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Treatment of chronic hypotension: Detail the protocols for the management of low blood pressure

Digestion, Heart | August 11, 2015 | Author: The Super Pharmacist

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Treatment of chronic hypotension: Detail the protocols for the management of low blood pressure

Chronic hypotension, or low blood pressure, is quite different from acute causes of low blood pressure such as blood loss, severe dehydration, infection of the blood, anaphylaxis or various forms of shock. Acute causes of low blood pressure are usually medical emergencies and can be life threatening. Most causes of chronic hypotension, on the other hand, are not serious. Nevertheless, chronic hypotension can cause several undesirable symptoms and increase a person's risk of fainting, losing consciousness, and suffering trauma to the head and body. Acute low blood pressure is usually treated in a hospital setting and often in an emergency department with intravenous fluids and/or blood transfusion. This article discusses the symptoms and treatment of chronic hypotension.

Symptoms of chronic hypotension

Symptoms of chronic hypotensionMost symptoms of chronic hypotension are caused by a lack of sufficient blood flow to the brain.

Not surprisingly, the most common symptoms of hypotension are dizziness, lightheadedness, fainting, problems with concentration, and blurry vision. Hypotension may not cause such specific symptoms, however.

Chronic hypotension can include subtle symptoms such as tiredness, weakness, fatigue, occasional leg buckling, and shortness of breath. 

People may also experience pain in the back of the neck, head, and shoulder region. 

People usually experience these symptoms of hypotension within minutes of standing or after eating a large meal, conditions called orthostatic hypotension and postprandial hypotension, respectively. In both of these situations, additional blood flow (and blood pressure) is required by the brain or the gastrointestinal tract.

When someone has low blood pressure, blood flow is inadequate and symptoms occur.

Diagnosis of chronic hypotension

The diagnosis of chronic hypotension can be tricky. It is much more common for people to experience high blood pressure or hypertension than low blood pressure. Thus, physicians are less likely to consider it is a cause of symptoms. This is especially true when patients experience subtle, vague symptoms of hypertension such as weakness, tiredness, and fatigue. Many patients with chronic hypotension go undiagnosed for some time until they begin to experience specific symptoms of hypotension. 

Initial diagnosis of hypotension begins simply—with a blood pressure cuff. Hypotension is a blood pressure reading less than 90/60 mmHg. If the top number (systolic), bottom number (diastolic), or both numbers are below this value, it is usually considered hypotension.

Hypotension may also be defined as a relative drop in blood pressure. The diagnostic difficulty, however, is that people may have normal resting blood pressure readings but experience hypotension in certain situations, such as standing or after a meal. In these cases, blood pressure must be taken during the situation, which can be difficult in a real world setting.

Orthostatic hypotension can be diagnosed by taking multiple blood pressure measurements under specific conditions. The patient starts by resting quietly on their back for 5 minutes and the first blood pressure measurement is taken. The patient then rises to a standing position and, after 2 minutes, a second blood pressure measurement is taken. If the systolic blood pressure falls by 20 mmHg and/or the diastolic blood pressure falls by 10 mmHg, the patient is considered to have orthostatic hypotension. If these procedures are followed closely and meticulously by health care professionals, the diagnosis of orthostatic hypotension can be made at the bedside in most patients.

People with other health conditions, physical limitations, or other possible autonomic disorders may be evaluated by a tilt table test. A tilt table test is similar to the hypotension testing described above except in a tilt table test, patients are connected to a heart monitor and the table moves mechanically (the patient does not need to stand). The tilt table test can provide physicians with additional information about the cause of hypotension. Blood work and electrocardiography may be necessary to rule out other causes of hypotension symptoms, such as anemia or cardiac arrhythmias.

Treatment of chronic hypotension

Remove the cause

The initial treatment of hypotension is to eliminate possible/probable causes of low blood pressure. Various prescribed and over-the-counter medications can lower blood pressure. Of course, drugs used to treat hypertension/high blood pressure can cause hypotension if they lower blood pressure too much. Drugs that are not prescribed to lower blood pressure can still achieve the same effect. For example, erectile dysfunction drugs can lower blood pressure as can certain antidepressants (particularly tricyclic antidepressants) and Parkinson's disease treatments. The treating physician will adjust dosages or stop certain medications if the drug-induced hypotension is severe. It may be possible to take the offending medications just before bedtime where hypotension should not cause symptoms.

Lifestyle modifications

The next step in hypotension treatment is usually to raise blood pressure/prevent low blood pressure without the use of medications. These are sometimes referred to as lifestyle modifications. Patients who suffer from chronic hypotension may benefit from:

  • Avoiding large, carbohydrate rich meals (if postprandial hypotension is a problem)
  • Limit the amount of alcohol consumed
  • Drink plenty of fluids; in people who can tolerate it, this may be up to 2.5 L per day
  • Some patients may need increased sodium (e.g. salt tablets, added table salt at meal times)
  • Specific exercise programs to avoid orthostatic hypotension
    • Rising slowly from a seated or lying position
    • Stand with legs crossed
    • Isometric contractions of the arms, legs, and abdomen
    • Toe raises
  • Thigh contractions
  • Squatting
  • Lower limb compression bandages may help circulate blood in the veins back toward the heart

Drug treatments

If lifestyle modifications fail to help people with hypotension, some prescription medications may increase blood pressure. In most cases, fludrocortisone is the first drug used to treat orthostatic hypotension and other troublesome forms of low blood pressure. Unfortunately, this drug is known to cause swelling of the arms and legs and weight gain. About one quarter of patients taking fludrocortisone develop low blood potassium levels. In select patients, midodrine and droxidopa can help increase blood pressure. Midodrine should not be used in patients who have kidney disease, severe heart disease, thyroid problems, or difficulty with urination. Midodrine should not be taken at night (after 6 PM) because it can cause high blood pressure when patients take it while lying down. Droxidopa may be used in people with autonomic nervous system failure leading to hypotension. Pyridostigmine can be used to treat hypotension but is often limited by its side effects including loose stools, chronic sweating, increased saliva production, and muscle twitches.

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References

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