Overview
Hypotension (postural or postprandial) is an alteration of blood pressure regulation, frequent with age. May be asymptomatic, but is a common cause of syncope (self-limited transient loss of consciousness, which usually leads to crash), falls and mortality in people over 65 years, often signifying physical fragility.
Controlling blood pressure (BP) is achieved through baroreflex mechanisms that regulate BP by increasing and decreasing the heart rate and peripheral vascular resistance in response to variations in BP. With age, the baroreflex response to hyper and hypotensive stimuli decreases, while the hypotension risk gradually increases. Baroreflex function is impaired in elderly with hypertension.
Contents
1. Overview
2. Postural or orthostatic hypotension
3. Postprandial hypotension
Postural or orthostatic hypotension
Postural hypotension (the passage from the “lying” position to “standing” or “orthostatic” position) in the elderly occurs by altering steps in response to changes in posture, maintaining a relatively fixed heart rate and vasoconstrictive reflexes disturbance. Its prevalence increases with age and with increasing BP increasing.
In healthy and well hydrated elderly people, despite a relatively fixed heart rate when passing in standing position, blood pressure and cardiac output are maintained at normal levels. There is a relationship between the hypertension in the decubitus and the hypotension in the orthostatic, the higher BP in lying, the decrease in standing BP is more obvious. High blood pressure increases the risk of cerebral ischemia by lowering BP in standing. Hypertensive elderly are more vulnerable to cerebral ischemia, even when there is a modest and short hypotension because cerebral autoregulation is impaired as a result of prolonged exposure to high blood pressure values.
When is caused by age, hypotension has great variability and is accompanied by increases in blood norepinephrine as response to postural changes. The most common cause of acute orthostatic hypotension is dehydration during different conditions (during which occur diarrhea, vomiting, fever, etc.).
Chronic hypotension is caused usually by abnormalities of autonomic system (which controls the activity of various tissues and organs) and is accompanied by manifestations of autonomic dysfunction (fixed heart rate, constipation, incontinence, inability to sweat, heat intolerance, impotence, fatigue), these abnormalities can occur in systemic diseases or degenerative neurological diseases.
Other causes of hypotension are: haemorrhage, aortic stenosis, loss of volume replacement from any cause, etc. Medicines, even in therapeutic doses, are important causes of orthostatic hypotension and in the elderly is a common cause, because different treatments, but also because metabolic and auto-purification changes occurred with age.
Elderly are particularly vulnerable to drugs that reduce venous return, particularly nitrates and diuretics because they depend on venous return to maintain a normal cardiac output. Other drugs that may cause hypotension are many antihypertensive drugs that decrease heart rate, anticholinergics (antihistamines, spasmolytic, antiemetic), tricyclic antidepressants, etc. If the cause of hypotension is not diagnosed, it means that it is due to pure failure of autonomic system.
Presentation:
- Dizziness to syncope,
- Accompanied by various visual manifestations,
- Weakness,
- Lethargy,
- Sub-occipital and paravertebral muscle pain,
- Low back pain,
- Claudication (pain in the legs appeared during walking)
- Angina (chest pain of cardiac origin).
Precipitating factors of orthostatic hypotension:
- Postural change speed
- Prolonged decubitus
- Increased intrathoracic pressure in case of defecation, coughing, micturition
- Intense or prolonged exercise
- Vasoactive medication (antihypertensives, nitrates)
Rating:
BP and heart rate measurement should be performed after at least 5 minutes of lying (lying in bed) and after 1 and 3 minutes of standing (in feet). Hypotensive response may be immediate or delayed. To detect a delayed response may require a longer period of standing or “tilt table” test (table that can tilt and return to the horizontal position).
Diagnosis may be missed in a regular BP measurement in the afternoon. Measurement should be repeated in the morning after maintaining decubitus for 10 minutes. Once diagnosed the hypotension, the doctor should search to identify the cause / causes.
Management of orthostatic hypotension:
1. Identify and treat correctable causes (fever, diarrhea, vomiting, loss of volume, bleeding, etc.): hydroelectrolytic rebalancing in cases of dehydration or loss of volume, blood transfusion, oral hydration, increased salt intake (in situations where the health permitting), etc.
2. Reduction or removal of drugs that cause hypotension;
3. Avoid situations that may exacerbate hypotension:
- Extended standing position
- Extended decubitus (“lying in bed” position)
- Hearty meals
- External heat
- Hot showers
- Defecation or urination effort
- Isometric exercises
- Ingestion of alcohol
- Hyperventilation (breathing frequency)
- Dehydration
4. Lifting (for the night) the end of the bed by 5-20 degrees
5. Compression stockings
6. Preventive measures: patients with chronic orthostatic hypotension are advised to rise slowly in orthostatic position after prolonged decubitus or sitting position; knees bending before lifting from the lying position, crossing limbs in orthostatic position
7. Avoid diuretics and fluid intake high in salt (in the absence of heart failure or kidney)
8. Conditioning exercise (to improve pressure control and heart rate)
9. Postural exercises with tilt table (table that can tilt and return to the horizontal position)
10. Medications:
- Caffeine
- Midodrine (sympathomimetic vasoconstrictor)
- Desmopressin
- Erythropoietin
Other drugs: NSAIDs, clonidine, yohimbine, selective beta 2 beta blockers, alpha-agonists, ergot alkaloids in combination with caffeine.
Treatment of hypotension in the elderly involves close monitoring of BP in lying, electrolyte balance and heart failure. One option for treatment of decubitus high blood pressure, which is combined with frequent nocturnal orthostatic hypotension is using nitroglycerin patch at night and taking midodrine 20 minutes before lifting out of bed. To assess the combination of decubitus hypertension with orthostatic hypotension is necessary to monitor the BT for 24 h. Postural hypotension in elderly patients frequently coexist with the prandial one.
Postprandial hypotension
In healthy elderly, there is a decrease in postprandial systolic BP of 11-16 mm Hg, and an increase in AV by 5-7 beats / minute, 60 minutes after the morning or evening meals. In more than a third of the cases, BP decreases with> = 20 mmHg at 75 minutes postprandial. Postprandial hypotension may be asymptomatic. In patients with hypertension, autonomic system failure or orthostatic hypotension, decreased postprandial BP is much higher and there is accompanied by increased heart rate. Postprandial decrease in BP is greater when foods are simple carbohydrates and when these have high energy content.
Hypotension occurs due to increased mesenteric and splanchnic blood flow (from the digestive tract, liver, pancreas) detrimental for the peripheral blood flow, but also postprandial hyperinsulinaemia, unmatched by increased activity of the sympathetic system. Vasodilatory effect of insulin and other intestinal peptide contributes to postprandial hypotension. Postprandial hypotension is another cause for recurrent syncope and falls in the elderly. In addition to lowering BP, postprandial decreases exercise tolerance and exacerbation of angina may occur.
Presentation: postprandial – dizziness, falls, syncope, cardiac or cerebral various symptoms.
Rating: in the symptomatic elderly – BP measurement before meals, 30 and 60 minutes after eating.
Management of symptomatic postprandial hypotension:
1. Lower carbohydrate content; replace it with complex carbohydrates or protein or lipid diets high frequent meals, low quantity;
2. Walking after meals may help, but hypotension may occur in gait termination;
3. Dose reduction of antihypertensive; take this drugs after meals;
4. Bed rest after lunch in symptomatic patients;
5. Medications: fludrocortisone, indomethacin, caffeine, caffeine administered orally at the table is useful both healthy elderly and those fragile, but it is preferable to administer morning as develop tolerance if taken throughout the day.
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