Toxin-Induced Coma and Central Nervous System Depression

Toxic and metabolic leukoencephalopathies in emergency department patients: a primer for the radiologist

One of the most common chief complaints in the emergency department (ED) is altered mental status (AMS). Imaging plays a critical role in triaging patients and identifying the etiology of AMS. Toxic and metabolic etiologies are one of the primary differential categories for AMS, leading to toxic leukoencephalopathies. Toxic leukoencephalopathies are white matter disorders that result from either exogenous or endogenous sources. Common exogeneous causes of toxic leukoencephalopathy include drugs of abuse (heroin and cocaine), alcohol, inhaled gases (carbon monoxide), industrial agents (pesticides, toluene, ethylene glycol), and neurotoxic medications (methotrexate, metronidazole, vigabatrine, etc.); endogenous causes include hyper- and hypoglycemia, hyperammonemia, hyponatremia, and uremia. The imaging findings of toxic leukoencephalopathies manifest through a combination of vasogenic and cytotoxic edema, resulting in white matter patterns. These white matter patterns have been found to be pathognomonic. In the ED setting, it is imperative to develop a diagnosis based off of the imaging due to the lack of history and context that is typically provided with a chief complaint of altered mental status (AMS). To offer expeditious and accurate diagnosis, we present the classic imaging features of toxic leukoencephalopathies and correlate these imaging findings with pathophysiology.

Environmentally realistic concentrations of cocaine in seawater disturbed neuroendrocrine parameters and energy status in the marine mussel Perna perna

Cocaine (COC) is a powerful illicit drug frequently detected in the aquatic environment. COC acts by inhibiting the reuptake of dopamine (DOPA) and 5-hydroxytryptamine (5-HT - serotonin) and causes endocrine disturbances in mammals. This study investigated similar effects from cocaine exposure in the marine mussel Perna perna, as well as neurotoxicity and energy imbalances. Mussels were exposed to COC (0.2 μg.L^-1 and 2 μg.L^-1) for periods of 48, 96, and 168 h. Acetylcholinesterase (AChE) was measured in adductor muscle tissue to determine neurotoxicity, and neurotransmitter levels (DOPA and 5-HT), monoamine oxidase (MAO) and cyclooxygenase (COX) activity, and energy status (mitrochondrial electron transport, MET, and total lipids, TLP) were evaluated in the mussels' gonads. COC decreased AChE activity in the mussels exposed to 0.2 μg.L^-1 and 2 μg.L -1 after 168 h, and all concentrations of COC increased neurotransmitter levels. Increases in MET (0.2 μg.L -1, for all exposure periods) and TLP (0.2 μg.L 1 after 48 h, and 2 μg.L -1 after 96 h and 168 h) were also observed. No significant change was detected in MAO activity. COC also decreased COX activity in the mussels exposed to 0.2 μg.L -1 (48 h and 96 h) and 2 μg.L -1 (96 h). These results suggest that COC may compromise neurotransmitter levels and COX activity. Furthermore, the changes in MET and LPT suggest that COC affects the energy balance of the mussels, and could negatively affect physiological processes such as metabolism, hormone production, and embryonic development.