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Background: The dermatological features and skin biopsy findings of short-term thallium intoxication have been described. However, the correlation between the dermatological findings and the thallium concentration, the prognosis of peripheral neuropathy, and a cutaneous nerve biopsy study are lacking. Observations: Two patients initially developed perioral numbness, erythematous facial rashes, and polyneuropathy after ingesting thallium-containing water. Severe diffuse alopecia was noted, and a skin biopsy specimen revealed parakeratosis and vacuolar degeneration of the basal layer. Examinations of the hair mount demonstrated a tapered appearance of the anagen root. A serial cutaneous nerve biopsy study showed a loss of epidermal nerves 7 weeks and even 1 year after the thallium intoxication. A toxicology survey disclosed a high concentration of thallium (about 3124 mg/L) in the water. The clinical dermatological features subsided completely, but polyneuropathy with severe painful feet persisted. The blood and daily urinary thallium concentrations decreased slowly in the following 3-month period. Conclusions: The clinical dermatological features subsided completely, but painful polyneuropathy persisted. The series cutaneous nerve biopsy specimens showed persistent damage to the sensory nerve endings. The disappearance of the dermatological features and the appearance of Mees lines correlated with the decrease of blood and urinary thallium concentrations. [ABSTRACT FROM AUTHOR]

Objective: To study a patient with axonal polyneuropathy due to acute dimethylamine borane (DMAB) intoxication. Patient: Confusion and drowsiness in the acute stage, followed by cognitive impairments and polyneuropathy, are reported in a chemical factory worker after acute exposure to DMAB. Results: Nerve conduction studies indicated axonal polyneuropathy, particularly in the motor nerves. Sural nerve biopsy studies 3 months later revealed an axonal degeneration with a mild decrease of fiber density in the large myelinated fibers. Quantitative sensory testing also disclosed an impairment of pinprick, temperature, and touch sensations. Cutaneous nerve biopsy studies 9 months later demonstrated a moderate loss of epidermal nerves. During the follow-up period of 1.5 years, the clinical features and serial nerve conduction studies showed a steady improvement. Conclusions: Since DMAB is a new product and has been widely used recently in the manufacturing of semiconductors and electronics, we conclude that DMAB intoxication may produce motor-predominant axonal polyneuropathy and that the establishment of a threshold limit value is warranted. [ABSTRACT FROM AUTHOR]

Chronic exposure to manganese may induce parkinsonism similar to idiopathic Parkinson’s disease (PD). However, clinical manifestations of manganism also have some features different from PD. The mechanisms of manganese-induced parkinsonism remain not fully understood. 99mTc-TRODAT-1 is a cocaine analogue that can bind to the dopamine transporter (DAT) site reflecting the function of presynaptic dopaminergic terminals. The purpose of this study was to evaluate DAT function using 99mTc-TRODAT-1 to investigate the integrity of the presynaptic dopaminergic terminals in manganese-induced parkinsonism. Brain 99mTc-TRODAT-1 single photon emission computed tomography was performed in 4 patients with chronic manganese intoxication in a ferromanganese smelting plant in Taiwan. Twelve PD patients and 12 healthy volunteers served as abnormal and normal controls, respectively. Clinically, all manganism patients had a bradykinetic-rigid syndrome. The scores of the Unified Parkinson’s Disease Rating Scale ranged between 19 and 64. The uptake values of the 99mTc-TRODAT-1 were 0.868±0.136 in the right corpus striatum and 0.865±0.118 in the left, as compared with 0.951±0.059 and 0.956±0.058, respectively for the normal controls. The data were significantly higher than 0.250±0.070 and 0.317±0.066 respectively for the PD patients. Interestingly, there was a mild decrease in the uptake of 99mTc-TRODAT-1 in the putamen and the ratio of putamen and caudate when compared with the normal controls. Although the DAT shows a slight decrease in the putamen of manganism patients as compared with that of the normal controls, the data indicate that the presynaptic dopaminergic terminals are not the main target of chronic manganese intoxication. In addition 99mTc-TRODAT-1 SPECT can provide a useful, convenient and inexpensive tool for differentiation between chronic manganism and PD. [ABSTRACT FROM AUTHOR]

Long-term exposure to carbon disulfide (CS[sub 2] ) may induce diffuse encephalopathy with parkinsonism, pyramidal signs, cerebellar ataxia, and cognitive impairments, as well as axonal polyneuropathy. The pathogenic mechanisms of diffuse encephalopathy are unclear, although vasculopathy and toxic demyelination have been proposed. Recently, we have encountered a patient who developed headache, limb tremors, gait disturbance, dysarthria, memory impairment, and emotional lability after long-term exposure to CS[sub 2] . The brain magnetic resonance images (MRI) showed diffuse hyperintensity lesions in T[sub 2] -weighted images in the subcortical white matter, basal ganglia, and brain stem. The brain computed tomography perfusion study revealed a diffusely decreased regional cerebral blood flow and prolonged regional mean transit time in the subcortical white matter and basal ganglion. To our knowledge, there have been few reports demonstrating diffuse white matter lesions in chronic CS[sub 2] encephalopathy using brain MRI. In addition, the [sup 99m] Tc-TRODAT-1 single photon emission computed tomography showed a normal uptake of the dopamine transporter, indicating a normal presynaptic dopaminergic pathway. We conclude that diffuse white matter lesions may develop after chronic exposure to CS[sub 2] , possibly through microangiopathy. In addition, CS[sub 2] poisoning can be considered as one of the causes of chronic leukoencephalopathy.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

We report the clinical manifestations and mitochondrial DNA (mtDNA) mutations of nine Chinese patients with Leber's hereditary optic neuropathy from seven families in Taiwan. The nine probands were all males, aged 19 to 43 years at the time of the study and with ages of onset ranging between 13 and 30 years. The were characterized by an acute or subacute onset of visual loss in one eye, which progressed to the other eye within a few weeks. Their visual outcome was poor, although improvement was noted in four patients. A muscle biopsy from one patient showed a decreased activity of cytochrome c oxidase and subsarcolemmal mitochondrial aggregation. All patients and unaffected maternal family members had a homoplasmic G11778A mtDNA mutation regardless of variations in clinical manifestation. High frequencies of environmental factors such as smoking, alcohol consumption, trauma, and /or military training were found in these patients. We conclude that even though a homoplasmic G11778A mtDNA mutation was found in all patients and their maternal family members, this mutation could not account for the presentation of the clinical features. Additional genetic, epigenetic, and /or environmental factors may be important trigger factors in the clinical expression. [ABSTRACT FROM AUTHOR]

Isolated cortical venous thrombosis (CVT) is rare, and the discrepancy between clinical features and neuroradiologic findings has not been adequately emphasized. A thirty-one- year-old woman presented with focal seizures and occasionally secondary generalization. There was no focal neurologic deficit except for Todd's paralysis. Electroencephalography showed intermittent theta waves at the left frontoparietal area:. Brain computed tomography (CT) and magnetic resonance imaging (MM) disclosed a large lesion in the left frontoparietal area. An extensive occlusion of the superior cerebral veins of the left hemisphere with a patency of the dural sinuses was noted in the cerebral angiography. Eight months later, the CT hypodense lesion disappeared. Her neurologic status was stationary, but the seizures, mostly focal, still occurred occasionally. In this report, the authors emphasize the dissociation between minor clinical features and larger CT and MM lesions in isolated CVT. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Case Report: The Clinical Toxicity of Dimethylamine Borane," by Y.T. Tsan and colleages in the previous issue.