Module 5 Discussion: Initial Post
When Psychosis Is an Antibody: Anti-NMDA Receptor Encephalitis and the Ovarian Teratoma Behind It
The misdiagnosis I researched is anti-NMDA receptor encephalitis, an autoimmune disease in which antibodies attack NMDA-type glutamate receptors in the brain. In young women it is often triggered by an ovarian teratoma, a tumor that can contain nerve tissue expressing the same receptors, so the immune response against the tumor turns against the brain. Because it begins with psychiatric symptoms, it is frequently mistaken for a primary psychiatric illness.
Clinical manifestations. Dalmau et al. (2008) described a series of 100 patients; 91 were women, and the median age was 23. All presented with psychiatric symptoms or memory problems, such as anxiety, agitation, paranoia, hallucinations, or bizarre behavior. As the disease progressed, most developed decreased consciousness, and many had seizures, abnormal movements, especially of the face and mouth, autonomic instability, and hypoventilation requiring ventilatory support. Of 98 patients evaluated for tumors, 59 percent had one, most commonly an ovarian teratoma.
Common differentials. Early on, the picture resembles acute psychosis, schizophrenia, bipolar mania, or substance-induced psychosis. Later, it can be confused with viral encephalitis, neuroleptic malignant syndrome if antipsychotics were given, or nonconvulsive status epilepticus.
Prevalence. The disease is rare but no longer considered exceptional. A multi-institutional study enrolled 577 patients over five years, with a median age of 21, and more than a third were children (Titulaer et al., 2013). It is now recognized as one of the more common causes of autoimmune encephalitis in young people.
Consequences of misdiagnosis. When the disease is treated as a psychiatric disorder, immunotherapy and tumor removal are delayed. Titulaer et al. (2013) found that early treatment and avoiding intensive care admission predicted good outcomes; 94 percent received first-line immunotherapy or tumor removal, 53 percent improved within four weeks, and 81 percent of those followed for 24 months had a good outcome. Delay means longer hospital stays, more intensive care, and a greater risk of lasting deficits or death. Antipsychotics given for presumed psychosis may also worsen rigidity and autonomic instability.
Prevention. New psychiatric symptoms in a young person with no psychiatric history should prompt a neurological question before a psychiatric answer. Red flags include seizures, abnormal movements, decreased consciousness, autonomic changes, and intolerance of antipsychotics. In these patients, assessment should include a neurological examination, cerebrospinal fluid analysis for NMDA receptor antibodies, EEG, MRI, and pelvic imaging for teratoma in women (Dalmau et al., 2008). Published diagnostic criteria now allow a probable diagnosis of anti-NMDA receptor encephalitis from rapid-onset symptoms plus supporting EEG or cerebrospinal fluid findings, so that treatment can begin before antibody results return (Graus et al., 2016). For advanced practice nurses, the lesson is that a careful physical assessment, including vital sign trends and neurological findings, can separate a first psychotic episode from a treatable autoimmune disease.
Has anyone encountered a patient whose "psychiatric" presentation turned out to be medical?
References
Dalmau, J., Gleichman, A. J., Hughes, E. G., Rossi, J. E., Peng, X., Lai, M., Dessain, S. K., Rosenfeld, M. R., Balice-Gordon, R., & Lynch, D. R. (2008). Anti-NMDA-receptor encephalitis: Case series and analysis of the effects of antibodies. The Lancet Neurology, 7(12), 1091-1098. https://doi.org/10.1016/S1474-4422(08)70224-2
Graus, F., Titulaer, M. J., Balu, R., Benseler, S., Bien, C. G., Cellucci, T., Cortese, I., Dale, R. C., Gelfand, J. M., Geschwind, M., Glaser, C. A., Honnorat, J., Höftberger, R., Iizuka, T., Irani, S. R., Lancaster, E., Leypoldt, F., Prüss, H., Rae-Grant, A., ... Dalmau, J. (2016). A clinical approach to diagnosis of autoimmune encephalitis. The Lancet Neurology, 15(4), 391-404. https://doi.org/10.1016/S1474-4422(15)00401-9
Titulaer, M. J., McCracken, L., Gabilondo, I., Armangué, T., Glaser, C., Iizuka, T., Honig, L. S., Benseler, S. M., Kawachi, I., Martinez-Hernandez, E., Aguilar, E., Gresa-Arribas, N., Ryan-Florance, N., Torrents, A., Saiz, A., Rosenfeld, M. R., Balice-Gordon, R., Graus, F., & Dalmau, J. (2013). Treatment and prognostic factors for long-term outcome in patients with anti-NMDA receptor encephalitis: An observational cohort study. The Lancet Neurology, 12(2), 157-165. https://doi.org/10.1016/S1474-4422(12)70310-1
How this N 518 Module 5 example is structured
N518 Module 5's discussion typically asks you to research a misdiagnosis case and describe its manifestations, common differentials, prevalence, the consequences of misdiagnosis and prevention; the prompt's example mentions ovarian teratomas. The module's ShadowHealth work is your own and is not sampled. Aspen revises courses, so check your classroom's prompt. This example answers each element in order with primary studies and ties prevention to physical assessment.
N518 Module 5 questions, answered
What does N518 Module 5 usually ask for?
The discussion asks you to research a case of misdiagnosis and describe the clinical manifestations, common differentials, prevalence, consequences of misdiagnosis and how it could be prevented. The prompt's example involves ovarian teratomas.
How is an ovarian teratoma linked to encephalitis?
Teratomas can contain nerve tissue that expresses NMDA receptors. The immune response against the tumor produces antibodies that also attack NMDA receptors in the brain, causing anti-NMDA receptor encephalitis.
What red flags suggest encephalitis rather than primary psychosis?
New psychiatric symptoms without prior history accompanied by seizures, abnormal movements, decreased consciousness, autonomic instability or intolerance of antipsychotics should prompt neurological evaluation, including CSF antibody testing, EEG, MRI and pelvic imaging in women.
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