What other diseases and conditions resemble Parkinson's disease?
A number of disorders can cause symptoms similar to those of PD. People with symptoms that resemble PD but that result from other causes are considered to have parkinsonism. Some of these disorders include:
Multiple system atrophy
Multiple system atrophy (MSA) refers to a set of slowly progressive disorders that affect the central and autonomic nervous systems. In MSA, the protein alpha-synuclein forms harmful filament-like aggregates in the supporting cells in the brain called oligodenreoglia. MSA may have symptoms that resemble PD. It may also take a form that primarily produces poor coordination and slurred speech, or it may involve a combination of these symptoms. Other symptoms may include swallowing difficulties, male impotence, constipation, and urinary difficulties. The disorder previously called Shy-Drager syndrome refers to MSA with prominent orthostatic hypotension—a fall in blood pressure every time the person stands up. MSA with parkinsonian symptoms is sometimes referred to as MSA-P (or striatonigral degeneration), while MSA with poor coordination and slurred speech is sometimes called MSA-C (or olivopontocerebellar atrophy). Unfortunately, many of the symptoms of MSA either do not respond to PD medications or the response is minimal or short-lived.
Dementia with Lewy bodies
Dementia with Lewy bodies is a neurodegenerative disorder associated with the same abnormal protein deposits (Lewy bodies) found in Parkinson’s disease but in widespread areas throughout the brain. Symptoms may range from primary parkinsonian symptoms such as bradykinesia, rigidity, tremor, and shuffling walk, to symptoms similar to those of Alzheimer's disease (memory loss, poor judgment, and confusion). These symptoms may fluctuate, or wax and wane dramatically. Visual hallucinations are often one of the first symptoms, and individuals may suffer from other psychiatric disturbances such as delusions and depression. Cognitive problems also occur early in the course of the disease. Levodopa and other antiparkinsonian medications can help with the motor symptoms of Dementia with Lewy bodies, but they may make hallucinations and delusions worse, and affected individuals may require treatment with atypical antipsychotic medications.
Progressive supranuclear palsy
Progressive supranuclear palsy (PSP) is a rare, progressive brain disorder that causes problems with control of gait and balance. The symptoms of PSP are caused by a gradual deterioration of cells in the brain stem. People often tend to fall early in the course of PSP. One of the characteristic features of the disease is an inability to move the eyes properly, which some people describe as having blurred vision. People with PSP often show alterations of mood and behavior, including depression and apathy as well as mild dementia. PSP is often misdiagnosed because some of its symptoms are much like those of PD, Alzheimer's disease, and other brain disorders. PSP symptoms usually do not respond to medication, or the response is minimal and short-lasting. PSP is characterized by aggregation of a protein called tau.
Corticobasal degeneration (CBD) results from atrophy of multiple areas of the brain, including the cerebral cortex and the basal ganglia. Initial symptoms may first appear on one side of the body, but eventually affect both sides. Symptoms are similar to some of the features found in PD, including rigidity, impaired balance, and problems with coordination. Often there is dystonia affecting one side of the body. Other symptoms may include cognitive and visual-spatial impairments, apraxia (loss of the ability to make familiar, purposeful movements), hesitant and halting speech, myoclonus (muscular jerks), and dysphagia (difficulty swallowing). Unlike PD, CBD usually does not respond to medication. Like PSP, it is characterized by deposits of the tau protein.
Several diseases, including MSA, CBD, and PSP, are sometimes referred to as "Parkinson's-plus" diseases because they have the symptoms of PD plus additional features.
Parkinsonism resulting from neurological disorders
Sometimes known as pseudoparkinsonism, vascular parkinsonism, or atherosclerotic parkinsonism, arteriosclerotic parkinsonism involves damage to the brain due to multiple strokes. Tremor is rare in this type of parkinsonism, while dementia and difficulties with gait are common. Antiparkinsonian drugs are of little help to people with this form of parkinsonism.
Also known as post-traumatic encephalopathy or "punch-drunk syndrome," parkinsonian symptoms can develop after a severe head injury or frequent head trauma associated with boxing or other activities. This type of trauma can also cause a form of dementia called chronic traumatic encephalopathy.
Sometimes called benign essential tremor or familial tremor, this common condition tends to run in families and progresses slowly over time. The tremor is usually equal in both hands and increases when the hands are moving. It may involve the head but usually spares the legs. Essential tremor is not the same as Parkinson’s disease and does not usually lead to it, although in some cases the two conditions may overlap in one person. People with essential tremor have no other parkinsonian features. Essential tremor does not respond to levodopa or to most other PD drugs, but there are medications to treat it.
Normal pressure hydrocephalus
Normal pressure hydrocephalus (NPH) is an abnormal increase of cerebrospinal fluid (CSF) in the brain's ventricles, or cavities. This causes the ventricles to enlarge, putting pressure on the brain. Symptoms include problems with walking, impaired bladder control leading to increased urinary frequency or incontinence, and progressive mental impairment and dementia. The person may also have a general slowing of movements or may complain that his or her feet feel "stuck." These symptoms may sometimes be mistaken for PD. They do not respond to Parkinson’s medications. Brain scans, intracranial pressure monitoring, and other tests can help to diagnose NPH. NPH can sometimes be treated by surgically implanting a CSF shunt that drains excess cerebrospinal fluid into the abdomen, where it is absorbed.
Parkinsonism accompanying other conditions
Parkinsonian symptoms appear in individuals with other, clearly distinct neurological disorders such as Wilson's disease, Huntington's disease, Alzheimer's disease, spinocerebellar ataxias, and Creutzfeldt-Jakob disease. Each of these disorders has specific features that help to distinguish it from PD.
Just after the first World War, the viral disease encephalitis lethargica affected almost 5 million people throughout the world, and then suddenly disappeared in the 1920s. Known as sleeping sickness in the United States, this disease killed one-third of its victims and led to post-encephalitic parkinsonism in many others. This resulted in a movement disorder that appeared sometimes years after the initial illness. (In 1973, neurologist Oliver Sacks published Awakenings, an account of his work in the late 1960s with surviving post-encephalitic patients in a New York hospital. Using the then-experimental drug levodopa, Dr. Sacks was able to temporarily "awaken" these individuals from their statue-like state). In rare cases, other viral infections, including western equine encephalomyelitis, eastern equine encephalomyelitis, and Japanese B encephalitis, have caused parkinsonian symptoms.
A reversible form of parkinsonism sometimes results from use of certain drugs, such as chlorpromazine and haloperidol, which are typically prescribed for patients with psychiatric disorders. Some drugs used for stomach disorders (metoclopramide), high blood pressure (reserpine), and others such as valproate can cause tremor and bradykinesia. Stopping the medication or lowering the dosage of these medications usually causes the symptoms to go away.
Some toxins can cause parkinsonism by various mechanisms. The chemical MPTP also causes a permanent form of parkinsonism that closely resembles PD. Investigators discovered this reaction in the 1980s when heroin addicts in California who had taken an illicit street drug contaminated with MPTP began to develop severe parkinsonism. This discovery, which showed that a toxic substance could damage the brain and produce parkinsonian symptoms, led to a dramatic breakthrough in Parkinson's research.
Parkinsonism-dementia complex of Guam
This disease occurs among the Chamorro populations of Guam and the Mariana Islands and may be accompanied by a motor neuron disease resembling amyotrophic lateral sclerosis (Lou Gehrig's disease). The course of the disease is rapid, with death typically occurring within 5 years.
Reference: National Institute of Neurological Disorders and Stroke
Last updated May 4, 2017
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