Essential Tremor

Introduction

-Essential Tremor (ET) is the most common movement disorder 

-It is characterized by high-frequency action tremor of the hands, forearms, head, and voice. 

-Family history is often present with autosomal dominant pattern of inheritance

-It is a chronic and slowly progressive disorder 

-It is postural and kinetic in nature 

It can present in childhood but often -often starts in the third or fourth decade of life 

-Absence of other etiologic factors and neurologic signs: Alcohol, Parkinsonism, medications, hyperthyroidism 

Symptoms & Signs 

-The tremor typically starts from either hands or forearms 

-It is typically bilateral and symmetric but can be asymmetric 

-The tremor is not present at rest, but emerges with action. 

-Tremor can be postural (occurring with outstretched arms), or kinetic (occurring during action such as writing) 

-In severe cases, interferes with activities of daily living, handwriting, vocalization 

-Alcohol provides short-lived relief 

Other than the tremor, neurologic examination should be normal

Diagnosis 

-ET is a clinical diagnosis based on history and physical examination 

-Labs to rule out thyroid dysfunction, Wilson disease, electrolyte disturbances 

-A DaT scan is normal, whereas it is abnormal in Parkinson’s disease.

Treatment 

If the tremor is mild and non-disabling, treatment may not be required. 

Behavioral: Stress reduction, Caffeine avoidance 

Occupational therapy: Adaptive utensils 

Pharmacotherapy: 

First-line agents: Propranolol, Primidone

Second-line agents: Gabapentin, topiramate, zonisamide

Surgical therapies: Unilateral thalamotomy, DBS (Deep Brain Stimulation) in the ventral intermediate (VIM) nucleus of the thalamus, High-frequency thalamic stimulation

Injections: Botulinum injections  

Prognosis 

-ET is a slowly progressive disorder and remains mild in the majority of cases. 

-Patients with essential tremor have a higher risk of developing Parkinson disease than the general population.

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