Orthostatic hypotension is a sudden fall in blood pressure that occurs when a person assumes a standing position. It is also known as postural hypotension, orthostasis, and colloquially as “head rush” or a dizzy spell.

Orthostatic hypotension is primarily caused by gravity-induced blood pooling in the lower extremities. It may also be caused by hypovolemia (a decreased amount of blood in the body), resulting from the excessive use of diuretics, vasodilators, or other types of drugs, dehydration, or prolonged bed rest.

The disorder may be associated with:

• Addison’s disease
• Atherosclerosis – build-up of fatty deposits in the arteries
• Diabetes
• Certain neurological disorders including Shy-Drager syndrome and other dysautonomias

The incidence of orthostatic hypotension increases with age.

Symptoms, which generally occur after sudden standing, include:

• Dizziness
• Lightheadedness
• Blurred vision
• Syncope – temporary loss of consciousness

The prognosis for individuals with orthostatic hypotension depends on the underlying cause of the condition.

When orthostatic hypotension is caused by hypovolemia due to medications, the disorder may be reversed by adjusting the dosage or by discontinuing the medication. When the condition is caused by prolonged bed rest, improvement may occur by sitting up with increasing frequency each day. In some cases, physical counterpressure such as elastic hose or whole-body inflatable suits may be required. Dehydration is treated with salt and fluids.