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For further information, see CMDT Part 24-14: Movement Disorders

Key Features

Essentials of Diagnosis

  • Any combination of tremor, rigidity, bradykinesia, and progressive postural instability ("parkinsonism")

  • Cognitive impairment is sometimes prominent

General Considerations

  • Risk factors

    • Age

    • Family history

    • Male sex

    • Ongoing herbicide/pesticide exposure

    • Significant prior head trauma

  • Dopamine depletion due to degeneration of the dopaminergic nigrostriatal system leads to an imbalance of dopamine and acetylcholine

  • Exposure to toxins and certain medications can lead to parkinsonism

    • Manganese dust

    • Carbon disulfide

    • Severe carbon monoxide poisoning

    • 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) (a recreational drug)

    • Neuroleptic drugs

    • Reserpine

    • Metoclopramide

  • Postencephalitic parkinsonism is becoming increasingly rare

  • Only rarely is hemiparkinsonism the presenting feature of a space-occupying lesion


  • Common disorder that occurs in all ethnic groups, with an approximately equal sex distribution

  • The most common variety, idiopathic Parkinson disease, usually begins in people between ages 45 and 65 years

  • May rarely occur on a familial basis

Clinical Findings

Symptoms and Signs

  • Cardinal features

    • Tremor

    • Rigidity

    • Bradykinesia

    • Postural instability

  • Nonmotor manifestations include

    • Affective disorders (depression, anxiety, and apathy)

    • Psychosis

    • Cognitive changes

    • Fatigue

    • Sleep disorders

    • Anosmia

    • Autonomic disturbances

    • Sensory complaints or pain

    • Seborrheic dermatitis

  • Dementia or mild cognitive impairment will eventually develop in many patients

  • Tremor

    • Four to six cycles per second

    • Most conspicuous at rest

    • Enhanced by stress

    • Often less severe during voluntary activity

    • Commonly confined to one limb or to one side for months or years before becoming more generalized

    • May be present about mouth and lips

    • May be absent in some patients

  • Rigidity causes the flexed posture

  • Bradykinesia is the most disabling symptom, ie, a slowness of voluntary movement and a reduction in automatic movements such as swinging of the arms while walking

  • The face

    • Relatively immobile with widened palpebral fissures

    • Infrequent blinking

    • Fixity of facial expression

    • Seborrhea of scalp and face

  • Mild blepharoclonus

  • Repetitive tapping (about twice per second) over the bridge of the nose producing a sustained blink response (Myerson sign)

  • Other findings

    • Saliva drooling from the mouth

    • Soft and poorly modulated voice

    • Variable rest tremor and rigidity in some or all of the limbs

    • Slowness of voluntary movements

    • Impairment of fine or rapidly alternating movements

    • Micrographia

  • Typically no muscle weakness and no alteration in the tendon reflexes or plantar responses

  • Difficulty rising from a sitting position and beginning to walk

  • Gait

    • Small shuffling steps and a loss of the normal automatic arm swing

    • There may be unsteadiness on turning, difficulty in stopping, and a tendency to fall

Differential Diagnosis

  • Essential tremor

  • Depression

  • Wilson disease

  • Huntington disease

  • Normal-pressure hydrocephalus

  • Multisystem atrophy (previously called Shy-Drager syndrome)

  • Progressive supranuclear palsy

  • Corticobasal ganglionic degeneration

  • Diffuse Lewy body disease

  • Creutzfeldt-Jakob disease

  • Drugs causing parkinsonism

    • Antipsychotic agents

    • Reserpine

    • Metoclopramide

    • MPTP



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