What is extreme constipation?

MedicineNet states that extreme cases of constipation are often associated with fecal impaction, which causes stool to harden to the point that no waste may pass. Some acute cases of constipation can be extremely painful, and immediate medical help is recommended.

Fecal impaction is often the result of a long or recurring case of constipation, which causes the formation of a dry lump of stool blocking the rectum, according to Medline Plus. The condition is especially common with people who use laxatives for long periods of time to treat constipation and then stop use. A hardened stool blocking the rectum is usually removed by hand or with an enema.