Anti-NMDA encephalitis | 56531

Investigación actual en Virología y Retrovirología


Anti-NMDA encephalitis

Nevzat Tarhan

Anti-NMDA receptor encephalitis was firstly described in 2007. Up-to this date more than 400 cases have been described, making the syndrome rather un-rare. It is an autoimmune disorder where the NMDA receptors are targeted. The disease may affect anyone at any age and any gender. The patients usually have a viral-like prodrome of lethargy, upper respiratory symptoms, headache, nausea, fever etc. The presenting symptoms of the syndrome are mainly psychiatric. The patients manifest various psychotic symptoms like delusions, disorganized thoughts and behaviors, paranoid ideation, hallucinations, mood lability and cognitive deterioration. After 1-3 weeks of neuropsychiatric symptoms, the patient suffers from neurological complications such as global alterations in consciousness, catatonic-like states, dysautonomia and seizures. The patients may need to be hospitalized for 3-4 months. Aggressive treatment with corticosteroids and immunotherapy is needed. Most patients respond to this treatment. However, they may have significant cognitive and behavioral abnormalities like deficits in executive functions, impulsivity and behavioral dis-inhibition and sleep disturbances that need further follow-up. Psychiatric and neurological symptoms are treated with psychotropic drugs as in other neuropsychiatric syndromes. Some patients may need neuro-rehabilitation. The diagnosis requires Cerebrospinal Fluid (CSF) work-up. In CSF lymphocytic pleocytosis, elevated protein and oligoclonal bands are found. Demonstrating antibodies against NMDA receptors in CSF and/ or serum gives a solid diagnosis of the disease. Cranial Magnetic Resonance Imaging (MRI) may be normal in half of the cases. Electroencephalography (EEG) is usually abnormal with slowed and disorganized activity. In this session a review of anti-NMDA encephalitis will be presented in light of a case that was diagnosed and followed-up in our clinic. This is an important neuropsychiatric syndrome that may go unnoticed unless the physician follows-up the patient closely, runs in-depth neuropsychiatric tests and collaborates with other physicians. Anti-N-methyl D-aspartate (NMDA) receptor (anti-NMDAR) encephalitis, caused by immunoreactivity against the 
NMDA receptor 1 (NR1) subunit of the NMDA receptor, is one of the most common autoimmune encephalitides, first described in 2007 by Dalmau and colleagues in which psychiatric and neurologic symptoms were found in women with ovarian teratomas. The condition was later confirmed to be not exclusively paraneoplastic. Later studies reported patients afflicted without tumor involvement. Although available data suggest the disease is more prevalent in adult women, and in the non-Caucasian population, the condition has been described in both genders, in multiple races, and throughout the lifespan. However, increasing case reports of anti-NMDAR encephalitis in the psychiatric literature have demonstrated the significant overlap between neurologic and psychiatric pathology associated with autoimmune encephalitis. The clinical progression of the encephalitis has also been more thoroughly defined, with a multiphase model currently in use. The prodromal phase is suggestive of a viral flu-like illness, in which fever, malaise, and fatigue may be prominent. This phase varies in duration and may also involve upper respiratory or gastrointestinal symptoms. The condition is often clinically recognized in the ensuing psychotic phase, in which delusions, hallucinations, paranoia, and agitation may be exhibited. During this phase, anti-NMDAR encephalitis is often misdiagnosed as a primary psychotic or substance-induced disorder. Following these psychotic symptoms is often the progression to a state in which catatonia, impaired attention, dyskinesias, and seizures may develop. In addition, significant autonomic instability, with wide-ranging fluctuations in body temperature, blood pressure, respiratory rate, and cardiac rhythm, may occur. It is important to note that anti-NMDAR cases may not follow a strict phasic progression as mentioned earlier and may not include all of the symptomatology mentioned earlier, thereby complicating diagnosis.