Which two tests are commonly considered to assess autoimmune etiologies in new-onset seizures in adults?

• A. EEG
• B. Autoimmune encephalitis antibody panels (e.g., NMDA receptor antibodies) and CSF analysis; MRI findings may support autoimmune processes.
• C. Brain biopsy
• D. VDRL

Answer: (B)

Autoimmune processes can cause new-onset seizures in adults, and identifying them relies on looking for immune-mediated targets in the brain. Testing for autoimmune encephalitis antibodies—such as NMDA receptor antibodies—and performing cerebrospinal fluid analysis directly targets these immune mechanisms. Detecting neuronal surface or synaptic antibodies in serum or, more reliably, in CSF, together with CSF inflammatory markers or intrathecal antibody production, provides concrete evidence that an autoimmune process is involved. MRI findings can support the diagnosis by showing inflammatory changes, especially in limbic structures, but they aren’t definitive on their own. EEG helps characterize seizure activity but doesn’t pinpoint an autoimmune cause. Brain biopsy is invasive and not routine for diagnosing autoimmune encephalitis, and VDRL screens for neurosyphilis rather than autoimmune etiologies. So, the combined autoimmune encephalitis antibody panels and CSF analysis best identify autoimmune causes in new-onset adult seizures.