Haemorrhoids are swollen veins (haemorrhoidal veins) in the lining of the anus. While there is no firm evidence indicating what the cause is, they are thought to be associated with an increase in pressure in the abdomen due, for example, to straining to pass hard faeces or heavy physical work. It is probable that there is an inherited component in some cases of haemorrhoids, particularly in those with a congenital (in-born) weakness of the anal veins, making them susceptible to swelling under pressure.
Haemorrhoids are classified according to their site, size and symptoms. They are termed external when they occur close to and around the anal opening and internal when they occur higher in the anal canal.
Are further classified as 1st degree to 4th degree according to symptoms and size:
- 1st degree: these are small and do not prolapse (displace such that they visibly protrude out of the anus). They are often associated with no symptoms at all. When symptoms occur, bleeding following a bowel movement is the most common complaint.
- 2nd degree: are slightly larger such that they often prolapse with a bowel movement, but spontaneously retract (reduce) back inside the anal canal. Symptoms are bleeding, mucous discharge and irritation.
- 3rd degree: are associated with essentially the same symptoms as 2nd degree haemorrhoids, except that when they prolapse, they require manual reduction.
- 4th degree: are of such a size that they are permanently prolapsed. Are also associated with bleeding, mucous discharge and discomfort.
3rd and 4th degree haemorrhoids may become strangulated or thrombosed (blocked with a blood clot), causing extreme pain. Otherwise, contrary to popular belief, pain is rarely a significant complaint with internal haemorrhoids, because haemorrhoidal tissue high in the anal canal does not contain any sensory (pain) fibres.
The most common complaint is irritation and moisture around the anus. Like internal haemorrhoids, they can become thrombosed and painful, but do not usually bleed. External haemorrhoidal tissue has sensory fibres and are, therefore, generally more sensitive than internal haemorrhoids. Most “external haemorrhoids” are not true haemorrhoids (swollen veins) at all, but just flaps of skin (“skin tags”).
It has been claimed that “almost everyone” has haemorrhoids at some stage in life. At any one time, approximately 37% of the population has haemorrhoids, with equal distribution between men and women. They are particularly common in Western, industrialized countries, probably due, at least in part, to the low fibre diets of the people in these countries. Approximately 40% of pregnant women develop haemorrhoids, either during the pregnancy of following child birth.
Diagnosis is made on the basis of a clinical history consistent with the above described symptoms. Examination of the lower rectum and anal canal should include palpation (touching) and viewing (proctoscopy or sigmoidoscopy) to confirm the diagnosis.
As rectal bleeding tends to be associated with other more serious conditions such as cancers, it is important that all patients who present with bleeding are appropriately examined to identify the cause. Proctoscopy is essential for internal haemorrhoids in particular, as they are not visible externally (unless they have become prolapsed).
Treatment and management
Treatment depends upon the classification of haemorrhoids as internal or external.