|[back] Misconceptions about Parkinson's Disease Dr Norlinah Mohamed Ibrahim - 21 May 2009|
Misconceptions About Parkinson's Disease
Consultant Neurologist (Movement Disorders) and Head,
Neurology Unit, Pusat Perubatan Universiti Kebangsaan Malaysia,
Medical Advisor, Persatuan Parkinson Malaysia
Parkinson'S DiseaseParkinson's disease is the second commonest late life neurodegenerative disease after Alzheimer's disease. It is prevalent throughout the world and predominantly affects patients above 60 years of age. It is caused by progressive degeneration of dopamine containing cells (neurons) within the deep structures of the brain called the basal ganglia and substantia nigra. Both motor and non-motor symptoms exist in PD, although the cardinal features and the diagnosis of PD is based purely on the presence of motor symptoms.
Diagnosis of PDDiagnosis of PD is purely clinical and requires the presence of bradykinesia or slowness of movement and one or more of the clinical features listed below:
Motor symptoms of PDSymptoms in PD can be divided into motor and non-motor. Typical motor symptoms include tremor of the hands and/or legs and slowness of movement. Tremor in PD is also known as 'pill-rolling' tremor, as it has the characteristic appearance of someone rolling a pill in his hands. It usually occurs when the patient is resting and become more pronounced with mental tasks or anxiety. Bradykinesia may affect any parts of the body including the face, causing reduced facial movements (hypomimia) and eye blinking resulting in a 'mask-like' or expressionless appearance. Hand-writing may become progressively smaller (micrographia) and patient may lose dexterity in carrying out daily tasks. The gait may also be affected, resulting in smaller strides with lack of arm swing, giving a shuffling appearance when walking. As the disease progresses, patients may develop freezing of gait, which could result in falls. The voice may become low-pitched and monotonous, with excessive drooling of saliva. In the beginning, symptoms of PD may be restricted to one side of the body (unilateral). However, with disease progression, both sides of the body will be affected, causing significant disability to patients if left untreated.
Non-motor symptoms (NMS)In addition to the motor symptoms, non-motor symptoms (NMS) such as constipation, sleep disturbances and depression also predominate in PD. Unlike the motor symptoms, NMS are usually poorly recognised and hence inadequately treated. Studies have shown that NMS are important determinant of quality of life, causing significant disability to patients if left untreated. Some of the NMS features such as depression and constipation may even predate the clinical diagnosis of PD by several years. The NMS complex of PD can be broadly categorised into the following groups.
Treatment of PDPD is a treatable disease. The motor symptoms of PD can be effectively treated with dopamine replacement therapies i.e. dopamine precursors (levodopa) or dopamine agonists (mimics the action of dopamine on the dopamine receptor). Other medical treatment available include monoamine-oxidase inhibitors (MAO-I), which aim to delay the breakdown of levodopa in the brain. Treatment of PD has to be individualised, taking into account the patient's age of onset, the disease severity, the presence of non-motor symptoms and the patients' expectations. Counselling is an important part of treatment, so that patients and carers are aware of the prognosis and the expectation of the disease.
In the beginning, symptoms of PD may be completely abolished by medications. However, with disease progression, patients may develop complications related to medications and other non-motor problems such as depression and dementia, which makes treatment extremely challenging. Appropriately selected patients with medication-related complications can further benefit from brain surgery such as deep brain stimulation or lesioning procedures.
ConclusionPD is a complex disease with both motor and non-motor manifestations. All patients should be screened for non-motor complaints as it has been shown to contribute to an overall poorer quality of life and institutionalised. Treatment of PD should be individualised and if possible should be managed by a multidisciplinary team, with aim to address all aspects of the disease.