Acute Shunt Obstruction and Cesarean Section image studies to measure the baseline size of the ventricles. During pregnancy in patients with shunts, the patients should be watched for symptoms and signs of increased intracranial pressure (ICP). Signs of increased ICP were reported in 58% of pregnancies with shunts (5). The most common symptoms are headache, nausea, vomiting, drowsiness, gaze paresis, ataxia, and seizures. However, the symptoms of increased ICP are not always associated with shunt malfunction (5, 10-12). Women with well functioning shunts frequently have symptoms of increased ICP during pregnancy because of an increase in brain water and venous distension (10). Therefore, brain images before conception are important for determining whether the shunt is functioning during pregnancy in patients with shunts. If the CSF shunt is functioning inappropriately dur- ing pregnancy, the imaging studies show greater enlargement of the ventricles compared to the preconception study. Mag- netic resonance imaging seems to be a safe, effective tool for monitoring ventricular dilatation and diagnosing shunt fail- ure (5, 7). In addition, the pregnancy of a woman with a CSF shunt differs from that of a normal pregnancy, primarily during the third trimester. The flow of CSF in pregnant women decreas- es either because the shunt is being compressed between the gravid uterus and other internal organs or because the intra- abdominal pressure has increased secondary to the large size of the uterus (2). As a ventriculo-atrial (VA) or ventriculo- pleural (VPL) shunt may be influenced less by the increased abdominal pressure, some studies have advocated that a VA shunt be considered on revision of a VP shunt or during the initial surgery for hydrocephalus in pregnant woman (2, 3, 5, 13, 14). VA or VPL shunts might be preferable to avoid uterine trauma on the placement of a distal catheter. More- over, shunt revisions in the case of VA shunts have also been reported (1). Endoscopic third ventriculostomy is one treat- ment modality for pregnant patients with newly diagnosed obstructive hydrocephalus and malfunction of a preexisting 649 shunt (15). Although a chance of shunt malfunction related to preg- nancy has always existed, few cases require shunt revision. Liakos et al. (1) reported that the rates of shunt malfunction and revision before delivery were 13.7% and 5.0%, respec- tively, in 138 shunt-dependent pregnancies. In their review of the literature, Okagaki et al. (13) found that only 2 (12.5%) of 16 pregnancies with CSF shunts required revision. Many patients with shunt malfunctions can be managed with bed rest and manual pumping of the flushing device of the shunt. In addition, one should remember that the symptoms of in- creased ICP may mimic those of preeclampsia and an appro- priate workup should be obtained (5). The outcomes of pregnancy in terms of live births are over- whelmingly favorable (1, 3, 16). The mode of delivery should be managed carefully in pregnancies with CSF shunts, and a vaginal delivery is preferred to a cesarean section (1, 2, 4, 5). Vaginal deliveries should be attempted in pregnancies with VP shunts unless cesarean sections are inevitably required for obstetrical or neurosurgical reasons (17). A shortened second stage is preferred to obviate straining and consequent eleva- tion of the ICP. General anesthesia is preferred for the surgi- cal delivery of such patients, while epidural anesthesia is not recommended because an inadvertent dural puncture might result in contamination of the CSF (3, 5). A cesarean section may cause adhesion formation around the shunt tip in VP shunts and may increase the possibility of shunt infections, as bacteremia occurs more often after cesarean sections (5). Meticulous hemostasis and profuse irri- gation of the peritoneal cavity should be performed to mini- mize the risk of future obstruction due to fibrin deposition on the end of the shunt (3). Fourteen women (10.1%) in 138 shunt-dependent pregnancies had postpartum revisions, of which eight were vaginal deliveries and six were cesarean sec- tions (1). However, no acute shunt failures occurred during the course of delivery in these reports. In our case, the shunt Table 1. Recommendations for management of shunt malfunction in shunt-dependent pregnancy Time of pregnancy Preconception Screening Type of complications Antepartum Delivery Postpartum Shunt malfunction Shunt malfunction without obstruction Shunt malfunction with obstruction Anesthesia Shunt obstruction due to blood clots during cesarean section Shunt obstruction Recommendations of management Imaging study (brain CT/MRI) Interdisciplinary consultation Following usual protocols for shunt failure Medical management Distal catheter revision Endoscopic third ventriculostomy Avoid epidural anesthesia Meticulous hemostasis, profuse irrigation of peritoneal cavity during cesarean section Revision of shunt device as usual Comments For monitoring ventricular dilatation Bed rest, pumping of flushing device appropriate workup for preeclampsia Ventriculo-atrial shunt, ventriculo-pleural shunt Risk of CSF contamination NSVD- recommended mode of delivery Ventriculo-peritoneal shunt preferred CT, computerized tomography; MRI, magnetic resonance imaging; CSF, cerebrospinal fluid; NSVD, normal spontaneous vaginal delivery.