A clinical TRIAD for early suspicion of autoimmune encephalitis as a possibility in patients presenting with progressive cognitive decline.

Patients with progressive cognitive decline mostly suffer from degenerative disease and carry a relatively poor prognosis. But small groups among these patients have a potentially treatable cause of illness and therefore every patient with dementia needs to be considered treatable unless proved otherwise. This group can be identified only by high degree of suspicion based on clinical clues. We have evaluated the validity of some simple clinical clues which we noticed in our patients with immune mediated dementias. The Panic score, Epsworth sleepiness score, catatonic symptoms and history of seizures were compared between 23 and 11 patients with serologically confirmed anti-NMDA antibody and anti-VGKC antibody associated encephalitis respectively. They were compared with 20 patients with probable behavioral variant of Frontotemporal dementia (bvFTD) and 20 patients with probable Alzheimer's disease (AD). Chi-square test was used to compare across the groups and there was significant difference (P < 0.05) across the 4 groups comprising anti NMDA encephalitis, anti VGKC encephalitis, FTD and AD among the four variables (Panic scores, Catatonic symptoms, Epsworth sleepiness score and seizures) studied. Our study revealed that panic and sleepiness is highly significant when tested across all groups and catatonia showed a trend towards NMDA and when compared with degenerative dementia versus immune mediated syndromes all the 4 parameters were highly significant This simple bedside TRIAD of panic, sleepiness with either of catatonia or seizures if found in patients it is appropriate to order antibody assessment before anything else is planned. This needs to be evaluated in a larger sample.