Parkinsonism: A Term for Conditions That Mimic Parkinson’s Disease

Parkinsonism is a general term that refers to a group of neurological disorders that cause movement problems similar to those seen in Parkinson’s disease, such as tremors, slow movement, and stiffness. Parkinsonism can have various causes, some of which are reversible and some of which are not. In this article, we will explore the different types, causes, symptoms, and treatments of parkinsonism.

Types of Parkinsonism

There are several types of parkinsonism, each with its own characteristics and causes. The most common types are:

• Idiopathic Parkinson’s disease (PD): This is the most common and well-known form of parkinsonism, affecting about 1% of people over 60 years old. The cause of PD is unknown, but it is believed to involve a combination of genetic and environmental factors that lead to the loss of dopamine-producing nerve cells in the brain. Dopamine is a chemical messenger that regulates movement, mood, and other functions. The main symptoms of PD are tremor, rigidity, slowness of movement, and postural instability. PD can also cause non-motor symptoms, such as depression, loss of smell, sleep problems, cognitive changes, and more. PD is a progressive and incurable condition, but treatments can help reduce the symptoms and improve the quality of life for people with PD.
• Drug-induced parkinsonism (DIP): This is the second most common type of parkinsonism, accounting for about 10% of cases. DIP can be caused by certain medications that affect dopamine levels in the brain, such as antipsychotics, anti-nausea drugs, calcium channel blockers, and stimulants. DIP can also be caused by exposure to toxins, such as carbon monoxide or manganese. The symptoms of DIP are similar to those of PD, but they usually affect both sides of the body equally and may be less severe. DIP is usually reversible if the causative drug or toxin is stopped or avoided.
• Vascular parkinsonism (VP): This type of parkinsonism is caused by reduced blood supply to the brain due to strokes or other vascular diseases. VP affects about 5% of people with parkinsonism. VP can cause problems with movement, balance, memory, mood, and speech. VP may also affect other parts of the body, such as the bladder or bowel. VP tends to progress more slowly than PD and may respond less well to dopaminergic treatments.
• Atypical parkinsonism or Parkinson’s plus syndromes: These are rare forms of parkinsonism that have additional features that distinguish them from PD. They include:
  • Multiple system atrophy (MSA): This is a degenerative disorder that affects multiple systems in the body, such as the autonomic nervous system (which controls blood pressure, heart rate, digestion, etc.), the cerebellum (which controls balance and coordination), and the basal ganglia (which control movement). MSA can cause symptoms such as low blood pressure, urinary problems, constipation, erectile dysfunction, speech difficulties, swallowing problems, sleep disorders, and abnormal eye movements. MSA usually progresses faster than PD and does not respond well to dopaminergic treatments.
  • Progressive supranuclear palsy (PSP): This is a disorder that affects the brainstem (which controls vital functions such as breathing and heart rate), the cerebellum (which controls balance and coordination), and the frontal lobes (which control personality and behavior). PSP can cause symptoms such as falls, difficulty moving the eyes up and down or side to side (called supranuclear gaze palsy), dementia, apathy, impulsivity, depression, hallucinations, and difficulty speaking and swallowing. PSP usually progresses faster than PD and does not respond well to dopaminergic treatments.
  • Corticobasal degeneration (CBD): This is a disorder that affects the cerebral cortex (the outer layer of the brain) and the basal ganglia (which control movement). CBD can cause symptoms such as asymmetric rigidity (stiffness on one side of the body), dystonia (abnormal muscle contractions), myoclonus (sudden jerks or spasms), apraxia (difficulty performing learned movements), alien limb phenomenon (feeling that one limb is foreign or has a mind of its own), cognitive impairment, language difficulties, and sensory loss¹. CBD usually progresses faster than PD and does not respond well to dopaminergic treatments.
  • Lewy body dementia (LBD): This is a disorder that affects both movement and cognition. LBD is characterized by the presence of abnormal protein deposits called Lewy bodies in the brain. LBD can cause symptoms such as fluctuating attention, visual hallucinations, delusions, sleep disorders, parkinsonism, and dementia. LBD may respond partially to dopaminergic treatments, but they may also worsen the cognitive and psychiatric symptoms.

Causes of Parkinsonism

The exact causes of parkinsonism are not fully understood, but they may involve a combination of genetic, environmental, and age-related factors. Some possible causes or risk factors are:

• Genetic mutations: Some forms of parkinsonism, such as PD, MSA, PSP, CBD, and LBD, may be linked to mutations or variations in certain genes that affect the function or survival of nerve cells in the brain. However, most cases of parkinsonism are not inherited and result from a complex interaction of genetic and environmental factors.
• Environmental toxins: Exposure to certain chemicals or metals, such as pesticides, herbicides, solvents, manganese, or mercury, may increase the risk of developing parkinsonism by damaging the nerve cells in the brain. However, the evidence for this link is not conclusive and more research is needed to establish a causal relationship.
• Medications: As mentioned earlier, some drugs can cause parkinsonism by blocking or depleting dopamine in the brain. These drugs include antipsychotics (such as haloperidol or risperidone), anti-nausea drugs (such as metoclopramide or prochlorperazine), calcium channel blockers (such as verapamil or diltiazem), and stimulants (such as amphetamines or cocaine). The risk of developing drug-induced parkinsonism depends on the dose, duration, and type of drug used.
• Vascular diseases: Conditions that affect the blood vessels in the brain, such as strokes, transient ischemic attacks (TIAs), or chronic cerebrovascular disease (CCD), can cause parkinsonism by depriving the nerve cells of oxygen and nutrients. This can lead to cell death or dysfunction in the areas of the brain that control movement.
• Infections: Some viral or bacterial infections can cause inflammation or damage to the nerve cells in the brain, leading to parkinsonism. These infections include influenza A, Epstein-Barr virus (EBV), hepatitis C virus (HCV), varicella-zoster virus (VZV), syphilis, tuberculosis, and Lyme disease. However, these cases are rare and usually occur in people with weakened immune systems.
• Traumatic brain injuries (TBIs): Head trauma can cause bleeding, swelling, or scarring in the brain, which can affect the function of the nerve cells that control movement. TBIs can also trigger an inflammatory response that may damage the nerve cells further. The risk of developing parkinsonism after a TBI depends on the severity, location, and frequency of the injury.

Symptoms of Parkinsonism

The symptoms of parkinsonism vary depending on the type and cause of the condition. However, some common symptoms that most forms of parkinsonism share are:

• Tremor: This is an involuntary shaking or trembling of a part of the body, usually the hand or arm. Tremor is often more noticeable at rest and may improve with voluntary movement. Tremor is one of the cardinal signs of PD and affects about 70% of people with PD. However, tremor is less common or absent in other forms of parkinsonism.
• Rigidity: This is an increased resistance to passive movement of a limb. Rigidity can cause stiffness, pain, cramps, and reduced range of motion. Rigidity is another cardinal sign of PD and affects about 90% of people with PD. Rigidity is also common in other forms of parkinsonism.
• Bradykinesia: This is a term that means slow movement. Bradykinesia can affect various aspects of movement, such as initiation, execution, amplitude, speed, and coordination. Bradykinesia can cause difficulties with walking, writing, dressing, eating, speaking, and facial expressions. Bradykinesia is the third cardinal sign of PD and affects almost all people with PD. Bradykinesia is also common in other forms of parkinsonism.
• Postural instability: This is a term that means impaired balance and increased risk of falls. Postural instability can result from a combination of factors, such as rigidity, bradykinesia, impaired reflexes, and sensory loss. Postural instability is a late sign of PD and affects about 40% of people with PD. Postural instability is also common in other forms of parkinsonism.

• Drug-induced parkinsonism (DIP): DIP may have some features that are uncommon in PD, such as:
  • Rapid onset and progression of symptoms
  • Symmetrical involvement of both sides of the body
  • Absence or mildness of tremor
  • Presence of other side effects from the causative drug, such as weight gain, sedation, or dry mouth
  • Improvement or resolution of symptoms after stopping or reducing the causative drug
• Vascular parkinsonism (VP): VP may have some features that are uncommon in PD, such as:
  • History of stroke or other vascular risk factors, such as hypertension, diabetes, or smoking
  • Abrupt or stepwise onset and progression of symptoms
  • Asymmetrical involvement of the lower limbs more than the upper limbs
  • Presence of other signs of vascular damage, such as pyramidal signs (such as weakness, spasticity, or hyperreflexia), pseudobulbar signs (such as dysarthria, dysphagia, or emotional lability), or cognitive impairment
• Atypical parkinsonism or Parkinson’s plus syndromes: These syndromes may have some features that are uncommon in PD, such as:
  • Poor or transient response to dopaminergic treatments
  • Early onset and rapid progression of symptoms
  • Prominent involvement of other systems besides movement, such as autonomic, cerebellar, ocular, cognitive, or psychiatric
  • Presence of specific signs that are characteristic of each syndrome, such as supranuclear gaze palsy in PSP, alien limb phenomenon in CBD, or visual hallucinations in LBD

Treatment of Parkinsonism

The treatment of parkinsonism depends on the type and cause of the condition. The main goals of treatment are to improve the symptoms, prevent complications, and enhance the quality of life for people with parkinsonism. Some general principles of treatment are:

• Medications: Medications are the mainstay of treatment for most forms of parkinsonism. The most commonly used medications are those that increase dopamine levels in the brain, such as levodopa (combined with carbidopa or benserazide), dopamine agonists (such as pramipexole or ropinirole), monoamine oxidase B inhibitors (such as selegiline or rasagiline), and catechol-O-methyltransferase inhibitors (such as entacapone or tolcapone). These medications can help reduce the motor symptoms of parkinsonism, such as tremor, rigidity, and bradykinesia. However, they may also cause side effects, such as nausea, drowsiness, dyskinesia (involuntary movements), hallucinations, or impulse control disorders. Moreover, they may not be effective for all types of parkinsonism and may lose their efficacy over time. Therefore, the dose and timing of these medications need to be adjusted individually and monitored regularly by a doctor.
• Non-dopaminergic medications: Some forms of parkinsonism may benefit from other medications that target different neurotransmitters or pathways in the brain. For example, anticholinergics (such as trihexyphenidyl or benztropine) may help reduce tremor and rigidity; amantadine may help reduce dyskinesia; antihistamines (such as diphenhydramine) may help reduce dystonia; clonazepam may help reduce myoclonus; botulinum toxin injections may help reduce spasticity; antidepressants (such as selective serotonin reuptake inhibitors or tricyclic antidepressants) may help reduce depression; antipsychotics (such as quetiapine or clozapine) may help reduce psychosis; and cholinesterase inhibitors (such as donepezil or rivastigmine) may help improve cognition. However, these medications may also have side effects and interactions with other drugs. Therefore, they should be used with caution and under medical supervision.
• Surgery: Surgery is a treatment option for some people with parkinsonism who have severe or refractory symptoms that do not respond well to medications. The most common type of surgery is deep brain stimulation (DBS), which involves implanting electrodes into specific areas of the brain and connecting them to a battery-powered device that delivers electrical impulses to modulate the activity of the nerve cells. DBS can help improve the motor symptoms of PD and some forms of atypical parkinsonism, such as MSA and PSP. However, DBS is not a cure and does not stop the progression of the disease. Moreover, DBS has risks and complications, such as infection, bleeding, hardware malfunction, or stimulation-induced side effects. Therefore, DBS is only recommended for carefully selected candidates who have realistic expectations and are willing to undergo regular follow-up and adjustments.
• Non-pharmacological interventions: Besides medications and surgery, there are other interventions that can help people with parkinsonism cope with their condition and improve their function and well-being. These include:
  • Physical therapy: Physical therapy can help people with parkinsonism improve their mobility, balance, strength, flexibility, and endurance. Physical therapy can also teach people how to use assistive devices, such as walkers or canes, and how to prevent falls and injuries. Physical therapy can also include exercises that target specific symptoms, such as LSVT BIG (Lee Silverman Voice Treatment) for bradykinesia or PWR! (Parkinson Wellness Recovery) for rigidity.
  • Occupational therapy: Occupational therapy can help people with parkinsonism improve their ability to perform daily activities, such as dressing, grooming, eating, writing, or using the computer. Occupational therapy can also provide strategies and adaptations to overcome the challenges posed by the symptoms of parkinsonism, such as using adaptive utensils, voice amplifiers, or electronic organizers.
  • Speech therapy: Speech therapy can help people with parkinsonism improve their communication skills, such as speech volume, clarity, fluency, and intonation. Speech therapy can also help people with parkinsonism improve their swallowing function and prevent aspiration pneumonia. Speech therapy can also include exercises that target specific symptoms, such as LSVT LOUD (Lee Silverman Voice Treatment) for hypophonia or SPEAK OUT! for dysarthria.
  • Psychological therapy: Psychological therapy can help people with parkinsonism cope with the emotional and social impact of their condition, such as depression, anxiety, stress, isolation, or stigma. Psychological therapy can also provide support and education to the caregivers and family members of people with parkinsonism. Psychological therapy can include various modalities, such as cognitive-behavioral therapy (CBT), mindfulness-based stress reduction (MBSR), or interpersonal therapy (IPT).
  • Complementary and alternative therapies: Some people with parkinsonism may seek complementary and alternative therapies to supplement their conventional treatments or to address their holistic needs. These therapies may include acupuncture, massage, yoga, tai chi, meditation, music therapy, art therapy, aromatherapy, or herbal remedies. However, the evidence for the effectiveness and safety of these therapies is limited or inconclusive. Therefore, these therapies should be used with caution and in consultation with a doctor.

Conclusion

Parkinsonism is a term that encompasses a variety of neurological disorders that cause movement problems similar to those seen in PD. Parkinsonism can have various causes, some of which are reversible and some of which are not. Parkinsonism can cause various symptoms, some of which are common to all types of parkinsonism and some of which are specific to each type. Parkinsonism can be treated with various interventions, some of which are aimed at improving the symptoms and some of which are aimed at enhancing the quality of life for people with parkinsonism. Parkinsonism is a complex and challenging condition that requires a multidisciplinary approach and individualized care.