A Case of Transient Global Amnesia due to Marijuana Use

Abstract

Transient amnesia is a temporary version of the amnestic syndrome. The most striking example of transient amnesia is the transient global amnesia (TGA) syndrome which lasts from several to 24 hours, with or without retrograde components of impairment, and any signs of neurological deficit in nature. In this syndrome, an otherwise cognitively intact individual suddenly loses memory of recent events, asks repetitive questions about his/her environment, and sometimes confabulates (1). TGA is typically described as amnesia of sudden onset regarding events of the present and the recent past (2). It can be caused by central vascular or ischemic lesions. Diagnosis is primarily clinical but includes laboratory tests and radiologic evaluation. TGA typically remits spontaneously, but may recur. There is no specific treatment for amnesia. General stabilization of the patient is indicated (2). Many patients are anxious or agitated and may repeatedly ask questions concerning transpiring events. In the neurologic examination only disturbed memory can be found (3). Upon mental status examination, language function is preserved, which indicates a preservation of semantic and syntax memory. Attention is spared, visual-spatial skills are intact, and social skills are retained. Symptoms typically last less than 24 hours. As the syndrome resolves, the amnesia improves, but the patient may be left with a distinct lapse of recollection for events during the attack. The patient’s behavior is normal except for incessant, repetitive questioning about his/her immediate circumstances (e.g., “What am I doing here?”; “How did we get here?”) (4). Cannabis is one of the most frequently used substances. Cannabis and its constituent cannabinoids are known to impair several aspects of cognitive function, with the most potent effects on shortterm episodic and working memory in humans (5). Marijuana is used by inhalation in cigars or taken orally. When it is taken by the oral route its effects are seen in a delayed manner, so the inhalation type is used mostly to achieve the desired psychoactive effects (6). After al the cigar was burnt, the peak effects are seen in 20 minutes and disappear in 3 hours. A cigar of marijuana contains 5-20 mg THC (tetrahydrocannabinol). Approximately 50% of the THC pass to the alveolar spaces. The most encountered psychotropic side effects of THC are; lethargy, sedation, euphoria, psychological relaxation, euphoria and sometimes, inhibition of the psychological inhibitions as alcohol does, disturbance in the perception of time and location (like feeling of delays in time and elongation of the distances), disturbance in the Abstract Transient global amnesia (TGA) has been a well-described phenomenon for more than 40 years. It presents with a paroxysmal, transient loss of memory. Immediate recall ability and remote memory are preserved. However, patiens experience striking loss of memory for recent events and an impaired ability to retain new information. In some cases, the degree of retrograde memory loss is mild. Marijuana induced transient global amnesia is a rare side effect. Here, we present a case of memory loss for a short period of time after use of marijuana. (JAEM 2012; 11: 190-2)