Dizziness - orthostatic hypotension

When we stand up from sitting or lying down, our blood vessels respond to gravity by narrowing to prevent our blood pressure falling. This ensures a steady supply of oxygenated blood to the brain. It happens when the blood vessels do not constrict (tighten) as you stand up.

It is usually a symptom of an underlying disorder rather than a disease in itself.

The condition is also known as postural hypotension

Everyone is likely to experience a mild form of postural hypotension at some time. It’s the lightheaded feeling you may get if you leap out of bed very quickly. The drop in blood pressure reduces the flow of oxygenated blood to the brain.

Symptoms may include: Fainting

Gravity dramatically affects blood flow whenever you stand up from sitting or lying down – on average, about 800ml of blood temporarily pools in the blood vessels of the legs. Sensors called baroreceptors located in the three major arteries – the aorta and the two carotid arteries – detect this drop in blood pressure.

In a healthy person, the cardiovascular system and the autonomic nervous system quickly respond by increasing the heart rate and directing blood vessels in the legs and abdomen to constrict (tighten).

These measures maintain adequate blood pressure to the brain. This compensatory mechanism to increase blood pressure does not occur, or may be delayed, in a person with orthostatic hypotension.

Their blood pressure remains low, which triggers symptoms

Blood pressure typically returns to normal once the person sits or lies down again, but this depends on the severity of the underlying cause.

Orthostatic hypotension usually results from an underlying disorder

It is not a disease in itself

Some of the many causes of orthostatic hypotension include:

• Heart problems including irregular heart beat (heart arrhythmia) congestive heart failure
• aortic stenosis or heart attack Shy Drager syndrome
• a degenerative disorder of the brain
• spinal cord that affects functioning of the autonomic nervous system Significant blood loss

Remember there are other causes of dizziness, light-headedness and nausea, apart from postural hypotension.

One example is ear disease

It is always important to seek medical advice for any unexplained symptoms.

The incidence of orthostatic hypotension increases with age

One US study found that every elderly participant had some degree of orthostatic hypotension. Factors that seem to increase the risk in elderly people include:

• – when you eat
• then digest food

– if you stand up for a long time, it causes a slow but steady drop in blood pressure. – these are more common in old age. Tests used to diagnose orthostatic hypotension include:

• Other tests
• depending on individual factors

Treatment depends on the cause

• Changes in medication or altered doses if drugs are the cause (sometimes
• stopping or altering the dose of a particular medication may cause more harm than good
• must be carefully considered in consultation with your doctor) Medications to treat orthostatic hypotension including pyridostigmine
• a drug used in the treatment of myasthenia gravis In some cases
• a lower body pressure suit is required

Be guided by your doctor, but general suggestions that may help you to manage orthostatic hypotension include: Prop your head up with pillows when you’re in bed to reduce the likelihood of orthostatic hypotension when you get up. Get up slowly from a sitting or lying position to allow your blood vessels time to adjust.

Wear support stockings to reduce the pooling of blood in the legs, which helps to boost blood pressure throughout the body. Eat small, frequent meals instead of three large meals per day. Drink plenty of fluids throughout the day to prevent dehydration.

Limit alcohol consumption

Alcohol can cause dehydration and dilation of blood vessels. Consider drinking small but regular doses of caffeine, which boost blood pressure. A cup of coffee or tea with each meal tends to reduce the severity of orthostatic hypotension.

Remember, however, that caffeinated drinks can cause dehydration, so moderation is the key. Try other drinks that contain caffeine, like hot chocolate or cola, if you don’t like coffee or tea. Avoid vigorous exercise, hot baths, saunas and any hot environment because heat causes blood vessels to widen (dilate).

Avoid standing without moving for long periods of time.

Avoid ascending quickly to high altitudes

See your doctor for regular blood pressure check-ups. NURSE-ON-CALL Tel. (616) 555-0024 – for expert health information and advice 24 hours, 7 days a week. Orthostatic hypotension is a form of low blood pressure Symptoms of orthostatic hypotension Blurry vision Dizziness Light-headedness Mental confusion Nausea Muscle tremors Blood pooling explained Causes of orthostatic hypotension Fever Prolonged bed rest Excessive amounts of alcohol Some medications, such as some diuretics or antihypertensive (high blood pressure) medications Dehydration due to vomiting, diarrhoea or both, as in gastroenteritis Certain conditions, such as anaemia, diabetes, varicose veins or adrenal insufficiency Nervous system disease, such as Parkinson’s disease or neuropathy Spinal cord conditions such as syringomyelia Other causes of dizziness Old age is an important risk factor Digestion Standing Frailty and chronic sickness Diagnosis of orthostatic hypotension Medical history, including medical conditions and drugs taken on a regular basis Physical examination Measuring blood pressure when lying down versus standing up Blood tests to check, for example, blood sugars or adrenal hormones Echocardiography, an imaging scan of the heart, to check for certain heart conditions Treatment of orthostatic hypotension Fluids to treat dehydration Management of diabetes, such as regular insulin injections Medication, surgery or both to treat heart conditions Medication to increase blood volume or pressure, including corticosteroids A range of treatments, since orthostatic hypotension may have two or more causes Self-help suggestions Where to get help Your doctor.

Key Points

• usually a symptom of an underlying disorder rather than a disease in itself
• Symptoms may include: Fainting
• These measures maintain adequate blood pressure to the brain
• Their blood pressure remains low, which triggers symptoms
• Remember there are other causes of dizziness, light-headedness and nausea, apart from postural hypotension