Clinical features
Signs
PD is a neurological disorder that is characterised by:
Tremor
In most people, the disease begins insidiously with a resting tremor (pill - rolling) of one hand. The tremor is slow and coarse and is maximal at rest. It lessens during movement and is usually absent during sleep. It is enhanced by emotional tension or fatigue. Usually the hands, arms and legs are most affected in that order. The jaw and tongue may also be affected. The tremor may become less prominent as the disease advances.
Muscle rigidity
Rigidity is increased resistance noted during passive joint movement (when the joint is moved by another person) and can develop a cogwheel character (the limb resists and gives way in small, step-like movements as if it was being controlled by a cog-wheel) when there is a tremor affecting the limb.
Bradykinesia
As rigidity progresses, movement becomes slow (bradykinesia), diminished (hypokinesia) or absent (akinesia), clumsy and difficult to initiate. Bradykinesia, rigidity and tremor often cause problems with fine hand and arm movement.
Postural instability
People can also have impaired postural reflexes (postural instability), which permit stability when standing, adjustment of stance and easy turning, usually in later disease. Impairment of postural reflexes causes poor balance and may increase the risk of falls. There may also be an associated drop in blood pressure on standing (postural hypotension) that may contribute to the tendency to fall.
The characteristic gait is slow and shuffling with reduced arm swing and may be festinant. Festination is an involuntary tendency to take short accelerating steps as if the person is trying to continuously catch up with their centre of gravity. PD sufferers can have difficulty in starting to walk (gait initiation) and the upper body is often flexed forwards. When they try to stop or change direction they are sometimes unable to do so. They may freeze into immobility when passing through a door or around furniture. When standing, a push may lead to tottering in the direction of the push until the person either falls or hits a solid object. There may be a tendency to fall forwards (propulsion) or backwards (retropulsion). The person may sit immobile and fixed like a statue.
Symptoms
Early on, people may appear depressed because facial expression is lacking (hypomimia or masking) and movements are decreased (hypokinesia and akinesia) and slowed (bradykinesia).
Speech is reduced in volume (hypophonic) with characteristic monotonous, stuttering dysarthria (slurred speech), with the words often coming in short rushes at variable rates due to poor breath control.
Hypokinesia and impaired control of distal musculature can cause micrographia (writing reduced in size) and activities of daily living become very difficult.
Rigidity and hypokinesia may contribute to muscular aches and sensations of fatigue.
Although there is a perception of weakness, strength, vision and hearing are usually normal. Smell (olfactory function) is abnormal in a majority of people and this can influence taste.
There may be an associated seborrhoeic (greasy and scaly) skin rash.
Difficulty in swallowing (dysphagia) may lead to drooling of saliva, the risk of aspiration (inhaling contents of the oral cavity into the lungs) and malnutrition.
Frequency, urgency and urge incontinence are common. Constipation is common but can usually be overcome by an appropriate diet and medication.
Sexual dysfunction is common, especially erectile failure.
Pain is a common problem and is usually due to cramp like pains due to muscular rigidity. It is therefore best treated by appropriate antiparkinsonian medication.
Frozen shoulder may occur leading to pain and restriction of movement in the affected shoulder.
Sleep disorders are very common. The commonest problem is “sleep fragmentation” characterised by recurrent waking due to joint pain, rigidity or tremor or the inability to turn over due to bradykinesia and may lead to daytime sleepiness.
There is a much higher frequency of the following in PD, some of which may precede the diagnosis by years and even decades:
- Restless Legs Syndrome
- REM (rapid eye movement) sleep disorder
- Periodic Limb Movements of Sleep
- Vivid dreams, nightmares and nocturnal hallucinations
Neuro-psychiatric problems
These are common and include:
- Depression, which occurs in 30% or more and can often precede the physical symptoms. People with major depression tend to have a significantly faster rate of functional decline than non-depressed people,
- A fluctuating confusional state, often secondary to drug treatment,
- Cognitive impairment. In the early stages cognition is usually normal although some people have some slowness of thought and slight difficulty with memory and word retrieval. As the disease progresses, there are increasing problems with speed of thought and memory. In the later stages, dementia occurs in between one third to one half of people.
Characteristically this involves:
- Deficits in attention and cognitive slowing causing problems with thinking and information retrieval,
- Memory is moderately impaired but not as severely as in Alzheimer’s disease,
- A fluctuating mental state, with anxiety and agitation, hallucinations and paranoid mental states with delusions and often prominent hallucinations is often seen,
- Visuo-spatial dysfunction is common.
The Unified Parkinson’s disease rating scale (UPDRS) is the most widely used clinical scale for the evaluation of clinical impairment in PD.
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Amended April 2008
