Chronic constipation is a disorder that is characterized by a difficulty evacuating that lasts for months or years, while anal incontinence (or the involuntary loss of stools) occurs when the muscles of the anal sphincters lose the ability to contract and therefore to remain closed.
In order to diagnose and treat these two disorders, which significantly compromise the daily lives of those who suffer from them, in Humanitas it is possible to use rectal manometry, a method of diagnosis but also of rehabilitation. To better understand what is it about and how it works, we talk with Professor Enrico Corazziari and Dr. Elisa Carlani, specialists in Gastroenterology in Humanitas, whose department is headed by Professor Alberto Malesci.
Chronic constipation: different causes, different therapy
There are two main mechanisms behind chronic constipation: a slowdown in the time it takes for fecal content to pass through a less contracting intestine, and a defect in the ability to coordinate the force exerted with the muscles of the abdomen with the release of the muscles at the anus level, a defect that ultimately hinders the expulsion of feces.
First of all, it is important to understand what form of constipation you suffer from because the therapy is different in both cases. If the problem lies in a slowed time of passage of the fecal contents, pharmacological therapy (laxatives, enterokinetics or secretagogues to accelerate the transit) and dietary measures will be used, while in the second case the physical rehabilitation of the muscles in charge of defecation is necessary.
The study of the intestinal transit time
Slow transit constipation typically manifests itself with a reduced frequency evacuating and a weakening or absence of the urge to evacuate. It is diagnosed by studying the intestinal transit time: the patient ingests 20-40 small grains of inert material visible by X-rays. After 4 days from ingestion, an X-ray of the abdomen is performed in order to calculate the time of passage of the fecal content through the intestine and identify where the slowing occurs.
Constipation due to poor coordination
Under normal conditions, the last part of the intestine (the anus) does not allow the accidental release of feces because it has two normally closed muscle rings (sphincters). When we feel the stimulus to visit the bathroom, the expulsion of the feces occurs by coordinating the contraction of the abdominal muscles, which cause an increase in pressure that forcefully pushes the contents of the intestine to the exit, with the release of the sphincters of the anus that no longer resist the transit of feces. Many people lose the ability to coordinate the contraction of the abdominal muscles with the release of the anal sphincters and therefore suffer from a form of constipation that is distinguished by the difficulty of expelling the feces. Characteristic symptoms occur during the act of defecation and may include: an effort followed by little or no emission of feces, a sense of anal blockage and the use of the fingers to facilitate the passage of feces.
In contrast, involuntary fecal loss (anal incontinence) occurs as a result of the loss of the sphincter muscles’ ability to contract and thus remain closed, which is a relatively frequent disorder with advancing age.
Anorectic manometry for the diagnosis of expulsive constipation and anal incontinence
The diagnosis and treatment of these defects of muscle contraction is carried out with an easy and risk-free examination: anorectic manometry.
The method consists in measuring the strength, contraction and release times of the anal sphincters by introducing a plastic tube a few millimeters in size into the anus with a latex balloon placed at the end, while the patient lies on the bed. This 10-15 minute examination allows for the diagnosis of expulsive constipation or incontinence.
Rehabilitation by biofeedback with anorectic manometry
Like all muscles, anal muscles can be rehabilitated to improve their ability to inhibit or contract in a time coordinated with the stimulus to evacuate.
The technique of anorectic manometry is also used to rehabilitate muscle coordination of both expulsive constipation and anal incontinence, and allows the patient to see the representation of contractions and releases of anal sphincters on a monitor. In this way, the patient learns to contract, release or modulate his muscles in the right time, under the guidance of an operator. In the case of expulsive constipation, the patient learns to coordinate the abdominal muscles with the anal sphincter muscles by looking directly on the monitor at the phases of contraction and relaxation of their muscles. In the case of anal incontinence, the patient exercises contracting the muscles of the anus guided by a rehabilitator and observing the effects of the exercise directly on the monitor.
The rehabilitation of the anal muscles usually takes place after a cycle of outpatient treatments to be performed in the presence of a rehabilitator and with exercises to be carried out at home.
Biofeedback with anorectic manometry has been shown to provide significant benefit in 70% of cases of both expulsive constipation and anal incontinence (Bharucha AE, Rao SSC, Bersma RF et al Anorectal disorders in Rome IV. Functional Gastrointestinal Disorders 4th Edition. Drossman DA, Chang L, Chey WD et al Eds. Rome Foundation Publisher, Raleigh, NC. Pages 1179-1236, 2016).
