Parkinson's Disease is a neurologic condition whose root cause is a decrease in dopamine levels, especially from the substantia nigra portion of the brain. The disease process has many symptoms, and the extrapyramidal system in the brain is prominently affected, resulting in a wide array of disorders. It is notable that this system is affected from any process where there is decreased dopamine in the body, and that includes other conditions like antipsychotic medication or metoclopramide use (both of which have anti dopamine effects in the body). It can seriously affect the extrapyramidal system, which regulates posture and skeletal tone, so these effects can dominate the clinical picture.
Dystonic Reactions
These are movement disorders and cover a wide spectrum. They include torticollis (muscular spasms of the neck), oculogyric crisis (spasms of the eyeballs) and involuntary movements of the tongue and jaw.
Akathisia
This is commonly described by patients as an unpleasant sensation of restlessness that comes from within. It presents in the affected patient with an inability to sit still, and it ranges from slight anxiety to overwhelming sense of doom and malaise.
Tremor
This is usually an asymmetric tremor that normally affects the arm but can involve the face, lips, chin and leg. It typically is worse when the patient is under stress or at rest, and it improves when they try to do something, such as reach for a glass of water for example. It is described as "pill rolling," with a characteristic back and forth motion of the thumb and forefinger.
Bradykinesia
This refers to slowness of movement and is a hallmark of Parkinson's Disease. This affects all aspects of activity including walking, reaching for objects and even speech. Along with the characteristic rigidity, this can result in unstable posture and frequent falls.
Rigidity
Rigidity is also a key finding in Parkinson's Disease. A classical sign of this is the cog-wheeling gait, which is a very ratchety sort of walk in which the patient walks with a very uneven and stiff gait. It also can also involve lots of shuffling.
Mask-like Facies
The muscles of facial expression are affected just like skeletal muscle by the extrapyramidal system dysfunction. This results in a characteristic mask-like face due to the decreased use of the facial muscles to create expression.
References
- "Textbook of Family Medicine, 7th Edition;" Rakel; 2007
- "Cecil Medicine, 23rd Edition;" Goldman; 2007
- Neurology. "The Scientific and Clinical Basis for the Treatment of Parkinson Disease." Olanow C, Stern M, Sethi K. Volume 72, Issue 21 Suppl 4 (May 2009)
