Guidelines for the diagnosis and treatment of essential tremor

Primary tremor (ET)

Also known as essential tremor

A common movement disorder characterized clinically by postural or action tremor at the distal extremities, which may be accompanied by head, orofacial or voice tremors
.

Between 30% and 50% of patients with ET have a family history
.

The conventional wisdom is that ET is a benign, familial, monosymptomatic disease, but ET is currently considered to be a slow-progressing, complex disease
that may be associated with family inheritance.

Clinical features

Age of onset: It can occur at all ages, more common in middle-aged and elderly people over 40 years old, and some people think that adolescents are another peak
of onset.
Familial onset is earlier than in patients with sporadic ET, more often before the age of 20 years
.

Clinical core symptoms: 4-12Hz postural or action tremor as the main feature, mostly occur in the hands and forearms, but can also involve the head (such as neck), lower limbs, voice, etc.
, occasionally involving the tongue, face, trunk and other parts
.
Tremor can affect multiple sites at the same time
, such as the forearm and head.
Daily activities such as writing, pouring water, and eating can worsen the tremor, and most patients have reduced
symptoms after drinking.
As the course of the disease increases, the tremor frequency decreases and the amplitude increases, leading to more severe dysfunction
.
Tremor involvement may increase gradually, usually several years after upper extremity involvement, and usually the trunk and lower extremities are usually affected later
.

Clinical grading of tremor: according to the tremor grading standard proposed by the National Institutes of Health Essential Tremor Research Group in 1996 for reference:

Grade 0: no tremor;

Grade 1: mild, imperceptible tremor;

Grade 2: moderate, tremor amplitude< 2cm, non-disabled;

Grade 3: obvious, tremor amplitude of 2-4cm, partially disabled;

Grade 4: severe, tremor amplitude of more than 4cm, disability
.

Diagnostic criteria

Core diagnostic criteria:

(1) Obvious and persistent postural and/or action tremor of both hands and forearms;

(2) not accompanied by other neurological signs (except for gear phenomenon and Directed sign);

(3) There may be only head tremor, but not accompanied by dystonia
.

Supported diagnostic criteria:

(1) The course of the disease is more than 3 years;

(2) Have a positive family history;

(3) Tremor is reduced
after drinking.

Exclusion Criteria:

(1) There are factors that cause physiological hyperkinetic tremor; Enhanced physiological tremor: Tremor movements
exist in normal people's limbs, head, tongue, and trunk.
When young, this tremor is rapid and subtle, and imperceptible, and with age, the amplitude of the tremor increases and the frequency slows down, especially in certain postures
.
This physiological tremor has little effect on daily life, but may worsen into irregular rocking tremor movements
when intense fear, anxiety, rage, insomnia, heavy alcohol consumption, or taking certain medications.

(2) Are or have recently used tremor-causing drugs or are in the withdrawal period;

(3) History of neurological trauma within 3 months before the onset of disease;

(4) have a history or clinical evidence of psychiatric (psychological) tremor; Such as hysteria;

(5) Sudden onset of disease or stepwise progression and deterioration
of the condition.

differential diagnosis

Physiological tremor, psychomental tremor, Parkinson's disease tremor, cerebellar tremor, dystonia tremor, erythronucleus tremor, primary orthostatic tremor, Wilson's disease tremor, tremor caused by internal medicine system diseases (such as hyperthyroidism, hepatic encephalopathy, etc
.
).

1.
Parkinson's disease tremor: mainly resting tremor, can be combined with action tremor, hand pill-like tremor and lower limb resting tremor is a typical manifestation of
Parkinson's disease.
In addition to tremor, Parkinson's disease patients are often accompanied by bradykinosis, muscle rigidity, postural gait abnormalities, and the late stage can be accompanied by reduced joint movements, freezing phenomenon, etc
.

2.
Cerebellar tremor: mainly intentional tremor of the upper and lower limbs, often accompanied by other signs of the cerebellum, such as ataxia, abnormal rotational movements, poor distance discrimination, etc.
, and ET patients are usually not accompanied by cerebellar symptoms
.

3.
Psychotic tremor: mostly occurs when there are certain mental factors such as anxiety, nervousness, fear, compared with ET, its frequency is faster (8-12 Hz), but the amplitude is small, there are corresponding psychological characteristics, remove the symptoms of the precipitating factor can disappear
.

Treatment of ET

Treatment of ET is divided into drugs (oral drugs and botulinum toxin type A) and surgical treatment
.

The principles of drug treatment are:

(1) Mild tremor does not require treatment;

(2) Due to work or social needs, mild to moderate patients can choose to take medication half an hour before the event to intermittently reduce symptoms;

(3) moderate to severe tremor that affects daily life and work and requires drug treatment;

(4) Drug-refractory severe patients can consider surgical treatment;

(5) Patients with head or voice tremor can choose type A botulinum toxin injection treatment
.

According to the recommended levels of A, B and C of evidence-based medicine, combined with the actual situation in China, the drugs for the treatment of ET are divided into first-line, second-line and third-line drugs
.

First-line drugs: propranolol, arololol, primidone;

Second-line drugs: gabapentin, topiramate, alprazolam, atenolol, sotalol, clonazepam;

Third-line medications: clozapine, nadolol, nimodipine, botulinum toxin
type A.

Propranolol, arrolol, and primidone are the preferred initial agents for ET and can be used in combination when monotherapy is ineffective; Botulinum toxin type A multipoint intramuscular injection may be effective in patients with head or voice tremors; Surgical treatment is suitable for patients with
severe symptoms and refractory drugs.

First-line recommended medications:

1.
Propranolol:

It is a non-selective epinephrine β blocker and is a classic first-line treatment
.
(non-selective, acts on β1 and β2 receptors )

(1) Usage: Start with a small dose (10mg / time, 2 times a day), gradually increase the dose (5 mg / time) to 30-60mg / d, you can have symptom improvement, generally not more than 90mg / d; Standard tablets are taken orally 3 times a day, controlled-release tablets are taken once a day, and the drug
is taken in the morning.

(2) Efficacy: It can effectively reduce the amplitude of limb tremor by 50% (the frequency is not reduced), but the efficacy of axial tremor (such as head, voice, etc.
) is not good
.

(3) Adverse reactions: most side effects are the corresponding epinephrine β receptor blocking effect, common pulse rate reduction and blood pressure drop, but the heart rate above 60 times / min can basically be tolerated, during the medication should closely observe the heart rate and blood pressure changes, such as heart rate < 60 times / min can be considered to reduce the dose, < 55 times / min to stop the drug; Other rare side effects include fatigue, nausea, diarrhea, rash, impotence, and depression
.

(4) Unstable cardiac insufficiency, high atrioventricular block, asthma, insulin-dependent diabetes and other relative contraindications
.

2.
Primidone: