Orthostatic Hypotension in Parkinson Disease

Abstract

Orthostatic hypotension (OH) is a sustained fall in blood pressure on standing that can cause symptoms of organ hypoperfusion. OH is associated with increased morbidity and mortality and leads to a significant number of hospital admissions. OH can be caused by volume depletion, blood loss, cardiac pump failure, large varicose veins, medications, or defective activation of sympathetic nerves and reduced norepinephrine release upon standing. Neurogenic OH is a frequent and disabling problem in patients with synucleinopathies such as Parkinson disease, multiple system atrophy, and pure autonomic failure, and it is commonly associated with supine hypertension. Several therapeutic options are available.

Keywords: Autonomic failure; Baroreflex dysfunction; Droxidopa; Midodrine; Neurogenic orthostatic hypotension; Norepinephrine.

Figure 1.. Neurotransmitter disorders in Parkinson disease.

Neurogenic orthostatic hypotension can be understood as a neurotransmitter disorder, similar to the motor dysfunction. Nigrostriatal dopaminergic denervation causing defective dopamine (DA) release results in the movement disorder, whereas postganglionic sympathetic denervation causing defective norepinephrine (NE) release when standing causes neurogenic orthostatic hypotension.