What are the causes of resting tremors (Parkinsonian tremors)?

From the Guidelines

Resting tremors are most effectively managed with a combination of medications, including levodopa-carbidopa, dopamine agonists, and MAO-B inhibitors, as well as lifestyle modifications, with the goal of improving quality of life and reducing morbidity and mortality. Resting tremors are involuntary, rhythmic muscle movements that occur when a body part is relaxed and supported against gravity, most commonly affecting the hands, causing a characteristic "pill-rolling" motion between the thumb and fingers. These tremors are primarily associated with Parkinson's disease, resulting from the degeneration of dopamine-producing neurons in the substantia nigra of the brain, as described in the study on Parkinsonian syndromes 1.

Some key points to consider in the management of resting tremors include:

• Medications like levodopa-carbidopa (Sinemet), starting at 25/100 mg three times daily, which replenishes dopamine levels
• Dopamine agonists such as pramipexole (Mirapex) or ropinirole (Requip) may be used as initial therapy in younger patients or as adjuncts
• MAO-B inhibitors like selegiline (5-10 mg daily) can also help by preventing dopamine breakdown
• For medication-resistant tremors, deep brain stimulation may be considered, as part of a comprehensive treatment plan 1
• Patients should maintain regular physical activity, consider occupational therapy for adaptive strategies, and avoid caffeine and stress which can worsen symptoms
• Early neurological consultation is important for proper diagnosis and treatment planning, as resting tremors can occasionally stem from other conditions like drug side effects or certain metabolic disorders, highlighting the importance of accurate diagnosis and treatment, as outlined in the study on movement disorders and neurodegenerative diseases 1.

In terms of diagnosis, correctly diagnosing a Parkinsonian syndrome on clinical features alone can be quite challenging, and imaging remains an essential diagnostic tool in the evaluation of a patient presenting with Parkinsonian symptoms, including resting tremors, as noted in the study on acr appropriateness criteria for movement disorders and neurodegenerative diseases 1.

From the FDA Drug Label

CLINICAL PHARMACOLOGY Mechanism of Action Parkinson’s disease is a progressive, neurodegenerative disorder of the extrapyramidal nervous system affecting the mobility and control of the skeletal muscular system. Its characteristic features include resting tremor, rigidity, and bradykinetic movements. This is thought to be the mechanism whereby levodopa relieves, symptoms of Parkinson’s disease

Levodopa is used to relieve symptoms of Parkinson's disease, including resting tremors. The drug works by increasing the levels of dopamine in the brain, which helps to reduce the symptoms of the disease.

• Key points:
  • Levodopa relieves symptoms of Parkinson's disease
  • Resting tremor is a characteristic feature of Parkinson's disease
  • Levodopa increases dopamine levels in the brain to reduce symptoms 2

From the Research

Definition and Classification of Resting Tremors

• Resting tremors are defined as an involuntary movement that is rhythmic and oscillatory, and may manifest in a variety of ways 3
• Tremor has a rich clinical phenomenology, and the diagnosis of tremor disorders can be challenging, with misdiagnoses being common 3
• Resting tremor is one of the two main types of tremors, the other being action tremor (ie, postural, kinetic, or intention tremor) 3

Causes and Associated Conditions of Resting Tremors

• Parkinson disease is the most common disorder of resting tremor 3
• Other conditions that may cause resting tremors include essential tremor, although this is more commonly associated with action tremors 4
• Resting tremors can also be a symptom of other neurodegenerative diseases, although the exact causes and associations are not fully understood 5

Treatment Options for Resting Tremors

• Treatment for resting tremors often involves dopaminergic pharmacotherapy, such as levodopa and dopamine agonists (e.g. pramipexole, ropinirole) 5, 6
• Other treatment options may include deep brain stimulation, focused ultrasound thalamotomy, and radiofrequency lesioning, although these are typically reserved for more severe cases 3, 4
• The choice of treatment will depend on the underlying cause of the resting tremor, as well as the individual patient's symptoms and medical history 7

Management and Safety Considerations

• The management of resting tremors requires a comprehensive approach, taking into account the patient's overall health and medical history 4
• Dopamine agonists, such as pramipexole and ropinirole, have been shown to be effective in treating resting tremors, but may be associated with adverse events such as nausea, dizziness, and hallucinations 6, 7
• The safety and tolerability of these medications should be carefully considered, and patients should be closely monitored for any adverse effects 7