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Year : 2005  |  Volume : 15  |  Issue : 1  |  Page : 107-108
Ultrasound diagnosis of intestinal ascariasis

Department Of Ultrasonography, Balku's Scan, Pvs Hospital, Calicut 2, Kerala 673 002, India

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Keywords: Ultrasound diagnosis, Ascaris lumbricoides, intestinal ascariasis

How to cite this article:
Balakumar K. Ultrasound diagnosis of intestinal ascariasis. Indian J Radiol Imaging 2005;15:107-8

How to cite this URL:
Balakumar K. Ultrasound diagnosis of intestinal ascariasis. Indian J Radiol Imaging [serial online] 2005 [cited 2020 May 30];15:107-8. Available from:

   Introduction Top

The conventional method of diagnosing ascariasis is by testing the stool for the presence of the eggs. When there are atypical abdominal symptoms in association with a vague abdominal mass, a routine ultrasound scan using the common 3-3.5 MHz probe yields no definite findings to diagnose intestinal ascariasis. If a high frequency probe of 5-10 MHz is used instead, intestinal ascariasis could be definitely established. This case illustrates a typical worm mass diagnosed with the help of a high frequency probe.

   Case report Top

A 7-year-old girl was referred for ultrasound scanning because of vomiting, abdominal pain of short duration and a vague mass in the central abdomen. There were no signs of peritonitis.

The routine abdominal scanning using a 3-3.5 MHz probe was inconclusive. However, on careful scrutiny one would have noticed the tiny linear shadows with in the bowel lumen [Figure - 1]. Actually, this was a retrospective interpretation. Otherwise, there was no definite definable mass in the abdomen. Another attempt using a high-density multifrequency linear probe of 5-10 MHz showed an entirely striking picture. There were multiple squirming brighter tubular shadows having an average diameter of 4 mm with a central hypoechoic core [Figure - 2]. A cross-sectional view of the worm with in the duodenum depicted a typical bright ring shadow [Figure - 3]. The overcrowded worms were causing subacute intestinal obstruction by forming an ill-defined intraluminal mass like a bundle of stacked tubes on ultrasonography [Figure 4]. These structural features were consistent with the diagnosis of intestinal ascariasis. The other visceral echoes were normal.

   Discussion Top

Ascaris lumbricoides is a common nematode infesting a major percentage of human beings worldwide (more than 1.4 billion). It grows to a maximum length of 35 cm. This species is host specific to human beings and lives longer (1-2 years) with in the small intestine. Infested individuals are mostly asymptomatic though it is a causative agent for some very common symptoms. The literature shows enough reports on biliary ascariasis [1],[2],[3],[4]. The ultrasound scanning is the specific diagnostic tool in case of biliary infestation. The detection is usually possible with the commonly used abdominal ultrasound probe of 3-3.5 MHz. However, as the bowel loops are just under the abdominal wall, the detection of intestinal ascariasis is difficult by routine abdominal probes. It demands the use of a higher frequency high-density probe of 5 - 10 MHz, as illustrated here. The live worm on longitudinal section appears as a writhing tubular shadow having brighter margins described by some as 'strip sign'. There is a hypoechoic core producing the 'inner tube sign'. The coiled worm appears as 'spaghetti' (5). The cross-sectional picture is also characteristic of a tubular body described as the ring sign or bull's eye sign if seen with in the CBD or a narrow lumen [2]. In the author's opinion, when the crowded worms form a ball like mass, the ultrasound sectional view can be called as the "stacked tubes sign". The diagnosis is specific for this large nematode mass, if these signs are discernable. This child was cured after a course of antihelminthic drug.

   References Top

1.Kedar RP & Malde HH. Biliary ascariasis associated with cholangiocarcinoma. Abdominal Imaging 1993; 18:76-77.   Back to cited text no. 1    
2.Ng KK, Wong HF, Kong MS et al. Biliary ascariasis: CT, MR cholangiopancreatography and navigator endoscopic appearance- report of a case with acute biliary obstruction. Abdominal Imaging 1999; 24 (5): 470-472.   Back to cited text no. 2    
3.Gonzalez AH, Regalado VC & Ende JV. Non-invasive management of Ascaris lumbricoides biliary tract migration: a prospective study in 69 patients of Ecuador. Tropical Med & International Health 2001; 6 (2): 146-150.   Back to cited text no. 3    
4.Mehta P, Rajagopal KV, Lakhkar BN. Radiological Quiz- Abdomen. Ind J Radiol Imaging 2002; 12 (1): 121-122. 5. Shobha Desai. Biliary ascariasis: Sonographic findings. AJR 1995; 164: 767-768.   Back to cited text no. 4    

Correspondence Address:
K Balakumar
Railway Station Road, Pvs Hospital, Calicut 2, Kerala 673 002
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-3026.28759

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[Figure - 1], [Figure - 2], [Figure - 3]

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