Differential Diagnosis

I refer to your report “Misdiagnosing disease” (The Star, April 23). Dr Chew Nee Kong, in attempting to clarify some cases of misdiagnosis among Parkinson’s Disease (PD) patients, was quoted as saying: “Patients suffering from depression may have slower movements but not tremors.”
This is factually inaccurate as clinical depression may cause slowing down of movement, sedation, headaches, confusion, as well as jitteriness and even tremors.
Further symptoms he described for PD include “slowing down in speech and body movement, softening of voice, and lacking in facial expression”.
Surely these, too, are symptoms that may be presented by an individual suffering from Clinical (Major) Depression.
It is also interesting to note, as Dr Chew pointed out, that dopamine (or the lack of it) is one of the factors associated with PD.
Similarly, dopamine, being a neurotransmitter, has been linked to a variety of other disorders such as anxiety disorder, ADHD, and other mood disorders.
Hence, some clinicians do prescribe dopamine (dopaminergic agents) in the treatment of Major Depression since an increase of this neurotransmitter in the frontal lobe can produce/boost feelings of pleasure.
Perhaps just as important a point for us to note is that we tend to categorise people into a singular slot like keys that fit only one lock.
In differential diagnosis, our goal indeed is to systematically eliminate possibilities until we reach a single most likely cause for the illness.
But in actual practice, we may find that an individual may be challenged with more than one issue at any given moment.
For example, a person diagnosed with PD may in fact also have depression.
The depression may set in after he has been informed of the PD diagnosis or, more often than not, the depression has already been developing since the patient rightfully would have noted changes in his own ability and such associated with PD.
I do agree with Dr Chew, however, on the point that there is insufficient training and understanding among many clinicians regarding the multitude of medical as well as psychological illnesses that exists.
I also note an extremely poor linking (cooperation) between the two fields here in Malaysia.
For example, when I resided in the US, almost all clients coming in to seek psychological services from me were immediately referred to a physician/psychiatrist/medical practitioner to rule out organic dysfunctions.
Sometimes a “psychological problem” may be merely a symptom of a medical issue.
Other times, a psychological issue has no medical basis, and sometimes the services of both a medical practitioner and a psychologist (therapist) are necessary.
It is extremely important to remember that our fields are not in competition but are often times complementary.

SYLVESTER LIM,
Kuala Lumpur.