A patient on antipsychotic for past 4 weeks is brought to the emergency with complaint of acute onset of fever, excessive sweating, confusion, rigidity of limbs and decreased communication. Examination reveals temperature of 104°F; P/R - 120/min, BP-150/100 with disorientation. What is the most probable diagnosis -
Lithium toxicity
Aggrevation of psychosis
Dystonia
Neurolept malignant syndrome