Central nervous system complications of cardiac surgery

The neurological complications of cardiac surgery are associated with significantly increased mortality, morbidity and resource utilization. The use of new surgical techniques, introduction of wider indications for surgery and increased public expectation has led to an increase in the average age of cardiac surgical patients and an increased incidence of repeat procedures. With these changes has come an increased risk of neurological complications. The likelihood of perioperative stroke varies between 1% and 5% in most published series and is dependent on a multitude of risk factors. Of these, patient age, aortic atheroma, symptomatic cerebrovascular disease, diabetes mellitus and the type of surgery appear to be most important. Cognitive deterioration after cardiac surgery is far more common, affecting as many as 80% of patients a few days after surgery and persisting in one-third. Despite an increase in the age of the cardiac surgical population, the reported incidence of cognitive dysfunction after cardiac surgery seems to have fallen in recent years. Whether this is a real phenomenon or the result of changes in the use of psychometric testing and the definition of cognitive decline remains unclear. Recognition that certain equipment, surgical practices and patient factors contribute to neurological morbidity has prompted 'neuroprotective' interventions. Some of these (e.g. arterial line filtration and alpha-stat management) have been shown to improve outcome. Despite these measures, a small number of patients will inevitably sustain cerebral injury during otherwise successful cardiac surgery. Although pharmacological neuroprotection may, in the future, offer some of these patients an improved outcome, it is unlikely that any single agent will prevent neurological injury. In the meantime, the CNS complications of cardiac surgery remain a fertile area of research.      

Central nervous system manifestations of Sj?gren's syndrome. A case report

A patient with primary Sj?gren's syndrome and a previous history of systemic vasculitis is presented to document neurological disease which suggests involvement of the brainstem and cerebellar connections with neuropsychiatric manifestations. The investigations and management are briefly outlined.     

Central nervous system neuromodulation for the treatment of epilepsy

We present here a review of the work on neuromodulation - defined as application of an inhibitory or excitatory current - on intracranial structures for the treatment of drug-resistant epilepsy. Near 250 patients were treated using a neuromodulation technique of the cerebellum (paravermian cortex), the CM-pf nucleus of the thalamus, the hippocampus, epileptogenic foci, and anterior ventral nucleus of the thalamus, with a one- to 15-year follow-up. Four contact strips were used for cerebellar and functional region neuromodulation, and DBS-type depth electrodes were stereotactically implanted for CM-pf and anterior nuclei of the thalamus and hippocampal neuromodulation. Electric stimulation was cyclic in almost all trials, using low frequency (10-40 Hz) for excitation and high frequency (60-185 Hz) for inhibition. Seizure frequency reduction was variable, depending on the neuromodulation site and patient selection, although seizure duration decreased in most patients. Cerebellar neuromodulation was followed by a 78% reduction in tonic and tonic-clonic seizures, CM-pf neuromodulation by an 83% reduction in tonic-clonic seizures and atypical absence of Lennox-Gastaut syndrome, with a 17.2% seizure-free and drug-free patient rate. Hippocampal neuromodulation was followed by a 73% reduction in partial complex seizures, with a 33% seizure-free patient rate. Anterior ventral nucleus of the thalamus was followed by a 63% reduction in tonic-clonic, tonic and atonic seizures. Several prognostic factors were identified in order to improve future results. There was no mortality and morbidity was limited to skin erosion at the neurostimulator site. Seizure reduction was associated with improved neuropsychological performance and better quality of life. Neuromodulation is safe and effective for the treatment of epileptic seizures of various origins. Several targets may be associated in a single patient, especially when bilateral hippocampal seizure foci are present.     

Treatment of hirudin overdosage in a dialysis patient with heparin-induced thrombocytopenia with mixed hemodialysis and hemofiltration treatment

We report a patient who developed type II heparin-induced thrombocytopenia (HIT) and accidentally received a recombinant hirudin (r-hirudin) overdosage. Treatment with hemodialysis (HD) using high-flux polysulfone dialyzer and hemofiltration was performed. Length of treatment was adjusted, monitoring activated partial thromboplastin time (aPTT) to 1.5-2.5 times the mean of the normal range. She developed deep venous thrombosis and occlusion of vascular access. Only after cessation of heparin lock catheter, platelet count began to increase. After one year of treatment with acenocoumarol and additional low-dose r-hirudin, neither bleeding nor thrombotic episodes have been reported.     

Central nervous system histoplasmosis

Involvement of the central nervous system (CNS) is recognized clinically in 5% to 10% of patients with progressive disseminated histoplasmosis. The risk of developing CNS histoplasmosis is increased in individuals with impaired cellular immunity, but not all patients with this condition are immunocompromised. Clinical syndromes include chronic meningitis, focal parenchymal lesions of the brain or spinal cord, stroke due to infected emboli, and diffuse encephalitis. CNS histoplasmosis should be considered in any patient with one of these syndromes who has resided in an area endemic for histoplasmosis. A high index of suspicion is necessary when extraneural signs and symptoms are absent. Culture of the causative fungus, Histoplasma capsulatum, from cerebrospinal fluid, brain tissue, or other sites is the gold standard for diagnosis. In culture-negative cases, detection of H. capsulatum antigen in cerebrospinal fluid, urine, or blood is helpful diagnostically. Aggressive and prolonged antifungal therapy is indicated in all cases of CNS histoplasmosis. There are no data from prospective comparative trials upon which to base specific recommendations for treatment. Expert opinion favors an initial course of liposomal amphotericin B, followed by at least 1 year of itraconazole.     

Central nervous system agents in the treatment of erectile dysfunction

In the last two decades, a better understanding of the mechanisms governing erectile function and the pathophysiologies underlying erectile dysfunction (ED) have led re-searchers to investigate novel treatment concepts. Selective type-5 phosphodiesterase inhibitors are recommended as first-line therapy because of their high efficacy, but 30% to 40% of patients who have ED do not respond adequately to these agents and require alternative methods. The central nervous system plays a fundamental role in sexual behavior. Animal models have advanced our understanding of the neuroanatomic and neuropharmacologic basis of centrally induced penile erections. Clinical research with apomorphine has demonstrated efficacy in men who have a range of ED. Recent interest has focused on other centrally acting agents for ED treatment, including the melanocortin receptor agonists.     

Central nervous system control of ejaculation

An overview is given of the regions in the spinal cord that are active during ejaculation. Motoneurons involved are the preganglionic sympathetic motoneurons in the upper lumbar spinal cord and the motoneurons in the nucleus of Onuf, located in the upper sacral cord. The first group is involved in the so-called emission phase of ejaculation, the last group in the expulsion phase. Both groups receive afferents from premotor interneurons in the so-called intermediomedial cell groups located at about the same level as the motoneurons themselves. A concept is put forward in which these premotor cell groups represent the central spinal pattern generators for ejaculation, one for the emission phase and one for the expulsion phase. Clinical observations in patients suffering from transection of the spinal cord indicate that the ejaculation motoneurons as well as their spinal central pattern generators are under strong influence of descending pathways originating in supraspinal parts of the brain. The various pathways possibly involved in ejaculation control are reviewed. Finally, the results of the brain activation of a PET-scan study in human males, ejaculating after penile stimulation by their female partner are discussed. Especially the ventral tegmental area and the cerebellum seem to be activated during ejaculation, while the amygdala region is deactivated. Apparently, a general lack of fear is necessary for ejaculation to occur.     

Central nervous system agents and erectile dysfunction

Several centrally acting agents have shown potential to improve erectile function in men with ED. They still lack adequate data in efficacy and tolerability. Nasal formulations of apomorphine and bremelanotide seem to be the most likely candidates for future approval. They may play a role, specifically in men who fail phosphodiesterase 5 (PDE5) therapy, are unable to take PDE5 inhibitors because of side effects, or are on nitrate therapy. This article reviews the centrally acting agents and the data on their efficacy.     

Central nervous system infections in patients with severe burns

Background

Central nervous system (CNS) infections develop in 3–9% of neurosurgical ICU patients and 0.4–2% of all patients hospitalized with head trauma. CNS infection incidence in burn patients is unknown and this study sets out to identify the incidence and risk factors associated with CNS infections.

Methods

A retrospective electronic chart review was performed from 1 July 2003 to 30 June 2008 evaluating inpatient medical records along with cerebrospinal fluid (CSF) microbiological results for the presence of CNS infection. The presence of facial and head injuries and burns, along with intracranial interventions were reviewed for association with CNS infections.

Results

There were 1964 admissions with 2 patients (0.1%) found to have CNS infection; 1 each with MRSA and Acinetobacter baumannii. Both patients had facial burns and trauma to their head that required intracranial surgery. Of note, both patients had bacteremia with the same microorganisms isolated from their CSF and both survived. Of all patients, 29% had head or neck trauma and burns; 0.35% of those had a CNS infection. Scalp harvest for grafts or debridement of burned scalp was performed on 125 patients of which 9 had an invasive surgical procedure that involved penetration of the skull. The 2 infected patients were from these 9 intracranial surgical patients revealing a 22% infection rate.

Conclusion

The incidence of CNS infections in patients with severe burns is extremely low at 0.1%. This rate was low even with head and face burns with trauma unless the patient underwent an intracranial procedure.     

Central nervous system germ cell tumors

Opinion statement Germ cells tumors most commonly affect children and adolescents, and occasionally arise in the central nervous system. Except for mature teratomas, they are all malignant. Pure germinomas are exquisitely sensitive to treatment and are highly curable with craniospinal radiation therapy [1], [2], [3]. Surgery plays no role other than to establish the histologic diagnosis [4]. Diagnostic confirmation includes normal levels of serum and cerebrospinal fluid alpha-fetoprotein and at most only minor elevations in beta human chorionic gonadotrophin (beta-hCG). Although it has become quite common to use chemotherapy to reduce the dose and field of radiation in the treatment of germinomas [5]-[7], longer follow-up in these patients is revealing a significant number of subarachnoid and ventricular recurrences [2], [8], [9]. A recent follow-up study in patients treated for intracranial germinomas showed no significant difference in the psychosocial functioning of those treated with chemotherapy and radiation compared with those treated with chemotherapy alone, which raises further questions about the rationale for modifying a proven successful treatment [10]. Malignant nongerminomatous germ cell tumors are much more resistant to treatment and difficult to cure [11], [12], [13]. Surgical resection appears to have prognostic significance [11], [14], although the predilection for midline structures makes complete resection difficult if not impossible at times. The best results have been obtained with platinum-based chemotherapy and full-dose craniospinal radiation therapy [15], [16]. Pure teratomas are not typically responsive to chemotherapy or radiation therapy and surgery is the only proven treatment modality.     

Central nervous system infections in transplantation

Opinion statement Central nervous system (CNS) infections are a rare but serious complication of transplantation. An appropriate diagnostic workup should be streamlined with stratification of infection risk by length and degree of immune suppression, lesion localization, and timing. Polymerase chain reaction has high sensitivity and specificity for rapid identification of viral infections and should be used when available. Early diagnosis is imperative, and biopsy should be pursued if a diagnosis is not readily obtained with noninvasive testing. Treatment is pathogen specific. Combination antifungal therapy should be considered for cerebral aspergillosis. Zygomycetes and related invasive fungi require surgical resection and high-dose antifungal therapy. Viral meningoencephalitis therapy should be continued until resolution of clinical signs and symptoms, and viral clearance is verified with repeat cerebrospinal fluid analysis. Cytomegalovirus encephalitis requires ongoing maintenance therapy until clearance of viremia or antigenemia. Bacterial meningitis is uncommon in transplantation and should be treated with 21 days of antibiotics. CNS bacterial abscesses, including nocardiosis, should be surgically drained if feasible and treated until resolution of clinical and radiographic evidence of infection.     

Central nervous system effects of bupivacaine.

The central nervous system and concurrent cardiovascular effects of bupivacaine infusion were studied in cats. It was possible to block cortical E.E.G. desynchronization resulting from a sensory stimulus with bupivacaine. The earliest subcortical change that occurred was rhythmic activity in the amygdala and later in the hippocampus. Occasionally, this activity appeared simultaneously in both these sites. Diazepam pretreatment raised the seizure threshold of bupivacaine. Diazepam was also effective in terminating established seizure activity resulting from bupivacaine. All animals pretreated with diazepam (Valium) or diazepam solvent developed cardiac dysrhythmias durind bupivacaine infusion. The possible clinical significance of the interaction of bupivacaine and diazepam solvent is considered.