The GP’s guide to Parkinson’s

Parkinson’s UK


Share on Google+
|
| Earn 0.5 Credits

Diagnosis

  • A definite diagnosis of Parkinson's is difficult. It is important that there is an early diagnosis. If the condition is suspected, a patient should quickly be referred – untreated – to a neurologist or a geriatrician with a special interest in Parkinson's. There may be a local 'movement disorder clinic'. The NICE Guideline Parkinson's: diagnosis and management in primary and secondary care says referral time should be no more than 6 weeks and should not exceed 2 weeks in cases where the condition is severe or complex
  • Signs and symptoms suggestive of Parkinson's are:
    • bradykinesia (slow movements)
    • tremor
    • hypokinesia (poverty of movement)
    • rigidity
  • The condition is diagnosed following a detailed clinical examination. The specialist should use the Parkinson's UK Brain Bank Criteria. There are no laboratory tests or easily available imaging tests to help make the diagnosis
  • While a DaTSCAN may assist in making the diagnosis, this is only available in some centres. It is more likely to be used to exclude other conditions that may have similar symptoms
  • Patients with Parkinson's should be reviewed regularly and the diagnosis reconsidered if atypical features appear. The rate of onset is extremely variable
  • There are some conditions that have symptoms similar to Parkinson's and are referred to as 'parkinsonism':
    • essential (familial) tremor
    • post-encephalic parkinsonism
    • other conditions include cerebrovascular parkinsonism, progressive supranuclear palsy (PSP), multiple systems atrophy (MSA), corticobasal degeneration, and Wilson's disease
  • Neuroleptic drugs, including anti-emetics, can induce symptoms of parkinsonism

Follow-up

  • Ideally, patients with Parkinson's should receive a follow-up by a Parkinson's specialist every 6–12 months to optimise the treatment and reassess the diagnosis
  • As the illness evolves, it is not unusual for the diagnosis to change
  • If the GP has a special interest in Parkinson's then the patient can be followed by using a local shared care protocol
  • If there is a Parkinson's Nurse Specialist (PDNS), they can co-ordinate optimal care with the patient, carer, GP, and specialist. The PDNS revolutionises care by bringing it into the community and the patient's home. All patients with Parkinson's should have access to a PDNS
  • Maintaining independence is a high priority, along with home safety
  • Occupational therapy and physiotherapy follow-up will facilitate independence. Speech therapy will help to preserve speech and swallowing
  • The GP can co-ordinate care by using a computerised register to ensure patients are not referred on and then forgotten about
  • Medication is usually provided by the GP, who is well placed, with the PDNS, to monitor compliance issues related to repeat prescribing
  • A medication review will ensure that no other medication is exacerbating the condition
  • Do not stop medication abruptly as it can cause neuroleptic malignant syndrome, which can be dangerous

Motor symptoms

  • Patients with Parkinson's become slower in all movements (bradykinesia) and gradually the characteristic parkinsonian rigidity takes possession of the limb, usually on one side – both sides will be affected as the condition progresses. On the affected side, the arm stops swinging when walking and the leg feels heavy
  • Hypokinesia (poverty of movement) manifests as loss of facial expression, loss of arm swing, and difficulty with movement
  • In the majority of patients, but not all, the tremor appears not when the limb is in motion but when at rest, or perhaps when carrying out a task such as holding up a newspaper. It is a fine, rhythmic movement – about two to five per second – and may appear in the thumb and index finger ('pill-rolling') or at the wrist. The leg also, when inadequately supported, will shake in the same way
  • The tremor is aggravated by fatigue, emotional stress, or the knowledge that the tremor is being looked at. It usually only affects one side of the body initially
  • Clinical examination should, as usual, begin with the observation of the patient as he/she approaches the examiner:
    • the face, the stance, and gait are all good indicators of Parkinson's
    • the arms and legs are not paralysed
    • the muscle tone is increased with the classic 'lead pipe' or 'cog-wheel' rigidity. Movements tend to be slow and restricted in range
    • the tendon reflexes are normal or even a little brisk and the planter reflexes are flexor. If reflexes are brisk, this raises the possibility of atypical parkinsonism
  • Imperceptibly, the natural mobility of the patient's face fades and this becomes a little set and, later, a 'masked' appearance develops. Although the voice tends to lose its natural inflexions and eventually becomes very weak
  • Although the lack of facial expression can give the wrong impression about the mental state, many patients have unrecognised depression

Non-motor symptoms

  • Early recognition of non-motor symptoms (NMS) is essential. The GP or PDNS can assess and monitor these continuously, providing specific advice and support for the person and their family, as well as ensuring referral on to the multidisciplinary team
  • A questionnaire for people with Parkinson's to complete to help health professionals assess their non-motor Parkinson's symptoms is available to download from parkinsons.org.uk
  • Neuropsychiatric symptoms include:
    • anxiety
    • apathy
    • depression
    • psychosis and visual hallucinations
    • dementia
    • sleep disturbances
    • restless legs syndrome (RLS)
    • rapid eye movement (REM) sleep behaviour disorder (RBD)
    • hypersomnolence
  • Autonomic disturbance (dysautonomia) symptoms include:
    • urinary dysfunction
    • constipation
    • sexual dysfunction
    • orthostatic (postural) hypotension
    • weight loss
    • dysphagia
    • excessive sweating (hyperhidrosis)
    • excessive saliva (sialorrhoea)
  • Sensory disturbances include:
    • pain
    • olfactory dysfunction

Treatment

  • Unless the GP has a special interest in the condition, treatment is best initiated by a Parkinson's specialist in liaison with the PDNS, using a local shared care protocol that the GP can refer to. The GP can then prescribe Parkinson's medication but only if a robust local shared guideline is available. Ideally the monitoring will be carried out by a PDNS
  • Communication by phone between GP, PDNS, and Parkinson's specialist will often smooth out any issues regarding responsibility and reluctance to prescribe drugs that a GP has no experience of prescribing
  • Your patient should have access to physiotherapy, occupational therapy, and speech and language therapy

Levodopa

  • Levodopa (L-dopa) is a dopamine precursor that is converted to endogenous dopamine within the brain by the enzyme dopa decarboxylase
  • L-dopa can be combined with either:
    • benserazide (co-beneldopa), which inhibits the actions of extracerebral dopa decarboxlase
    • carbidopa (co-careldopa)
      • also available as an intestinal gel, which is administered directly and continuously to the upper part of the small intestine, via a permanent intestinal tube. This ensures that the drug is absorbed into the blood at a constant rate
    • carbidopa and entacapone
  • These drugs remain the mainstay of therapy and it is important to titrate the dosage to the patient's requirement
  • The problem with L-dopa is that, in the longer term, the timing of each dose becomes critical, as there is frequently loss of effect before the next dose is administered
  • This can give rise to unexpected involuntary movements (dyskinesia). In addition, patients experience sudden switches from normal movement (being 'on') to immobility (being 'off')
  • In time, the majority of patients on this drug will experience these adverse effects
  • Manipulation of the dosage, time of administration, and type of preparation will help. In addition, attention should be paid to diet, as a high-protein diet can interfere with the absorption of L-dopa from the gastrointestinal tract, and some patients benefit from taking their medication about 45 minutes before meals

Dopamine agonists

  • An alternative strategy is to use drugs that have a dopamine-like action. The dopamine agonists stimulate dopamine receptors and can be used either alone or in conjunction with L-dopa
  • They produce fewer long-term side-effects
    but they are much more likely to cause hallucinations in older patients. In addition, they have to be introduced very gradually, as they do cause nausea, sickness, ankle swelling, and dizziness related to low blood pressure. They have to be used with care but are very useful
  • Preparations include bromocriptine, cabergoline, and pergolide (ergot derived)
  • While some dopamine agonists can have a side-effect of heart valve fibrosis and reddening of the legs, others, including pramipexole, ropinirole and apomorphine, do not
  • Studies have also shown that a small, yet significant, percentage of people with Parkinson's who have been prescribed certain dopamine agonists will experience impulsive and compulsive behaviour, which affects around 17% of people on dopamine agonists, but also affects 7% of people on levodopa:
    • patients and carers should be asked if there have been any changes to the patient's behaviour as they may not recognise the changes or be willing to acknowledge the problem. Examples include spending more, including gambling, aggressive outbursts, an increase in risk-taking behaviour, an increase in sexual desire or developing other obsessive behaviours
    • this can have a seriously detrimental effect on the lives of the person directly affected, as well as their families. Studies have highlighted that drug reduction or withdrawal can, in many cases, reduce excessive behaviours
  • Rotigotine is delivered once daily by skin patch. Although it has not yet been officially approved by NICE it is in clinical use
  • Apomorphine can only be administered subcutaneously and is helpful in patients who have severe fluctuations in their symptoms. With appropriate training, it can be self-administered and there is now a preparation for continuous
    • subcutaneous infusion with a syringe driver

Dopamine agonist withdrawal syndrome

  • Dopamine agonist withdrawal syndrome occurs when a person's dopamine agonist treatment is stopped or reduced. People who experience impulsive or compulsive behaviour as a side effect of dopamine agonists are most at risk of developing dopamine agonist withdrawal syndrome
  • Symptoms may include anxiety, panic attacks, depression, dysphoria, agitation, insomnia, dizziness, nausea, irritability, fatigue, pain, orthostatic hypotension, and drug cravings

Other drugs

  • Amantadine:
    • the action is uncertain but it is likely to promote dopamine action by inhibiting the excitatory amino acid glutamate
    • it is relatively mild in effect but is useful in reducing drug-induced dyskinesia
  • MAO-B inhibitors (e.g. selegiline and rasagiline):
    • these drugs block the enzyme monoamine oxidase type B (MAO-B), which breaks down dopamine in the brain
    • it can be used on its own in the early stages of the condition or in conjunction with L-dopa. In this situation, it reduces the required dosage and prolongs the action of the L-dopa
  • Cathecol-O-methyl transferase (COMT) inhibitors (entacapone and tolcapone):
    • COMT inhibitors work by blocking an enzyme called catechol-O-methyl transferase (COMT), which breaks down L-dopa
    • as a result they slow the destruction of L-dopa in the body
    • COMT inhibitors are, therefore, prescribed for use with L-dopa to prolong the duration of action
  • Anticholinergics (e.g. trihexyphenidyl):
    • these were the first drugs to become available for the treatment of Parkinson's
    • while they tend to help the tremor, they are no longer recommended due to high risk of side-effects, especially in the elderly, and concerns about their effect on cognitive function
  • Antidepressants:
    • as depression is present in up to 45% of people with Parkinson's, these are often important in the management of the condition
    • there are no specific rules for their use and GPs should use drugs they are familiar with
    • selective serotonin-reuptake inhibitors, e.g. citalopram, are possibly the most useful but there is a rare adverse interaction with selegiline and rasagiline (hypertension and CNS excitation)
  • Anti-emetic drug of choice is domperidone
  • Drugs that are best avoided in Parkinson's:
    • prochlorperazine
    • metoclopramide
    • perphenazine
    • flupentixol
    • chlorpromazine
    • fluphenzine
    • haloperidol
    • pimozide
    • sulpiride
    • trifluoperazine

Withdrawal of therapy

  • If any of the drugs used for treating Parkinson's need to be stopped, it is important this is done gradually. Abrupt withdrawal of certain drugs can result, albeit rarely, in neuroleptic malignant syndrome. This is a very serious condition that may cause death from complications of the respiratory, cardiovascular or renal system

References

full guidelines available from…
Parkinson's UK, 215 Vauxhall Bridge Road, London SW1V 1EJ (Tel – 020 7931 8080)
Email – enquiries@parkinsons.org.uk
Website – http://www.parkinsons.org.uk

Parkinson's UK. The Professional's Guide to Parkinson's Updated September 2012
First included: Oct 11.


People who read this also read....

COPD diagnosis, management and prevention
Global Initiative for Chronic Obstructive Lung Disease
Management of chronic heart failure
Scottish Intercollegiate Guidelines Network
Management of asthma in adults over 65 years of age
Development group: Gruffydd-Jones, McArthur, Murphy, Russell & Wise.
This management algorithm was developed by a multidisciplinary expert panel: Gruffydd-Jones K et al with the support of a grant from Teva UK Limited.



Share or Comment on this Article
Add to Favourite Add to favourite
Please login to rate this article, view others comments or make your own.