Teaching Case

A female, developed hydrocephalus, secondary to viral encephalitis, for which a ventriculo-peritoneal shunt surgery was performed. She was admitted in our hospital, ten years later, because of a massive and progressively deteriorating distention of the abdomen.

The patient developed hydrocephalus, secondary to viral encephalitis, for which a ventriculo-peritoneal shunt surgery was inserted. She was admitted in our hospital, when she was 27-year-old, because of a massive and progressively deteriorating distention of the abdomen.
Physical examination revealed generalized abdominal dullness, a fluid wave, and a large, palpable, mildly tender mass, with no signs of intracranial hypertension.
Abdominal CT revealed quite a large cystic mass occupying nearly the whole abdominal cavity, smoothly displacing the adjacent organs, and measuring 18 x 15 x 8 cm (Fig.1a,b). The tip of the peritoneal catheter was within the cystic cavity.
A small midline laparotomy was performed and a large intraperitoneal pseudocyst identified and opened. More than 2000 ml of clear fluid were rapidly drained under pressure, and CSF dripped freely from the end of the catheter. No definite cyst wall was present, only adherent small intestinal loops held together by granulation tissue (pseudocyst). The adhesions were lysed as was possible, the old peritoneal tube was removed, and a new ventriculo-peritoneal shunt converted to a ventriculoatrial route. All cultures yielded no bacterial growth.
Our patient is still symptoms free, with no recurrence, after 5 years of follow-up.

The use of the peritoneal cavity for cerebrospinal fluid absorption in ventriculo-peritoneal shunting was introduced in 1905 by Kausch and this procedure has become a standard in the management of hydrocephalus. As more patients with treated hydrocephalus survive and live longer, more complications arise. The extracranial complications of ventriculo-peritoneal shunts are classified into mechanical ones and those secondary to intraperitoneal inflammatory reactions. Numerous reports of various and unusual complications from the presence of the catheter in the peritoneal cavity have been published. Most abdominal complications are not acutely life-threatening, but they can cause shunt dysfunction and create diagnostic and therapeutic difficulties.
An intraperitoneal cerebrospinal fluid pseudocyst, like in our case, is an important, but not very common complication in patients with ventriculo-peritoneal shunts. There are only few reports with adults, when most cases have been reported in children. Several predisposing factors for pseudocyst formation have been reported such as infection, peritoneal adhesions from previous surgery, multiple shunt revisions, increased CSF protein, malabsorption of CSF secondary to subclinical peritonitis and an allergic or non-specific inflammatory response to the peritoneal catheter or to a component of CSF.
A non- specific local tissue reaction against peritoneal tubing material was the most likely aetiological mechanism in our case with the pseudocyst formation. Our patient developed the pseudocyst ten years after the primary shunt insertion and, to our knowledge this is the longest period among reported adult cases.
Familiarity with a wide spectrum of complications arising from ventriculo-peritoneal shunt surgery is essential for the appropriate management of this progressively growing patient population, and modern imaging studies are adjuncts in making the clinical diagnosis. Awareness of these conditions among all neurosurgeons and prompt differential diagnosis could save valuable time and decrease the chance of further serious shunt complications.