Orthostatic Hypertension

Orthostatic hypertension is a medical condition consisting of a sudden and abrupt increase in blood pressure when a person stands up. Orthostatic hypertension is diagnosed by a rise in systolic blood pressure of 20 mmHg or more when standing. Orthostatic diastolic hypertension is a condition in which the diastolic raises to 98 mmHg or over in response to standing; however, this definition currently lacks clear medical consensus and is thus subject to change. Orthostatic hypertension involving the systolic is known as systolic orthostatic hypertension.

If affecting an individual's ability to remain upright, orthostatic hypertension is viewed as a form of orthostatic intolerance. The body's inability to regulate the blood pressure can be a type of dysautonomia.

Baroreflex and autonomic pathways normally ensure that blood pressure is maintained despite various stimuli including postural change. The precise mechanism of orthostatic hypertension remains unclear, but it is thought that alpha-adrenergic activity may be the predominant pathophysiologic mechanism of orthostatic hypertension in elderly hypertensive patients. Other mechanisms are proposed for other groups with this disorder.

A prevalence of 1.1% was found in a large population study. The risk of orthostatic hypertension has been found to increase with age, with it being found in 16.3% of older hypertensive patients.

Signs and symptoms

• Mild or moderate orthostatic hypertension may present without any symptoms other than the orthostatic hypertension BP findings. More severe orthostatic hypertension may present with the typical symptoms of hypertension.
• Orthostatic venous pooling is common with orthostatic diastolic hypertension. This occurs in the legs while standing.

Connections to other disorders

• Essential hypertension
• Other kinds of dysautonomia may coexist, e.g., postural orthostatic tachycardia syndrome is common with this condition, orthostatic hypotension with the BP going both high and low at times due to autonomic dysfunction
• Type 2 diabetes
• Vascular adrenergic hypersensitivity: Orthostatic hypertension can be secondary to this
• Anorexia Nervosa: Many people suffering From anorexia experience orthostatic hypertension
• Hypovolemia can cause orthostatic hypertension
• Renal arterial stenosis (narrowing of the kidney arteries) with nephroptosis (kidney drops on standing) have been known to cause orthostatic hypertension.
• Aortitis (inflammation of the aorta) with nephroptosis: "This orthostatic hypertension largely may be due to an activation of the renin system caused by nephroptosis and partly due to a reduced baroreflex sensitivity caused by aortitis"
• Pheochromocytoma

Risks

• Blood pressure variability is associated with progression of target organ damage and cardiovascular risk.
• Orthostatic hypertension was positively associated with peripheral arterial disease.
• Increased occurrence of silent cerebrovascular ischemia
• Systolic orthostatic hypertension increases stroke risk.

Diagnosis

The condition can be assessed by a tilt table test. If the test is positive the diagnosis is hyperadrenergic postural orthostatic tachycardia syndrome.

Treatments

There are no officially recommended treatments currently for orthostatic hypertension as the condition is still little known and can be due to different causes. Hence, treatment for those with this disorder is still a trial and error experimental treatment. Some treatments which have been successfully used for this condition are medications doxazosin, carvedilol, captopril, and propranolol hydrochloride. Treatment of coexisting conditions, e.g., hypovolemia. Some specialists in severe cases give saline IVs for the hypovolemia which, if it is the cause, brings the orthostatic hypertension down to a safe level. Pressure garments over the pelvis and the lower extremeties may be used as part of treatment, due to the blood pooling issue occurring in many with the disorder.