a.k.a. paraneoplastic encephalitis, a.k.a. paraneoplastic limbic encephalits
A combination of serology, clinical features and identification of underlying tumor
Subacute impairment, seizures, temporal lobe seizures & hallucinations,
Other features may occur:,
Limbic encephalitis (medial temporal lobe, hippocampus, amygdala, cingulate gyrus, inula), thalamus, brainstem encephalitis, cerebellum, spinal cord grey matter, dorsal root ganglia (sensory neuropathy), peripheral nerves, myenteric plexus.
Gross: bilateral necrosis.
- CNS: Massive neuronal loss, neuronophagea. Astrocytic gliosis, rod-shaped microglia. Perivascular & intraparenchymal lymphocytic infiltrates.
- Ganglia: loss of ganglion cells. Prominent inflammatory infiltrates.
- Peripheral nerves: axonal degeneration with secondary demyelination. Mild perivascular & parenchymal mononclear infltrates.
Findings on Investigations:
MRI: usually bilateral involvement of temporal lobes. Atrophy of the temporal lobe is common. Brainstem or hypothalamic involvement may occur. Hemorrhage is rare. T2 hyperintense, FLAIR hyperintense.
- Limbic encephalitis autoantibodies:
- Some of these autoantibodies are more strongly associated with neoplasm that others
- Anti-: Hu (ANNA-1), amphiphysin, CV2/CRMP5, LGI1, CASPR2, VGKC, NMDA (NR1), GAD65, MaTa,
- Voltage-gated potassium channels VGKC, usually not paraneoplastic
- Anti-NMDA receptor antibodies: ovarian teratoma. Associated with orolingual dyskinesias & catatonia like state.
Treat the underlying tumor
Consider IVIg, plasma exchange,