Detection of multidrug-resistant tuberculosis from stored DNA Samples: A multicenter study.

Background: In low-income countries, rapid detection of tuberculosis (TB) drug resistance is often restricted by the difficulties of transporting and storing sputum samples from remote health centers to the reference laboratories where molecular tests are available. The aim of this study was to evaluate the performance of four transport and storage systems for molecular detection of rifampicin (RIF) and isoniazid (INH) resistance. Methods: This was a multicenter study. Molecular detection of RIF and INH resistance was performed directly from smear-positive TB sputa spotted on a slide, FTA card, GenoCard, and ethanol using the Genotype MTBDRplus assay. The performance of the DNA extraction method from each storage support to detect drug resistance was assessed by calculating their sensitivity and specificity compared to the phenotypic method. Results: From all sites, the overall sensitivity and specificity for RIF-resistance detection was 88% and 85%, respectively, for slides, 86% and 92%, respectively, for GenoCard, 87% and 89%, respectively, for FTA card, and 88% and 92%, respectively, for ethanol. For INH-resistance detection, the overall sensitivity and specificity was 82% and 90%, respectively, for slides, 85% and 96%, respectively, for GenoCard, 86% and 92%, respectively, for FTA card, and 86% and 94%, respectively, for ethanol. Conclusion: Smear slides and filter cards showed to be very useful tools to facilitate DNA extraction from sputum samples with the potential to accelerate the detection of drug resistance in remote areas.

Combined approach to the identification of clinically infrequent non-tuberculous mycobacteria in Argentina.

SETTING: Over 150 potentially pathogenic non-tuberculous mycobacteria (NTM) species have been described, posing an onerous challenge for clinical laboratory diagnosis. OBJECTIVE: To evaluate different approaches for the identification of 40 clinically relevant NTM isolates whose species were not reliably identified using our routine diagnostic workflow comprising phenotypic tests and hsp65 polymerase chain reaction restriction analysis. DESIGN: We used 1) sequencing analysis of four conserved gene targets: 16S rRNA, rpoB, hsp65 and sodA; 2) two commercial reverse hybridisation assays; and 3) protein analysis using matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF MS). RESULTS: Combined, but not individual, sequence analysis allowed reliable species identification for 30/40 (75%) isolates, including species previously unknown to be circulating in Argentina. Commercial kits outperformed our routine identification in only 5/35 isolates, and misclassified many more. MALDI-TOF MS accurately identified species in 22/36 (61%) isolates and did not misidentify any. CONCLUSIONS: Commercial kits did not resolve the problem of species of NTM isolates that elude identification. Combined DNA sequence analysis was the approach of choice. MALDI-TOF MS shows promise as a powerful, rapid and accessible tool for the rapid identification of clinically relevant NTM in the diagnostic laboratory, and its accuracy can be maximised by building up a customised NTM spectrum database.

Antimicrobial susceptibility of rapidly growing mycobacteria using the rapid colorimetric method.

Drug susceptibility testing (DST) of rapidly growing mycobacteria (RGM) are recommended for guiding the antimicrobial therapy. We have evaluated the use of resazurin in Mueller-Hinton medium (MHR) for MIC determination of RGM and compared the results with those obtained with the reference standard broth microdilution in Mueller-Hinton (MH) and with the resazurin microtiter assay (REMA) in 7H9 broth. The MIC of eight drugs: amikacin (AMI), cefoxitin (FOX), ciprofloxacin (CIP), clarithromycin (CLA), doxycycline (DOX), linezolid (LZD), moxifloxacin (MXF) and trimethoprim-sulfamethoxazole (TMP-SMX) were evaluated against 76 RGM (18 species) using three methods (MH, MHR, and REMA) in a 96-well plate format incubated at 37 °C over 3-5 days. Results obtained in the MH plates were interpreted by the appearance of turbidity at the bottom of the well before adding the resazurin. MHR and 7H9-REMA plates were read by visual observation for a change in color from blue to pink. The majority of results were obtained at day 5 for MH and 1 day after for MHR and 7H9-REMA. However, the preliminary experiment on time to positivity results using the reference strain showed that the resazurin can be added to the MH at day 2 to produce the results at day 3, but future studies with large sets of strains are required to confirm this suggestion. A high level of agreement (kappa 1.000-0.884) was obtained between the MH and the MHR. Comparison of results obtained with 7H9-REMA, on the other hand, revealed several discrepancies and a lower level of agreement (kappa 1.000-0.111). The majority of the strains were resistant to DOX and TMP-SMX, and the most active antimicrobials for RGM were AMI and FOX. In the present study, MHR represented an excellent alternative for MIC determination of RGM. The results could be read reliably, more easily, and more quickly than with the classical MH method.

Integrated detection of multi- and extensively drug-resistant tuberculosis using the nitrate reductase assay.

It currently takes 2-3 months to obtain a diagnosis for multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB). We evaluated the rapid non-commercial nitrate reductase assay (NRA), which is capable of the simultaneous detection of MDR- and XDR-TB, and compared the results with the proportion method (PM). The sensitivity was respectively 97%, 99%, 100% and 94.6% for rifampicin (RMP), isoniazid (INH), ofloxacin (OFX) and kanamycin (KM). The specificity was respectively 100%, 95%, 95.7% and 99% for RMP, INH, OFX and KM. The turnaround time for NRA was 10-14 days, compared to 4-6 weeks for the PM. Our study showed that NRA provided sensitive and specific detection of resistance to first- and second-line drugs.

Evaluation of the TB Ag MPT64 Rapid test for the identification of Mycobacterium tuberculosis complex.

Rapid identification of Mycobacterium tuberculosis complex in cultured samples is important for starting appropriate treatment. We evaluated the performance of the TB Ag MPT64 Rapid test directly from 131 BACTEC MGIT 960 culture-positive samples: 113 were identified as M. tuberculosis complex and 18 as non-tuberculous mycobacteria. The sensitivity and specificity of the TB Ag MPT64 Rapid test were respectively 96.5% and 100% compared to the polymerase chain reaction. The overall concordance of the TB Ag MPT64 Rapid test was 969%. The TB Ag MPT64 Rapid test is easy, sensitive, and does not require a high level of skill or specific equipment.

Diagnosis of drug-resistant tuberculosis: reliability and rapidity of detection.

With the emergence of multidrug-resistant tuberculosis (MDR-TB), the need for rapid drug susceptibility testing (DST) is felt globally. National tuberculosis control programmes (NTPs) may find it hard to choose from the bewildering variety of rapid tests. We give an overview of the most important methods, discussing their merits and shortcomings, emphasising techniques that offer an alternative to the commercial systems and genotypic tests. Correlation between phenotypic and genotypic DST remains problematic due to our insufficient knowledge of the mutations underlying drug resistance, besides the past standardisation of phenotypic DST. Rapid growth-based DST tends to be less accurate due to growth retardation of some resistant strains. To arrive at optimal resistance monitoring and management of MDR-TB without overloading the laboratories, the test indications and definition of a suspect need careful consideration, while excellent microscopy remains crucial but challenging. The hitherto little-studied fluorescein diacetate vital staining technique may offer the solution, reconciling earlier detection and appropriate pre-selection for rapid DST. For the choice of methods, appropriateness and sustainability should be considered in conjunction with the prospects for complete population coverage. Excellent coverage will only be feasible through decentralisation of simple, low-requirement methods or alternatively by centralised genotypic DST with, in principle, easy specimen referral. The small differences in DST turnover time are relatively unimportant, provided primary culture isolation is not required. No test is fully accurate, and proper pre-selection may allow the use of less accurate but simple screening methods. Conventional slow DST will still be needed for confirmation and for epidemiological monitoring.

Thin-layer agar for detection of resistance to rifampicin, ofloxacin and kanamycin in Mycobacterium tuberculosis isolates.

BACKGROUND: In low-income countries there is a great need for economical methods for testing the susceptibility of Mycobacterium tuberculosis to antibiotics. OBJECTIVE: To evaluate the thin-layer agar (TLA) for rapid detection of resistance to rifampicin (RMP), ofloxacin (OFX) and kanamycin (KM) in M. tuberculosis clinical isolates and to determine the sensitivity, specificity and time to positivity compared to the gold standard method. METHODS: One hundred and forty-seven clinical isolates of M. tuberculosis were studied. For the TLA method, a quadrant Petri plate containing 7H11 agar with RMP, OFX and KM was used. Results were compared to the Bactec MGIT960 for RMP and the proportion method for OFX and KM. RESULTS: The sensitivity and specificity for RMP and OFX were 100% and for KM they were 100% and 98.7%, respectively. The use of a TLA quadrant plate enables the rapid detection of resistance to the three anti-tuberculosis drugs RMP, OFX and KM in a median of 10 days. CONCLUSION: TLA was an accurate method for the detection of resistance in the three drugs studied. This faster method is simple to perform, providing an alternative method when more sophisticated techniques are not available in low-resource settings.

Multicentre study of nitrate reductase assay for rapid detection of rifampicin-resistant M. tuberculosis.

SETTING: Four regional laboratories belonging to the Mycobacteria Reference Laboratory of São Paulo State, Brazil. OBJECTIVE: To evaluate the nitrate reductase assay (NRA) for rifampicin (RMP) susceptibility testing of Mycobacterium tuberculosis directly from clinical sputum samples of patients with pulmonary tuberculosis (TB). DESIGN: Performance of the NRA for detection of M.tuberculosis susceptibility to RMP was evaluated with 210 clinical sputum samples received by the participating laboratories during 2005 and 2006 and compared with the results of the direct proportion method. RESULTS: Susceptibility tests performed using the NRA and the direct proportion method showed 204 susceptible isolates and six isolates resistant to RMP by both methods. NRA sensitivity and specificity for RMP was 100%. The NRA results of susceptibility tests against RMP were available in 15 days for 87% of the samples. The results showed that NRA may yield a rapid answer in determining resistance for the majority of sputum samples with smear results reported as 3+ and 2+. CONCLUSION: The results demonstrate the feasibility of NRA for screening resistant strains in sputum samples from patients with pulmonary TB. NRA represents a rapid and low-cost alternative method that might be used in microbiological laboratories where resources are scarce.

Evaluation of the accuracy of the microplate Alamar Blue assay for rapid detection of MDR-TB in Peru.

Tuberculosis control is hampered by the widespread increase in multidrug resistance. Rapid drug susceptibility testing would greatly aid in the adequate treatment of the disease. This study evaluates the usefulness of the colorimetric method using Alamar Blue for the rapid detection of resistance to rifampicin and isoniazid in 63 clinical isolates of Mycobacterium tuberculosis in Peru. Results obtained by receiver operating characteristic curve analysis and measures of gain in certainty showed greater diagnostic accuracy than with the gold standard, the proportion method on Löwenstein-Jensen medium.

Rapid drug resistance detection in Mycobacterium tuberculosis: a review of colourimetric methods.

Several new methods to detect drug resistance in Mycobacterium tuberculosis have been proposed in recent years. Colourimetric methods that use redox indicators or the nitrate reduction assay have received increasing attention because of their simplicity and the absence of any requirement for sophisticated equipment or highly trained personnel. Several studies have evaluated their accuracy and performance in comparison with reference standard methods, particularly for the detection of resistance to rifampicin and isoniazid, which are the two most important drugs used for the treatment of tuberculosis. This review describes the development, evaluation and implementation of these methods as rapid alternative tests for the detection of multidrug resistance in M. tuberculosis. Based on published evidence and the high accuracy of colourimetric methods for detecting drug resistance in M. tuberculosis, these methods seem to be appropriate for implementation in high-burden low-resource countries.

Evaluation of a rapid culture method for tuberculosis diagnosis: a Latin American multi-center study.

SETTINGS: Tuberculosis (TB) diagnostic laboratories in Latin America. OBJECTIVES: Evaluation of thin-layer agar (TLA) compared to Löwenstein-Jensen (LJ) culture for the diagnosis of TB. DESIGN: Phase II prospective study in six laboratories. Samples included sputum and extra-pulmonary specimens from patients with a clinical diagnosis of TB. Respiratory samples were decontaminated using NaOH/ NALC; all samples were centrifuged, stained with Ziehl-Neelsen for acid-fast bacilli (AFB), cultured on LJ and TLA and identified according to recommended procedures. Sensitivity and likelihood ratios (LR), growth detection time and contamination rate were calculated for both media. RESULTS: A total of 1118 clinical specimens were studied. Cultures detected Mycobacterium tuberculosis in all AFB-positive samples, whereas for AFB-negative specimens LJ detected 3.2% and TLA 4.4%. Sensitivity was 92.6% (95%CI 87.9-95.9) and 84.7% (95%CI 78.8-89.0) for TLA and LJ, respectively. Positive and negative LRs were similar. Contamination was 5.1% for TLA and 3.0% for LJ. Median time to detection of a positive culture was 11.5 days (95%CI 9.3-15.0) for TLA and 30.5 days (95%CI 26.9-39.0) for LJ (P < 0.0001). CONCLUSION: Difference in the characteristics of the participating laboratories, the disease prevalence and the number and type of specimens processed did not affect the overall performance of TLA as compared to LJ, supporting the robustness of the method and its feasibility in different laboratory settings.

Comparison of redox and D29 phage methods for detection of isoniazid and rifampicin resistance in Mycobacterium tuberculosis.

Rapid, accurate and inexpensive methods are essential to detect drug-resistant Mycobacterium tuberculosis and allow timely application of effective treatment and precautions to prevent transmission. The proportion method, the MTT and Alamar Blue redox methods, and the D29 mycobacteriophage assay, were compared for their ability to detect resistance to isoniazid and rifampicin. When tested against a panel of known M. tuberculosis strains, the redox methods and the D29 assay showed good sensitivity and specificity compared to the proportion method, suggesting that they could be useful alternatives for identifying multidrug resistance in M. tuberculosis.

Multicenter study of MTT and resazurin assays for testing susceptibility to first-line anti-tuberculosis drugs.

OBJECTIVE: A multicentre evaluation was performed to assess two rapid low-cost methods, MTT (3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide) and resazurin assays, for testing the susceptibility of Mycobacterium tuberculosis to the first-line anti-tuberculosis drugs rifampicin (RMP), isoniazid (INH), ethambutol (EMB) and streptomycin (SM). METHODS: Thirty coded M. tuberculosis strains were sent to seven laboratories located in Latin America, representing six countries. Each site performed the colorimetric assays, MTT and resazurin, blind for the first-line drugs RMP, INH, EMB and SM. The minimum inhibitory concentration results obtained were compared to the conventional proportion method on Lowenstein-Jensen medium. RESULTS: After establishing the breakpoint concentrations, excellent results were obtained for RMP, INH and EMB, with levels of specificity and sensitivity of between 96% and 99%. CONCLUSION: MTT and resazurin assays are promising, accessible new alternative methods for middle- and low-resource countries that need low-cost methods to perform rapid susceptibility testing of M. tuberculosis to key anti-tuberculosis drugs.

Nonconventional and new methods in the diagnosis of tuberculosis: feasibility and applicability in the field.

Tuberculosis (TB) remains one of the major causes of death from a single infectious agent worldwide. Of great concern for TB control is the emergence of drug resistance. Since there is no cure for some multidrug-resistant strains of Mycobacterium tuberculosis, there is concern that they may spread around the world, stressing the need for additional control measures, such as new diagnostics, better drugs for treatment, and a more effective vaccine. Pulmonary TB can be diagnosed by its symptoms, chest radiography, sputum smear microscopy and by cultivation of M. tuberculosis, which is considered as the gold standard. Recent advances in molecular biology and molecular epidemiology, and a better understanding of the molecular basis of drug resistance in TB, have provided new tools for rapid diagnosis; however, the high cost of most of these techniques, and their requirement for sophisticated equipment and skilled personnel have precluded their implementation on a routine basis, especially in low-income countries. Other nonconventional diagnostic approaches proposed include the search for biochemical markers, detection of immunological response and early detection of M. tuberculosis by methods other than colony counting. In the present article, some of these approaches will be reviewed and the feasibility for their implementation in diagnostic laboratories will be discussed.

HDM2 overexpression and focal loss of p14/ARF expression may deregulate the p53 tumour suppressor pathway in meningeal haemangiopericytomas. Study by double immunofluorescence and laser scanning confocal microscopy.

AIMS: To investigate the p53 pathway in meningeal haemangiopericytomas (MHPCs), p14/ARF, p53 protein expression and two wild-type (wt) p53-induced proteins (HDM2 and p21/WAF1) were studied in 18 MHPCs, 11 primary, four of them recurrent on one, one, two and four occasions. METHODS: Immunohistochemical detection of p14/ARF, p53, p21/WAF1, HDM2 and Ki67 proliferative index (PI) protein expression. RESULTS: Ki67 index was > 5% in eight out 18 cases (44.4%). The PI in recurrent cases increased with neoplastic progression. Simultaneous p53 and wt p53 transactivated gene (p21/WAF, HDM2) expression occurred in all cases. This argues against p53 mutation. HDM2 overexpression was observed in 10 cases (55.5%). Double-immunofluorescence staining and laser scanning confocal microscopy (LSCM) displayed HDM2 and p53 colocalization. This strongly suggests that HDM2 binds and inactivates p53 that could be pathogenic for MHPCs, by a different mechanism than point mutation. p14/ARF expression > 5% was observed in 12 cases (66.6%). A normal (diffuse) pattern of expression was seen in 13 cases (72.2%). Focal loss of expression was observed in five patients (27.7%): three primary cases and two recurrences. Therefore, p14/ARF down-regulation may also contribute to the development of MHPC. CONCLUSION: HDM2 overexpression, sometimes combined with focal loss of p14/ARF expression, may play a pathogenic role in MHPCs.

Unruptured dural arteriovenous malformation of the transverse-sigmoid sinus presenting with focal symptoms and coma.

We are presenting the case of a 63 year-old man with a dural arteriovenous malformation of the transverse sigmoid sinus who developed focal deficits followed by less localized symptoms such a disorientation, lethargy and eventually comatose status. Initial cerebral angiography showed retrograde filling of the cortical and deep cerebral venous system with marked delay in venous empting. Following embolization clinical symptoms completely cleared at the time that control angiography showed retrograde venous flow turning anterograde. Patient's symptoms recurred four months later when there was a relapse of retrograde cerebral venous drainage at the time he developed thrombosis of the superior longitudinal and right transverse sinuses. Sinus thrombosis and thrombosis of the central retinal artery were coincidental with hypercoagulability related to hyperhomocysteinemia. Since control angiography still showed persistence of the AV shunting radical excision of the involved dural sinuses was performed. The final outcome was excellent. The physiopathological mechanism responsible for neurological deficits in our patient most likely was ischemia of venous origin secondary to venous hypertension resulting from retrograde cerebral venous drainage. The clinical and angiographic presentation in few similar cases reported in the literature is reviewed.

Meningiomas of the basal posterior fossa. Surgical experience in 80 cases.

INTRODUCTION: Despite recent improvements in microsurgical and radiotherapy techniques, treatment of basal posterior fossa meningiomas still carries an elevated risk of morbidity. We present our results in a series of patients with this type of tumor and review the recent literature looking for the results obtained with different approaches and the new tendencies and algorithms proposed for managing these challenging lesions. MATERIAL AND METHODS: We analyzed retrospectively the clinical presentation and outcome of 80 patients consecutively operated between 1979 and 2003 for basal posterior fossa meningioma (foramen magnum tumors excluded). All patients had preoperative CT scans and the majority MRI studies. A total of 114 operations were performed including two-stage operations, reoperation for recurrence, CSF diversion, and XII-VII anastomosis. The most commonly used approaches were lateral suboccipital retrosigmoid, subtemporal-transtentorial, frontotemporal pterional and supra-infratentorial presigmoid. Thirteen patients received postoperative radiotherapy. RESULTS: There were 59 (73.7%) women and 21 men (mean age = 51.5 years; range = 18-78 yrs). Most common presenting symptoms were cranial nerve dysfunction, gait disturbances and intracranial hypertension. The mean duration of symptoms was 2.9 years. 70% of the tumors were over 3 cm in size. Fifty patients (62.5%) had a complete resection, 22 (27.5%) subtotal resection (> 90% tumor volume removed), and 8 (10%) only partial resection. Postoperative complications included hematoma, CSF leak, and infection. Fifty four (67.5%) patients developed new or increased cranial nerve deficits and 12.5% somatomotor, somatosensory or cerebellar deficits immediately after surgery with subsequent improvement in most cases. Following initial surgery 67 patients made a good recovery, 10 developed variable degrees of disability and 3 died. Eleven patients died later in the course for tumor recurrence with or without reoperation, malignant meningioma or unrelated causes. There were 9 recurrences in the subgroup of patients having complete resection initially (mean follow-up = 8.6 years). The majority of patients having initial subtotal or partial resections have been managed without reoperation during a mean follow-up period of 6.5 years (radiosurgery and/or observation). DISCUSSION AND CONCLUSION: Current microsurgical and radiotherapy techniques allow either a cure or an acceptable control of basal posterior fossa meningiomas. In patients with tumor invasion of the cavernous sinus, extracranial extension, violation of the arachnoidal membranes in front of the brainstem, or encasement and infiltration of major arteries, a subtotal excision seems preferable followed by observation and/ or radiosurgical treatment. Apart from the patients age and the clinical presentation (symptomatic or not), the size and secondary extensions of the tumor must be taken into account for planning treatment in the individual patient.

[Idiopathic subarachnoid hemorrhage; comparison of different bleeding patterns and long-term outcome]. / Hemorragia subaracnoidea no filiada: comparación de diferentes patrones de sangrado y evolución a largo plazo.

INTRODUCTION: Idiopathic subarachnoid haemorrhage (ISAH) represents approximately 15-30% of all subarachnoid haemorrhages. On the basis of the diagnostic CT and depending on the location of the subarachnoid bleeding, patients with ISAH may be classified into three groups: a) Patients with normal CT and diagnosis made by lumbar puncture (ISAHNCT); b) patients with a pure perimesencephalic pattern (ISAHPM) and c) patients with a bleeding pattern resembling that of aneurismatic rupture (ISAHA). This classification could permit the establishment of differences in the management and prognosis. OBJECTIVES: To describe the clinical and radiological characteristics of these three classes of patients and analyse their medium and long term outcome and moreover, compare these with those observed in patients suffering aneurysmal subarachnoid haemorrhage (ASAH). MATERIAL AND METHODS: A series of 122 patients consecutively admitted to Hospital 12 de Octubre Madrid between 1990 and 2000 with the diagnosis of ISAH were retrospectively reviewed. Patients were considered to have suffered ISAH when the first complete four vessel angiography did not show the presence of any aneurysm or vascular lesion responsible for the bleeding. Patients were classified depending on the pattern of bleeding into ISAHNCT, ISAHPM as described by Van Gijn et al., and ISAHA. The angiography study was repeated when: a) the first study was incomplete or had poor quality, b) vasospasm was present, c) in those patients who had an aneurysmal pattern of bleeding in the initial CT. Different clinical and radiological characteristics were recorded as well as complications that occurred during the hospital stay. Final outcome was evaluated by means of the Glasgow Outcome Score (GOS). With the purpose of comparing these clinical and radiological characteristics and the outcome of patients with ISAH with those suffering aneurysmal subarachnoid haemorrhage (ASAH), 294 patients diagnosed with ASAH during the same study period were also reviewed. RESULTS: 27% of patients admitted to our hospital with the diagnosis of non-traumatic subarachnoid hemorrhaged were diagnosed as ISAH. Of these, 41% presented with a ISAHA pattern, 39% ISAHPM and 20% ISAHNCT. The average age was similar in the different subgroups of SAH, being around 55 years. There was a greater frequency of male patients in the ISAHNCT and ISAHPM groups. In comparison with ASAH, ISAH characterises by patients presenting with less frequency a bad clinical grade and also loss of consciousness at stroke. There are fewer complications in patients with ISAH than ASAH, with a frequency of rebleeding and ischemia much less (5 and 6% respectively). Within the ISAH group, patients with ISAHA pattern of bleeding present more complications. Outcome is excellent for patients with ISAHNCT and ISAHPM, and rather worse for patients with ISAHA (median followup 5.8 years). CONCLUSIONS: This study confirms that the frequency of ISAH in our environment reaches the higher limit of that shown previously in the literature, replicating the results previously published by our group. Patients with ISAH have a better prognosis and a smaller risk of complications than patients with ASAH, the prognosis of patients with ISAHCTN and ISAHPM being particularly good. Patients with ISAHA present initially with a severe clinical situation, probably related to the bigger amount of bleeding, as well as a higher frequency of systemic complications, cerebral ischemia and hydrocephalus. However, if the absence of vascular lesions is confirmed, the long term prognosis is similar to that of the other subgroups of ISAH.

[Parasplenial arteriovenous malformations. Report of 15 surgically treated cases]. / Malformaciones arteriovenosas paraesplénicas. A propósito de 15 casos tratados quirúrgicamente.

INTRODUCTION: Yasargil called paraesplenial those AVMs located at the confluence of the hippocampus, the isthmus of the cingulate girus and the girus occipitotemporalis medialis. Large AVMs at this location are among the most difficult to delineate and to treat. OBJECTIVE: Analyze the clinical presentation, the findings in the imaging studies, the surgical management and the final outcome in 15 patients with paraesplenial AVMs treated with embolization (the last 4 cases), and microsurgical removal. RESULTS: Nine patients (60%) were female and 6 males of ages between 15 and 39 years (mean = 24 yrs). Eleven (75%) presented with hemorrhage, (intraventricular in most cases) and the remaining with epilepsy. The Spetzler-Martin grade was II in one Case, III in 5 cases, IV in 8 cases and V in one case. Preoperative embolization clearly improved surgical management. All the patients had complete resection of the lesion, 13 in a single stage and 2 in two stages. The final outcome was good but four patients developed defects of the visual field not seen preoperatively. CONCLUSIONS: The authors comment the peculiarities of paraesplenial AVMs which can be safely and completely removed with microsurgery and the aid of preoperative embolization.