Parkinson’s disease: a difficult diagnosis

At the beginning of the disease, the diagnosis of Parkinson’s disease is difficult because the symptoms can go unnoticed. Nevertheless, several criteria can now wear a reliable diagnosis … if not early.

The symptoms of Parkinson’s disease is progressive and nonspecific: fatigue, pain, rheumatism, depression … This is why the National Agency for Accreditation and Evaluation in Health (predecessor of the High Authority for Health) listed specifically in 2000 the criteria for Parkinson’s diagnosis could and should be established.

Parkinson's Disease

The clinical criteria for Parkinson’s disease
The diagnosis of Parkinson’s disease based on a review and examination of the patient, for symptoms previously observed.

The three cardinal signs of Parkinson’s disease most often used are:
Resting tremor: It is slow and repetitive but disappears during voluntary movements or during sleep. It is usually the symptom that causes the patient to consult. But some Parkinson’s patients do not tremble and never tremble;
Bradykinesia: There is a difficulty in initiating movements, which will be slow and difficult;
Muscle rigidity: It is due to hypertension of all muscles that can give the impression of a frozen body.
Other clinical signs may be observed and facilitate the diagnosis of Parkinson’s disease:
The asymmetry of symptoms: one side of the body is affected more than the other;

A marked response to L-dopa.
Resting tremor, bradykinesia and asymmetric symptoms have the best positive predictive value (PPV). PPV is the probability that the symptom is observed when the disease is diagnosed. In other words, the higher the PPV is high, the disease is more likely if the symptom is present.

Diagnosis of Parkinson’s disease
The combination of the three cardinal signs associated with asymmetry gives a PPV of 90% for the diagnosis of Parkinson’s disease. But the criteria state that the diagnosis should be questioned at any time and must adapt to the changing characteristics of the disease:

In the early symptoms: clinical criteria with a strong VPP should be preferred. Any other unusual symptoms should be investigated to exclude the diagnosis of another disease. At this stage, the response to L-dopa is not significant in the development of diagnostic.

After a period of 3 to 5 years , the pharmacological response is a criterion used if there is a 50% improvement in symptoms in response to dopaminergic therapy, according to the UPDRS (Unifed Parkinson’s Disease Rating Scale);
After a decade: the pharmacological response is confirmed and is frequently accompanied by involuntary and uncontrolled movements (dyskinesias).

The diagnosis is based on the identification and association of clinical signs. It is confirmed by the effectiveness of dopaminergic therapy.

The importance of early diagnosis of Parkinson’s disease.Other examinations, order or neurological imaging are not necessary to diagnose Parkinson’s disease, but they can intervene when doubt exists.In general, in patients less than 40 years, MRI ( Magnetic Resonance Imaging ), neuropsychological testing and / or electrophysiological urodynamic explorations and some laboratory tests can be performed. A determination of copper may be required to exclude Wilson’s disease , which reaches her as the nervous system .

The early diagnosis of Parkinson’s disease based on the observation of clinical symptoms (or default on their description) and allows a more rapid response with a significant improvement in the quality of life of patients.