Organic psychiatry: autoimmune encephalitis: practice question

A Psychiatry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Psychiatry · Organic psychiatry: autoimmune encephalitis

Sample item

A 23-year-old woman develops, over two weeks, agitation, paranoid delusions and insomnia after a flu-like illness, followed by seizures, orofacial dyskinesias and autonomic instability. MRI is normal and CSF shows lymphocytic pleocytosis. What is the most likely diagnosis and the key additional step?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Anti-NMDA receptor encephalitis, with a search for an ovarian teratoma and immunotherapy

Anti-NMDA receptor encephalitis typically affects young women, with a psychiatric prodrome followed by seizures, dyskinesias, decreased consciousness and autonomic instability. Antibodies against the GluN1 subunit are found in CSF. An ovarian teratoma is present in a substantial proportion of young women, and its removal with immunotherapy (steroids, IVIG or plasma exchange, then rituximab or cyclophosphamide) improves outcomes. Antipsychotics are poorly tolerated and may worsen movement abnormalities.

Option by option

  • A. Anti-NMDA receptor encephalitis, with a search for an ovarian teratoma and immunotherapy (correct)

    Correct. This combination of features and demographics suggests this antibody-mediated encephalitis, needing tumour screening and immunotherapy.

  • B. Herpes simplex encephalitis, with no further tests

    HSV encephalitis typically shows temporal lobe abnormalities on MRI and should be covered with acyclovir while this is excluded.

  • C. First-episode schizophrenia, with long-term antipsychotic therapy alone

    Schizophrenia does not cause seizures, dyskinesias and CSF pleocytosis.

  • D. Neuroleptic malignant syndrome, with dantrolene

    NMS follows antipsychotic exposure with rigidity, fever and raised creatine kinase.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Psychiatry question

What is the answer to this Psychiatry question?

The best answer is A, Anti-NMDA receptor encephalitis, with a search for an ovarian teratoma and immunotherapy. Anti-NMDA receptor encephalitis typically affects young women, with a psychiatric prodrome followed by seizures, dyskinesias, decreased consciousness and autonomic instability.

Why is "Herpes simplex encephalitis, with no further tests" not the answer?

HSV encephalitis typically shows temporal lobe abnormalities on MRI and should be covered with acyclovir while this is excluded.

Why is "First-episode schizophrenia, with long-term antipsychotic therapy alo…" not the answer?

Schizophrenia does not cause seizures, dyskinesias and CSF pleocytosis.

Why is "Neuroleptic malignant syndrome, with dantrolene" not the answer?

NMS follows antipsychotic exposure with rigidity, fever and raised creatine kinase.

What concept does this question test?

It tests Organic psychiatry: autoimmune encephalitis in Psychiatry. Antibodies against the GluN1 subunit are found in CSF. An ovarian teratoma is present in a substantial proportion of young women, and its removal with immunotherapy (steroids, IVIG or plasma exchange, then rituximab or cyclophosphamide) improves outcomes. Antipsychotics are poorly tolerated and may worsen movement abnormalities.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Organic psychiatry: autoimmune encephalitis?

Learn each diagnosis by its core features and its first-line treatment. Then use the flashcards and the other Psychiatry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.