History Taking and Diagnosis
Altered Bowel Habit
Altered bowel habit is very common and can be acute or chronic.
Causes
There are various definitions of
constipation, but these are not very useful in clinical situations.
What is important is an alteration in bowel habit. Has there been a change? What kind of change? What is the frequency and consistency of the stool?
Causes
- Dietary / drug induced
- Opiates and analgesics are particularly common, but there are loads more!
- Calcium intake is also very important.
- Cationic compounds
- Functional – e.g. IBS
- Mechanical obstruction – e.g. strictures
- Metabolic /systemic disease – e.g. thyroid disease – particularly common is under active thyroid in older age.
- Local anorectal dysmotility – Anismus
- Neurological disorders
Prevelance of functional constipation
- This is a condition where there is no underlying pathological condition
- It affects 3% of the population
- Often these people won’t go to GP, they will just go to chemist and get laxatives
Disease associated with chronic constipation
- Often constipation is a consequence of lack of mobility, rather than a direct consequence of the disease itself. This is particularly common in neurological conditions, e.g. parkinsons
- Systemic diseases such as thyroidism.
- Ano-rectal dysmotility (aka anismus) – this is common in younger people, particularly women. They will present at the stage where they are already taking lots oflaxatives and controlling their diet (e.g. taking lots offluids and eating lots of fibre). It is caused by an in-co-ordination of muscles actions. When they try to defacate, instead of the rectal angle decreasing and straightening up, instead the angle will increase, and thus making it virtually impossible to defacate.
Taking the History
- Determine onset, evolution and related symptoms
- If the patient seems vague, consider a diary of symptoms
- Does the patient’s definition of constipation match your definition? Ask the patient exactly what they mean, and exactly what their symptoms are.
- If it is long standing – why have they presented now.
- Are there any co-factors? Psychological, stress, dietary, environmental.
Examination
- Signs of systemic disease? E.g. in hypothyroidism – look at facial features – coarsening official features, weight gain.
- Any abdominal mass, or faecal loading?
- Anal disease? Haemorrhoids or fissure? A fissure can be caused by something hard in the faeces – it causes damage to the colonic wall. Often it will just cause acute constipation
- You should always do a rectal exam!
- Neuromuscular disease
Investigations
- Blood tests – TFT’s and calcium
- Plain abdo X-ray
- Sigmoidoscopy – this excludes a mechanical cause. You don’t need to do a full colonoscopy.
- Do a colonic transit study. Get them to eat markers on different days, and then a weekor so later, do an x-ray. You can see how far round the markers have got! Normal transit should be less than 5 days.
Hirschprung’s disease
Common in teenagers / children (neonates). It is caused by neural disease, and prevents peristalsis of the colon. Sometimes the section of colon is very small, and you can remove it. This disease is often not picked up quickly if the section of bowel affected is small – you might just think they have a bit of
constipation.
Management
- High fibre diet, increase fluid intake, and avoid constipating drugs
- Identify and treat metabolic or structural diseases.
- Consider some patients for psychological help.
Laxatives
There are loads of these on the market!!
The most common are the bulk forming. They basically perform the same role as dietary fibre. They attract fluid and form a nice bulk that can be easily passed through the colon.
- Osmotic laxatives – these are much more aggressive at keeping fluid in the bowel. The active ingredient in many of these is movicol. Often these are dissacharides that have no enzyme in the human to break them down. They are broken down by bacteria into osmotic compounds that help hold fluid in the colon.
- Stimulants – these should be avoided if at all possible. Senna is a common one. It is an anthraquinones. They can damage young people’s colon, but generally in adults there is no evidence they cause any damage.
-
$(function(){
var pertama = $('#herb-dict .herblist li:first-child').attr('class');
$('#herb-dict .herblist li.'+pertama).show();
$('#herb-dict .alphlist li#'+pertama+' a').addClass('active');
$('#herb-dict .alphlist li a').click(function(){
var target = $(this).attr('rel')
$('#herb-dict .herblist li').hide();
$('#herb-dict .herblist li.'+target).show();
$('#herb-dict .alphlist li a').removeClass('active');
$(this).addClass('active');
});
});
