Parkinson's Disease

Parkinson’s disease is an age-related degenerative brain condition, meaning it causes parts of your brain to deteriorate. It’s best known for causing slowed movements, tremors, balance problems and more. Most cases happen for unknown reasons, but some are inherited. The condition isn’t curable, but there are many different treatment options.

Causes #

Familial Parkinson’s disease #

• Parkinson’s disease can have a familial cause, which means you can inherit it from one or both of your parents. However, this only makes up about 10% of all cases.

• Experts have linked at least seven different genes to Parkinson’s disease. They’ve linked three of those to early-onset of the condition (meaning at a younger than usual age). Some genetic mutations also cause unique, distinguishing features.

Idiopathic Parkinson’s disease #

• Experts believe idiopathic Parkinson’s disease happens because of problems with how your body uses a protein called α-synuclein.

• Proteins are chemical molecules that have a very specific shape. When some proteins don’t have the correct shape a problem known as protein misfolding your body can’t use them and can’t break them down.

• With nowhere to go, the proteins build up in various places or in certain cells (tangles or clumps of these proteins are called Lewy bodies). The buildup of these Lewy bodies (which doesn’t happen with some of the genetic problems that cause Parkinson’s disease) causes toxic effects and cell damage.

• Protein misfolding is common in many other disorders, such as Alzheimer’s disease, Huntington’s disease, multiple forms of amyloidosis and more.

Induced Parkinsonism #

There are conditions or circumstances experts have linked to parkinsonism. While these aren’t true Parkinson’s disease, they have similar features, and healthcare providers may consider these causes while diagnosing Parkinson’s disease.

The possible causes are:

Medications #

Several medications can cause a parkinsonism like effect. The Parkinson’s like effects are often temporary if you stop taking the medication that caused them before the effects become permanent. However, the effects can linger for weeks or even months after you stop taking the medication.

Encephalitis #

Inflammation of your brain, known as encephalitis, can sometimes cause parkinsonism.

Toxins and poisons #

Exposure to several substances, such as manganese dust, carbon monoxide, fumes from welding, or certain pesticides, can lead to parkinsonism.

Damage from injuries #

Repeated head injuries, such as those from high-impact or contact sports like boxing, football, hockey, etc., can cause brain damage. The term for this is post-traumatic parkinsonism.

Symptoms #

Slowed movements (bradykinesia) #

A Parkinson’s disease diagnosis requires that you have this symptom. People who have this describe it as muscle weakness, but it happens because of muscle control problems, and there’s no actual loss of strength.

A tremor while muscles are at rest #

This is a rhythmic shaking of muscles even when you’re not using them and happens in about 80% of Parkinson’s disease cases. Resting tremors are different from essential tremors, which don’t usually happen when muscles are at rest.

Rigidity or stiffness #

Lead-pipe rigidity and cogwheel stiffness are common symptoms of Parkinson’s disease. Lead-pipe rigidity is a constant, unchanging stiffness when moving a body part. Cogwheel stiffness happens when you combine tremor and lead-pipe rigidity. It gets its name because of the jerky, stop-and-go appearance of the movements (think of it as the second hand on a mechanical clock).

Unstable posture or walking gait #

The slowed movements and stiffness of Parkinson’s disease cause a hunched over or stooped stance. This usually appears as the disease gets worse. It’s visible when a person walks because they’ll use shorter, shuffling strides and move their arms less. Turning while walking may take several steps.

Non-motor symptoms (with the potential early warning symptoms in bold) include:

• Autonomic nervous system symptoms - These include orthostatic hypotension (low blood pressure when standing up), constipation and gastrointestinal problems, urinary incontinence and sexual dysfunctions.

• Depression.

• Loss of sense of smell (anosmia).

• Sleep problems such as periodic limb movement disorder (PLMD), rapid eye movement (REM) behavior disorder and restless legs syndrome.

• Trouble thinking and focusing (Parkinson’s-related dementia).

Diagnosis #

• Blood tests (these can help rule out other forms of parkinsonism).

• Computerized tomography (CT) scan.

• Genetic testing.

• Magnetic resonance imaging (MRI).

• Positron emission tomography (PET) scan.

• Spinal tap - One of these tests looks for misfolded alpha-synuclein proteins in cerebrospinal fluid, which is the fluid that surrounds your brain and spinal cord. This test involves a spinal tap (lumbar puncture), where a healthcare provider inserts a needle into your spinal canal to collect some cerebrospinal fluid for testing.

• Skin biopsy - Another possible test involves a biopsy of surface nerve tissue. A biopsy includes collecting a small sample of your skin, including the nerves in the skin. The samples come from a spot on your back and two spots on your leg. Analyzing the samples can help determine if your alpha-synuclein has a certain kind of malfunction that could increase the risk of developing Parkinson’s disease.

Treatment #

Medications #

Adding dopamine #

Medications like levodopa can increase the available levels of dopamine in your brain. This medication is almost always effective, and when it doesn’t work, that’s usually a sign of some other form of parkinsonism rather than Parkinson’s disease. Long-term use of levodopa eventually leads to side effects that make it less effective.

Simulating dopamine #

Dopamine agonists are medications that have a dopamine-like effect. Dopamine is a neurotransmitter, causing cells to act in a certain way when a dopamine molecule latches onto them. Dopamine agonists can latch on and cause cells to behave the same way. These are more common in younger patients to delay starting levodopa.

Dopamine metabolism blockers #

Your body has natural processes to break down neurotransmitters like dopamine. Medications that block your body from breaking down dopamine allow more dopamine to remain available to your brain. They’re especially useful early on and can also help when combined with levodopa in later stages of Parkinson’s disease.

Levodopa metabolism inhibitors #

These medications slow down how your body processes levodopa, helping it last longer. These medications may need careful use because they can have toxic effects and damage your liver. They’re most often used to help as levodopa becomes less effective.

Adenosine blockers #

Medications that block how certain cells use adenosine (a molecule used in various forms throughout your body) can have a supportive effect when used alongside levodopa.

Deep brain stimulation #

In years past, surgery was an option to intentionally damage and scar a part of your brain that was malfunctioning because of Parkinson’s disease. Today, that same effect is possible using deep-brain stimulation, which uses an implanted device to deliver a mild electrical current to those same areas.