The diagnosis of Parkinson’s Disease
The reader needs to understand the term “parkinsonism” before knowing how the neurologist makes the diagnosis of Parkinson’s Disease (PD). It is also important to understand that parkinsonism is not a disease by itself, but rather a syndrome that is the end result of various types of insults to the brain such as follow:
a) Primary parkinsonism or PD
This refers to the type of parkinsonism, that is the main focus of the present discussion, and occurs without any obvious medical cause.
b) Secondary parkinsonism
A variety of medical disorders can cause parkinsonism. They include exposure to drugs (especially medications used to treat psychiatric patients), Wilson’s disease, stroke, encephalitis, etc.
c) Parkinsonism-plus syndromes
This refers to another form of parkinsonism which is also caused by a degenerative process in the brain. In contrast to PD, the degenerative process in parkinsonism-plus syndromes is much more widespread and complicated. Thus, patients with parkinsonism-plus syndromes have unusual physical signs that are not usually seen in PD, such as abnormal eye movement, muscle weakness, loss of coordination and impairment of memory – giving rise to the term “parkinsonism-plus” syndrome.
It is important to recognize secondary parkinsonism and parkinsonism-plus syndromes because they are generally not responsive to levodopa (the active chemical in Madopar / Sinemet / Stalevo), other PD drugs, or brain surgery. Furthermore, the physical disability in these two disorders advances much faster than in PD.
How does the doctor establish the diagnosis of PD?
A definite diagnosis of PD can only be made by brain biopsy, a procedure that involves inserting a needle into the brain and removing a piece of brain tissue to be examined in the laboratory. This is not routinely practiced because of the risks of brain surgery *bleeding in the brain).
In clinical practice, the diagnosis of PD is made by going through the following steps (Fig. 1):
a) Evaluation of medical history
The neurologist enquires about the early symptoms of PD as described earlier. Drug and family history is also important because of the possibility of secondary parkinsonism.
Fig. 1. The algorithm for the diagnosis of PD at the outpatient clinic.
b) Physical examination (PE)
A thorough examination of the nervous system is performed. This includes observation of patient’s movement – walking, writing, buttoning up the shirt, etc. The neurologist looks for evidence of parkinsonism such as bradykinesia, rigidity and tremor. A characteristic feature of parkinsonism is “mask-like” facial appearance, with reduced or absent facial expression (Picture 1). When asked to stand up, patients often have a stooped posture; the body and head are bent forward (Picture 2). When walking, there is reduced arm swing while the footsteps are short and shuffling.
In addition, the neurologist attempts to detect the presence of “unusual” physical signs (as mentioned above) that are suggestive of parkinsonism-plus syndromes.
Picture 1 (left). The unmistakable and typical “mask-like” facial appearance helps to clinch the diagnosis as soon as a patient walks into the clinic. Picture 2 (right). The typical “stooped” body posture while standing.
c) Trial of medications
The symptoms of PD are caused by deficiency of dopamine. Levodopa is converted to dopamine in the body. The depleted dopamine stores in the brain are thereby replenished, thus improving the symptoms. Levodopa is the active ingredient in Madopar, Sinemet and Stalevo.
The next step in the evaluation is a trial of adequate dose of dopamine agonists. The patient is monitored every two weeks for the response to the dopamine agonists. If dopamine agonists fail to relieve the symptoms of PD, subsequently levodopa (usually a total of 600 mg daily, sometimes up to 1200 mg daily)is administered for at least four weeks. A significant improvement in the patient’s symptoms supports the diagnosis of PD (Hughes AJ et al, 1992).
Lack of improvement suggests alternative diagnoses such as secondary parkinsonism and parkinsonism-plus syndromes (Wenning GK et al, 2000).
Are further investigations needed for the diagnosis of PD?
Further investigations such as blood tests and brain scans (Computerized Tomography or CT scan; Magnetic Resonance Imaging or MRI scan) are not usually necessary because they are not helpful in making the diagnosis of PD.
Where can you get neurological consultation?
The first thing to do is to request your general practitioner or family physician to refer you to the Neurologist. The following is a list of government and private hospitals in Malaysia where neurological consultation is available:
University of Malaya Medical Centre (previously known as University Hospital), Kuala Lumpur.
Kuala Lumpur General Hospital.
National University of Malaysia, Kuala Lumpur.
Penang General Hospital, Penang.
Science University of Malaysia, Kubang Kerian, Kelantan
Sultanah Aminah Hospital, Johor Baru, Johor.
Kuching General Hospital, Sarawak.
Pantai Cheras Medical Centre, Kuala Lumpur.
Sunway Medical Centre, Kuala Lumpur.
Adventist Medical Centre, Penang.
Subang Medical Centre, Kuala Lumpur.
Gleneagles Medical Centre, Penang.
Sabah Medical Centre, Kota Kinabalu, Sabah.
Gleneagles Medical Centre, Kuala Lumpur.
*Your general practitioner can help you to find out the names of the neurologists who practice in these hospitals.
After the diagnosis is established, what about follow-up visits?
Patients with mild physical disability who can still cope with the illness can continue their follow-up with their general practitioners, especially if they live very far from the neurology centres. Those who have moderate to severe physical disability with significant impairment of daily function should continue to see the neurologist. This is because these are complicated cases that need expert advice.
Chew NK, Goh KJ, Tan CT. Parkinson’s Disease in University Hospital, Kuala Lumpur. Neurol J Southeast Asia 1998; 3: 75-80.
Hughes AJ, Ben-shlomo Y, Daniel SE, Lees AJ. What features improve the accuracy of clinical diagnosis in Parkinson’s disease: a clinicopathologic study. Neurol 1992: 42: 1142-1146.
Wenning GK, Ben Schlomo Y, Hughes A, Daniel SE, Lees A, Quinn NP. What clinical features are most useful to distinguish definite multiple system atrophy from Parkinson’s disease? J Neurol Neurosurg Psychiatry 2000; 68: 434-440.