Characteristics of Chronic Constipation

 

Constipation is difficult to define; there is no one exact definition of "normal" that can be applied to stool frequency or consistency. Moreover, no single definition applies to all persons. Still, there are some guidelines that can be used to determine if a person has chronic constipation.

Chronic, persistent, or difficult to manage constipation is a symptom, not a disease. Sometimes it may result from a serious medical illness, such as hypothyroidism or diabetes; a structural abnormality of the colon, like a colonic stricture (narrowing); or by other diseases of the colon or rectum. Less commonly, it may result from a disorder of the neuromuscular control of the process of defecation, or an abnormality that affects the pelvic musculature, spinal nerves, and the muscles of the anorectal region.

Although there are many possible causes, most cases of chronic constipation have none that are identifiable. Such constipation may be said to be "idiopathic" or "functional," which means that the primary abnormality is an alteration in the way the body works (physiological function) – rather than a metabolic or structural abnormality. While the primary cause is unknown, functional constipation can be worsened by one or more of the following: poor general health and inactivity, use of certain medications, laxative abuse, depression or psychological distress, low fiber diet, or certain medical diseases. Often, constipation may have several contributing factors.

Constipation can be broadly divided into 3 classes based upon the underlying physiologic cause: 

1. Normal-transit constipation
2. Slow-transit constipation
3. Pelvic floor dysfunction

In normal-transit constipation, colonic motility (the way muscles contract and relax to move contents through the colon) is unaltered; stool moves through the colon at a normal rate. However, patients with normal-transit may experience more difficulties in stool passage, for example due to harder stools. In contrast, in slow-transit constipation colonic motility is decreased and bowel movements are infrequent, leading to more severe symptoms of straining and harder stools.

Persons with pelvic floor dysfunction have a functional outlet obstruction, a defect in the coordination necessary for stool evacuation. This usually occurs due to the failure of the pelvic floor muscles (including the anal sphincter) to relax appropriately during evacuation efforts, thus making stool passage much more difficult regardless of whether stool transit in the colon is normal or delayed. In some cases, individuals contract their pelvic muscles instead of relaxing them (pelvic floor dyssynergia).

The majority of persons seen by a doctor have normal-transit constipation, followed by pelvic floor dysfunction, and slow-transit constipation. Some patients can have a combination of slow transit and pelvic floor dysfunction (functional outlet obstruction).

The onset and duration of the constipation are important factors to consider. Most persons who see a doctor have had longstanding constipation. A sudden (acute) onset of symptoms should prompt a doctor visit. This is especially important if constipation is accompanied by pain, bleeding, or a recent change in bowel habit.

The range of "normal" bowel habit is very wide. Not everybody has a bowel movement every day. "Normal" frequency generally ranges from three bowel movements per day to three per week (although some persons are fine with less) Normal stools are soft and formed (not hard or lumpy), and passed without urgency or straining. A sudden change from a person's normal pattern should be reported to a doctor.

The Rome Foundation is an international organization that classifies the functional gastrointestinal disorders and by using the best evidence establishes criteria for their diagnosis.

Functional Constipation

The Rome Foundation defines functional constipation as persistent symptoms of difficult, infrequent, or seemingly incomplete defecation. Doctors diagnose functional constipation by identifying certain accompanying symptoms and ruling out organic disease, especially colon (large intestine) obstruction. The Rome diagnostic criteria are a useful guide for diagnosing functional constipation.

Functional constipation is the presence of two or more of the following:

1. Straining during at least 25% of bowel movements,
2. Lumpy or hard stools in at least 25% of bowel movements,
3. Sensation of incomplete evacuation for at least 25% of bowel movements,
4. Sensation of anorectal obstruction or blockage for 25% of bowel movements,
5. Manual maneuvers to facilitate at least 25% of bowel movements and/or,
6. Infrequent (fewer than 3) bowel movements per week.

While the Rome definition attempts to quantitate these symptoms, doctors must ask questions about frequency and severity, in order to determine how important they are.

Loose stools are normally not present in chronic constipation unless laxatives are used. Constipation is common in irritable bowel syndrome (IBS) but in that condition there is abdominal pain and the bowel habit is changeable with normal and diarrheal defecations occurring from time to time. It is important to exclude other medical disorders.

Pelvic Floor Dysfunction (Dyssynergia)

Defecatory disorders, such as pelvic floor dyssynergia, are thought to contribute to about 25% of occurrences of chronic constipation.(2) Pelvic floor dyssynergia (also referred to as anismus) is a functional disorder marked by the failure of pelvic floor muscles to relax, or a paradoxical contraction of the pelvic floor muscles, with defecation. The pelvic floor is composed of a group of muscles that span the underlying surface of the bony pelvis, which function to allow voluntary urination and defecation. "Paradoxical contraction" refers to an abnormal increase of pelvic floor muscle activity with defecation, rather than the normal decrease in muscle activity that is necessary in order to have a normal bowel movement. This condition is uncommon. Its diagnosis requires specialized investigations that will require referral to a medical center.

Referral is necessary only if the constipation fails to respond to the usual treatment measures. Because pelvic floor muscles can be controlled voluntarily, their function can be improved through various learning procedures – such as biofeedback.

Talking to Your Doctor about Constipation

To identify symptoms and exclude other causes of constipation, the doctor will begin by obtaining a complete medical history and performing a physical examination, including a rectal examination. The doctor will also check for "alarm" symptoms, such as blood in the stool, anemia, weight loss, or fever. These cannot be explained by functional constipation.

When talking to a doctor it is helpful to be prepared to describe the nature of the symptoms, when symptoms started and how long they have persisted, past medical procedures, and any medications being taken. The more information the doctor has, the better he or she will be able to exclude structural disease with appropriate tests and design an appropriate treatment plan. Therefore, it is important to talk freely about personal bowel habits and be specific about the stool form or consistency. Since many of us find this topic embarrassing, it often helps to write down symptoms and other factors ahead of time. Click here to open a printable worksheet to help you.

The doctor will look for any diet or lifestyle factors that could contribute to constipation. These might include:

• Too little fiber in the diet
• Certain medications
• Poor bowel habits or inadequate access to toilet facilities

Depending on the results of the medical history and physical examination, a doctor may recommend a variety of tests help rule out structural or organic causes. Tests might include:

• Blood tests to identify anemia, a high white cell count, or a metabolic disorder (e.g., hypothyroidism, if indicated).
• Referral to a specialist for barium enema studies (radiologist) or endoscopy – sigmoidoscopy or colonoscopy – (physician).
  • A barium enema consists of the injection of radiation-dense barium through the anus into the colon. The doctor may then see the colon outline on x-ray films. The amount of radiation involved is usually not worrisome, but women who are pregnant or unsure whether they are pregnant should tell their physician, as this test should not be done in such cases.
  • Endoscopy involves the use of a long, flexible instrument to look inside the gastrointestinal system without the need for surgery. Sigmoidoscopy looks at the sigmoid colon, part of the large intestine, or bowel, where feces are stored before defecation. Colonoscopy is a similar procedure that allows the doctor to view the entire colon, or large bowel. The latter is more costly and requires sedation.

Chronic Constipation is an Important Personal Issue

Perhaps a quarter of people are constipated from time to time, but many fewer have symptoms that fail to respond to simple measures and require medical attention. Among those with recent, severe constipation, and with chronic constipation, some have a structural or metabolic cause that will require certain testing.

But, regardless of the underlying cause chronic constipation impairs quality of life and productivity in many of those with the condition, and places high demands on healthcare resources.

In two surveys, one of 311 practicing primary care physicians (PCPs) recruited from an American Medical Association database[3], and one of over 550 patients with chronic constipation recruited by screening over 24,000 members of a U.S. consumer panel[4], both reported constipation to be bothersome and to negatively impact quality of life. Between 58% and 80% of patients reported straining, passing hard stools, and feeling incompletely evacuated after passing stool, to be their most frequent symptoms.

Patients clearly indicated constipation negatively impacted work and reduced productivity. A majority of patients reported constipation impaired daily activity as well. Thus, many of those with constipation can be greatly troubled and have an impaired quality of life.

Summary

Constipation is common, and for those who seek medical care it is not a trivial symptom. Chronic constipation significantly affects healthcare resource use, healthcare cost, work and social activity, and individual quality of life.

When a person has constipation that starts abruptly, or becomes chronic, persistent, and unmanageable it is important that he or she discuss it with a physician. Remember, constipation is a symptom. Working with a physician to accurately determine its cause is the first step in devising the most effective treatment plan that best meets individual needs and circumstances.