Neurological Disorders: Parkinsons Disease (PD)

What is PD?

This disease, also called as idiopathic Parkinsons disease, is a degenerative neurological disorder, presents with certain characteristic manifestations, and is more commonly seen in older people. A Neurologist is frequently involved in the care of PD patients.

Although typically begins with only minor neurological dysfunctions, however during the later stages it usually effectuates a crippling effect on its sufferers. There are several neurological disorders that produce similar clinical picture, however the above term is used only when it is idiopathic (the cause is unknown), also only if certain clinical criteria are fulfilled. Otherwise terms like Parkinsonism etc are used depending upon what we are dealing with.

What causes Parkinsons Disease?

The prime problem in these patients is a deficiency in the brain, of a neuro-chemical substance called as dopamine, especially in a region called basal ganglia. This deficiency also results in the unrestrained activity of another chemical called acetylcholine. The deficiency of dopamine is due to the degeneration of the brain cells that produce this chemical, however what triggers this degeneration of brain cells is still not clear. Various hypotheses including exposure to toxins on a long term basis have been speculated but nothing has been convicted yet. There is an increase in the incidence of Parkinsons disease in the rural areas questioning role for toxic pesticides.

Who are the sufferers?

Pakinsons-Disease occurs all over the world and incidence typically increases with age and majority of patients are >60 years. However younger people are not totally immune from this disease. In fact there are early and juvenile onset subtypes. About 95% occur sporadically (randomly) and only about 5% of cases are hereditary. As noted above rural living has been associated with some increased frequency of this disease.

How does patient present?

The manifestations of idiopathic PD are highly characteristic and an experienced neurologist rarely goes wrong. The four most typical symptoms include;
  • Bradykinesia/akinesia
  • Rigidity (stiffness)
  • Resting tremors
  • Postural imbalance

Bradykinesia/akinesia:

This means slowing of motor activities. A patient with PD will typically take longer time to finish a task which they used to finish quicker before. For example patient will take longer time to come out of the chair or bed. In fact almost all daily motor activities may slow down including walking, turning, chewing the food, swallowing, bending etc. As disease advances their eye blinking decreases, facial expressions diminish and give a mask like facial appearance.

Rigidity:

This is a form of muscle stiffness and impairs their motor activities. The rigidity seen with Parkinsons disease is called medically as cog wheel type.

Resting tremors:

The PD tremors are characteristically resting type means they mostly occur and bother when the patient is not using the limbs and as patients’ initiate activities with the affected limb the tremor disappears or diminishes however usually return promptly when that limb is rested again.

Postural imbalance:

This is a very bothersome symptom although generally it is seen only during later stages of PD.

Parkinson disease symptoms characteristically begin on one side of the body then slowly spread to the other side and as disease progresses more and more disability accrues.

As the disease advances some of these patients may develop a subcortical type of dementia characterized by slowness of mental abilities, decreased attention, concentration and some memory loss. This is in contrast to cortical type of dementia e.g. Alzheimer’s disease where memory loss, especially short term type, is a prominent early finding associated with other findings like language deficits.

Diagnosis

PD is one of the few neurological diseases that can be diagnosed just clinically with a high degree of certainty. If the presentation is very typical then most often there is no need of any investigations however if atypical presentation is seen then it is safer to order a brain MRI scan or at least a brain CT scan to start with.

These investigations may pick neurological disorders that produce parkinsonian features like NPH (normal pressure hydrocephalus, multiple system atrophy, basal ganglial growths etc).

Treatment

Early stages of PD may not require any medications but later they are invariably needed.

The following drugs are the choices;

• Levodopa + carbidopa
• Dopamine agonists like pramipexole, ropinirole
• Amantadine
• COMT inhibitors like entacapone
• Levodopa+carbidopa+entacapone
• MAO B inhibitors like selegeline, rasagiline
• Anticholinergics like trihexyphenydyl etc

Medically refractory parkinsons disease patients or those who cannot tolerate any PD medications they try, then they have surgical options. Deep brain stimulation (DBS) is one such choice.

Physical therapy is done as tolerated.



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