Parkinson's Disease: Symptoms, Causes and Treatment

Parkinson’s disease is a brain condition that slowly affects movement. It happens when nerve cells that make dopamine, a chemical messenger that helps control movement, wear out and die. The best-known signs are a shaking hand at rest, slow movements and stiff muscles. There is no cure yet, but medicines, exercise and therapy can control symptoms well for many years.

Key points

About 1 million people in the US live with Parkinson’s disease. It usually starts after age 60 and is more common in men.
Symptoms often start on one side of the body and get worse slowly over years.
Many people also have problems that don’t involve movement, such as loss of smell, constipation, acting out dreams, low mood and anxiety.
Levodopa, which the brain turns into dopamine, is the most effective medicine.
Regular exercise is one of the most helpful things you can do.

What causes Parkinson’s disease

Deep in the brain, a small area called the substantia nigra makes dopamine. In Parkinson’s, a protein called alpha-synuclein folds the wrong way and builds up in clumps (Lewy bodies), and the dopamine-making cells slowly die. By the time movement symptoms appear, many of these cells are already gone.

Why this happens isn’t fully known. Age is the biggest risk factor. About 1 in 10 to 15 people with Parkinson’s have a gene change linked to it, such as in the LRRK2 or GBA1 genes. Long-term contact with some pesticides and the solvent trichloroethylene (TCE), and past head injuries, raise the risk a little.

Parkinson’s disease symptoms

Movement symptoms

Tremor. A rhythmic shake, often in one hand, that’s most noticeable when the hand is resting in your lap. It may look like rolling a pill between the thumb and finger, and it often eases when you use the hand.
Slowness (bradykinesia). Everyday tasks take longer. Handwriting gets smaller, the voice gets softer, the face shows less expression, and steps become short and shuffling with less arm swing.
Stiffness (rigidity). Muscles feel tight or achy, often in the shoulder or neck.
Balance problems. These usually come later and raise the risk of falls. Some people feel their feet “freeze” to the floor for a moment.

Not everyone with Parkinson’s has a tremor.

Other symptoms

Some of these can start years before the movement problems:

Loss of smell
Constipation
Acting out dreams, such as kicking or shouting in sleep (REM sleep behavior disorder)
Depression, anxiety or loss of motivation
Dizziness on standing, from a drop in blood pressure
Bladder urgency, sweating and drooling
Later on, problems with memory and thinking, or seeing things that aren’t there

How Parkinson’s is diagnosed

There is no single test. A doctor, ideally a neurologist who specializes in movement disorders, makes the diagnosis from your history and exam. They will watch you walk, tap your fingers, turn your hands and write. A clear improvement on levodopa also supports the diagnosis.

RELATED REPORTS

Exenatide does not slow Parkinson’s disease progression compared to placebo

The Scan by 2 Minute Medicine®: Florida Trans Youth Care Ban Halted, Tendon Injuries in Basketball, A Blood Test for Parkinson’s Disease, Screen Time and Language Development

Other tests may help when the picture is unclear:

An MRI of the brain, to look for other causes such as strokes or fluid buildup
A DaTscan, a type of brain scan that shows whether dopamine nerve endings have been lost
Newer tests that look for abnormal alpha-synuclein in a small skin sample or in spinal fluid

Several conditions look like Parkinson’s at first. These include drug-induced parkinsonism (from some antipsychotics or the nausea drug metoclopramide), multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration (CBD) and dementia with Lewy bodies. They tend to progress faster and respond less to levodopa.

How Parkinson’s disease is treated

Medicines

Dopamine itself can’t get from the bloodstream into the brain. Parkinson’s medicines work around this by supplying a building block the brain turns into dopamine, copying dopamine’s effects, or making dopamine last longer.

Levodopa with carbidopa (Sinemet and others) is the strongest treatment. It comes as tablets, extended-release capsules, an inhaled powder for sudden “off” times, and pumps that deliver it all day under the skin or into the intestine. Nausea and dizziness can happen early. After some years, many people notice the effect wearing off between doses, or extra twisting movements (dyskinesias).
Dopamine agonists such as pramipexole, ropinirole and the rotigotine patch copy dopamine’s effects. They can cause sleepiness, leg swelling and, in some people, compulsive gambling, shopping, eating or sexual behavior. Tell your doctor if you or your family notice these.
MAO-B inhibitors (selegiline, rasagiline, safinamide) and COMT inhibitors (entacapone, opicapone) help dopamine or levodopa last longer.
Amantadine can reduce dyskinesias.
Apomorphine, as an injection or a film under the tongue, works within minutes to rescue “off” times.

Doctors also treat constipation, low blood pressure, sleep problems, depression and hallucinations, which can affect daily life as much as the movement symptoms.

Never stop Parkinson’s medicine suddenly. It can cause severe stiffness, high fever and confusion. If you’re in the hospital, ask that your doses be given on your usual schedule.

Exercise and therapy

Regular exercise improves walking, balance, strength and mood. Brisk walking, cycling, dancing, tai chi and boxing-based classes are all good choices. Physical therapists teach balance and fall prevention, occupational therapists help with daily tasks, and speech therapists work on a soft voice and swallowing problems.

Surgery

Deep brain stimulation (DBS) places thin wires in the brain, connected to a pacemaker-like device under the skin of the chest. It helps people who still respond to levodopa but have troublesome tremor, wearing-off or dyskinesias. Focused ultrasound, guided by MRI, can treat a tremor on one side without cutting the skin.

Living with Parkinson’s disease

Parkinson’s is a long-term (chronic) condition that changes slowly. Many people keep working and stay active for years after diagnosis. Make your home safer by removing loose rugs and adding grab bars and good lighting. Support groups and a care team that includes a neurologist, therapists and a mental health professional can make a real difference for you and your family.

When to see a doctor

A tremor, slowness or stiffness that’s new or getting worse
Falls or near-falls
Changes in mood, memory or behavior, or seeing things that aren’t there
Trouble swallowing or choking on food
New urges to gamble, shop or eat after starting a medicine

Common questions about Parkinson’s disease

Is a slight tremor in my hands a sign of Parkinson’s?

Usually not. A slight shake in both hands when you hold a cup or write is more often essential tremor, or a normal tremor made worse by caffeine, stress or some medicines. Parkinson’s tremor is usually on one side and shows most at rest. Essential tremor is often treated with propranolol or primidone.

Does Parkinson’s disease cause muscle weakness?

Not true weakness. Muscle strength usually stays normal, but slowness and stiffness make movements feel heavy and tiring. Real loss of strength points to another cause and should be checked. Exercise, strength training and physical therapy help people with Parkinson’s feel stronger and move more easily.

Is Parkinson’s disease hereditary?

Mostly not. About 1 in 10 to 15 people with Parkinson’s carry a gene change that raises their risk, and having a parent or sibling with it raises your risk slightly. Most people with a family member who has Parkinson’s never develop it. Genetic testing is available if you’re curious.

Does CBD help Parkinson’s symptoms?

The evidence is weak so far. Small studies of cannabidiol (CBD) and cannabis have shown mixed results for sleep, anxiety and pain, and little effect on tremor or slowness. Products vary in strength and purity, and cannabis can worsen dizziness and confusion. Talk to your neurologist before trying them.