Background The younger generation in Korea easily exposed to nitrous oxide (N2O) under the name “Happy Balloon” may abuse it. N2O can irreversibly oxidize vitamin B12 and cause abnormal hematopoiesis or nervous system toxicity such as subacute combined degeneration (SCD). The objective of this study was to assist in early diagnosis of N2O-induced SCD of spinal cord by characterizing its clinical manifestations.
Methods Four patients with myelopathy after abusing N2O were enrolled. To characterize N2O-induced myelopathy, previously reported cases of N2O-induced SCD were searched through PubMed and KoreaMed. Collected cases and our four patients were analyzed.
Results A total of 30 patients with N2O-induced myelopathy (26 males and 4 females with mean age of 24 years) were analyzed. These patients took a median dose of 650 canisters for a median duration of 3.5 months. All patients presented sensory disturbances, which involved the lower extremities more frequently (100%) than the upper extremities (63.3%). Gait ataxia (76.7%), weakness in the upper (23.3%) and lower (36.7%) extremities, bladder symptoms (26.7%), Rhomberg sign (43.3%), and Lhermitte’s phenomenon (10.0%) were observed. Serum vitamin B12 levels were decreased in many (63.3%) patients and homocysteine levels were elevated in all. Of 20 patients who underwent magnetic resonance imaging (MRI) of the spine, 19 had abnormal findings. Three patients presented with contrast enhancement in lesions.
Conclusions We strongly recommend that history of N2O abuse should be asked for young patients with suspected myelopathy, especially those presenting with gait ataxia and sensory disturbances suggesting posterior column dysfunction and those presenting long-segment lesion involving the upper cervical cord on MRI.
Klippel-Trenaunay syndrome (KTS) is a rare congenital malformation syndrome involving blood and lymph vessels, which is characterized by triad of cutaneous hemangioma, venous varicosities, and overgrowth of the affected limbs. Because vascular malformation in KTS can be located anywhere except the face and brain, the clinical presentation could be extremely variable. But there are only rare case reports that KTS is associated with spinal cord lesion. We report a case of recurrent myelopathy in a patient with KTS.
Background Transcranial magnetic stimulation (TMS) is a non-invasive diagnostic method particularly suited to investigation the long motor tracts. The clinical value of TMS in most spinal cord diseases has still to be made. Diagnostic value of magnetic motor evoked potential (MEP) parameters in intramedullary spinal cord lesions was investigated.
Methods MEP elicited by TMS was recorded in 57 patients with clinically and radiologically defined intramedullary myelopathy. Twenty five patients with cervical myelopathy (CM) and 32 thoracic myelopathy (TM) were included. Recordings were performed during resting and minimal voluntary contraction at both abductor pollicis brevis (APB) and tibialis anterior (TA) muscles. Stimulation threshold(ST), amplitude, and central motor conduction time (CCT) were measured at resting and facilitated conditions. CCT was calculated by two means; central motor latency (CML)-M using magnetic transcranial and root stimulation, and CML-F using electrical F-wave study. The results were compared between patient groups and 10 normal control group.
Results Facilitated mean ST recorded at TA was elevated in both CM and TM compared with control group. Resting mean CML-M at TA was significantly prolonged in both CM and TM, and CML-M was absent or delayed in 37.1% of CM and 8% of TM at APB with facilitation. Facilitated mean MEP amplitude at ABP was lower in CM than in TM, while MEP/M ratios were not different significantly between groups.
Conclusions Magnetic motor evoked potential has diagnostic value in intramedullary myelopathy and localizing value in differentiating between CM and TM by recording at APB and TA. It is a noninvasive way to investigate the functional status of motor tracts of spinal cord.
High voltage electrical injury can cause considerable damage to the nervous system including spinal cord, but, thepathophysiology of myelopathy remains to be studied. A 44-year old man with paraparesis after electrical injury wasdiagnosed as electrical injury induced- myelopathy by normal spine MRI and somatosensory evoked potential showingcentral conduction abnormality. It implicates that the presumed mechanism of the myelopathy prefers the electroporationor electroconformational protein denaturation to the joule heating.
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