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Information sheet - Low Blood Pressure (Word, 85KB)

By Dustin Lawson,2014-04-08 20:40
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Information sheet - Low Blood Pressure (Word, 85KB)

Low Blood Pressure and Parkinson’s

    People with Parkinson’s disease can experience problems with low blood pressure (hypotension) as a result of the symptoms of Parkinson’s and as a side effect of some of the drugs used to treat the condition. This information sheet provides you with facts about the nature of low blood pressure in Parkinson’s and gives you some tips to help manage it.

What is blood pressure?

    Blood pressure refers to the pressure in the circulatory system of the body. The heart pumps blood, circulating it first through the blood vessels in the body and returning it to the heart, then to the lungs for replenishment with oxygen, and back again to the heart. This pumping mechanism is controlled automatically and blood pressure goes up and down as a normal response to activities of daily living. It will go up in response to stress or physical activities, and go down when a person is resting.

    Blood pressure is determined by three main factors:

     the blood pumped out by the heart per minute (called cardiac output) ;

    which is the product of the heart rate and blood pumped out with each

    heart beat (stroke volume)

     the volume of blood in the circulatory system ;

     the resistance to blood flow offered by the blood vessels. This is called the ;

    peripheral resistance and mainly occurs in the small branches of the

    arterial tree called arterioles.

    The circulatory system is capable of holding large amounts of blood. The capacity of the blood vessels is chiefly determined by the tension (tone) in arteries and veins. Higher tone increases the resistance and reduces the capacity, while a lower tone in the vessels allows more blood to the area. If the tone is too low and the vessels are fully relaxed, blood pressure will fall precipitously. As there is only a certain amount of blood in our bodies, the distribution of blood within our circulatory system is very cleverly managed, allowing the blood to be taken to the areas most in need. Take digestion for example. When we have eaten a meal, the tone in the arteries to the digestive system is reduced to encourage blood to flow to the intestines to aid the digestion process. At the same time, tone to other parts of the body is increased to divert blood away from these sites to the intestine. If this process is not automatically controlled, so that blood is diverted to the intestine without a reduction to areas with less need, blood pressure will fall. Sometimes the brain blood flow can be sufficiently reduced by

    this process to result in a fainting attack (syncope) if severe, or light-headedness or dizziness if mild.

    Similarly, during exercise the blood pressure should automatically alter to supply the working muscles.

    The blood ‘diversion’, as seen in the two examples above, results in an initial overall drop in blood pressure, so the heart responds by increasing its rate to maintain the blood pressure at an acceptable level. These adjustments are made largely through a part of our nervous system called the autonomic nervous system (ANS), which includes nerves to the blood vessels and heart. In some conditions, for example in an unusual type of parkinsonism called multiple system atrophy (MSA), the ANS is faulty, so this adjustment cannot be made. Fainting can occur every time the person with this condition stands up (unless treated). Blood pressure readings are usually given as two numbers, for example 120 over 70 (written as 120/70). The first number is the systolic blood pressure reading and represents the maximum pressure exerted when the heart contracts. The second number is called the diastolic blood pressure reading and represents the pressure in the arteries when the heart is at rest. Generally, the normal values for blood pressure are approximately 120/7080.

    However, the variation in blood pressure in one person during the course of a day can be enormous. There can also be great variations in blood pressure from one person to the next. What is ‘low blood pressure’ to one person may be normal for another.

    However, in considering whether a person has abnormally high or low blood pressure (see below), the change in blood pressure and how it affects that person is more important than the actual blood pressure reading. For example, a person with high blood pressure may find their blood pressure drops to a low level when they take tablets to treat it, but their blood pressure may still be higher than a person with normal blood pressure.

High blood pressure (hypertension)

    High blood pressure (hypertension) is an extremely common condition, affecting 1020% of the UK adult population. It means that a person’s blood pressure is

    above the normal range expected in a particular age group. High blood pressure can cause conditions such as heart failure and stroke, but controlling high blood pressure stops their development. Risk factors for high blood pressure include being overweight or eating a poor diet, smoking, age, inherited factors, and medication you are taking.

    Parkinson’s does not generally cause high blood pressure. Many people with Parkinson’s, particularly older people, may also have high blood pressure, but it is

    not directly related to their Parkinson’s. Medication to treat high blood pressure

    may, however, cause problems with low blood pressure and so the dose has to be carefully adjusted by the doctor.

Low blood pressure

    Low blood pressure is much less common than high blood pressure. Unlike high blood pressure, there is no generally accepted level of blood pressure to indicate low blood pressure, although many text books will regard a blood pressure reading where the systolic is below 100 as low blood pressure.

    It is also not generally accepted in the UK and USA as a separate clinical condition. Germany is one of the few countries that accept lo blood pressure as a specific condition characterised by fatigue, listlessness and dizziness. In the UK, low blood pressure describes a situation where the blood pressure is low enough to produce symptoms either as a complication of another condition or as a side effect of medication.

    These symptoms can occur in emergency situations such as reduction of blood volume through loss of blood or through loss of fluid (dehydration as in severe diarrhoea or vomiting), reduced pumping of the heart (for example in an acute heart attack) or where the capacity of the blood vessels is suddenly increased (like in anaphylactic shock caused by a severe allergic reaction).

Parkinson’s and low blood pressure

    Parkinson’s and the drugs used to treat the condition can cause low blood pressure. The most common type experienced by people with Parkinson’s is

    orthostatic or postural hypotension, which occurs only with a change of posture such as moving from a lying to a standing position or from being seated to a standing position.

    Normally, when a person comes up to stand, blood pools in the legs and abdominal cavity, consequently lowering blood pressure. This is prevented by an increase in heart rate (reflex tachycardia) and an increase in the tone of arterioles (reflex vasoconstriction). Arterioles are small branches of arteries that lead into many smaller vessels known as capillaries. By their constriction and dilation, they are the principal controllers of blood flow and pressure.

    If these adaptive changes are slow to occur or do not occur, the blood pressure will fall and the person will feel dizzy or may even faint. The adaptive mechanisms are impaired in Parkinson’s and almost all the drugs used to treat Parkinson’s, (levodopa and dopamine agonists) can lead to poor arteriolar contraction (impaired vasoconstriction).

    How do I know if I have it?

    Symptoms are variable but predictable, which is useful for management. They

    include:

     dizziness/light-headedness (in the extreme this can result in a fall) ;

     changes in vision, such as blurred, tunnel, greying or blacking vision ;

     angina-like pain in the chest ;

     weakness ;

     fatigue ;

     loss of confidence to walk alone or without support ;

     feeling muddled or confused ;

    These symptoms are most likely to happen when there is an increased demand

    for blood for activities throughout the day. For instance:

     In the morning, as more urine is passed overnight and the blood ;

    volume is lower and as a consequence of lying flat for several hours and the reduction of the effect of gravity on your blood pressure.

     After a quick change in position, particularly from a lying down to a sitting ;

    or standing position, because the blood regulatory mechanism can’t be activated quickly.

     On exertion, as the increased demand for blood from exercising muscles ;

    decreases the circulation to the brain.

     After meals, more blood is needed by the digestive system and the blood ;

    supply available to the brain is reduced. Alcohol has a similar effect as it tends to dehydrate the body.

     After inactivity, especially bed rest. ;

     In the warmth of a centrally heated room, hot bath or summer days. ;

    Peripheral circulation (to the fingers and toes) increases due to the dilation (enlarging) of blood vessels in a warm environment, which can cause low blood pressure.

     Sometimes, when constipated, the effort of straining lowers blood ;

    pressure. This can also occur when coughing, or if there is any effort required in passing urine. People with Parkinson’s can be particularly prone to constipation. See the Parkinson’s Disease Society (PDS) booklets Parkinson’s and Diet and Looking After Your Bladder and Bowels in Parkinsonism, and the PDS information sheet Constipation

    and Parkinson’s.

     Illnesses, ranging from a cold to more serious conditions, can cause low ;

    blood pressure, often as a result of dehydration. It is important to

    remember that an increase in symptoms may be a sign of illness.

     Anxiety can cause over-breathing which lowers the blood pressure. ;

    You are more at risk of low blood pressure if you are older, have diabetes, are already taking blood pressure-lowering pills to treat high blood pressure, or if you are a male who takes tablets to ease your urine flow because of prostate problems (e.g. tamsulosin, indoramin, terazocin). Your doctor should always look carefully at any other tablets you may be taking for conditions other than Parkinson’s.

Is it dangerous?

    On the whole, the answer is no. Normally, it cannot cause major problems, but it can be a hazard because low blood pressure can make you faint or black out and, as a result, you could fall and suffer an injury. Fainting is nature’s way of trying to preserve blood flow to the brain. The moment a

    person who is standing faints because the blood pressure is low, they are protecting their brain, because it is much easier for the heart to pump blood into the brain when the body is horizontal. If a person with a tendency to low blood pressure faints, it is important to keep them flat and not try to stand them up. The sense of weakness and faintness is very unpleasant. Sometimes the lack of blood reaching the brain can cause mild confusion, which can be frightening, but the confusion should clear when the blood pressure returns to normal. See the PDS information sheet Falls and

    Parkinson’s for information to help you cope with falls.

    What can be done medically to help overcome low blood pressure problems? Postural hypotension can often be reduced by the self-help measures described below. However, medical intervention may be necessary. The first step is to discuss the symptoms you are having with your doctor or health specialist. Your doctor or health specialist should measure lying and standing blood pressure before starting treatment with any drug for Parkinson’s. If you feel dizzy or light-

    headed when you stand up, or feel faintish after a heavy meal or exercising, you may have postural hypotension.

    If the dose of the drug to treat Parkinson’s is built up gradually, your blood pressure is closely monitored and you take the precautions mentioned in this information sheet (such as getting up slowly), you should not experience any serious consequences from postural hypotension.

    It is important to ensure that you take your medication as prescribed. If you find that it does not seem to be working as well as it used to, it may mean that you need to have your drugs reviewed.

    Postural hypotension alone is not by itself a reason to change drugs, but its presence requires you to take precautions. In some cases, it is severe enough to warrant the gradual withdrawal of the drug gradually and substitution with another drug.

    If you have been taking medication to lower your blood pressure, it is advisable to have it checked as this, combined with the effects of Parkinson’s described on page 3, may be making your blood pressure too low.

    In some people, the postural hypotension can also be controlled by using drugs that increase the blood volume, such as fludrocortisone.

    Some people find that wearing support stockings to stimulate the circulation can be helpful. These are usually available in the form of tights or men’s socks, either on prescription or over the counter. Your local pharmacist may stock them or be able to advise you where to obtain them.

    Some people find putting on such garments difficult. If your feet get swollen during the day, it is best to put them on before you get out of bed (before your feet have swollen). There are various items of equipment available to help with dressing and putting on footwear, but we recommend that you get advice from an occupational therapist before you buy, to ensure that an item is appropriate for your needs. The Disabled Living Foundation (tel: 0845 130 9177 or website: www.dlf.org.uk) should also be able to advise further.

    Are there any simple strategies that I can adopt to help myself cope with low blood pressure?

    Yes. These include:

     Do not sit in the sun, or any overheated environment, for too long. Try ;

    to curtail unnecessary activity when it is too hot, and keep hydrated

    with extra fluids. You may wish to use a fan to cool your body in

    warm environments.

     Try not to sit or stand still for long periods, for example doing the ironing. ;

    The length of time varies greatly from person to person. Sit while getting

    dressed, do tasks sitting down and not all at once. If you are doing a task

    that means you have to stand, then move about a little by rocking on your

    toes and then heels alternately, or change tasks for a while.

     Some dizzy spells can be avoided by taking time to alter your position ;

    such as rising from a chair to standing position. Get up slowly from the

    sitting position, especially if you have been dozing. Do not rush to answer

    the phone or the doorbell. On rising, do not walk away from your chair

    straight away. Stand for a while until you feel steady. Before getting out of

    bed, allow your feet to dangle on the floor for a few minutes before rising. Then rise slowly.

     When bending or reaching, do so slowly, holding on to something if you ;

    need to.

     If someone has episodes of low blood pressure, it helps to raise the head ;

    of the bed so that the person becomes used to the upright position and experiences less of a postural drop when standing up from the bed.Blocks for the bed legs, a foam wedge or an electric bed raiser can be used to do this. An occupational therapist can advise further.

     Eating small, frequent meals, increasing fluid intake, avoiding caffeine at ;

    night and avoiding alcohol may also help. Your doctor or dietician can advise whether an increase in dietary salt may also be beneficial.

     Taking some medication on an empty stomach may aggravate the ;

    problem, as medication is absorbed more quickly. Ensure you read the instructions carefully.

     Large, heavy hot meals may add to the problem. When we eat, the blood ;

    goes from our brain to our stomach to help digest the food, so keep meals small and frequent if you feel faint after eating.

     Recognising what triggers your symptoms, and what makes them better or ;

    worse, will help manage the problem. You may find it helps to keep a note for a few days.

     Exercise can help, for instance leg exercises, flexing the ankle and foot up ;

    and down, or squeezing the calf muscle, gentle marching movements, crossing and uncrossing legs. Most of these can be done sitting, standing or lying in bed. A physiotherapist can advise further on exercises and management of falls. See the PDS information sheet Physiotherapy and

    Parkinson’s for more information on the role and how to access one.

     If you feel dizzy or faint, sit (preferably with your legs raised) or lie down ;

    immediately, until the feeling passes. Always take your time when rising. If your symptoms are severe, discuss them further with your doctor. Some people with severe symptoms also find it helpful to use a Derby or shooting stick to sit on. These are devices that look like lightweight walking canes, but can convert to a chair when needed allowing a person to rest

    whenever they need to. Sporting shops, especially those that cater for country outdoor pursuits, often sell them.

     Sometimes, taking a small drink of water before you get up can help ;

    reduce the effects of your blood pressure dropping.

Can low blood pressure affect my driving?

    Yes, low blood pressure can affect your ability to drive and consequently your car insurance. You should discuss this further with your doctor or health specialist. For general information on driving, see the PDS booklet, Driving and Parkinson’s.

Acknowledgements

    The PDS would like to thank Dr Anna Jones, Mel Phillips (PDS Helpline Nurse), Bhanu Ramaswamy and Dr Brian Williams for their contributions to this information sheet.

    ****************************************************************************************

    Parkinson’s Disease Society

    215 Vauxhall Bridge Road, London SW1V 1EJ, UK

    Tel: 020 7931 8080 Fax: 020 7233 9908

    Helpline: 0808 800 0303. (The Helpline is a confidential service.

    Calls are free from UK landlines and some mobile networks)

    Email: enquiries@parkinsons.org.uk Website: www.parkinsons.org.uk

    ? Parkinson’s Disease Society of the United Kingdom (2008)

    Charity registered in England and Wales No. 258197 and in Scotland No. SC037554.

    A company limited by guarantee. Registered No. 948776 (London)

    Registered office: 215 Vauxhall Bridge Road, London SW1V 1EJ

    Revised March 2009

    To obtain any PDS resource, please go online to www.parkinsons.org.uk or contact

    Sharward Services Ltd, the appointed PDS Distribution House, at Westerfield

    Business Centre, Main Road, Westerfield, Ipswich, Suffolk IP6 9AB

    tel: 01473 212115, fax: 01473 212114,

    email: pds@sharward.co.uk

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