Essential tremor (N) Flashcards
Define essential tremor.
Progressive, mainly symmetrical, rhythmic, involuntary oscillation movement disorder of the hands and forearms, that is usually absent at rest and present during posture and intentional movements
What are the causative factors for essential tremor? (3)
- ageing
- genetics
- environmental toxins
What is the most common cause of essential tremor?
Positive family Hx - autosomal dominant condition
What demographics are most often affected in essential tremor?
Binomial distribution - teens and elderly
What areas of the brain are involved in essential tremor? (3)
- cerebellum
- brainstem
- thalamus
What has been reported to abolish essential tremor?
Acute cerebellar stroke
What type of tremor is essential tremor?
Action tremor
What are some types of action tremor (low yield)? (9)
- essential tremor
- enhanced physiological tremor - present equally in outstretched arms and legs - thyrotoxicosis, hypoglycaemia etc
- Parkinson’s disease - resting tremor alongside rigidity, bradykinesia, postural instability
- adult-onset idiopathic dystonia - tremor irregular and jerky
- Wilson’s disease - dystonia, dystonic tremor and/or resting tremor
- cerebellar outflow tremor - irregular tremor with goal-directed movements, ataxic component, other cerebellar signs e.g. slurred speech, eye findings, abnormal gait
- Holme’s tremor - irregular, coarse proximal upper extremity tremor with large amplitude
- orthostatic tremor - rare, not visible, cannot stand still
- psychogenic tremor - distractibility, suggestibility and trainability
What are the clinical features of essential tremor? (6)
- bilateral upper limb action tremor - with absence of other neurological signs (cerebellar signs e.g. ataxia, dystonia, parkinsonism)
- worse with sustained voluntary movements (i.e. when arms outstretched), stress or anxiety
- problems with fine motor tasks
- involves - hands (90%), head (30%), voice (15%)
- may be accompanied by an intention tremor or resting tremor
- improves with alcohol consumption, BZs, barbiturates or gabapentin (drugs affecting GABA systems)
What examinations do you do for essential tremor?
Cranial nerves, upper and lower limb neurological exams
What are some risk factors for essential tremor? (3)
- advanced age
- family Hx
- environmental toxins - organochloride pesticides, lead, mercury, beta-carboline alkaloids
What type of diagnosis is essential tremor?
Clinical diagnosis - no first-line investigations
What scans can we do for essential tremor?
Head CT or MRI - only when there is a focal neurological sign
What scan can differentiate essential tremor from Parkinson’s disease?
SPECT Scan (Single-Photon Emission Computed Tomography) - normal putamen value (Parkinson’s would be different)
What are the differential diagnoses for essential tremor? (6)
- Parkinson’s disease - would see DANISH symptoms
- dystonia
- Wilson’s disease - resting and action tremor, Kayser-Fleischer rings, abnormal LFTs
- enhanced physiological tremor
- drug-induced tremor
- psychogenic tremor
