Understanding Parkinson’s disease

By Dr N. K. CHEW

THE most common reaction for most people first diagnosed with Parkinson’s disease would be one of disbelief. This would quickly progress to denial. Family members and friends would also be equally affected by the news.

It would be understandable if the first question that crops up is: “How are we going to cope?”

That denial kicks in almost immediately for many Parkinson’s sufferers and their families is a given. However, getting over the denial is a crucial if a sufferer and caregiver want to cope with the consequences of a positive diagnosis of this disease.

So it is paramount to learn as much about the disease, and understand how treatment can help sufferers improve their quality of life.

What is Parkinson’s disease?

Parkinson’s disease (PD) is a brain disorder that occurs when certain nerve cells or neurons in the brain die or become impaired. When this happens, these cells no longer produce a chemical called dopamine, which facilitate the smooth, coordinated function of our muscles. When about 80% of these neurons die or get damaged, that’s when Parkinson’s makes an appearance.
One of the misconceptions about Parkinson’s disease is that it’s a disease of old age. It’s not. Just ask Michael J. Fox, who was diagnosed with the disease when he was 30 years old.

The tell-tale signs include tremors, slowness of movement, rigidity, difficulty with balance, small, cramped handwriting, stiff facial expressions, a shuffling walk, muffled speech, and depression.

There is a misconception that Parkinson’s is an old-age disease but, in fact, about 15% of people diagnosed with Parkinson’s come from the 50-year-old and below age bracket. The disease strikes anyone regardless of gender, age, social status, culture, or profession.

And it gets worse as the process of diagnosing the disease is difficult, at best, as there is no one simple test when it comes to confirming the presence of Parkinson’s. A doctor can only arrive at a diagnosis for the condition only through a patient’s medical history and a series of physical examinations.

Magnetic resonance imaging (MRIs) and blood tests can help rule out other conditions that have similar symptoms, but those who are suspected to be suffering from Parkinson’s should seek out a neurologist who specialises in Parkinson’s Disease.

Parkinson’s is also not just a movement disorder as patients can also suffer from a long list of non-motor symptoms such as depression, confusion, hallucination, anxiety, and dementia as well as intestinal disorders, loss of sense of smell, and sleep disturbances.

It is also believed that several non-motor symptoms such as loss of sense of smell, depression, sleep disorders, fatigue, anxiety, and constipation may precede the motor symptoms of Parkinson’s by a few years, and thus can be considered as early symptoms of the disease.

Can it be treated?

Parkinson’s remains an incurable illness. Due to the progressive loss of brain cells, Parkinson’s progresses with time, resulting in gradual and inevitable deterioration of the initial motor symptoms. As the illness advances, the non-motor symptoms such as psychiatric disorders also become more frequent, especially during the advanced stage of illness.

In addition, many patients also develop involuntary body movements and suffer reduced effects of medications towards the later stage of the illness. All these complications result in long-term disability in Parkinson’s patients and in almost all aspects of life – physical, mental, occupational, and social.

There are, however, a number of effective medicines that help ease the symptoms of the disease. Most symptoms are caused by a lack of dopamine, and medicines most commonly used will attempt to either replace or mimic dopamine, which help to reduce tremors, lessen rigidity, and improves slowness of movements associated with Parkinson’s disease. Several new medicines are also being studied that may slow the progression of the disease. Many promise to improve the lives of people with the disease.

Medications used in the treatment of Parkinson’s disease in Malaysia

When it comes to treating Parkinson’s disease, there are different classes of drugs used at different stages of the disease – most often in combination or sometimes on its own depending on the severity of the condition, the age of the sufferer, and tolerance to medication. Initial treatment is individualised.

The classes of drugs used are levodopa, dopamine agonists, COMT-inhibitors, MAO-B-inhibitors, and anticholinergic drugs. Constant monitoring by the neurologist, patient and caregiver is crucial in determining the right dosages and types of medications to treat the condition. And each case is unique.

For early (initial) to moderate stages of Parkinson’s (five to 10 years), most patients (especially younger Parkinson’s patients) are prescribed dopamine agonist drugs such as ropinirole and can live a reasonably good quality of life while delaying the onset of motor complications or dyskinesia and the need for levodopa treatment. Levodopa will be used at a more advanced stage.

Dopamine agonist medications help to enhance the activity of dopamine in the brain to relief the symptoms of Parkinson’s. As the disease advances, they can also be used to treat motor fluctuations.

However, as the physical disability of Parkinson’s patients become more severe with time – after 10-15 years – many of them have difficulty carrying out daily activities despite taking maximum medications – a combination of many of the classes of medications.

Also, it has to be emphasised that Parkinson’s patients can only expect up to 90% level of improvement even with the best medications. Parkinson’s treatment cannot completely compensate for the dopamine deficiency in the brain. It is important that Parkinson’s patients be realistic in their expectations – there are no ideal medications for this illness. When the illness advances, and when patients’ symptoms are no longer well-controlled with medications (e.g. uncontrollable tremors), brain surgery can be effective in relieving the main symptoms of Parkinson’s such as slowness of movement and tremors. Currently, surgical treatment or Deep Brain Stimulation (DBS) surgery is available in Malaysia, but the treatment is costly.

Living with the treatment – its side effects

The side effects generally associated with Parkinson’s drugs are nausea, vomiting, and dizziness. The most serious side effects are involuntary body movements, which usually manifest as uncontrollable and unpredictable jerky body movements, and are triggered via prolonged use of levodopa.

The problem about the involuntary body movements is their irreversibility – once they have started, they persist for life. They are also an important cause of social stigma, as Parkinson’s patients frequently feel embarrassed by the stares of the general public – the involuntary body movements make Parkinson’s patients look “odd”.

As such, levodopa is best avoided during the early stages of Parkinson’s in order to prevent the development of the involuntary body movements or dyskinesia.

This has led to the suggestion that dopamine agonists should be used for initial treatment in newly-diagnosed Parkinson’s patients. A dopamine agonist drug has longer duration of effect on brain cells than levodopa and reduces the “wearing off” phenomenon while improving the 24-hour control of symptoms when taken regularly.

Dopamine agonist drugs can cause side-effects such as nausea, dizziness, sleepiness (sleep attacks), confusion, and low blood pressure. Fortunately, new medications like ropinirole appear to have a significantly lower frequency of side-effects and perhaps future drugs will lower the frequency even more.

Still, it is very important for Parkinson’s patients to follow a schedule of medications strictly, especially the timing of medication. Medications have to be taken at regular intervals in order to avoid or minimise the “on” and “off” periods.

When medication wears off, patients will experience stiffness and trembles – the “off” period. These fluctuations occur during the more advanced stages of the disease when the effect of medications is no longer sustained or consistent.

Other possible treatments

The discovery of Deep Brain Stimulation (DBS) surgery in the late 1990s was a major breakthrough in the treatment of Parkinson’s. The improvement in the symptoms of Parkinson’s following DBS surgery is dramatic. This surgery is suitable for those in the advanced stages of Parkinson’s after the effects of medications have diminished.

Apart from DBS surgery, there have not been many breakthroughs in treatment for Parkinson’s disease.

Stem cell treatment (through transplantation) for Parkinson’s has received a lot of attention recently. However, stem cell treatments overseas have not been proven effective. Many technical issues still need to be resolved before it can be recommended to Parkinson’s patients.

There are too many issues attached to stem cell treatment, namely on ensuring the survival of transplanted brain cells and the use of aborted human foetus. The procedure itself is also very expensive as it requires the highest level of technology and medical expertise.