Neurology
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Utilizing the Olmsted County, Minnesota, population-based records-linkage resource at Mayo Clinic, we identified an incidence and a prevalence cohort with multiple sclerosis (MS), a head injury cohort, and a lumbar disk surgery cohort to evaluate the association between mechanical trauma and MS onset or exacerbation. The MS cohorts consisted of 225 incidence cases (1905 to 1991) and 164 prevalence cases (December 1, 1991) of definite MS in the population of Olmsted County. We assessed the effect of mechanical trauma in the form of spinal injury or extremity fracture with regard to precipitation of MS or exacerbation of an existing neurologic deficit. ⋯ In a cohort of 819 head injury cases from the Olmsted County population, none developed MS within 6 months of the trauma. In a lumber disk surgery cohort of 942 local residents, there were five with MS, but onset of MS had preceded the spinal surgery in four of the five. Thus, we found no association of head injury and spinal disk surgery with onset of MS.
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We examined 111 consecutive patients with primary or metastatic brain tumors identified by CT or MRI to characterize brain tumor headache. The median age was 44 years; 34% had primary and 66% metastatic tumors. Headaches were present in 48%, equally for primary and metastatic brain tumors. ⋯ Unlike true tension-type headaches, brain tumor headaches were worse with bending over in 32%, and nausea or vomiting was present in 40% of patients. The "classic" early morning brain tumor headache is uncommon. Nausea, vomiting, an abnormal neurologic examination, or a significant, change in prior headache pattern suggest that the headache may be caused by a tumor.
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We recently found that vibratory detection threshold is greatly influenced by the algorithm of testing. Here, we study the influence of stimulus characteristics and algorithm of testing and estimating threshold on cool (CDT), warm (WDT), and heat-pain (HPDT) detection thresholds. We show that continuously decreasing (for CDT) or increasing (for WDT) thermode temperature to the point at which cooling or warming is perceived and signaled by depressing a response key ("appearance" threshold) overestimates threshold with rapid rates of thermal change. ⋯ Near threshold, only the initial direction of thermal change from skin temperature is perceived, and not its return to baseline. Use of steps of stimulus intensity allows the subject or patient to take the needed time to decide whether the stimulus was felt or not (in 4, 2, and 1 stepping algorithms), or whether it occurred in stimulus interval 1 or 2 (in two-alternative forced-choice testing). Thermal thresholds were generally significantly lower with a large (10 cm2) than with a small (2.7 cm2) thermode.(ABSTRACT TRUNCATED AT 250 WORDS)
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Treatment of brain embolism should depend on the nature of the embolic material, if discoverable or predictable, not on whether the source was cardiac or intra-arterial. The middle cerebral artery territory is the most common recipient site for emboli, but many emboli do go to the carotid arteries and the posterior circulation. ⋯ The carotid arteries are probably the most common sources of intra-arterial emboli to the brain, but emboli also frequently arise from the aorta and the vertebral arteries. Potential embolic materials probably frequently enter the circulation but rarely cause strokes.
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We analyzed retrospectively pain relief from an intravenous lidocaine infusion (5 mg/kg/hr for 60 to 90 minutes) in 111 patients with chronic nonmalignant pain. Patients with peripheral nervous system (PNS) injury reported substantially more pain relief than those with central nervous system (CNS) injury or with pain of unknown etiology. These findings suggest that (1) the pathophysiology of chronic pain due to PNS injury is different from that due to CNS injury and idiopathic pain, and that (2) pain due to PNS damage may be suppressible by local anesthetic antiarrhythmic agents.