Richard J. Edwards

Conservative management of patients with cerebrospinal fluid shunt infections.

OBJECTIVE:In patients with cerebrospinal fluid (CSF) shunt infection, removal of the shunt and antibiotic administration is the current standard of care. In 1986, we developed a protocol for the conservative management of patients with infected but functioning shunts. Treatment was based on the administration of a combination of intraventricular and systemic antibiotics. Intraventricular antibiotics were instilled via a separate access device. The purpose of this report is to describe our experience with this therapeutic intervention. METHODS:An observational study of all patients treated for CSF shunt infection between 1986 and 2003 was undertaken. Cure was defined by sterile CSF after completion of therapy and sterile shunt components at next revision or long-term freedom from recurrent infection (follow-up period, 6–88 mo). RESULTS:In total, 43 of 122 patients with CSF shunt infections were treated conservatively according to our protocol. Overall, 84% of these patients were cured, with a 92% success rate for patients with infections caused by bacteria other than Staphylococcus aureus. This included 30 coagulase-negative staphylococcal infections, of which two were treatment failures. We abandoned conservative treatment of patients with Staphylococcus aureus infections after early experience demonstrated that the success rate (four treatment failures in seven patients) was markedly lower than that for other pathogens. During the treatment and follow-up periods, there were three deaths, two of which were unrelated to shunt infection; treatment failure could not be completely excluded in the remaining patient. There was no toxicity related to intraventricular antibiotic administration. The incidence of shunt blockage among patients who were treated conservatively was not significantly different from that among a large cohort of patients with uninfected shunts. Ten patients received part of their courses of treatment as outpatients. CONCLUSION:The success rate of conservative management of patients with CSF shunt infections caused by coagulase-negative staphylococci is comparable with those in the published literature for patients treated conventionally. This form of management avoids surgical intervention, with its attendant risks, and is safe.

Chronic hydrocephalus in adults

Chronic hydrocephalus is a complex condition, the incidence of which increases with increasing age. It is characterised by the presence of ventricular enlargement in the absence of significant elevations of intracranial pressure. The clinical syndrome may develop either as a result of decompensation of a “compensated” congenital hydrocephalus, or it may arise de novo in adult life secondary to a known acquired disturbance of normal CSF dynamics. The latter may be due to late onset acqueductal stenosis or disruption of normal CSF absorptive pathways following subarachnoid hemorrhage or meningitis (“secondary” normal pressure hydrocephalus (NPH)). In some cases the cause of the hydrocephalus remains obscure (“idiopathic” NPH). In all forms of chronic hydrocephalus the clinical course of the disease is heavily influenced by changes in the brain associated with aging, in particular cerebrovascular disease. Recent research has challenged previously held tenets regarding the CSF circulatory system and this in turn has led to a radical rethinking of the pathophysiological basis of chronic hydrocephalus.

Routine placement of a ventricular reservoir at endoscopic third ventriculostomy

OBJECTIVEEndoscopic third ventriculostomy (ETV) failure may be abrupt in onset, causing a potentially life-threatening increase in intracranial pressure. ETV failure may also have a more insidious onset, and in these cases, diagnosis on clinical and radiological grounds can be difficult. This study evaluates the usefulness of routine ventricular reservoir placement at the time of ETV for subsequent emergency ventricular access or the diagnosis of ETV failure. METHODSA retrospective review of 84 consecutive patients undergoing ETV with routine insertion of a ventricular reservoir during a 4-year period (1996–2000) was undertaken. The mean follow-up period was 14.8 months. End points for ETV failure were shunt insertion or revision of ETV. The diagnostic and therapeutic use of the reservoir was quantified. RESULTSThe reservoir was used in 32% of patients (n = 27). The reservoir allowed life-saving emergency ventricular access in two cases of acute recurrent hydrocephalus. In patients with symptoms but equivocal radiological evidence of recurrent hydrocephalus, the reservoir allowed for assessment of intracranial pressure (n = 19) and/or a therapeutic trial of cerebrospinal fluid aspiration (n = 5). Seven of these patients subsequently required revision ETV or shunt insertion. In the 14 patients who had normal intracranial pressure, conservative management was successful. The reservoir also facilitated intrathecal drug administration for postoperative ventriculitis (n = 2). No patients requested reservoir removal. CONCLUSIONRoutine insertion of a ventricular reservoir allows life-saving emergency therapeutic cerebrospinal fluid aspiration to be performed for sudden neurological deterioration caused by ventriculostomy failure. It also assists in the diagnosis of ETV failure and allows intrathecal drug administration.

Foreign Accent following Brain Injury: Syndrome or Epiphenomenon?

87 worsening of the OSAS. Due to the very high frequency of recurrent and long-lasting nocturnal apnea episodes, the onset of the stroke during one of the apnea-hypopnea episodes was highly probable. An atherothrombotic or cardioembolic mechanism was not supported by medical history, transthoracic echocardiography, duplex ultrasonography of the neck vessels and the prompt normalization without treatment of blood pressure values. However, even if a possible role of postattinic lesions could not be excluded, they were minimal, asymptomatic and remote in time. We hypothesize that the ischemic stroke might have been triggered by the severe oxygen desaturation during the repeated and prolonged nocturnal apnea-hypopnea episodes. Besides, the presence of asymptomatic bilateral basal ganglia lacunes strenghtens the hypothesis that repetitive nocturnal apnea episodes might have caused those asymptomatic lesions. Early diagnosis and treatment of OSAS might help to avoid severe oxygen desaturation episodes, and thus prevent stroke. Further studies are needed to better clarify which AHI values might indicate a very high risk.

Brain biopsy in cryptogenic neurological disease

Objective. Brain biopsy is standard clinical practice when CNS malignancy is suspected. Its value has not otherwise been clearly established. We reviewed the indications for, complications and outcome of diagnostic brain biopsies performed between 2003 and 2008 in a single UK centre. Methods. Subjects were retrospectively identified using theatre log books and histopathology reports. Case records were analysed by a neurologist and neurosurgeon. Cases were excluded when the pre-operative diagnosis was clearly malignancy or infection. Results. Of all (432) brain biopsies performed, 56 were performed in 52 patients with cryptogenic neurological disease. There were no permanent deficits or deaths. Histopathological reports were classified as definitive (45%), suggestive (20%) or non-diagnostic (36%). Brain biopsy made an immediate contribution to determination of diagnosis in 55% (31 of 56) and a confident diagnosis was eventually made in 40 of 52 patients (77%). Management was altered as a consequence of biopsy in 63%. Successful biopsy of a radiologically identified target increased the proportion of biopsies considered diagnostic to 78% (odds ratio 8.9) whereas non-targeted biopsy was non-diagnostic in 71%. Although a significant proportion of patients died or had progressive disease, this was not uniformly the case; 31% stabilised and 27% improved. Conclusion. We present the highest reported frequency of brain biopsy for cryptogenic neurological disease. The risk associated with the procedure was low and the biopsy results impacted significantly upon diagnosis and management. We therefore propose that the procedure should no longer be considered one of last resort.

Preliminary Evaluation of a Novel Intraparenchymal Capacitive Intracranial Pressure Monitor

OBJECT Intracranial pressure (ICP) monitors are currently based on fluid-filled, strain gauge, or fiberoptic technology. Capacitive sensors have minimal zero drift and energy requirements, allowing long-term implantation and telemetric interrogation; their application to neurosurgery has only occasionally been reported. The aim of this study was to undertake a preliminary in vitro and in vivo evaluation of a capacitive telemetric implantable ICP monitor. METHODS Four devices were tested in air- and saline-filled pressure chambers; long-term capacitance-pressure curves were obtained. Devices implanted in a gel phantom and in a piglet were placed in a 3-T MR unit to evaluate MR compatibility. Four devices were implanted in a piglet neonatal hydrocephalus model; output was compared with ICP obtained through fluid-filled transduction and a strain-gauge ICP monitor. RESULTS The capacitance-pressure relationship was constant over 4 weeks, suggesting minimal zero drift during this period. There were no temperature changes around the monitor. Signal loss at the sensor was minimal in both the phantom and the piglet. Over 114,000 measurements were obtained; the difference between mean capacitive ICP and fluid-transduced ICP was 1.8 ± 1.42 mm Hg. The correlation between ICP from the capacitive sensor and fluid-filled transducer (r = 0.97, p < 0.0001) or strain-gauge monitor (r = 0.99, p < 0.0001) was excellent. In vivo monitoring was restricted to 48 hours due to problems with robustness in the clinical environment. CONCLUSIONS This preliminary study demonstrates minimal long-term zero drift in vitro, good MR compatibility, and good correlation with other methods of ICP monitoring in vivo in the short term. Further long-term in vivo study is required.

The constant flow ventricular infusion test: a simple and useful study in the diagnosis of third ventriculostomy failure

OBJECT The evaluation of third ventriculostomy function in hydrocephalic patients is challenging. The utility of the constant flow infusion test in predicting response to shunt insertion in normal-pressure hydrocephalus, as well as in identifying shunt malfunction, has been previously demonstrated. The object of this study was to evaluate its usefulness in determining whether a revision CSF diversion procedure was indicated in patients presenting with recurring symptoms and persisting ventriculomegaly after endoscopic third ventriculostomy (ETV). METHODS The authors conducted a prospective study of all patients who, after undergoing ETV at their institution, presented postoperatively with recurring symptoms and persisting ventriculomegaly. RESULTS Forty-six patients (mean age 40.7 years, including 11 patients younger than 18 years) underwent 56 constant flow ventricular infusion tests (VITs) at a mean of 24.7 months post-ETV. Thirty-three patients with resistance to CSF outflow (R(out)) less than 13 mm Hg/ml/min underwent follow-up (median 17 months) and experienced resolution of symptoms. In 10 episodes R(out) was greater than 13 mm Hg/ml/min; the patients in these cases underwent revisional CSF diversion. Two patients demonstrated high and frequent B (slow) waves despite a low R(out); these patients also underwent successful revisions. Patients who improved after surgery had increased B wave activity in the plateau phase of the VIT (p = 0.01). Thirty-four patients underwent MR imaging at the same time; 4 had high R(out) despite evidence of flow across the stoma. These 4 patients underwent surgery and experienced resolution of symptoms. Of 9 patients without flow, R(out) was less than 13 mm Hg/ml/min in 4; these patients were successfully treated conservatively. CONCLUSIONS The VIT is a useful and safe adjunct to clinical and MR imaging evaluation when ETV failure is suspected.

Brain biopsy in benign neurological disease.

Brain biopsy is well established in clinical practice when there is suspicion of CNS malignancy. However, there is little consensus regarding the indications for brain biopsy in non-malignant neurological disease. This is due in no small part to limitations in the available literature pertaining to diagnostic brain biopsies. The published evidence largely comprises small, retrospective, single-centre analyses performed over long time periods, including non-homogeneous patient groups with considerable variation in reported outcomes. Here we present pragmatic guidance for those clinicians considering diagnostic brain biopsy in a patient with non-neoplastic neurological disease and highlight practice points with the aim of maximising the probability of gaining clinically useful information from the procedure.

Side-effects of risperidone therapy mimicking cerebrospinal fluid shunt malfunction: implications for clinical monitoring and management

Risperidone is an atypical antipsychotic used in the treatment of several psychiatric disorders in both children and adults. We present two patients with hydrocephalus and learning difficulties who were admitted to the neurosurgical unit with a suspected cerebrospinal fluid shunt malfunction and raised intracranial pressure. They had both been commenced on risperidone for the treatment of aggressive outbursts. Twelve days after commencing risperidone, the first patient developed symptoms of headache, nausea, vomiting, drowsiness, lethargy and two episodes of collapse. The second patient presented with similar symptoms 4 days after his risperidone dose was increased. An unnecessary shunt exploration was averted in both cases when it was noted that the side-effect profile of risperidone mimicked exactly those of shunt malfunction. Discontinuation of the drug resulted in complete resolution of all symptoms within 72 h. Many patients with shunted hydrocephalus have associated developmental disorders that may warrant treatment with risperidone. Clinicians should be aware of the potential symptom overlap between shunt malfunction and risperidone side-effects in these patients.

Amnesia due to spontaneous haemorrhage into a colloid cyst.

Abstract Anterograde amnesia is a recognised complication of colloid cyst excision, occurring usually as a result of forniceal injury. However, spontaneous amnesia due to intra-cyst haemorrhage prior to excision has not been reported previously. We report such a case in which amnesia completely resolved following endoscopic cyst excision.