Sunday, June 01, 2008

Limbic encephalitis : An expanding concept: teratomas and "things"

Graus F, Saiz A. Neurology 2008; 70: 500-501 (editorial) . Also see re VGKC antibodies in particular.

A syndrome of encephalitis in 12 women with teratomas of the ovary follows a predictable clinical pattern. A prodromal fever, is followed in a few days by a prominent psychiatric syndrome or short term memory loss, then, seizures, then progressive unresponsiveness (catatonia like stage) , dyskinesias, autonomic instability, and central hypoventilation. ICU support for weeks or longer may be necessary, and patients recover generally after tumor removal or immunotherapy (pheresis or IVIG). MRI is usually negative (9/12). All patients had CSF and serum antibodies against components of NMDA receptor (NMDAR) especially 2 subunits NR1/NR2). These particular patients express NR1, which is ubiquitously expressed in brain, but in these patients distributes with NR2 (basal forebrain) and disappears with treatment. This contrasts with NR2B which is seen in Rasmussen's excephalitis, refractory epilepsy, and stroke. In neuropsych lupus, this epitype leads to apoptosis.

Iizuka et al. now describe this epitype in Japanese juvenile non-herpetic encephalitis (with NMDAR). They emphasize the abnormal movements, especially orolingual after initial psychiatric syndrome and catatonic like state. These patients can reverse even after long periods of ventilator dependence.

Update  pearls for NMDAR  from Neurology 2014; 82: 550-551 (editorial)

1.  Tests for:  CSF with HEK cells expressing GluN1/2 subunuts of the NMDAR cell based assay. or serum.  with serum there is a 15 % false negative/positive result

2.  Adult men more often presented with seizures (18 %) whereas women more oftenpresent with behavior/psych symptoms  

3.  Among women, 41 % had tumors, all ovarian teratomas.  Among men only one had a tumor likely unrelated schwannoma. 

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