Endocrine Abstracts

JOINT2010

Introduction: Hydrocephalus is a complication resulting from an obstruction in the cerebrospinal fluid pathway, and is frequently observed in encephalic tumors. Symptomatic treatment consists of cerebrospinal fluid bypass, either ventriculoperitoneal or external. Diabetes insipidus is a rarely reported complication of ventriculoperitoneal shunting. We report a clinical observation of transient diabetes insipidus complicating the placement of a ventriculoperitoneal derivation (VPD).

Clinical Case: Sixteen years-old female patient, admitted for investigation of a 15-day history of cerebellar syndrome associated with intracarnal hypertension. A cerebral CT scan revealed a lesional process in the posterior cerebral fossa responsible for tri-ventricular hydrocephalus with incipient involvement of the cerebellar tonsils. This was confirmed on brain MRI, showing a process at the expense of the cerebellar vermis. Workup noted Na: 137 mmol/land K: 3,8 mmol/l. The patient initially benefited from a Ventriculo-Peritoneal shunt, then underwent psoteromedian surgery with macroscopic subtotal excision of a friable hemorrhagic non-encapsulated mass with removal of VPD. The histological study is in progress. After surgery and during her stay in the intensive care unit, the patient presented a polyuropolydipsic syndrome with 6.8 l in and 6.54 l out, with clear and hypotonic urine. Urinary osmolarity was at 188 mosm/land Na at 145 mmol/l. At this stage the diagnosis of diabetes insipidus was evoked. Monitoring of the water balance was intensified, with progressive and spontaneous regression of the input-output values, with urine concentration becoming normal at day 12 post-shunt.

Discussion: Treatment of hydrocephalus saves countless patients, but CSF bypass procedures are sometimes responsible for complications of varying severity. The most common complications reported in the literature are infection, hemorrhage and shunt valve migration. Diabetes insipidus was rarely described. The pathogenic mechanism behind this complication is that when the 3rd ventricle is dilated to a large extent, the shunt valve’s position at its floor impinges on the hypothalamus and pituitary stem, exerting a mass effect on ADH neurons, when compression is reversible, diabetes insipidus would be transient, another mechanism is a distortion of the V3 wall with pituitary compression. This was the case in our patient, whose diabetes insipidus spontaneously regressed following removal of the VPD.

Conclusion: Transient diabetes insipidus is a rare complication of CSF shunts for the treatment of tumor-induced hydrocephalus. This fact should be borne in mind in order to detect this manifestation and institute any necessary therapeutic measures.

Key words: hydrocephaly, ventriculoperitonel derivation, insipidus diabetes.