<prompt> A patient with pneumonia for 5 days is admitted to the hospital now with an altered sensorium. He suddenly ceases to recognize the doctor and staff. He thinks that he is in jail and complains of scorpion attacking him. His probable diagnosis isAcute DementiaAcute deliriumAcute schizophreniaAcute paranoia  <response>: Ans.B. i.e. Acute deliriumDeliriumAcute confusional state occurring in various medical, surgical, metabolic, toxic post-operative conditions. It is characterized by acute agitation, disorientation, and inability to sustain attention, form memories or reason. Characteristic features include- Clouding of consciousness i.e, decreased awareness decreased ability to respond to environmental stimuli- Disorientation in time place person- Hallucinations mostly visual illusions- Autonomic dysfunction, agitation, insomnia- Carphologiafloccilation picking movements at clothes coversheets occupational delirium pantomimes as if continuing the usual occupation in a hospital bedThis patient in question has- disturbance in consciousness altered sensorium - disorientation - to place thinks, he is in jail- ceases to recognize the doctor staff- hallucination complaints of scorpions attacking him - after an acute medical illness.All these features are consistent with the diagnosis delirium. 