Relationship of aneurysmal subarachnoid hemorrhage to changes in atmospheric pressure: results of a prospective study.

OBJECT: The purpose of this study was to evaluate the relationship between atmospheric pressure and subarachnoid hemorrhage (SAH) in a region in the English Midlands. METHODS: All patients with angiographically proven SAH for the calendar year 1998 were analyzed. A geographical allocation was made based on the patients' origin within the region. The events were then compared with the data available for the local atmospheric pressures. One hundred nine patients had an SAH during the time period studied. The median atmospheric pressure recorded was 1014.5 millibars. Atmospheric pressure was modestly correlated with the number of SAHs per day (Spearman's rank correlation, r = 0.33; p < 0.0001); the daily change in atmospheric pressure also correlated mildly (r = 0.34, p < 0.0001). No other statistically significant association was found. CONCLUSIONS: The authors have shown a relationship between high atmospheric pressure and increased incidence of SAH. The underlying reason for this remains obscure.

Primary non-Hodgkin's lymphoma of the CNS treated with BVAM or CHOD/BVAM chemotherapy before radiotherapy.

PURPOSE: To assess whether chemotherapy that includes drugs that cross the blood-brain barrier improves survival in primary CNS non-Hodgkin's lymphoma (PCNSL) when combined with radiotherapy. PATIENTS AND METHODS: Thirty-four patients, with no evidence of human immunodeficiency virus type 1 (HIV-1) infection, were treated with the related chemotherapy regimens of carmustine (BCNU), vincristine, cytarabine, and methotrexate (BVAM; 12 patients), cyclophosphamide, doxorubicin, vincristine, and dexamethasone (CHOD)/BVAM (17 patients) and intensified CHOD/BVAM (five patients) between 1986 and 1994. The median age was 60 years (range, 16 to 73) and 47% had a performance status of 3 or 4 (Eastern Cooperative Oncology Group [ECOG]/World Health Organization [WHO]). Ten patients were treated with BVAM chemotherapy between 1986 and 1989, and subsequently 17 patients were treated with CHOD/BVAM (cytarabine 3 g/m2). Twenty of these 27 patients received whole-brain radiotherapy (craniospinal in four). RESULTS: The complete response (CR) rate at the completion of chemotherapy was 63% for BVAM and 67% for CHOD/BVAM; more neutropenia occurred with CHOD/BVAM. The 5-year actuarial probability of survival of all 34 patients was 33% (95% confidence interval [CI], 14% to 52%), with so far only one recurrence after 2 years. Using multivariate analysis, age (P = .0005) and number of tumors at diagnosis (P = .0358) were prognostic factors. All five patients aged > or = 70 years died during or shortly after chemotherapy. Performance status was not an independent variable. CONCLUSION: The BVAM or CHOD/BVAM regimens can be delivered despite neutropenia without significant treatment delay or dose reduction in patients less than 70 years of age. Further intensification of this type of chemotherapy is probably not possible with patients of this age, many of whom have a poor performance status.

Cervical myelopathy caused by pseudogout.

A case of pseudogout manifesting as a cervical myelopathy is presented. Surgery can offer the definitive treatment with removal of the compressing crystalline mass. This diagnosis should be considered in a progressive myelopathy in the elderly person shown to have extradural compression, even in the absence of other stigmata of gout.

Intracranial aneurysms and arteriovenous malformations: transcranial colour-coded sonography as a diagnostic aid.

Transcranial colour-coded sonography (TCCS) is a new development in noninvasive cerebral vascular imaging. We studied 5 patients with known intracranial aneurysms and 12 patients with arteriovenous malformations (AVM). We were unable to image any of the aneurysms (all 5 mm or less in diameter) using colour flow ultrasound. Similarly, pulsed wave Doppler interrogation failed to reveal any flow disturbances. Nine out of 12 AVMs were successfully visualised as serpiginous structures and the principal feeder vessels were identified in 11 cases. Blood flow velocities in the feeder vessels were elevated compared with the same vessel contralaterally (median [cm/s]; peak systolic 227 vs. 89, P = 0.001; mean 178 vs. 57, P = 0.001; end diastolic 138 vs. 37, P < 0.0005). Pulsatility indices (PI) and resistance indices (RI) in the feeder vessels were reduced relative to the same vessel contralaterally (median PI 0.46 vs. 0.94, P < 0.0005; median RI 0.37 vs. 0.59, P < 0.0005). At present, TCCS appears of little value in the diagnosis of intracranial aneurysms, but it shows promise for the imaging of AVMs and their haemodynamic study.

Somatosensory evoked potentials in intracranial hypertension: analysis of the effects of hypoxia.

The loss of somatosensory evoked potentials (SSEP's) was investigated in a feline model of intracranial hypertension. Threshold values of cerebral perfusion pressure (CPP) and cerebral blood flow (CBF) required for maintenance of SSEP's are defined using a mathematical model. The model describes loss of amplitude of SSEP's using the form of a dose-response curve. Amplitude of the SSEP's declined to 50% of control values at a CBF of 15 ml/100 gm/min and a CPP of 20 mm Hg in the normoxic animal; in the presence of mild hypoxia (8 to 9 kPa), a significant increase in these values to 18 ml/100 gm/min and 32 mm Hg, respectively, occurred. No reliable changes in latency or central conduction time were demonstrated. It is concluded that given adequate oxygenation, evoked electrical activity is lost at too low a level of CPP for this parameter to be useful in clinical monitoring. However, even mild hypoxia, when combined with intracranial hypertension, produces a major risk to neuronal integrity.

Type III collagen mutations cause fragile cerebral arteries.

Premature vascular aneurysms and fragility of cerebral arteries are commonly associated with type III collagen mutations and physical signs suggesting a generalized abnormality of connective tissue. Sometimes these traits are clearly genetically transmitted. Here we present seven examples of early cerebrovascular aneurysms or fragility including five examples of carotid cavernous sinus aneurysms. With one exception in which we suspect the mutation is too small to be detected, all of them had easily visible abnormalities of their type III collagen proteins. Further work in progress will eventually allow the characterization of their mutations at gene sequence level and will be followed by the ability to prevent transmission of the mutant genes in these families.

Brain abscess in the 1980s.

Brain abscess was reviewed in 24 patients admitted to University Hospital, Nottingham over a period of 3 years. Chronic ear infection was the most common predisposing factor, but in 11 patients the focus of infection remained unknown. CT scanning, carried out in all patients, was negative in one patient with clinical signs of meningitis. Polymicrobial and anaerobic infections were common. Actinomyces species were isolated in mixed culture from seven patients; in five the abscess was located in the cerebellum. Therapy was most often a combination of surgical drainage and antimicrobial therapy with beta-lactam agents and metronidazole. Evidence suggests that cefotaxime may offer a suitable alternative to chloramphenicol and benzylpenicillin in the treatment of brain abscess.

A new motor-driven surgical probe and its in vitro comparison with the Cavitron Ultrasonic Surgical Aspirator.

The Cavitron Ultrasonic Surgical Aspirator (CUSA) has been applied in neurosurgery for several years, but its mode of action is not yet clear and its efficiency at removing soft tissue has not been quantified. We describe here how we have measured the rate of removing soft tissue per unit time, taking ox-liver tissue as the test material. A motor-driven vibrator/aspirator has been developed in our laboratory. It has permitted us to examine the effect of varying independently frequency, amplitude of the vibration, and suction pressure on the removal rate. The results of this investigation show that beyond a certain tip acceleration amplitude (about 100 g) the removal rate does not increase significantly. Also the removal rate is more or less independent of vibration amplitude within the range between 300 micron and 1 mm. Our in vitro experiments with the new probe show that a tip acceleration of about 100 g is enough to remove ox-liver tissue and then the rate of removal is comparable to that obtained with the CUSA operating at maximum vibration amplitude. Analysis of the particle size of the debris collected from CUSA and from our motor-driven device shows that the particle size distribution is similar over the range of 0.5 micron less than d less than 250 micron.