First off, they can experience hemorrhoids, or swollen veins in the rectum. These can be very painful, and might even require surgery to fix. Hemorrhoids can also sometimes burst and bleed, which requires immediate medical attention. However, this happens rarely, and usually isn’t a cause for concern so long as the patient seeks treatment before it happens.
Another possible situation is when hard stool causes tears in the tissues of the anus. These are known as anal fissures and usually go away over time. Though, if someone has chronic constipation, these fissures can eventually get deeper or even fail to heal. There are even cases where these fissures can extend to the muscles controlling the anus. When this happens, medical treatment is necessary to fix the problem.
Constipation can also lead to a condition known as diverticulitis. This refers to inflammation of the abnormal pockets (called diverticula) that develop in a person’s colon. In some cases, trapped stool can be responsible for this inflammation. If this is the cause of diverticulitis, then it’s important to get it treated as soon as possible since it can lead to systemic infection.