Ascaris lumbricoides and its invasion of the accessory cystic duct: An unusual presentation

Case report

A 25-year-old woman, with no known co-morbidity, presented with complaints of abdominal pain, constipation and jaundice over the previous 5 days.

Eight days prior to this, she produced a vomitus which contained worms, for which she self-medicated with albendazole for 3 days. Thereafter she had acute generalized abdominal pain, moderate in intensity and continuous in nature. This was followed by multiple episodes of bilious vomiting and absolute constipation. She subsequently became jaundiced.

On examination, the patient was oriented in time, place and person, was normotensive but febrile (38 ℃) with a sinus tachycardia of 110 beats per minute. Jaundice was noted. The abdomen was soft but distended, with tender hepatomegaly. Bowel sounds were absent and digital rectal examination was unremarkable. Haematologic investigations showed a haemoglobin of 12.0 g/dL, a white count of 15,400 × 10⁹/L and a normal platelet count. Liver function tests showed a total bilirubin of 6.58 mg/dL, and direct bilirubin of 4.80 mg/dL, alkaline phosphatase of 375 U/L, and mildly raised transaminases (AST 40 U/L, ALT 74 U/L), a pattern consistent with cholestatic jaundice. Serum electrolytes, coagulation profile and urinalysis were within normal limits and the pregnancy test was negative.

Abdominal radiography showed findings consistent with small bowel obstruction. An ultrasound scan of the abdomen demonstrated multiple linear echogenic foci in the distal small bowel suggestive of worms, a hepatomegaly, and a single 2.1  cm calculus, compressing the common bile duct.

The patient underwent exploratory laparotomy with findings of over 100 worms inside the small bowel, for which an enterotomy was made in the ileum 30 cm from the ileo-caecal junction. Evacuation of worms was effected by manual decompression. The enterotomy was closed with a long-acting absorbable 3/0 suture, using Gambee’s technique, and reinforced by Lambert’s sutures. OPEN IN VIEWER

The gallbladder was thick-walled and inflamed, containing a single stone in Hartman’s pouch compressing the CBD, which explained the obstructive jaundice. Owing to the presence of numerous intestinal Ascaris worms, and suspicion of a palpable worm in the common bile duct, Kocherization of the duodenum was performed, but no worm was found. Cholecystectomy was then carried out, during which a small accessory cystic duct was noted opening into the common bile duct just superior to the main cystic duct. Before ligating this accessory duct, a 10-cm worm was found emerging from it and was grasped and removed by forceps.

ERCP was carried out on the third postoperative day, and showed a widened ampulla, with a mildly dilated common bile duct but no filling defect or leakage. A balloon sweep was unremarkable, and therefore no sphincterotomy or stenting was warranted.

The patient had an uneventful postoperative recovery, with gradual disappearance of her jaundice. She was discharged on the ninth postoperative day.

Discussion

Ascaris lumbricoides, the round worm, is found in 25% of the world’s population, and is the most common helminthic infection globally. ¹

It is prevalent predominantly in low and middle-income countries, mainly among children aged 2–10 years. ¹ Poor sanitation, inadequate public health standards, overcrowding, malnutrition and poverty aid its spread.^1–3

In humans, Ascaris is found mostly in the small bowel. While the adult worm can migrate into the biliary tree, it rarely infests the gallbladder as well, as the narrow, curved cystic duct impedes easy passage. ³

In an Indian study of 500 patients with hepatobiliary and pancreatic disease due to Ascaris, 34.2% were found to have worms in the biliary tree, but only 1.6% in the gallbladder itself. ⁴

While intestinal Ascaris can usually be treated medically, except in the case of bowel obstruction, biliary ascaris require extraction, either endoscopically or surgically. Symptoms subsequently usually subside immediately. ⁴

The main presenting complaint of patients with biliary Ascaris is biliary colic. ⁵ Complications may result in acute cholecysitis, cholestatic jaundice, acute cholangitis or pancreatitis. ⁶

Ultrasound is very useful in the early diagnosis of Ascaris infestations, ¹ demonstrating worms as tubular structures, lying parallel to the long axis of the duct. Its main limitation is its operator-dependency.

Where ERCP facilities are limited, manual palpation of the common bile duct intraoperatively may help in diagnosing biliary Ascaris where clinical suspicion exists. ⁷ However, this may not be completely reliable and an on-table T-tube cholangiogram may be necessary to confirm the diagnosis. The migration of Ascaris into the biliary tree is well known, but thus far none have been reported in an accessory cystic duct.

Conclusion

With the increasing use of ultrasonography and other imaging techniques like ERCP, it is not a routine practice to palpate the CBD in all cases with a positive history for Ascaris.

However, we recommend palpation of the CBD in all cases of acute abdomen, coming from Ascaris endemic areas, undergoing exploratory laparotomy. As demonstrated by Rehman et al., routine palpation of the CBD during laparotomy for acute abdomen identified cases of biliary ascariasis that were missed by ultrasound. This emphasises the fact that ultrasonography is not only operator-dependent, but also depends upon giving special consideration to the CBD during scanning.