A 7-month-old boy, with a right-sided Ventriculo-peritoneal (VP) shunt in-situ for 2 months, presented with shunt tube protruding through anus for 2 hours. The infant was treated for acute diarrhea till 2 days ago. There were no signs of meningitis or peritonitis. Perineum showed a ‘bunch of shunt coils’ dripping cerebrospinal fluid (Fig. 1). Abdominal X-ray showed point of entry of the shunt tube into the sigmoid colon with no pneumoperitoneum (Fig 1). The shunt was divided through small subcostal incision; cranial end was removed and the peritoneal end was pulled out through anal opening.

Fig. 1 (a) Infant with ‘bunch of coils’ of shunt tube protruding through the anus with securing sutures in situ (red arrow); (b) Abdominal X-ray showing point of shunt entry into the sigmoid colon (red arrow) and shunt coils lying in the perianal region(white arrow).

Besides infection, malfunction, and CSF loculations, the shunt tube can migrate into any visceral organ [1]. Intestinal perforation caused by shunt procedures is rare, and about 50% occur in infants. Anal protrusion of shunt is an extremely rare complication [1,2].

Often, some surgeons keep sufficient length of shunt tube to accommodate for the linear growth of the baby by coiling the peritoneal end and securing the ‘bunch of coils’ with an absorbable suture in the supra-hepatic space so that shunt does not spread itself all over the peritoneal cavity between the intestinal loops. This decreases the chances of intestinal perforations and spontaneous knotting. Despite this effective technical modification to tackle peritoneal complications, anal protrusion still occurred in this child, and the entire ‘bunch of intact coils’ of shunt protruded en-masse through the anus without any peritonitis. Such protrusion should create a big rent in the eroded sigmoid colon or cause peritonitis but strangely there was none, suggesting that shunt erosion is a slow process where erosion and healing by shunt induced adhesions takes place simultaneously to conceal a free perforation. The shunt tip adheres and erodes the bowel by continuous friction, and is then propelled distally by peristalsis to protrude anally [3,4]; diarrhea may further aggravate the process of protrusion.

Mechanisms responsible for silent erosion and anal protrusion are multifactorial. Predisposing factors for anal protrusions are stiff shunt tube, thin bowel wall with strong peristalsis in infants, malnutrition, infection and foreign body reaction. Exaggerated peristalsis in diarrhea can predispose to en-masse protrusion of shunt coils. Redundant sigmoid colon is the most favorable site for shunt erosion and subsequent anal protrusion. Abdominal X-ray does not show pneumoperitoneum because shunt perforations are usually concealed. Anal protrusion of shunt without peritonitis is treated by percutaneous division and removal of the cranial end, and the peritoneal end is pulled out through the anus [3,5]. The perforation is usually sealed by a chronic fibrous sheath around the shunt track, and laparotomy is usually not required [3,5].

1. Ho KJ. Recurrent meningitis associated with intragastric migration of a ventriculoperitoneal shunt catheter in a patient with normal-pressure hydrocephalus. South Med J. 1992;85:1145-8.

2. Sathyanarayana S, Wylen EL, Baskaya MK, Nanda A. Spontaneous Bowel Perforation after ventriculoperitoneal shunt surgery: Case report and a review of 45 cases. Surg Neurol. 2000;54:388-96.

3. Digray NC, Thappa DR, Arora M, Mengi Y, Goswamy HL. Silent bowel perforation and transanal prolapse of a ventriculoperitoneal shunt. Pediatr Surg Int. 2000;16:1;94-5.

4. Ansari S, Nejat F, Dadmehr M. Extrusion of ventriculoperitoneal shunt catheter through the rectum and retrograde meningitis. Pediatr Infect Dis J. 2005;24:1027.

5. Jamjoom AB, Rawlinson JN, Kirkpatrick JN. Passage of tube per rectum: An unusual complication of a ventriculoperitoneal shunt. Br J Clin Pract. 1990;44: 525-6.