HAEMORRHOIDS

HAEMORRHOIDS

Haemorrhoids are symptomatic enlargements of the internal haemorrhoidal venous plexus (Greek: haima = blood, rhoos flowing; synonym: piles, Latin: pila = a ball). Internal haemor rhoids characteristically lie in the 3, 7 and 11 o’clock positions (with the patient in the lithotomy position). Secondary haem orrhoids may develop between the primary positions. External haemorrhoids relate to venous channels of the inferior haem orrhoidal plexus deep in the skin surrounding the anal verge and are frequently confused with anal skin tags that are not true haemorrhoids. The internal haemorrhoidal plexus constitutes the sub mucosal component of the anal cushions that are important in sealing the anal canal. Man’s upright postur e, the absence of valves in the portal venous system and raised abdominal pressure due to pregnancy or particularly thr ough straining during defecation contribute to venous plexus engorgement and development of varicosities. Shearing forces lead to mucosal trauma (bleeding) and caudal displacement of the anal cushions (prolapse). This in turn leads to impaired venous drainage, progressive venous engorgement, local stasis and transudation of fluid (pruritus). With time, fragmentation of the supporting structures (a normal consequence of ageing but perhaps accelerated in those with haemorrhoids) leads to loss of elasticity of the cushions such that they no longer retract following defecation.