Types of Constipation
Functional, or primary, constipation can be divided into three types: slow-transit constipation, pelvic floor dysfunction, and normal-transit constipation (Jamshed 2011).
Slow-transit constipation. In this type of constipation, motility (gut movement) is decreased, and transit time (the time it takes for food to pass from the beginning to the end of the digestive tract) is increased (Rao 2014; Jamshed 2011). Slow-transit constipation symptoms may include infrequent bowel movements, bloating, and abdominal discomfort (Jamshed 2011; Leung, Riutta 2011).
Outlet constipation, or pelvic-floor dysfunction. In this type of constipation, discoordination of the musculature of the pelvic floor results in either inappropriate anal contraction, a failure of anal relaxation, or inefficient propulsion of stool. Outlet constipation symptoms often include straining to pass stool, soft stools that do not pass easily, and discomfort in the rectum. This type of constipation is less likely to respond to traditional medical therapies (Jamshed 2011; Leung, Riutta 2011).
Normal-transit constipation. Some individuals with primary chronic constipation have neither slow transit nor an outlet problem, but rather a condition known as normal-transit constipation. Those with normal-transit constipation may even have daily bowel movements, yet describe themselves as constipated due to a persistent sense of difficult evacuation, with hard stools and abdominal bloating and discomfort. This type of constipation may be associated with elevated psychosocial distress. Normal-transit constipation is a very common type of chronic constipation (Andromanakos 2015; Jamshed 2011).
Secondary constipation can be caused by metabolic disturbances like hypothyroidism; neurological problems like Parkinson’s disease, multiple sclerosis, and spinal cord injuries; celiac disease; and diseases of the large intestine such as colon cancer (Rao 2014; Jamshed 2011; Leung, Riutta 2011; Volta 2011) and diverticular disease (Strate 2012; Boynton 2013). Several medications can cause secondary constipation as well (see Causes and Risk Factors).
Individuals with chronic constipation often have other digestive problems that involve disordered motility, such as indigestion, gastroesophageal reflux disease, diverticular disease, and irritable bowel syndrome (IBS) (Arora 2012; Rao 2014; Vakil 2014). In fact, the overlapping symptoms of primary constipation and constipation-predominant irritable bowel syndrome (IBS-C) make them difficult to distinguish, leading some researchers to suggest they may be the same condition (Basilisco 2013; Lee 2014; Suares 2011a). Hemorrhoids are associated with constipation as well (Ehrlich 2013).