Constipation is a common health problem that affects a person’s ability to make normal bowel movements. People who are constipated may have:
- infrequent bowel movements
- stools (faeces) that are hard and difficult to pass
- excessive straining when trying to pass stools
- pain when passing stools.
Eating, drinking and exercise stimulates the passage of waste matter through the large intestine, so a poor diet and/or a lack of exercise is often the main cause of constipation. However, constipation may also be caused by hormonal or anatomical factors, such as impairment of muscle relaxation, or could be an unfortunate side effect of a patient’s medication.
Although constipation may be embarrassing or a nuisance, in most cases it is unlikely to cause serious problems. But if symptoms are severe, it may make you feel unwell, nauseous or lethargic, and it can make older people confused and restless. Constipation may also make bladder emptying difficult, or become so urgent that incontinence results.
How might Parkinson's affect the bowels?
Bowel problems can occur in anyone. But some problems, especially reduced bowel movement or constipation, are particularly common in people with Parkinson’s. This tends to be as a result of bradykinesia. This slowness, limited movement and muscle rigidity, which are visible symptoms of the disease, also affects the muscles we can’t see – including the bowel muscles - which in turn causes a reduction or slowness of bowel movements.
Poor bowel function may be exacerbated if a person finds it difficult to chew and swallow food, which is quite common with Parkinson’s. This may make it harder to eat a diet that is rich in fibre - for example fruit, vegetables and whole grains – which help form soft, bulky stools and aid bowel function.
Exercise may also play role in efficient bowel function. But people with Parkinson’s may find it difficult to remain active and this leads to reduced stimulation of the bowel and the intestines become sluggish.
Diarrhoea may occur as a side effect of certain Parkinson’s medications. If you experience diarrhoea it is important to talk to your doctor as they may be able to alter your medication regime in order to overcome this.
Constipation is particularly common with this condition, possibly affecting up to 65% of those with it. Tremors and the subsequent fear of spillages can mean some people unintentionally reduce their fluid intake. But this can make stools hard and more difficult to pass. When stools remain unpassed for a long time, they become harder as the body absorbs more water from them. If stools build up in the rectum they can become impacted and block the rectum. They may also overflow as lumps of stool or watery mucus.
Delayed gastric emptying, or gastroparesis, is also common in Parkinson's, leading to a variety of symptoms such as feeling full quickly when eating, abnormal discomfort from bloating, nausea, vomiting, weight loss and malnutrition. It can also interfere with how effectively medications work.
Also, if a person is anxious about their bowel movements, possibly because of the effect of certain medications, such as levodopa and anticholinergics, they might find it difficult to relax their bodies and muscles effectively to allow a stool to be passed, and constipation ensues. Such anxiety can also reduce the effectiveness of Parkinson’s medications. Parkinson’s itself can impair automatic relaxation of the pelvic floor which is necessary to straighten the last part of the intestine and allow the faeces to pass. This happens particularly during ‘off’ periods.
Background: the stomach, Parkinson's and levodopa
Levodopa is not absorbed from the stomach, but the stomach plays an important role in controlling how levodopa reaches its absorptive sites in the small bowel. Some medicines, including dopamine agonists and anticholinergics, can also delay gastric emptying, as can severe stomach acidity, although over-treatment of this problem can also prevent dissolution of levodopa tablets, leading to incomplete absorption.
Moreover, gastric emptying can be delayed by Parkinson’s itself or by constipation caused by the colon-gastric reflex. Levodopa tablets may remain in the stomach for a long time, leading to delayed absorption in the small intestine and a delayed response to the treatment.
An enzyme called dopa-decarboxylase that is present in the stomach lining can convert levodopa trapped in the stomach into dopamine, making it unavailable to the central nervous system. Furthermore, dopamine formed in the stomach may stimulate gastric dopamine receptors, leading to stomach relaxation and reduced gastric motility, and this can worsen the problem.
Liquid levodopa may improve motor fluctuations by ensuring better absorption. Levodopa methyl ester and dispersible formulations are absorbed more quickly than standard preparations, especially when taken after meals. Subcutaneous infusion of the dopamine agonist apomorphine is effective in controlling motor fluctuations by bypassing the gastrointestinal tract.
People with Parkinson’s should try to eat small meals and take medicines when fasting. Dopaminergic D2 receptor antagonists, such as domperidone, improve gastric emptying in Parkinson’s. Similar effects can be induced by the 5-HT4 receptor agonists mosapride, presumably by increasing local release of the neurotransmitter acetylcholine.
Treatment and management of bowel problems
The first step in dealing with bowel disorders is to identify the problem and seek advice. Your doctor will probably review your medication to see if this is a contributory factor. Whilst it is usually possible to control any difficulties with diet, fluid intake and exercise, your doctor or Parkinson’s Disease Nurse Specialist will be able to advise further, and may, for example, prescribe laxatives in severe cases of constipation.
The following healthcare professionals can also advise on aspects of bowel care:
- a dietician will be able to advise on diet and fluid
- a physiotherapist may be able to help with advice and abdominal exercises which will help in passing stools
- a speech and language therapist can help with swallowing problems. They may be able to advise on ways of relaxing your throat, and give guidance on posture and exercises to help overcome any difficulties you have
- an occupational therapist may also be able to suggest practical ways to overcome any difficulties you have with eating and drinking.
Very often constipation can be controlled through diet, fluid intake and exercise but if this does not work, then laxatives may be helpful in managing the problem. But they should be used with caution and only under the direction of a doctor, because some may cause permanent damage to the bowel.
There are several types available including fibre-based laxatives and ‘osmotic’ laxatives which draw water into the bowel and retain it there to soften and bulk up stools, so making them easier to pass. One such example is Movicol®, a solution which delivers water to the large intestine, increasing the bulk of the stool. This triggers the muscles of the bowel to contract and produce a bowel movement. The water in Movicol solution is not absorbed into the body so it can also soften and lubricate the stools to promote comfortable bowel movements.
It is crucial that, at first, your doctor checks regularly that the dose of any laxative is right for you. Once this is achieved, you will probably be able to maintain the right balance on a day-to-day basis, taking account of what you do and how you feel from one day to another.
When oral laxatives have not been successful, enemas (a liquid inserted into the rectum through a tube, usually with the aim of triggering bowel movement and the passage of stools) can be very effective in improving severe constipation.
How can I help myself?
It is easy to become obsessed with bowel activity, but it is not necessary to have a bowel movement every day – it can be quite normal for some people to empty their bowels only three or four times a week. What is important, is that passing stools is not painful nor causes unnecessary strain. Focus on what is normal and healthy for you and remember that bowel activity is affected by food and exercise, so will vary according to what you are eating and doing.
Remember that learning to manage your bowels will take time and patience, so don’t expect to solve problems overnight. It may take a few weeks to adjust diet etc, so don’t give up too quickly. There are also plenty of ways you can help yourself:
A healthy lifestyle will enhance bowel efficiency and increased fibre and fluid are key factors. However, too much bulk from fibre can increase constipation so the balance needs to be right – your doctor should be able to refer you to a dietician for help with this.
Any increase in fibre should be gradual to avoid flatulence (wind) or bloating. There are many ways in which you can increase fibre in your diet, including:
- eating wholegrain cereals and bread
- eating fruits and vegetables - fresh, frozen, raw and cooked. If you have trouble chewing and swallowing, look for soluble varieties and fruit juice drinks. Prunes are particularly good, natural laxatives
- drinking plenty of fluids, which will help the digestion of fibres, so try to drink approximately eight cups (8oz/225ml) throughout the day, including water, tea, coffee, milk and juice. Carbonated drinks may cause bloating and alcohol can act as a diuretic, which can make constipation worse, so it may be best to drink these only in small quantities
- having a warm drink and something to eat as soon as you get up in the morning, as both stimulate bowel activity.
But if you feel unable to increase your fluid and fibre intake because of eating and drinking difficulties, you could try these practical suggestions:
- use insulated cups for warm drinks, if necessary with a lid and spout to avoid spillages. Weighted cups are also useful if you have a tremor
- if large meals are too daunting because eating is slow or you have difficulty chewing, try several smaller meals a day instead
- place a rubber mat under your plate to prevent it slipping
- try special cutlery to make eating easier, such as a combined knife/fork; a 'rocking' knife that allows cutting one handed. An occupational therapist can advise further.
However, you may find increasing your natural fibre and fluid intake does not relieve your bowel difficulties. If constipation is the problem, then medications such as bulk formers or stool softeners may help. There are several products on the market so ask your doctor or a dietician for advice.
Physical exercise may help in relieving or preventing bowel problems. Exercise can stimulate the bowel muscles and improve your ability to pass stools. It can also strengthen the pelvic floor muscles, which helps reduce constipation.
If you find exercise difficult, a physiotherapist can advise further. Parkinson Italia also suggest very useful exercises Gymnastics for patients with Parkinson's Diseas - see Parkinson Italia website.
Going to the toilet
It is important to try to relax when going to the toilet. Try not to rush and make sure that you do not become too preoccupied with your bowels. If your feet do not touch the floor when sitting on the toilet, then try putting a small stool under them, so that they are resting on something and you are more comfortable. Don’t sit on the toilet for more than about five minutes and don’t strain hard to pass a stool. Listen to your body, leave it for a while and try again later. If possible, try to pass stools when you are ‘on’.
It is important to be proactive in initiating a dialogue with healthcare professionals in order to best manage your symptoms. At one time, the non-motor symptoms, such as constipation, received far less attention than the motor symptoms, but there is now a growing awareness of this aspect of the disease. You can help manage your constipation by recognising that assistance is needed and talking to the healthcare professionals that can provide such help.
Unfortunately, failure by healthcare professionals to recognise those most at risk of developing bowel difficulties used to be a major stumbling block in managing the condition. This, coupled with the patient’s embarrassment in approaching the subject, meant that any problems often went undiagnosed or untreated for some time. Fortunately, most of those at risk are now identified early and preventative measures can be put in place to reduce the risk of severe complications. A proactive approach to treatment really can reduce the impact that bowel disorders have for most people.
- Eat frequent, small meals throughout the day
- Avoid foods with a high fat content, such as fatty meats, butter and cream
- Avoid foods that increase stomach acidity
- Consume fibre to improve colon motility or movement
- High levels of protein are only problematic when associated with fat
- Carbohydrates may be preferred to protein, but large quantities delay gastric emptying
- Caffeine can be helpful; alcohol should be consumed with care because of hypotension
- Levodopa should preferably be taken on an empty stomach, but you should always follow your doctor's instructions
Our thanks to Parkinson's UK for permission to use the following source(s) in compiling this information: