A rare etiology of idiopathic acute pancreatitis.

A 33-year-old Indian female presented with an episode of acute mild pancreatitis. There was no history of alcohol or drug intake. She was diagnosed as idiopathic acute pancreatitis (IAP) as her blood investigations, ultrasonography, computerized tomography (abdomen), and magnetic resonance cholangiopancreatography were normal. A linear endoscopic ultrasonography (EUS) was performed to determine the etiology of IAP [Figures 1 and 2].

Figure 1

Linear EUS from the stomach showed linear echogenic structure without acoustic shadow in the pancreatic duct (“single-tube sign” or “strip sign”)

Figure 2

The linear structure had two hyperechoic linear strips on either side of the longitudinal anechoic lumen representing fluid filled alimentary canal of the worm (“double tube sign” or “inner tube sign”)

QUESTION

What is the diagnosis?

ANSWER

Linear EUS from the stomach showed linear echogenic structure without acoustic shadow in the pancreatic duct (PD) (“single-tube sign” or “strip sign”) [arrow, Figure 1]. This linear structure had two hyperechoic linear strips on either side of the longitudinal anechoic lumen representing fluid filled alimentary canal of the worm (“double tube sign” or “inner tube sign”), which confirms the diagnosis of Ascaris Lumbricoides [arrow, Figure 2 and Figure 3]. On side-viewing endoscopy, one creamy white worm was seen in the lumen of the duodenum extruding from the papilla [Figure 4]. The worm was removed with biopsy forceps and identified as A. Lumbricoides. Patient underwent treatment with albendazole. On follow-up, EUS revealed normal pancreatic duct.

Figure 3

EUS showing the characteristic features of Ascaris

Figure 4

On side-viewing endoscopy, one creamy white worm was seen in the duodenal lumen

A. lumbricoides (round worm) infestation is endemic in tropical countries. A. lumbricoides is the most common helminthic infection in the world. Most infections by A. lumbricoides are asymptomatic. Although intestine is the normal habitat of adult worm, occasionally these worms migrate to bile duct or PD.[1] PD ascariasis is a rare entity. Abdominal ultrasound has low sensitivity for the diagnosis of PD ascariasis. EUS may be more sensitive for the diagnosis due to high frequency probes and better visualization of pancreas.[2] Pancreatic ascariasis should be considered in IAP particularly in developing nations. Treatment is removal of worms on side-viewing endoscopy if worms are seen extruding from the papilla with dormia basket, rat tooth forceps, or biopsy forceps.[34] Ascaris-induced pancreatitis is generally mild and worm extraction is associated with rapid relief of symptoms.[2]

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