The patient’s unmet needs (PUNs)
‘It’s no better’, announces your next patient, a 75-year-old man. He had first attended a few months previously with a tremor, worse on sustained movement such as carrying a cup of tea. You diagnosed essential tremor and you’ve been prescribing a gradually increasing dose of primidone since then – he suffers asthma and so cannot take β-blockers. ‘Are you sure it’s not Parkinson’s disease?’ he asks, anxiously. ‘Don’t you think I ought to see a specialist?’
The doctor’s educational needs (DENs)
What are the features that would confirm a tremor to be an essential tremor rather than Parkinson’s? What are the other differentials?
Classical essential tremor consists of a bilateral, largely symmetrical postural or kinetic tremor (an action tremor as opposed to a rest tremor) involving the hands and forearms. Essential tremor has a bimodal age of onset with the median age of onset being 15 years, and a second peak in the seventh decade. There may also be a head tremor – no-no or yes-yes – but without abnormal posturing (in contrast to dystonic tremor), and sometimes a jaw or leg tremor.
The classical presenting tremor in Parkinson’s disease is asymmetric at onset and present at rest (a rest tremor). It is described as re-emergent on posture – there is a brief delay when the hands are put into a new sustained position and then tremor starts again in this new ‘resting position’.
In older patients presenting with tremor, differentiating between essential tremor and a tremor presentation of Parkinson’s can be difficult. The tremor of essential tremor may be asymmetric at onset and can have a rest component. Although Parkinson’s tremor typically spreads to the ipsilateral leg and then bilaterally, early in its course it can become a predominantly bilateral arm tremor and can have prominent postural and kinetic components.
Clinical signs such as reduced arm swing and reduced facial expression (hypomimia), frequently associated with Parkinson’s disease, may have a number of different causes and are common in the elderly. They are insufficient to make a diagnosis of Parkinson’s – the clinical diagnosis of Parkinson’s requires the presence of bradykinesia, festinant gait and micrographia.
What are the other differentials?
The exclusion criteria for essential tremor include1:
- other abnormal signs (dystonia – abnormal sustained postures, Parkinsonism and ataxia at presentation)
- the presence of drugs that cause an enhanced physiological tremor (beta agonists, valproate, cyclosporin, verapamil)
- sudden onset, isolated position-specific or task-specific tremor (writer’s dystonia), and isolated leg tremor.
The differential diagnosis of essential tremor includes:
- functional (psychogenic) tremor
- physiological tremor – a non-pathological tremor that we experience when excited or stressed, and which can be enhanced by drugs such as caffeine and beta-agonists and endocrine disorders such as hyperthyroidism.
- toxins such as lead and mercury and alcohol withdrawal states
- dystonic tremor
- Parkinson’s disease and Parkinsonism
- neuropathic tremor (typically associated with a IgM demyelinating neuropathy)
- orthostatic tremor – 18Hz tremor of both legs often presenting as unsteadiness on standing
- midbrain and cerebellar lesions – can be a cause of postural tremor and titubation
- fragile X tremor ataxia syndrome – may present with a slowly progressive postural and action tremor with or without ataxia
The tremor of essential tremor is progressive, worsening in severity over time and causing increased disability. The tremor often spreads to involve the head, as well as the arms, but less commonly the legs. The amplitude of the tremor in essential tremor should not vary with position and typically should not be greater with the hands held up to the face – increased amplitude in this position is more typical of dystonic tremor. The frequency of tremor in essential tremor is very variable (4-12 Hz) and the amplitude and frequency are inversely correlated. The postural tremor of essential tremor may be present throughout an action (for instance, on finger nose testing) but it does not have the terminal dysmetria, seen in cerebellar tremor, when it nears its target.2
The tremor component of Parkinson’s tends to be one of the less disabling symptoms in terms of motor function, even though many patients find it socially embarrassing. The tremor may involve the legs, face, jaw and tongue but head and voice tremor is unusual in these patients.
Many patients find that alcohol relieves the symptoms of essential tremor. Is it reasonable if the tremor causes only ‘situational problems’ – such as embarrassment in social situations or when doing hobbies – to recommend occasional dose of alcohol as a treatment?
In about 50% of cases of essential tremor alcohol at a dose of 2-4 units suppresses the tremor, but with a rebound after 4-6 hours. An alcohol effect predicts a good response to β-blockers (propranolol) and these can be used on an as-required basis if tolerated. Before recommending alcohol as an occasional symptomatic treatment, it would be important to be sure that the tremor had not already been exacerbated by alcohol use and to assess for the likelihood of alcohol dependency.
The frequency of the situations in which alcohol might be required should be assessed – once or twice a week might be reasonable but more frequent use of alcohol to suppress the tremor may result in exacerbation of the tremor in the long term and alcohol dependency. ‘On the spot’ relaxation techniques can be used in the management of stress/anxiety exacerbated tremor and neuro-occupational therapists may be able to teach these.
A response to alcohol is not diagnostic of essential tremor – patients with dystonic tremor, myoclonus dystonia, and sometimes Parkinson’s may have an alcohol-responsive tremor.
Are there investigations that the GP can do to clarify or confirm the diagnosis? Are TFTs necessary in the absence of other symptoms or signs of hyperthyroidism?
Thyroid function should be checked in all patients presenting with an action (postural or kinetic) tremor. Further investigations would depend on the presentation and other signs. In patients under 50 years of age presenting with an action tremor, a neurologist would routinely send serum copper levels and caeruloplasmin to exclude Wilson’s disease.
Patients with a unilateral tremor not typical of Parkinson’s or of sudden onset require brain imaging, as do patients with cerebellar or upper motor neurone signs. Nerve conduction studies and blood tests for IgM dysgammaglobulinanaemia are indicated in patients with signs of peripheral neuropathy.
Parkinson’s and essential tremor are both clinical diagnoses. Single photon emission computed tomography (SPECT) can help to distinguish essential tremor and neuroleptic-induced tremor (in both of these the scan is normal) from Parksinon’s (where the scan is abnormal and shows loss of dopamine reuptake sites). The DaTSCAN does not distinguish between different forms of Parkinson’s and technical problems and reporting errors may produce false positives and false negatives. These scans are expensive and often unnecessary and, in my opinion, are not substitutes for assessment by a neurologist.
How effective are the first-line treatments such as β-blockers or primidone? If these are ineffective or contra-indicated what other options are available to the GP?
Propranolol – up to 360mg daily with a starting dose of 20-80mg – and primidone, up to 250mg tds with a starting dose of 25mg/d, are the main symptomatic treatments for essential tremor.3 The combination of propranolol and primidone is more effective than either alone. Propranolol is more effective than sotolol or atenolol.
Clonazepam may be useful for patients with kinetic prominent essential tremor. Other symptomatic treatment options worth trying include gabapentin and topirimate. Botulinum toxin can be useful for upper limb tremor interfering with activities of daily living.
Referral to occupational therapy for an assessment of how the tremor impacts on the patient’s daily life and practical tips – e.g. avoidance of caffeine, use of electric razors, online banking, anti-tremor software – as well as the provision of aids such as kettle tippers and anti-slip placemats is an important step in management. The occupational therapist may also be able to teach on the spot relaxation techniques, important for the control of tremor, and direct the patient to tremor support groups or patient organisation websites.
Stereotactic surgery – deep brain stimulation of the thalamic nucleus ventralis – for moderate to severe essential tremor may reduce tremor by up to 90%.
Which patients require referral? What treatments might a specialist offer?
Patients in whom the diagnosis is uncertain or in whom Parkinson’s is suspected should be referred to a neurologist or elderly care physician with an interest in movement disorders for help with diagnosis and guidance on treatment. Patients with task-specific tremor and other dystonic tremors may benefit most from Botulinum toxin treatment and have a poor response to oral therapies. The specialist team may include expert neuro-occupational therapy for advice on aids for daily living.
Dr Thomasin Andrews is a consultant neurologist at Guys and St Thomas’ NHS Foundation Trust
- Bain PJ. The management of tremor. Journal of Neurology, Neurosurgery and Psychiatry, 2002; 72 (suppl. 1): i3-i9
- Deuschl G, Bain PG, Brin M. Consensus statement of the movement disorder society on tremor. Movement Disorders, 1998; 13 (suppl. 3); 2-23
- Deuschl G, Raethjen J, Hellriegel H, Elble R. Treatment of patients with essential tremor. Lancet neurology, 2011; 10 (2): 148-161
- Ivan Donaldson, C. David Marsden, Susanne Schneider and Kailash Bhatia. Marsden’s Book of Movement Disorders. OUP Feb 2012 ISBN-13: 9780192619112