Agrypnia is severe, total insomnia of long duration. Recognized causes include trauma to the brainstem and/or thalamus, prion disease (fatal familial and sporadic fatal insomnia), Morvan’s syndrome, von Economo’s disease, trypanosomiasis, and a relapsing-remitting disorder of possible autoimmune pathogenesis responding to plasma exchange.
Batocchi AP, Della Marca G, Mirabella M et al. Relapsing-remitting autoimmune agrypnia. Annals of Neurology 2001; 50: 668-671