The oldest convincing descriptions of haemorrhoids date back to 1500 BC in Mesopotamia, and Biblical references to plagues of ‘emerods’ [arch. haemorrhoids] cement their position as a proctological condition of the ages. Ancient treatment for haemorrhoids makes for equally interesting reading, and has varied between hot iron cauterisation, leech application, and the Hippocratic suggestion of “transfixing them with a needle and tying them with a very thick and large woollen thread”.
A widely accepted theory in the pathogenesis of internal haemorrhoids is that fragmentation of Treitz’s muscle leads to anal cushion descent. Anal cushions are thus no longer restrained from engorging excessively with blood, and the prolapsed cushion has an impaired venous return. This results in dilation and stasis of the internal haemorrhoidal plexus, and transudation of fluid. Further congestion of these vascular cushions leads to pain and anal spasm that prevent reduction, leading to a vicious cycle of prolapse and progressive swelling of the vascular cushions.
Fragmentation of Treitz’s muscle may be caused by shearing forces incurred during prolonged and repeated downward stress, often observed with straining at defaecation. Accordingly, risk factors for haemorrhoids are those associated with excessive straining and/or increased intra-abdominal pressure (i.e., constipation, hard stools, pregnancy). Human civilisation has adopted the sitting rather than squatting position during defaecation, which does not permit the straightening of the anorectal angle and thus necessitates greater effort and exaggerated intraabdominal pressure for passage of stool. To this end, time spent during defaecation has been linked to the development of haemorrhoids, with one study identifying that patients with proctoscopically confirmed haemorrhoids spent more time during defaecation and reading on the toilet than controls. This has led to the recommendation to limit time spent defaecating to no more than 5 minutes per day.
Ann Coloproctol 2020;36(3):133-147 https://doi.org/10.3393/ac.2020.05.04