Neurology
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We reviewed the results of motor evoked potential (MEP) and somatosensory evoked potential (SEP) monitoring during 116 operations on the spine or spinal cord. We monitored MEPs by electrically stimulating the spinal cord and recording compound muscle action potentials from lower extremity muscles and monitored SEPs by stimulating posterior tibial or peroneal nerves and recording both cortical and subcortical evoked potentials. We maintained anesthesia with an N2O/O2/opioid technique supplemented with a halogenated inhalational agent and maintained partial neuromuscular blockade using a vecuronium infusion. ⋯ In four cases, the changes in the monitored signals led to major alterations in the surgery. We believe that optimal monitoring during spinal surgery requires recording both SEPs and MEPs. This provides independent verification of spinal cord integrity using two parallel but independent systems, and also allows detection of the occasional insults that selectively affect either motor or sensory systems.
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Myotonia, defined as delayed relaxation of muscle after contraction, is seen in a group of genetic disorders that includes autosomal dominant myotonia congenita (Thomsen's disease) and autosomal recessive myotonia congenita (Becker's disease). Both disorders are characterized electrophysiologically by increased excitability of muscle fibers, reflected in clinical myotonia. These diseases are similar except that transient weakness is seen in patients with Becker's, but not Thomsen's disease. ⋯ The Arg-338-Gln and Gly-230-Glu mutations were found in patients with different phenotypes from those of previous reports. Further study of the Arg-338-Gln and Gln-230-Glu alleles may shed light on variable modes of transmission (dominant versus recessive) in different families. Physiologic study of these mutations may lead to better understanding of the pathophysiology of myotonia in these patients and of voltage-gated chloride channel structure/function relationships in skeletal muscles.
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Case Reports
Autonomic ganglionitis with severe hypertension, migraine, and episodic but fatal hypotension.
We report the clinical, pathologic, and immunohistochemical features of a severe hypertensive patient with recurrent migraine-induced hypotension. The patient died of migraine-induced vasomotor paralysis despite prompt institutions of fluid and sympathomimetic and parasympatholytic agents. Postmortem study revealed autonomic ganglionitis and neuritis.
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Persistently elevated intracranial pressure (ICP) has been associated with poor clinical outcome after severe brain injury, such as neurotrauma, intracerebral hemorrhage, and subarachnoidal hemorrhage. Although ICP monitoring is increasingly being used in intensive care treatment of patients with ischemic stroke, its value has not been established. ⋯ ICP monitoring of large hemispheric infarction can predict clinical outcome. Pharmacologic intervention had no sustained effect. ICP monitoring was not helpful in guiding long-term treatment of increased ICP. It remains doubtful that ICP monitoring in acute ischemic stroke has a positive influence on clinical outcome.
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A new generation of Atraumatic (blunt tipped) needles now exists in addition to the traditional Quincke (cutting tip) needles for LP. We wished to identify the optimal size and type of needle that should be used for this technique. Requirements include rapid and accurate transduction of CSF pressure and adequate flow rate for CSF collection purposes while minimizing headache and other neurologic sequelae. ⋯ Some of the 22-gauge Atraumatic needles rapidly measured CSF pressure, but their flow rates were only suitable for small volume CSF collection. There is extensive literature to support that neurologic sequelae are reduced using Atraumatic needles. Diagnostic LP can be easily and accurately performed by using a large Atraumatic needle with the potential for considerable reduction in post-LP headache and related neurologic sequelae.