General constitutional symptoms of manganese toxicity include asthenia, headache, hypersomnolence, nervousness, muscle cramps, and decreased libido. These symptoms tend to manifest early, shortly following the exposure. Manganese madness was described in mining villages of northern Chile. Behavioral manifestations tend to precede the akinetic-rigid manifestations of manganese toxicity. Other parkinsonian features including bradykinesia, hypokinesia, and rigidity will gradually evolve with continued exposure.
Postural reflexes are commonly impaired with anteropulsion, retropulsion, and en-bloc turning.
Gait disturbances are common, with a characteristic cock-walking pattern. Patients with manganese-induced parkinsonism, in contrast to patients with idiopathic Parkinson s disease, typically walk with trunk extended, arms flexed, and an appearance of strutting on their toes. When present, tremor is typically a low amplitude postural tremor mainly involving the upper extremities. Dystonia may be associated with Mn toxicity. Patients may exhibit intermittent dystonic posturing of the limbs, and sometimes severe dystonia of the trunk.