Orthostatic hypotension

It is a sudden drop in blood pressure, which is noted as the patient is quickly returned to an upright position in the dental chair.

Orthostatic hypotension is defined as a decrease in systolic blood pressure of 20 mm Hg or a decrease in diastolic blood pressure of 10 mm Hg within three minutes of standing when compared with blood pressure from the sitting or supine position.

This condition is due to disturbances of the autonomic nervous system, and is the second most frequently observe cause of transient loss of consciousness in the dental patient after fainting.

Almost any disease of the spinal cord can be accompanied by orthostatic hypotension. Many conditions usually manifesting as peripheral neuropathies can be accompanying autonomic neuropathy and orthostatic hypotension. These include amyloidosis, Guillain-Barré syndrome, diabetes, bronchogenic carcinoma.
Orthostatic hypotension

Definition of Hypotension

Hypotension is abnormally low blood pressure readings, which may be found among very ill or elderly individuals or among those with severe hyperthyroidism, pituitary failure and Addison’s disease. Clinically, when the systolic blood pressure is less than 9 mm Hg, it is considered hypotension.

There are two types of hypotension: orthostatic hypotension and Shy-Grager syndrome. Idiopathic orthostatic hypotension also known as postural hypotension is a syndrome of symptoms due to degeneration of postganglionic sympathetic neurons confined to the autonomic system. It is sudden drop in blood pressure (about 20 mm Hg in the systolic pressure) that occurs when person changes from a lying down to a sitting-up position or from sitting-up to a standing position.

Shy-Grager syndrome is due to multiple systems degeneration with more widespread neurologic damage, including autonomic dysfunction with cerebrellar atraxia, parkinsonism, corticospinal, and corticobulbar tract dysfunction, and amyotrophy.

Hypotension can be dangerous because it can impair people so much they experience severe falls and fractures.
Definition of Hypotension