To understand the causes of faecal incontinence it is important to appreciate the mechanisms which prevent the leakage of material from the anus. As infants we are faecally incontinent and we generally learn to control our bowel actions during ‘potty training’. This learning process involves getting to know what it feels like when faecal material accumulates in the rectum and subconsciously keeping the anus shut by contraction of surrounding muscles until it is convenient to empty the bowels. Hence, the essential elements of faecal continency are: |
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Brain control over bowel action developed by learning |
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The nerve connections between the brain and the
muscles in the pelvic floor that relay sensations from the
rectum and anus to the brain and others that convey
instructions to the muscles which control the opening and
shutting of the anus. |
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The muscles of the pelvic floor which pass around the
rectum and anus. |
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| Faecal incontinence can occur when one or more of these elements are defective. Some common examples are: |
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Damage to the muscles of the pelvic floor, often sustained
during childbirth. |
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Loss of brain control as in dementia or stroke |
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Damage to the nerve connections between the rectum
and anus and the brain, as may arise from spinal injury
or multiple sclerosis. Nerve damage can also result from
diabetes. |
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Weakening of the muscles around the anus. This can
occur with ageing, but can also occur in younger people,
especially women, for no apparent reason. |
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| In addition, disturbances occurring within, or damage to, the bowel or rectum can cause faecal incontinence. For example, the sudden onset of diarrhoea occurring when it is not possible to get to the lavatory may result in faecal incontinence. |
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| Constipation
Long standing constipation can cause faecal incontinence in two ways. Firstly, straining to empty the bowels may damage the pelvic floor muscles and the passage of hard stools may injure the anus, giving rise to tears (fissures) which can be extremely painful. Secondly, when the bowels are not emptied regularly, water is reabsorbed from the faeces by the rectum which causes them to become extremely hard. The faeces get stuck in the rectum and cannot be expelled by the muscle contractions which usually empty the bowel during defecation. This condition is known as faecal impaction. As more faecal material build up behind the impacted faeces, irritation to the lining of the rectum occurs and the faecal material is broken down by bacteria into a foul smelling liquid. This seeps around the impacted faeces and leaks from the anus.
Anal fistula
An anal fistula is an abnormal channel that forms from within the anal canal to the outside through which faecal material can leak. It may be caused by injury or infection and can be treated surgically with excellent results.
Lack of Mobility
Faecal incontinence can arise in the absence of any of the above causes simply because the person is unable to get to the lavatory in time. This may be due to physical conditions that limit mobility such as arthritis, Parkinsonism and paralysis. |
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Dr Alan Riley's
Guide to Faecal
Incontinence |
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In this section: |
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Other Articles by Dr Riley
Medical Consultant: |
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Any sudden change
in bowel habit should
prompt you to seek advice
from your doctor.
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These guides are also available
as booklets FREE from Milton.
Call us FREE to order one |
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0800 0185108 |
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You can E-mail us if you wish
to order FREE copies of these
booklets or if you need advice |
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It is important not
to let embarrassment
or fear stop you
seeking medical advice
from your doctor.
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