Bilateral hippocampal infarction as etiology of sudden and prolonged memory loss

Long-term exposure to ephedrine leads to neurotoxicity and neurobehavioral disorders accompanied by up-regulation of CRF in prefrontal cortex and hippocampus in rhesus macaques

Drug addiction continues to threaten the health and welfare of people worldwide, and ephedrine abuse is a serious drug problem in many areas of the world. Ephedrine toxicity is thought to induce behavioral effects primarily through actions on the central nervous system. The corticotropin-releasing factor (CRF) system plays an important role in regulating behavioral effects induced by addictive drugs, but whether CRF is related to ephedrine toxicity remains unclear. This study seeks to examine whether there is a correlation between the CRF and chronic ephedrine neurotoxicity. To this end, we established a chronic ephedrine (0.4-1.6 mg/kg/d) exposure model in rhesus macaques, assessed its effects on body weight and behavior, examined neuronal changes in the prefrontal cortex and hippocampus, and measured the CRF expression in the prefrontal cortex and hippocampus. After 8-weeks of exposure to ephedrine, the toxic effects of ephedrine included significant weight loss and induction of behavioral changes in rhesus macaques. In particular, in the modeling group, the abnormal behavioral changes mainly manifested as irritability and behavioral sensitization. Meanwhile, the histological abnormalities included neuronal morphological changes, pyknosis and irregular shapes of neurons in the prefrontal cortex and hippocampus. In addition, the expression levels of CRF mRNA and protein were increased in the prefrontal cortex and hippocampus of ephedrine-treated animals. In summary, the finding of this study indicated that ephedrine neurotoxicity can cause neuronal damage in cerebral cortex, which in turn can result in certain neurobehavioral abnormalities, and that CRF expression in prefrontal cortex and hippocampus is elevated in response to ephedrine exposure. These observations suggested that long-term exposure to ephedrine might be causing neurotoxicity and leading to neurobehavioral disorders accompanied by up-regulation of CRF in prefrontal cortex and hippocampus.

Posterior hippocampal stroke presenting with transient global amnesia

The acute onset of isolated amnesia is an intriguing challenge for neurologist, because the lack of associated signs can be misleading for diagnosis. The most common cause is transient global amnesia (TGA), a benign condition, but rarely it results from abuse of substance/alcohol or cerebrovascular diseases. In the latter, the brain region involved is the hippocampus. We describe a patient with presenting symptoms of TGA, but affected by an ischemic hippocampal stroke. The computed tomography angiography helped the etiologic diagnosis showing an hemodynamic stenosis of the posterior P2P segment. Interestingly, neuropsychological features were consistent with those found in patients suffering TGA.

Unilateral hippocampal infarction associated with an attempted suicide: a case report

INTRODUCTION

In our case report we describe the case of a patient who experienced a stroke in her left hippocampus that was found following an attempted suicide via glyphosate overdose. To the best of our knowledge this is the first case report to describe a hippocampal infarction associated with a drug overdose.

CASE PRESENTATION

A 64-year-old Japanese woman was brought to our emergency department after ingestion of an unknown dose of glyphosate surfactant herbicide in order to attempt suicide. On admission, she was assumed to be presenting with depression or psychiatric illness, however, sudden-onset memory deficit became apparent. The patient manifested delirium, confusion, and severe anxiety. In addition, short-term memory loss was prominent, with the patient forgetting her attempted suicide. Following an array of standard tests and a brain computed tomography scan (which only showed an old infraction), we performed a magnetic resonance imaging scan and neuropsychological evaluations. The brain magnetic resonance image revealed a small high-intensity lesion in the dorsal part of the left hippocampal body, and memory tests demonstrated severe short-term recall deficits. We diagnosed her with a left hippocampal infarction and administered a course of 75mg of clopidogrel. She gradually became less confused over the course of a week, and a follow-up memory test revealed partial improvement in some domains. No abnormalities were found on a follow-up brain scan. However, despite rehabilitation, memory impairments remain.

CONCLUSIONS

It is important to note that had the symptom of short-term memory been absent or less severe, she might have been misdiagnosed with depression or another psychiatric illness. Although a computed tomography scan failed to detect hippocampal lesions, a diffusion-weighted magnetic resonance imaging scan clearly revealed a lesion within the left hippocampus. Therefore, in addition to assessments focusing on psychiatric illnesses that might be the root cause of an attempted suicide, organic factors should be considered along with radiological examination and precise memory assessments for diagnosing similar cases.