Parkinson's disease describes a degenerative neurological condition characterized by tremors, rigidity, impaired balance and bradykinesia---a slowness of movement. Parkinson's disease occurs when nerve cells in the brain stem responsible for producing the chemical dopamine are destroyed. Other conditions affecting the central nervous system due to different causes can exhibit symptoms similar to Parkinson's disease. Doctors describe patients with these diseases, classified as types of Parkinson's disease, as suffering from parkinsonism.
Postencephalitic Parkinsonism
Encephalitis lethargica, a condition with an unknown cause, is a disease characterized by a high fever, headache, double vision, delayed physical and mental response, lethargy, tremors and rigidity, as described by the National Institute of Neurologic Diseases and Stroke. Often referred to as "sleeping sickness," encephalitis lethargica has not caused a significant epidemic since the outbreak between 1917 and 1928. Many patients died as a result of the disease, while others developed symptoms similar to Parkinson's disease, known as post-encephalatic parkinsonism, even years after the illness.
Drug-Induced Parkinsonism
Medications that affect the actions of dopamine and dopamine receptors in the brain can cause symptoms of Parkinson's disease, a condition referred to as drug-induced parkinsonism. Medications prescribed to treat psychiatric disorders, such as haloperidol and perphenazine, most commonly cause drug-induced parkinsonism, according to information published by Drs. Alvarez and Evidente in "Neurology." Other medications that may cause drug-induced parkinsonism include metoclopramide and prochlorperazine, which doctors prescribe to treat gastric motility disorders.
Toxin-Induced Parkinsonism
Toxic substances can damage the brain and cause symptoms of parkinsonism. A substance known as MPTP, short for 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, damages nerve cells in the substantia nigra of the brain. This causes a decrease in dopamine, similar to Parkinson's disease. Other toxic substances known to cause toxin-induced parkinsonism include manganese dust, carbon disulfide and carbon monoxide.
Arteriosclerotic Parkinsonism
Blood vessels that supply the brain can become blocked due to a buildup of fatty tissue, known as plaque. This inhibits the flow of blood, and, therefore, oxygen, to the brain leading to a stroke---a condition in which brain cells die due to a lack of oxygen. Multiple small strokes can cause brain damage that leads to symptoms of parkinsonism. This type of Parkinson's disease, known as arteriosclerotic parkinsonism or vascular parkinsonism, comes on suddenly and may affect only one side of the body, as described by the Baylor College of Medicine.
Post-Traumatic Parkinsonism
A severe head injury, such as can occur in boxing or a car accident, can damage the brain cells in the brain stem, resulting in symptoms of parkinsonism. This type of Parkinson's disease, known as post-traumatic parkinsonism, can also result in dementia.
