2.1.1
Haemorrhoids (piles) occur when the vascular anal cushions become enlarged. They may cause bleeding, itching or discomfort (grade 1) and, if large, may prolapse out of the rectum. Haemorrhoids that prolapse may reduce (return into the anal canal) spontaneously after defaecation (grade 2); they may need to be reduced digitally (grade 3); or they may not be reducible, remaining continually prolapsed (grade 4).