[Blood pressure disorders during idiopathic Parkinson's disease]

SEVERAL EXPLANATIONS FOR THE HIGH PREVALENCE: In Parkinson's disease, the prevalence of symptomatic orthostatic hypotension (OH) concerns more than 20% of the patients. At least 2 factors explain this high prevalence. Dopamine-mimetic drugs may induce or enhance the occurrence of OH. Parkinson's disease is a cause of primary autonomic failure with involvement of the peripheral nervous system. CHARACTERISTIC HISTOLOGICAL AND PHARMACOLOGICAL ELEMENTS: Histology indicates that Lewy bodies exist in the sympathetic glands. Pharmacology reveals cardiac sympathetic denervation. These histological and pharmacological characteristics clearly differentiate autonomic failure of Parkinson's disease from multiple system atrophy (Shy-Drager's syndrome). If autonomic abnormalities appear to be present since the early stages of the disease, the early onset, within the first year, of symptomatic OH in the course of a parkinsonian syndrome can be considered as an exclusion criterion for idiopathic Parkinson's disease. REGARDING TREATMENT: No specific clinical trials have assessed the efficacy of antihypotensive drugs in the treatment of OH in Parkinson's disease. The management of this symptom requires education of the patient and the development of non-pharmacological measures. Drug therapy should be reserved for symptomatic patients who do not improve with the preceding methods. Among the drugs available, domperidone, although widely used, has no proven effect on OH like the cardiovascular analeptics. The alpha1-adrenergic agonists (midodrine) or mineralocorticosteroids (fludrocortisone) are the most frequently used drugs.