Anti-NMDA Encephalitis

7-yo African-American male with seizures. No fever.

Initial CT scan and labs: normal.

EEG: diffuse slowing over the left cerebral hemisphere.

Brain Biopsy (left temporal lobe): Focal necrosis, dystrophic calcification, chronic inflammation, and microglial activation (the latter suggested an infectious etiology, such as a virus, but no infectious agent was identified).

Two weeks after initial work-up he was found to have +NMDA receptor antibodies.

As part of the search for the etiology of these NMDA receptor antibodies, a testicular ultrasound, Beta-HC, AFP, PET were performed to r/o malignancy — all of these studies were negative. CT of chest, abdomen, and pelvis also showed no masses but we know that approximately 40% of anti-NMDA receptor antibodies are found in the absence of a tumor.

We are interested in finding out if someone else has seen this rare condition.

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Anti-NMDA Encephalitis
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Marcela Posada • University of North Carolina, Chapel Hill

2 thoughts on “Anti-NMDA Encephalitis

  • June 16, 2009 at 1:28 pm
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    We have recently had a case of this in a 17 year-old girl. She had a short prodrome of confusion before presenting with status epilepticus. Initial CT and MRI of the head were normal. EEG showed unusual epileptiform activity in the form of spikes and very high amplitude slow waves, maximal anteriorly. Anti-NMDAR antibodies were detected one month into the illness.There was no evidence of an underlying tumor on pelvic US, pelvic MRI, CT of the chest/abdo/pelvis, thyroid US or on whole body PET/CT.

    Brain MRI three weeks after presentation showed only subtle cortical swelling and hyperintensity in the left temporal lobe on FLAIR, which we attributed to recent seizure activity. There was no restricted diffusion and no abnormal contrast enhancement.

    After two rounds of plasma exchange she made a good recovery and no anti-NMDAR antibodies were detectable thereafter.

  • June 25, 2009 at 5:21 pm
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    There has been a case series published from Penn with 100 patients diagnosed with Anti-NMDA- receptor encephalitis and only 9 were men. Overall 58 had tumors. Most commonly ovarian teratomas. Of the 9 males only 2 had diagnosed neoplasms. The ages of the males are not specified in the published manuscript.
    Ref:
    Anti-NMDA-receptor encephalitis: case series and analysis of
    the effects of antibodies
    Josep Dalmau, *Amy J Gleichman, *Ethan G Hughes, Jeff rey E Rossi, Xiaoyu Peng, Meizan Lai, Scott K Dessain, Myrna R Rosenfeld

    Lancet Neurol 2008; 7: 1091–98

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