Methyl bromide intoxication and acute energy deprivation syndromes

Metronidazole-induced encephalopathy after prolonged metronidazole course for treatment of C. difficile colitis

A 65-year-old woman with a diagnosis of Clostridium difficile colitis undergoing prolonged treatment with metronidazole was admitted to hospital for altered mentation, slurred speech and weakness. She was diagnosed with metronidazole-induced encephalopathy, confirmed with brain MRI and improved when the offending agent was removed. This case report highlights encephalopathy as a complication of prolonged metronidazole treatment, which has become more common in clinical practice for the treatment of C. difficile infection.

MRI brain in monohalomethane toxic encephalopathy: A case report

Monohalomethanes are alkylating agents that have been used as methylating agents, laboratory reagents, refrigerants, aerosol propellants, pesticides, fumigants, fire-extinguishing agents, anesthetics, degreasers, blowing agents for plastic foams, and chemical intermediates. Compounds in this group are methyl chloride, methyl bromide, methyl iodide (MI), and methyl fluoride. MI is a colorless volatile liquid used as a methylating agent to manufacture a few pharmaceuticals and is also used as a fumigative insecticide. It is a rare intoxicant. Neurotoxicity is known with both acute and chronic exposure to MI. We present the characteristic magnetic resonance imaging (MRI) brain findings in a patient who developed neuropsychiatric symptoms weeks after occupational exposure to excessive doses of MI.

The neurological effects of methyl bromide intoxication

Used primarily as a fumigant or as a substrate in chemical processes, methyl bromide is a highly toxic gas. The gas is usually absorbed by inhalation and effects on the lungs, gastrointestinal tract, skin, and brain are seen. Numerous instances of acute and chronic neurologic injury have been reported: acute poisoning results in seizures, myoclonus, ataxia or cerebral oedema beginning as early as 30 min after exposure while subacute or chronic intoxication presents with diverse slowly progressive neurological and neurobehavioral symptoms. Serum bromide levels may be elevated, but often return rapidly to normal. Electroencephalography may show frontally-predominant slow waves or polyspikes with following slow wave, and MRI reveals characteristic involvement in the dentate nucleus of the cerebellum, the brainstem, and the splenium of the corpus callosum. Symmetric and selective lesions in characteristic sites are observed on imaging and on histopathological examination. These are likely produced by methylation of intracellular lipids, protein and glutathione; production of toxic metabolites; defective neurotransmitter function; and abnormal oxidative phosphorylation. This article reviews the toxic effects of this gas, the pathophysiology and symptoms of its effects on the nervous system, and characteristic findings on MRI; and presents an illustrative case of methyl bromide intoxication due to exposure at a factory producing the compound commercially.

Encéphalopathie de Gayet-Wernicke associée a une intoxication chronique au disulfiram

INTRODUCTION

We report the case of a patient with an unusual association of Wernicke encephalopathy and chronic disulfiram intoxication.

CASE REPORT

A 41-year-old man presented with progressive frontal decline and akineto-rigid parkinsonism under chronic disulfiram therapy. He also developed acute confusion with ataxia, blepharospasm, and supranuclear ophthalmoplegia following a severe malnutrition due to refusal of food intake. Brain MRI revealed symmetrical and reversible hyperintense lesions on T2 and FLAIR in the posterior putaminal regions, dorso-medial thalamic and subthalamic nuclei, the periaqueducal gray matter, the cerebellar peduncles, and the pontine tegmentum. A slow partial clinical recovery with persistent frontal syndrome was observed after discontinuation of disulfiram and parenteral administration of thiamine.

DISCUSSION

The symmetry and reversibility of the MRI lesions in the basal ganglia and brain stem were suggestive of a deficiency, a toxic or a metabolic neurological disease. The dorso-medial thalamo-subthalamic and brainstem localizations, as well as their occurrence in a state of malnutrition, were consistent with Wernicke encephalopathy. Moreover, chronic disulfiram intoxication might explain the frontal syndrome and the akineto-rigid parkinsonism, associated with MRI putaminal lesions. Similar MRI lesions have been described in the so-called "energy deprivation syndromes", which are toxic, genetic or nutritional disorders that disrupt enzymes involved in energy generating metabolic pathways such as glycolysis and pyruvate oxidation.

Methyl bromide induced neuropathy: a clinical, neurophysiological, and morphological study

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