Overview
Parkinsonism refers to a group of neurological disorders that cause movement abnormalities similar to those seen in Parkinson’s disease, including tremors, slow movements (bradykinesia), stiffness, and balance problems. It can result from various conditions such as Parkinson’s disease, multiple system atrophy, progressive supranuclear palsy, or certain medications. Parkinsonism occurs due to the disruption of dopamine production in the brain, which plays a vital role in controlling motor functions. Early symptoms may include subtle changes in movement or posture, which progressively worsen over time. While there is no cure, treatments like medications, physical therapy, and lifestyle modifications can help manage symptoms and improve quality of life.
It’s characterized by the impairment of motor control, and its hallmark symptoms include tremors, stiffness, and slowed movement.
Causes:
1. Primary (Idiopathic Parkinson’s Disease): No known cause; the most common form.
2. Secondary Parkinsonism:
– Medications: Certain drugs, especially antipsychotics, can cause drug-induced parkinsonism.
– Infections: Encephalitis or other brain infections.
– Toxins: Exposure to chemicals like manganese, carbon monoxide,
– Trauma: Repeated head injuries, e.g., in athletes.
– Vascular Parkinsonism: Multiple small strokes affecting the basal ganglia.
– Other neurodegenerative diseases: Such as multiple system atrophy (MSA) or progressive supranuclear palsy (PSP).
Risk Factors:
1. Age: Most cases occur after the age of 60.
2. Genetics: Family history of Parkinson’s disease can increase risk.
3. Environmental Exposure: Long-term exposure to toxins (e.g., pesticides).
4. Gender: Males are slightly more prone to developing the condition.
Pathophysiology:
Parkinsonism arises due to the degeneration of dopamine-producing neurons in the substantia nigra, a region of the brain that regulates movement. Dopamine is essential for transmitting signals within the motor control pathways, and its depletion leads to the characteristic motor symptoms.
– Lewy bodies: Abnormal protein deposits (alpha-synuclein) are often found in the brains of those with Parkinson’s disease.
– Disruption of basal ganglia circuitry: The loss of dopamine affects the regulation of movement, leading to bradykinesia, rigidity, and tremors.
Signs and Symptoms:
1. Tremor: Resting tremor (e.g., pill-rolling tremor) is one of the classic signs.
2. Bradykinesia: Slowness of movement.
3. Rigidity: Muscle stiffness throughout the range of motion (cogwheel rigidity).
4. Postural Instability: Trouble with balance and coordination, leading to falls.
5. Non-motor symptoms: Include depression, constipation, cognitive impairment, sleep disturbances, and autonomic dysfunction (e.g., orthostatic hypotension).
Investigations:
1. Clinical Evaluation: Diagnosis is mostly clinical, based on motor symptoms and response to dopamine replacement therapy.
2. Imaging:
– PET scan is the investigation of choice
– MRI/CT: Often used to rule out other causes like stroke or brain tumors.
– DAT Scan (Dopamine Transporter Imaging): Can assess dopamine function in the brain.
3. Blood Tests: To rule out secondary causes, like thyroid or metabolic disorders.
4. Genetic Testing: May be done if there’s a family history of Parkinsonism.
Treatment:
– Levodopa/Carbidopa: The mainstay treatment; levodopa is converted into dopamine in the brain.
– Dopamine Agonists: Stimulate dopamine receptors (e.g., pramipexole, ropinirole).
– MAO-B Inhibitors: Inhibit the breakdown of dopamine (e.g., selegiline, rasagiline).
– COMT Inhibitors: Extend the effect of levodopa (e.g., entacapone).
– Anticholinergics: Help with tremors (less commonly used due to side effects).
