Delayed orthostatic hypotension is a form of low blood pressure where the drop occurs more than three minutes after standing up. Unlike the immediate drop in the classic form, this delay can make it difficult to connect symptoms to the act of standing. When a person stands, gravity pulls blood into the lower body. The autonomic nervous system normally counteracts this by constricting blood vessels and increasing heart rate to maintain blood flow to the brain.
In delayed orthostatic hypotension, this response is sluggish, causing an eventual drop in blood pressure. This condition is distinct from postural orthostatic tachycardia syndrome (POTS), where the heart rate increases upon standing with little change in blood pressure.
Recognizing the Symptoms
Symptoms of delayed orthostatic hypotension appear several minutes after a person has been standing. The most common sensations are dizziness and lightheadedness, which can range from a mild feeling of being off-balance to a more intense sensation of spinning. These feelings arise because the brain is not receiving adequate blood flow.
Accompanying the dizziness, individuals may experience blurred vision, weakness, or fatigue that makes it hard to remain standing. Some people report neck and shoulder pain, known as “coat hanger pain,” from poor circulation to the muscles. In severe cases, the drop in blood pressure can cause fainting, also known as syncope.
Underlying Causes and Associated Conditions
Delayed orthostatic hypotension often signals an issue with the autonomic nervous system, which cannot respond quickly enough to standing. Neurodegenerative disorders that directly affect autonomic function are a significant cause, and DOH can be an early indicator of these diseases. Such disorders include:
- Parkinson’s disease
- Multiple system atrophy
- Pure autonomic failure
- Lewy body dementia
Other health conditions can also contribute to DOH. Diabetes is a common cause, as high blood sugar levels can damage autonomic nerves over time, a complication known as autonomic neuropathy. Certain medications are also known triggers, including alpha-blockers, some antidepressants, and diuretics. Other factors include dehydration and advancing age.
The Diagnostic Process
Diagnosing delayed orthostatic hypotension involves measuring blood pressure and heart rate during postural changes. The primary tool is the active stand test, a procedure that tracks cardiovascular responses as a person moves from lying down to standing. The process begins with the patient lying down for at least five minutes to establish a baseline blood pressure and heart rate.
After standing, measurements are taken at one and three minutes to check for classic orthostatic hypotension, but for the delayed form, measurements must continue for up to 10 minutes. The diagnostic criteria are met with a sustained drop in systolic blood pressure of at least 20 mmHg or a drop in diastolic blood pressure of at least 10 mmHg that occurs after three minutes of standing.
If an active stand test is inconclusive, a head-up tilt table test may be used. During this test, the patient is secured to a table that is gradually tilted upwards, simulating standing in a controlled environment while blood pressure and heart rate are continuously monitored.
Management and Treatment Approaches
Managing delayed orthostatic hypotension focuses on reducing symptoms and improving quality of life. The approach begins with non-pharmacological strategies involving lifestyle adjustments and physical techniques.
Non-Pharmacological Strategies
A primary recommendation is to increase fluid and salt intake to expand blood volume, which should be done under medical supervision. Wearing compression garments, such as waist-high stockings or an abdominal binder, can also be beneficial. These garments apply external pressure to the legs and abdomen, which helps prevent blood from pooling in the lower body. Elevating the head of the bed by four to six inches can also help manage overnight blood pressure fluctuations.
Patients are also taught to avoid triggers like standing still for long periods, hot environments, and large meals. Physical counter-maneuvers can be employed at the first sign of symptoms. Actions like crossing one’s legs, squatting, or tensing leg and buttock muscles can help pump blood back toward the brain and temporarily raise blood pressure.
Pharmacological Options
When lifestyle strategies are not sufficient, a physician may consider medications to raise standing blood pressure. Fludrocortisone works by helping the body retain more salt and water, thereby increasing blood volume. Another common medication is midodrine, which acts by constricting blood vessels to prevent blood pressure from dropping upon standing. The decision to start medication requires careful consideration, as these drugs can have side effects, including high blood pressure while lying down.