Intraperitoneal cerebrospinal fluid pseudocyst with ventriculoperitoneal shunt.

Ventriculoperitoneal (VP) shunting is mostly used in the treatment of hydrocephalus and many complications have been reported with this method. Abdominal Pseudocyst (APC) are relatively uncommon but important complications in patients with VP shunts. We herein report the case of a 9-year-old boy with VP shunt who presented with abdominal distension, abdominal pain, malaise, and decrease of appetite. Abdominal pelvic computed tomography confirmed a diagnosis of APC. Laparotomy was done and VP shunt was placed into the other side of peritoneal cavity again. Also here, etiology, presentation, diagnosis, and treatment of APC were reviewed.

INTRODUCTION

Hydrocephalus is a common disease characterized by cerebrospinal fluid (CSF) secretion, circulation, and absorption abnormalities, which results in ventriculomegaly.[1] Ventriculoperitoneal (VP) shunting is the most frequent operative procedure for the management of hydrocephalus and the peritoneal cavity is the best site for CSF absorption.[2] The other distal diversion sites for CSF include the right atrium of the heart, ureter, gall bladder, and pleural space.[34] An abdominal pelvic pseudocyst is a rare, important complication of VP shunts.[456] Cyst is surrounded by a wall of nonepithelial tissue, so it is classified as pseudocysts.[37] Typical clinical presentation includes abdominal pain and/or distention, nausea, vomiting, decreased appetite, fever, and shunt malfunction signs such as headache and lethargy.[6] Abdominal signs such as abdominal pain/distension and palpable abdominal mass are predominant in adults and shunt malfunction symptoms such as headache, nausea, and vomiting are common in podiatrists.[4] This article describes a 9-year-old boy, a case of APC after VP shunt insertion and reviewed the etiology, clinical picture, diagnosis, radiological findings, and surgical treatment of APC.

CASE REPORT

The patient was a 9-year-old boy, a known case of seizure since birth on clobazam and sodium valproate who had a VP shunt for congenital hydrocephalus when he was 3 months old. He underwent three times’ shunt revision, the last of which was performed when he was 3.5 years old due to shunt infection. The patient was admitted here with the chief complaint of abdominal distension and malaise. On examination, the patient was lethargic with slight fever. The abdomen was markedly distended without tenderness and normal bowel sound. Ultrasonography revealed severe free fluid in the abdominal pelvic cavity. Abdominal pelvic computed tomography (CT) showed an enlarged loculated cyst in the abdominal cavity with pressure effect on the bowel loops and displacement of them to the posterior part [Figures 1-3]. The tip of the VP shunt is noted in the peritoneal cavity. Shunt tap and CSF analysis was done. The CSF was clear with protein: 10 mg/dL and glucose 57 mg/dL. CSF Gram stain revealed no organism and the culture was negative. The leukocyte and erythrocyte counts were 0 and 150, respectively. The patient underwent laparotomy and cyst drainage was done with removal of the cyst wall; then, the VP shunt was placed into the other side of the peritoneal cavity. Abdominal fluid was clear with leukocyte 3, segment: 2, lymphocyte: 1, protein: 1.2, glucose: 99, and negative culture on Gram stain. We observed recollection of the APC, two months after open marsupialization of the cyst by the paediatric surgeon. Thus the site of the catheter was changed form the peritoneal cavity to the pleural cavity. No more symptoms were recorded and the patient was symptom-free at 6-month follow-up.

Figure 1

Axial section of abdominopelvic computed tomography scan with intravenous and oral contrast showing nonenhanced simple cyst

Figure 3

Coronal section of abdominopelvic computed tomography scan that filled with a large simple cyst and with the tip of shunt catheter in it

Sagittal section of abdominopelvic region showing a large simple cyst that filled whole of the abdominopelvic cavity and causing abdominal distension

DISCUSSION

VP shunting may result in many complications such as mechanical VP shunt failure, infection, and abdominal complications. Abdominal complications include bowel obstruction and perforation, peritonitis, volvulus, ileus, and APC.[89] APC is an uncommon complication of VP shunt.[10] The pathogenesis of CSF pseudocysts is still controversial. Low-grade shunt infections, chronic inflammation, multiple shunt revision, peritoneal adhesion, increased CSF protein content, malabsorption of CSF secondary to subclinical peritonitis, silicon allergy, etc., are the predisposing factors for CSF pseudocyst formation, but the pathophysiology is still unknown.[11]

The diagnosis of APC depends on the detailed history taking and a high index of suspicion. Ultrasonography and CT scan are the principal diagnostic imaging techniques that help the physicians reach a definite diagnosis. Sonography is an easy way for rapid and reliable diagnosis of APC. Sonographic findings may show a sonolucent mass without septation, the so-called railroad sign. CT scan indicates a definitive diagnosis of abdominal CSF pseudocysts, especially when abdominal pseudocysts are not defined by ultrasonography. The imaging criteria for the diagnosis of APC include a large fluid-filled collection delimited by a thin wall adjacent to the catheter tip and without septation.[1712] The most common differential diagnoses of abdominal cystic mass are abdominal abscess, mesenteric cyst, benign cystic lymphangioma, cystic spindle cell tumor, pancreatic pseudocysts, and duplication cyst.[713] Surgical treatment options include laparotomic or laparoscopic-assisted fluid drainage with or without wide excision of the APC walls, removal of shunt/shunt externalization and placement of shunt catheter in different abdominal quadrants, or conversion to either a ventriculoatrial or ventriculopleural system.[13]

CONCLUSION

Abdominal CSF pseudocysts are an uncommon but important complication of VP shunt, so early diagnosis and treatment of APC would improve the clinical outcome. Close clinical and radiographic follow-up for recurrent APC or shunt malfunction is recommended.

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The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.