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 is

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- Carphologia/floccilation (picking movements at clothes coversheets) & occupational delirium (pantomimes as if continuing the usual occupation in a hospital bed)This 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.