Parkinson's disease

Parkinson's disease (PD; paralysis agitans) is a neurodegenerative disease of the substantia nigra (an area in the basal ganglia of the brain). The disease was first discovered and its symptoms documented in 1817 (An Essay on the Shaking Palsy) by the British physician Dr. James Parkinson; the associated biochemical changes in the brain of patients were identified in the 1960s. Some genes were identified only recently; others remain unknown.

Symptoms

Symptoms may vary among patients, and additionally may vary greatly over time in a single patient.

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However, the cardinal symptoms are:

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• tremor (while this is the best known symptom, it is not displayed by an estimated 30% of patients. The classical Parkinsonian tremor is 4-7Hz, often unilateral, decreased by supination and pronation, and responds to dopaminergics and anticholinergics. In addition, tremors of the chin and lips tend to be Parkinsonian where tremors of the whole head suggest essential tremor.),
• rigidity (increased tone or stiffness in the muscles),
• bradykinesia (slowness of movement) and akinesia (lack of spontaneous movement),
• failing balance,
• walking problems.

(The mnemonic TRAP (Tremor; Rigidity; Akinesia/bradykinesia; Postural instability) can be used to remember these symptoms.)

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Additionally, the following signs and symptoms are commonly associated with Parkinson's Disease:

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• Psychological and cognitive
• depression (occurs in 40-70% of cases)(20% of depression cases are major depressive disorder)
• anxiety or panic attacks

Note: 70% of individuals with parkinson's disease diagnosed with pre-existing depression go on to develop anxiety; 90% of parkinson's disease patients with pre-existing anxiety subsequently develop depression)

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• dementia, in approximately 20-30% of all patients, typically starting with slowing of thought and progressing to difficulty organizing thoughts
• memory loss
• apathy
• altered sexual function
• sleep disturbances
• Sensory
• impaired visual contrast sensitivity, colour discrimination, convergence insufficiency (characterized by double vision) and oculomotor control
• dizziness
• loss of sense of smell (anosmia),
• pain
• Physical
• speech problems (hypophonia; vocal cords can also be affected, causing monotonous, soft speech qualities),
• stooped or flexed posture,
• constipation,
• fatigue (up to 50% of cases),
• oily skin and sebborheic dermatitis,
• difficulty in swallowing,
• masked facies (a mask-like face also known as hypomimia, with infrequent blinking),
• drooling,
• micrographia (small, cramped handwriting)
• decreased arm swing
• difficulty rolling in bed
• slowness of gait
• urinary incontinence, typically in later disease progression

Symptoms usually only begin to appear after about 80% of the dopamine in the brain has been lost. More recent data based on PET scans suggests that symptoms may occur when 50-60% of dopaminergic neurons are lost. The level of dopamine will continue to fall slowly over time, with an attendant worsening of symptoms.

Related Topics:
Dopamine - PET scans

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It is an incapacitating disease, disturbing some important human functions and in some cases resulting in a substantial reduction in quality of life. As in many neurologic diseases, psychological complications are often extremely serious and require the patient's family members and relatives to pay keen attention to the emotional fragility that usually follows the emergence of the disease; indeed, the depression which often results is seen by many as one of the worst aspects of the disease. In some cases drugs are employed, especially in the fight against depression (given that Parkinson's-related depression is mainly induced by a complex of chemical-physical factors). Also, some common side effects of therapy can put the patient in a condition of humble self-consideration. External help is required to control the administration of the prescribed therapy: since patients are often confused or depressed, there is a risk of their improperly implementing the therapeutic regimen if left to their own devices, leading to symptoms not being adequately controlled.

Related Topics:
Neurologic diseases - Psychological - Depression

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Parkinson's disease is very widespread, with about 150-200 cases per 100,000 population at any given time. About 2% of the population develops the disease some time during life. Cases are reported at all ages, though it is quite rare in people younger than 30 and the average age at which symptoms begin is 58-60; the risk of developing it substantially increases with age. It occurs in all parts of the world, but appears to be more common in people of European ancestry than in those of African ancestry. Those of East Asian ancestry have an intermediate risk. It is more common in rural than urban areas and men are affected slightly more often than women.

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