ReMed 2019 Urgences ReMed Magazine Numéro 7-8 (6) | Page 26

Sciences de la Santé inhibiting the ion current. When a depolarization of the post-synaptic membrane occurs by the opening of AMPA channels for instance, Mg2+ molecules are removed from their inhibitory sites, and allow Ca2+ and Na+ ions to enter. When let it in normal amounts, Ca2+ ionsgenerate signalling pathways that reinforce synaptic transmission. A process which is fundamental for special types of memories. What also grabs our attention concerning these receptors, is the presence of a site in the pore of the channel that could inhibit the NMDA receptor if bound to a hallucinogenic drug phencylidinePCP (also known as angel dust). It owns its name to the hallucinations induced by blocking the NMDA receptors. We acknowledge therefore, that any kind of disturbance of the natural mechanism of NMDA receptors would highly influence the synaptic plasticity which plays a considerable role in the storage of information and other higher brain functions. When the antibodies addressed against NMDAR bind to them, they leadto their internalization from the cell surface and to a state of relative NMDA receptor hypofunction. Resulting in the symptoms of the disease which were proved to be reversible with the removal of the antibodies (4,5). Phases of theillness in anti-NMDA receptor en- cephalitis: Viral prodromal phase: Most patients present in the first 5 days (no more than 2 weeks) non-specific cold or viral-like symptoms: fever, drowsiness, asthenia, headaches, myalgias, upper respiratory symptoms, nausea and even diarrhea. Preceding the beginning of psycho- behavioural changes. Initial psychiatric symptoms: Considering the common absence of neurologic manifestations in this period, patients usually see a psychiatrist first. For this reason, the diagnosis of anti NMDA encephalitis could be confused at this stage with other mental illnesses such as schizophrenia. They often experience various mental symptoms over which schizophrenia-like symptoms govern; chiefly psychosis, which is characterized as a defective or lost contact with reality, resulting in delusional ideas, suspiciousness, hallucinations, disorganized speech, such as switching topics erratically and loss of self-awareness. Moreover, patients usually show emotional disturbances (anxiety, fear, loneliness, apathy…), strange behaviours (such as smiling oddly at their own reflection in a mirror) and agitation in addition to paranoia, mood changes and personality transitions. They can easily and suddenly become cantankerous and aggressiveleading to their withdrawalfrom society. Furthermore, short-term amnesia, confusion and cognitive impairment can be difficult to detect at the onset of the phase, because of the prominence of the psychiatric signs and could even be sub-syndromal. Interestingly, children show different symptoms: sleep dysfunction, irritability, behavioural flare-ups, hyperactivity and hyper-sexuality seem to take the place of psychotic symptoms. This phase usually lasts from 1 to 3 weeks but could be protracted in some cases in a less severe manner. Seizures can occur at this phase and the patients fall into unresponsiveness driving them to the hospital. Unresponsive phase: Patients at this stage go through a debilitated state. Akinetic, they undergo progressive decay in speech and language such as a reduced fluency of speech (alogia), mimicking the examiner’s movements or words (echolalia) and uttering; along with a catatonic behaviour by being unresponsive to verbal commands and mutism despite their eyes being open. Paradoxically, they can occasionally be passive to some ‘’suggestive’’orders of the examiner. This phase is also accompanied by Catalepsy-like symptoms (presenting muscle rigidity and fixity of posture despite external stimuli) and athetoid dystonic 26 AUTOMNE 2018 /HIVER 2019