogenic strips on either side of the longitudinal anechoic lumen of the ascaris worm.

Endoscopic ultrasonography (EUS) was done for investigation of idiopathic recurrent acute pancreatitis in a 30-year-old man. Visualizations from the stomach, the descending duodenum, and the duodenal bulb, on clockwise and anticlockwise rotation of the probe, showed features of the ascaris infestation. Side-viewing endoscopy showed two worms in the duodenal lumen, one extruding from the papilla; these were removed using biopsy forceps.

Fig. 2 Side-viewing endoscopy showed two ascaris worms in the duodenal lumen; one was extruding from the papilla. They were removed with biopsy forceps.

Fig. 3 Two creamy white roundworms seen after removal.

To conclude, pancreatic ascariasis should be considered as a possible cause of idiopathic pancreatitis.

Endoscopy_UCTN_Code_CCL_1AF_2AF_3AZ

• References

• 1 Khuroo MS. Hepatobiliary and pancreatic ascariasis. Indian J Gastroenterol 2001; 20 (Suppl. 01) C28-C32
• 2 Mangiavillano B, Carrara S, Petrone MC et al. Ascaris lumbricoides-induced acute pancreatitis: diagnosis during EUS for a suspected small pancreatic tumor. JOP 2009; 10: 570-572
• 3 Khuroo MS, Zargar SA, Yattoo GN et al. Ascaris-induced acute pancreatitis. Br J Surg 1992; 79: 1335-1338
• 4 Stevens T. Role of endoscopic ultrasonography in the diagnosis of acute and chronic pancreatitis. Gastrointest Endosc Clin N Am 2013; 23: 735-747
• 5 Smith I, Ramesh J, Kyanam Kabir Baig KR et al. Emerging role of endoscopic ultrasound in the diagnostic evaluation of idiopathic pancreatitis. Am J Med Sci 2015; 350: 229-234