Saturday, June 06, 2009

Treatable autoimmune encephalitis

Bataller L et al. Autoimmune limbic encephalitis in 39 patients: immunophenotypes and outcomes. JNNP 2007: 78: 381-385.

17 patients were studied at University of Pennsylvania, as well as 22 "outside cases" with sera sent in. . The most important points were that

1. Most of the patients were accurately diagnosed clinically before antibodies were returned.

2. 9/17 had antibodies to known neuronal antigens (paraneoplastic or VGKC's) and 5/17 to novel cell membrane antigens (hippocampus/cerebellum). For the whole group, including the sent in cases, the numbers were 19/39 had antibodies to known antigens, 17/39 to nCMA's.

3. A significant treatment response effect was seen in those with VGKCA's and nCMA's.

4. Those with known intraneuronal antigens (anti Hu, anti Ma) are associated with cancer and may be associated with a worse prognosis than the antibodies to VGKCA's and nCMA's

5. Ovarian teratoma and thymoma are paraneoplastic treatable and benign conditions once the tumor is excised

6. No MRI or CSF characteristics help in diagnostic process.

In another article, some cases of ovarian teratoma associated paraneoplastic encephalitis are related to NMDA receptor antibodies (NMDAR) (Dalmau J, et al. Ann Neurol 2007; 61: 25-36. ) Posner's group described 12/12 with teratomas of ovary who had NMDAR with antibodies to the NR2 subunit, which binds glutamate in the forebrain and hippocampus, AND, a VIRUS LIKE PRODROME.

In yet another article, Mathew et al. (Neurology 2007; 68: 900-905) described orchiectomy for Ma2 related encephalitis as successful in showing otherwise undocumented tumors in 6/25 patients who underwent the procedure (the other 19 had known germ cell tumors). The criteria for orchiectomy were 1) present Ma2 antibodies with clinical/MRI evidence of encephalitis 2) life threatening or progressive neurologic deficits 3) age< 50 4) absent evidence for other tumors 5) new testicular enlargement, microcalcifications on testicular ultrasound, cryptorchidism or other evidence of testicular disease. All testicular specimens showed germ cell tumors. Tumor markers, body CT, PET, and other tests were negative in those undergoing the procedure.

Other antibodies reported include Hu, Ri, Ma1, Ma2, CAR, CRMP 3, amphiphysin, and others.

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