Parkinson's disease is the second most common degenerative brain disease after dementia. It is caused by a deficiency of an important chemical in the brain called dopamine, a lack of which causes slowness of an individual along with rigidity and tremors of hands and legs. For decades various medications have been used to alleviate the symptoms of Parkinson's disease, aiming at improving the quality of life. But like all other degenerative disorders, this disease also continues to worsen, not only gradually disabling the patient, but also increasing caregiver burden. To know more about this disease and how head trauma can trigger it, we spoke to Dr Ishu Goyal, Associate Consultant, Neurologist, Sir HN Reliance Foundation Hospital. Here is what the expert wants you to know.
Traumatic Brain Injury and Parkinsonism
After the famous American boxer Muhammed Ali suffered from Parkinson's disease at the young age of 42 years, it was highly debated whether Parkinson's disease is related to head injury or not. Many studies were conducted trying to find the correlation between the same but none was conclusive. Some found a positive correlation while others didn't. It has been postulated that repeated injuries may disturb the cortico-basal-thalamic-cortical circuitry which is paramount in maintaining normal body movements. Any disturbance in this physiology may predispose to the development of Parkinsonism. In some cases, like subdural haemorrhage, there may be sudden development of Parkinsonian features owing to direct compression of basal ganglia. The exact mechanism still remains unclear.
Parkinson's disease is conventionally considered to be an 'idiopathic' disorder where in the majority of patients, the cause cannot be determined. However, this concept is slowly becoming obsolete with the recognition that approximately 15% of patients have a positive family history of this disease. There are many genes that are implicated in the development of Parkinson's disease are PARK7, PINK1, LRRK2, SNCA etc. Many more genes are yet to be discovered, hence underlining the importance of the genetic aspect of this disorder.
As the disease progresses, along with worsening of motor symptoms, patients start developing decreased social interaction, progressive cognitive decline, autonomic disturbances in the form of blood pressure abnormalities, urinary dysfunction, and sexual abnormalities. They may also suffer from sensory impairments like visual decline, smell problems, difficulty in colour discrimination, generalized pain and fatigue. Progressive weight loss, malnutrition, decreased appetite, and lack of confidence contribute to the already increasing frailty and general loss of strength. Some of the problems like constipation, depression and sleep disturbances may predate the development of motor symptoms by many years. It is equally important to actively probe for and address these issues for an overall improvement in the quality of life of patients.
The diagnosis of Parkinson's disease is mostly clinical and depends on the expertise of the clinician. The cardinal features of Parkinson's disease are quite typical and can seldom be missed by an experienced eye. However, sometimes the clinical signs and symptoms of the disease may be complicated by concomitant long-term use of certain drugs like antidepressants, and gastric medications like lesuride which produce Parkinsonian clinical scenarios. A careful drug history is thus important to discern the cause of Parkinson's disease. Often, overlap can be seen between typical and atypical variants of Parkinson's disease and in the initial stage of the disease, reaching an accurate diagnosis may be difficult. In such cases, Fluoro-dopa or Dopa-Pet scan may be helpful which gives a clue about specific patterns of tracer uptake, thus hinting towards diagnosis.
Parkinson's disease although a progressive and uncurable disorder, still is treatable by available medications, with the help of which, a significant improvement in quality of life can be achieved.