Parkinson's disease occurs when nerve cells in the base of the brain, the area known as the brain stem, become damaged due to a combination of genetic and environmental factors. The major symptoms of Parkinson's disease include tremors, rigidity, and bradykinesia, a neurological condition that leads to difficulty in walking and also balance problems. Because so many conditions exist that cause symptoms resembling Parkinson's disease, doctors refer to parkinsonism as a syndrome characterized by these symptoms.
Encephalitis Lethargica
Encephalitis lethargica, often referred to as sleeping sickness, describes a condition of swelling of the brain usually caused by a viral infection. Although a rare disease now, following World War I 5 million cases occurred world-wide resulting in the death of approximately one-third of those with the condition, according to the National Institute of Neurologic Disorders and Stroke. Many symptoms of encephalitis lethargica resemble those of Parkinson's disease, including muscle pains, upper body weakness, tremors and neck rigidity.
Drug-Induced Conditions
Some medications can induce the characteristic symptoms of parkinsonism. Neuroleptic medications, such as haloperidol and perphenazine, block the actions of the dopamine D2 receptors and can therefore induce symptoms of parkinsonism. The good news, according to the American Academy of Neurology, is that symptoms of drug-induced parkinsonism should resolve once the patient stops taking the medication.
Toxin-Induced Conditions
The symptoms of parkinsonism can also be induced by exposure to toxins. Carbon monoxide, an odorless, colorless gas, competes with oxygen to bind with hemoglobin. As cells carry the carbon monoxide through the body, the gas causes injuries to cells, including cells in the brain. As brain cells die, lesions form in the brain resulting in symptoms resembling Parkinson's disease. Other toxins that can induce symptoms of parkinsonism include manganese and cyanide.
Arteriosclerotic Parkinsonism
Arteriosclerosis describes a process in which the walls of the arteries become thick and stiff, usually due to increased pressure on the walls caused by high blood pressure. As the walls thicken it restricts blood flow. When this occurs in the arteries leading to the brain, the brain fails to receive enough oxygen, resulting in the death of cells and a condition known as arteriosclerotic parkinsonism. The symptoms include rigidity, a masklike face and a short-stepped gait, according to the American Heart Association.
Post-Traumatic Encephalopathy
Post-traumatic encephalopathy describes a condition of brain swelling and damage caused by a traumatic brain injury. Nucleus Medical Media reports that between 2.5 and 6.5 million Americans suffer from a traumatic brain injury. The location of the brain injury determines the type of symptoms. Although rare, movement disorders that resemble Parkinson's disease can develop years after injury to the basal ganglia portion of the brain, according to Nucleus Medical Media.
References
- National Institute of Neurologic Disorders and Stroke: Parkinson's Disease
- American Academy of Neurology: Understanding Drug-Induced Parkinsonism
- Parkinson's Disease Diagnosis and Clinical Management: Toxin-Induced Parkinsonism
- American Heart Association: Neurological Signs and Frontal White Matter Lesions in Vascular Parkinsonism
- Nucleus Medical Media: Traumatic Brain Injury
