Relapses vs. ongoing symptoms of brain injury
A common concern for encephalitis survivors is whether or not they will suffer a relapse i.e. a return of inflammation. Fortunately, this does not occur in cases of infectious encephalitis (though uncommonly autoimmune encephalitis (AE) can arise later, such as in the case of HSV-1 encephalitis triggering the development of anti-NMDA receptor encephalitis). As for AE, a relapse is possible; but it is more likely that fluctuating symptoms are a result of brain injury. It is common for survivors to experience a degree of variability in symptoms such as energy level, attention, emotional regulation, and stress tolerance from day to day.
AE is generally monophasic, though inflammation can return in instances where immunotherapy is withdrawn too soon. Expert opinion differs on the length of treatment necessary and whether or not maintenance therapy is required for several years. It is important that patients be evaluated on a case-by-case basis to determine relapse risk and to optimize strategies for long-term stability.
AE is generally monophasic, though inflammation can return in instances where immunotherapy is withdrawn too soon. Expert opinion differs on the length of treatment necessary and whether or not maintenance therapy is required for several years. It is important that patients be evaluated on a case-by-case basis to determine relapse risk and to optimize strategies for long-term stability.
Differentiating between a relapse warranting further immunosuppression vs. residual symptoms of brain injury can be a difficult clinical task. A sudden return of symptoms that interfere with the execution of previously resumed activities e.g. at work or school may raise the suspicion for a relapse. In this case, doctors may re-run diagnostic testing to look for evidence of recurring inflammation or offer empiric treatment depending on their clinical judgement.
The likelihood of a relapse depends on a number of factors including AE subtype, how quickly treatment was initiated from symptom onset, and the treatment strategy employed. Some experts are starting to favour the use of Rituxan (rituximab) in certain patients as recent studies (Thaler et al., Neurology 2018) indicate that use of a second-line treatment may decrease the risk of relapse. A 2018 review by Dr. Josep Dalmau and Dr. Francesc Graus, Antibody-Mediated Encephalitis indicates that published relapse rates range from 12-35% for encephalitis associated with antibodies against NMDAR, AMPAR, LGI1, CASPR2, and DPPX.
Relapse risks, detection, and strategies for prevention remain an important area of study.
The likelihood of a relapse depends on a number of factors including AE subtype, how quickly treatment was initiated from symptom onset, and the treatment strategy employed. Some experts are starting to favour the use of Rituxan (rituximab) in certain patients as recent studies (Thaler et al., Neurology 2018) indicate that use of a second-line treatment may decrease the risk of relapse. A 2018 review by Dr. Josep Dalmau and Dr. Francesc Graus, Antibody-Mediated Encephalitis indicates that published relapse rates range from 12-35% for encephalitis associated with antibodies against NMDAR, AMPAR, LGI1, CASPR2, and DPPX.
Relapse risks, detection, and strategies for prevention remain an important area of study.