What is parkinsonism?

Progressive neurological disorder of muscle movement, destruction of DA neurons in substantia nigra, leads to reduced DA action in corpus striatum, leads to appearance of lewy bodies. Features: bradykinesia, muscular rigidity, resting tremor, impairment of postural balance [gait disturbance]. Genetic factors and environmental toxic agents 2ary parkinsonism: drugs like phenithiazine and haloperidol which are D2 Rs antagonists.