1/59. "Pseudo-conduction block" in vasculitic neuropathy. The predominant electrophysiologic feature of vasculitic mononeuropathy multiplex is axonal loss. Electrophysiologic findings interpreted as conduction block have, however, also been reported to occur in neuropathy secondary to necrotizing vasculitis. We report 3 patients with mononeuropathy multiplex and biopsy proven vasculitis in whom eight nerves met criteria for conduction block. In each circumstance, serial study demonstrated conversion of the electrophysiologic findings to those most consistent with severe axonal loss. "Conduction block" in vasculitic mononeuropathy multiplex is secondary to focal axonal conduction failure presumably related to infarctive axonal injury. The term conduction block should be used with caution in this disorder and only if serial studies demonstrate findings consistent with this electrophysiologic diagnosis. ( info) |
| BACKGROUND: The mechanism of a progressive lacunar infarction is not well understood, and changes in ischemic tissue after onset have not yet been clarified clinically. OBJECTIVE: To investigate the pathophysiological characteristics of a case of progressive lacunar infarction using diffusion-weighted and conventional magnetic resonance imaging (MRI) scans. PATIENT: A 73-year-old woman was hospitalized 18 hours after stroke onset and was diagnosed as having a lacunar infarction in the perforating territory of the left middle cerebral artery. Despite treatment, the hemiparesis worsened, with the peak on the fourth day after onset. diffusion-weighted and conventional MRI scans provided clues to the pathogenesis. FINDINGS AND CONCLUSIONS: In the acute stage, gradual enlargement of the hyperintense lesion, reflecting fresh ischemic tissue, and neurological deterioration were observed by serial examination of diffusion-weighted MRI scans. A conventional coronal MRI scan revealed a 2-layered ischemic lesion, suggesting the involvement of perforating arteries. These findings indicated that hemodynamic impairment of the microcirculation in the perforators was the major cause of the lacunar infarction. ( info) |
3/59. Endoneurial vasculitis and tubuloreticular inclusions in peripheral nerve biopsy. We describe 3 patients in whom nerve biopsy revealed endothelial tubuloreticular inclusions in association with peripheral nerve endoneurial vasculitis. Two of the patients had systemic lupus erythematosus (SLE), while the third was hiv-positive. review of our biopsy material featuring the much more common finding of epineurial vasculitis failed to disclose any instances in which endothelial tubuloreticular inclusions (TRIs) were present. We conclude that TRIs and endoneurial vasculitis are closely associated. Moreover, if detected on a nerve biopsy specimen, TRIs are very suggestive of SLE or hiv infection. Finally, literature evidence is cited to suggest that an "acid-labile" alpha-interferon may be pathogenically related to the vasculitic process in these patients, perhaps through a process mediated by tumor necrosis factor. ( info) |
| We report two patients displaying hyperintensities on diffusion-weighted imaging (DWI) in the area of wallerian degeneration (WD) at 12 days after stroke. High signal intensities were more conspicuous on DWI than on T2-weighted images. Both patients showed decreased diffusion anisotropy resulting in elevated apparent diffusion coefficient in the area of WD. These patients illustrate that DWI may be useful in the detection of the early stage of WD. ( info) |
5/59. A histopathological analysis of the human cervical spinal cord in patients with acute traumatic central cord syndrome. STUDY DESIGN: We have applied conventional histochemical and morphometric techniques to study the changes within the human spinal 'hand' motor neuron pool after spinal cord injury in patients who presented with acute traumatic central cord syndrome (ATCCS). OBJECTIVE: To determine whether a reduction of large alpha motor neurons at the C7, C8 and T1 spinal cord levels underlies the mechanism which causes hand dysfunction seen in patients with (ATCCS). BACKGROUND: The etiology of upper extremity weakness in ATCCS is debated and injury and/or degeneration of motor neurons within the central gray matter of the cervical enlargement has been advanced as one potential etiology of hand weakness. methods: The spinal cords of five individuals with documented clinical evidence of ATCCS and three age-matched controls were obtained. The ATCCS spinal cords were divided into acute/sub-acute (two cases) and chronic (three cases) groups depending on the time to death after their injury; the chronic group was further subdivided according to the epicenter of injury. We counted the motor neurons using light microscopy in 10 randomly selected axial sections at the C7, C8 and T1 spinal cord levels for each group. We also analyzed the lateral and ventral corticospinal tracts (CST) in all groups for evidence of wallerian degeneration and compared them to controls. RESULTS: A primary injury to the lateral CST was present in each case of ATCCS with evidence of wallerian degeneration distal to the epicenter of injury. There was minimal wallerian degeneration within the ventral corticospinal tracts. In the chronic low cervical injury group, there was a decrease in motor neurons supplying hand musculature relative to the other injury groups where the motor neurons sampled at the time of death were not reduced in number when compared to the control group. CONCLUSIONS: We hypothesize that hand dysfunction in ATCCS can be observed after spinal cord injury without any apparent loss in the number of motor neurons supplying the hand musculature as seen in our acute/sub-acute (n=2) and our chronic high injury (n=1) groups. The motor neuron loss seen in the chronic low level injury was felt to be secondary to the loss of C7, C8, and T1 neurons adjacent to the injury epicenter. ( info) |
| A 25-year-old woman with maple syrup urine disease (MSUD) developed generalized weakness over 1 week. She had severe leg and moderate arm weakness, areflexia, and distal sensory loss. plasma branched-chain amino acid concentrations were elevated, reflecting an acute exacerbation of the disease. Electrodiagnostic studies indicated an acute axonal polyneuropathy and sural nerve biopsy revealed acute wallerian degeneration without inflammation. Peripheral neuropathy, although not identified previously as a clinical feature of MSUD, may become more common as chronic dietary restrictions and improved management of the disease allow survival into adulthood. ( info) |
7/59. "Pseudo-conduction block" in a patient with vasculitic neuropathy. A 63-year-old man presented with progressive asymmetric weakness and numbness in his hands of 2 weeks duration. Nerve conduction studies showed low amplitude motor evoked potentials of both median nerves. The right ulnar, left tibial and peroneal nerves had normal potentials on distal stimulation with markedly decreased amplitudes proximally, suggestive of "conduction block". Three weeks later, amplitudes were decreased throughout. The patient was diagnosed with vasculitis. The acute ischemic injury presumably resulted in axonal damage between the distal and proximal stimulation sites, with subsequent wallerian degeneration. ( info) |
8/59. Fixation-off sensitivity in an adult with symptomatic occipital epilepsy. An adult patient had EEG occipital spike fixation-off sensitivity and spontaneous occipital seizures due to perinatal asphyxia with bioccipital hemorrhage. EEG abnormalities consisted of repetitive posterior spikes that occurred when the eyes were closed and other conditions of fixation-off. magnetic resonance imaging (MRI) documented severe posterior lesions with wallerian degeneration of the optic radiation. Electron capture detector single-photon emission computed tomography (ECD-SPECT) during the state of fixation-off showed regional hyperperfusion in the right posterior regions. We suggest that partial denervation of the primary visual cortex in this patient resulted in an increased cortical excitability and that the inhibitory effect of central vision and fixation leads to a suppression of spontaneous epileptic activity. This unusual symptomatic case may serve as a model for the pathophysiology in the more often reported cases of idiopathic benign epilepsy syndrome of childhood. ( info) |
9/59. Histological findings after hemicerebellectomy in man: anterograde, retrograde and transneuronal degeneration. Histological changes are described in the brain of a patient in whom a hemicerebellectomy had been performed 14 years before death. There is cell and fibre loss, partial or total, in nuclei known to have direct connections with the cerebellum. In some nuclei the sequel to cell loss is marked fibrillary gliosis. In other nuclei the cells have disappeared without trace. The degeneration of these tracts with a direct connection with the cerebellum has also led to degeneration of other tracts in synaptic relationship with them. This transneuronal degeneration has occurred in the corticopontine tracts and in the central tegmental tract, in the former definitely, and in the latter probably, retrogradely. It is probable that transneuronal degeneration has also occurred in other tracts. The extent of the degeneration and, in particular, the occurrence of overt transneuronal degeneration, suggest that the examination of material after a very long term of survival might be of value in experimental work concerned with mapping neuroanatomical networks. ( info) |
10/59. Cerebral germinoma with hemiatrophy of the brain: report of three cases. BACKGROUND: The authors report three cases of cerebral germinoma that occurred in young adults with unusual presentation. METHOD: All three patients presented with hemiparesis and were treated at Seoul National University. A histological diagnosis of germinoma was made by a stereotactic biopsy in all three cases. FINDINGS: Magnetic resonance (MR) images showed that their tumors were located in the internal capsule and thalamus, and were associated with ipsilateral cerebral hemisphere and brain stem atrophy. The hemiparesis slowly progressed and this was accompanied by a haemorrhagic cyst in each patient. INTERPRETATION: Clinical diagnosis was not easy because of the unusual clinical presentations and atypical MR imaging findings. It is suggested that cerebral germinoma should be included in the differential diagnosis of a haemorrhagic mass which is associated with cerebral atrophy in the thalamus, basal ganglia, or internal capsule, especially in adolescents or young adults. ( info) |