Essential Tremor

Question 1

… … is a type of action tremor that is very common in the general population.

Answer 1

Essential tremor is a type of action tremor that is very common in the general population.

Question 2

The estimated prevalence of essential tremor is ..% worldwide. Development of this type of action tremor increases with age and there is often a family history. The inheritance is suspected to be autosomal dominant. There is thought to be a slight male predominance.

Answer 2

The estimated prevalence of essential tremor is 1% worldwide. Development of this type of action tremor increases with age and there is often a family history. The inheritance is suspected to be autosomal dominant. There is thought to be a slight male predominance.

Question 3

Any tremor may also be described in terms of frequency and amplitude:

Answer 3

Frequency: this is essentially how quick the tremor is, or in other words, the oscillations (back and forth movement) per second. It is measured in cycles per second (Hertz - Hz)
Amplitude: this is essentially the amount of movement, or in other words, the degree of displacement of the limb or body part. Large amplitude tremors (i.e. associated with more movement) are usually more disabling

Question 4

Exacerbating and relieving factors - essential tremor

Answer 4

An essential tremor characteristically improves with a small amount of alcohol. Unlike a physiological tremor, it is not worsened by caffeine.

Question 5

The diagnosis of essential tremor is made clinically.

A diagnosis of essential tremor is typically based on the following four features:

Answer 5

Isolated upper limb action tremor
With/without tremor in other sites (e.g. head)
Duration >3 years
No other neurological features

Question 6

A dopamine transporter scan (DaTscan) can be used to reliably distinguish Parkinson’s disease or Parkinsonism from patients with …

Answer 6

A dopamine transporter scan (DaTscan) can be used to reliably distinguish Parkinson’s disease or Parkinsonism from patients with essential tremor. It is a specialised type of scan that looks for loss of dopaminergic neurons in the basal ganglia.

Question 7

Management of essential tremor depends on its severity.

Answer 7

Basic management steps should be completed first including removing any potential precipitant that makes the tremor worse. Pharmacological treatment may be considered in patients with persistent functional or psychological disability caused by the tremor. More invasive treatments are available for refractory cases.

Ultimately, essential tremor is a progressive disease and patients should be warned that symptoms will worsen over time.

Question 8

Essential tremor
Several medical therapies may be offered to patients with persistent functional or psychological disability. These include:

Answer 8

Propranolol: non-selective beta-blocker used in many conditions to reduce sympathetic activity
Primidone: anti-epileptic drug that has an unclear mechanism. Possibly activates gamma-aminobutyric acid (GABA) receptors and alters voltage-gated sodium channels

Question 9

First line for essential tremor?

Answer 9

Propranolol is commonly chosen first-line due to side-effect profiles. Both have been associated with reduction in tremor amplitude by 50%. Importantly, some patients may not see an effect.

Question 10

Second-line options if propranolol/primidone fail in essential tremor?

Answer 10

Switching to the alternative first-line
Add both first-line medications in combination
Add or switch to another agent (e.g. gabapentin, topiramate)

Question 11

Patients with refractory tremor despite pharmacotherapy may be offered a range of further treatments with variable efficacy. This is highly specialist but options may include:

Answer 11

Neuromodulation (e.g. nerve stimulation devices)
Botulinum toxin injections
Deep brain stimulation