Constipation

Constipation, costiveness, or irregularity is a condition of the digestive system in which a person (or animal) experiences hard feces that is difficult to expel. This usually happens because the colon absorbs too much water from the food. If the food moves through the gastro-intestinal tract too slowly, the colon may absorb too much water, resulting in feces that are dry and hard. Defecation may be extremely painful, and in severe cases (fecal impaction) lead to symptoms of bowel obstruction. The term obstipation is used for severe constipation that prevents passage of both stools and gas. Causes of constipation may be dietary, hormonal, anatomical, a side effect of medications (e.g., some opiates), or an illness or disorder. Treatments consist of changes in dietary and exercise habits, the use of laxatives, and other medical interventions depending on the underlying cause.

Definition

Types 1 and 2 on the Bristol Stool Chart indicate constipationIn common constipation, the stool is hard, difficult, and painful to pass. Usually, there is an infrequent urge to void. Straining to pass stool may cause hemorrhoids. In later stages of constipation, the abdomen may become distended and diffusely tender and cramp, occasionally with enhanced bowel sounds.

The definition of constipation includes the following:

• infrequent bowel movements (typically three times or fewer per week)
• difficulty during defecation (straining during more than 25% of bowel movements or a subjective sensation of hard stools), or
• the sensation of incomplete bowel evacuation.
• Severe cases ("fecal impaction") may feature symptoms of bowel obstruction (vomiting, very tender abdomen) and "paradoxical diarrhea", where soft stool from the small intestine bypasses the impacted matter in the colon.

Differential diagnosis

The main causes of constipation include:

Hardening of the feces

• Insufficient intake of dietary fiber
• Dehydration from any cause or inadequate fluid intake
• Medication, e.g., diuretics and those containing iron, calcium, aluminum

Paralysis or slowed transit, where peristaltic action is diminished or absent, so that feces are not moved along

• Hypothyroidism (underactive thyroid gland)
• Hypokalemia
• Injured anal sphincter (patulous anus)
• Medications, such as loperamide, opioids (e.g., codeine and morphine) and certain tricyclic antidepressants
• Severe illness due to other causes
• Acute porphyria (a rare inherited condition)
• Lead poisoning
• Lactose Intolerance
• Dyschezia (usually the result of suppressing defecation)
• Diverticula
• Tumors, either of the bowel or surrounding tissues

Obstructed defecation, due to:

• Mechanical causes from morphological abnormalities of the anorectum including megarectum, rectal prolapse, rectocele, and enterocele
• Functional causes from neurological disorders and dysfunction of the pelvic floor muscles or anorectal muscles, including anismus, descending perineum syndrome, and Hirschsprung's disease
• Retained foreign body or a bezoar
• Psychosomatic constipation, based on anxiety or unfamiliarity with surroundings.
• Functional constipation
• Constipation-predominant irritable bowel syndrome, characterized by a combination of constipation and abdominal discomfort and/or pain
• Smoking cessation (nicotine has a laxative effect)
• Abdominal surgery, other types of surgery, childbirth
• Severe dehydration

Some causes are with particular respect to infants:

• Switching from breast milk to bottle feeds, or to solid meals
• Potty training anxiety
• Hirschsprung's disease – a condition from birth where the child has a nerve cell defect that affects communication between the brain and bowels

Treatment

In people without medical problems, the main intervention is to increase the intake of fluids (preferably water) and dietary fiber. The latter may be achieved by consuming more vegetables and fruit and whole meal bread, and pulses such as baked beans and chick peas and by adding linseeds to one's diet. The routine non-medical use of laxatives is to be discouraged as this may result in bowel action becoming dependent upon their use. Enemas can be used to provide a form of mechanical stimulation. However, enemas are generally useful only for stool in the rectum, not in the intestinal tract.

Lactulose, a nonabsorbable synthetic sugar that keeps sodium and water inside the intestinal lumen, relieves constipation. It can be used for months together. Among the other safe remedies, fiber supplements, lactitiol, sorbitol, milk of magnesia, lubricants, etc., may be of value. Electrolyte imbalance, e.g., hyponatremia may occur in some cases especially in diabetics.

In alternative and traditional medicine, colonic irrigation, enemas, exercise, diet, and herbs are used to treat constipation. The mechanism of the herbal, enema, and colonic irrigation treatments often includes the breakdown of impacted and hardened fecal matter.

Laxatives

Laxatives may be necessary in people in whom dietary or other interventions are not effective or are inappropriate. Laxatives should be used with caution and only as necessary. The following sequence of laxative use is recommended: bulk forming, then stool softeners, then osmotic, then stimulants, then suppositories, and finally enemas (only as a last resort). The reason for this cautious use is because laxatives can lead to dependence, and like all medications they have side effects. Laxatives should not be used if there are signs and/or symptoms of a bowel obstruction.

Physical intervention

Constipation that resists all the above measures requires physical intervention. Manual dissimpaction (the physical removal of impacted stool) is done for those patients who have lost control of their bowels secondary to spinal injuries. Manual dissimpaction is also used by physicians and nurses to relieve rectal impactions. Finally, manual dissimpaction can occasionally be done under sedation or a general anesthetic—this avoids pain and loosens the anal sphincter.

Many of the products are widely available over-the-counter. Enemas (clysters) are a remedy occasionally used for hospitalized patients in whom the constipation has proven to be severe, dangerous in other ways, or resistant to laxatives. Sorbitol, glycerin and arachis oil suppositories can be used. Severe cases may require phosphate solutions introduced as enemas.

Children

Lactulose and milk of magnesia has been compared to PEG (polyethylene glycol) in children. They had similar side effects but PEG was more effective at treating constipation. Osmotic laxatives are recommended over stimulant laxatives.

Prevention

Constipation is usually easier to prevent than to treat. The relief of constipation with osmotic agents, i.e., lactulose, polyethylene glycol (PEG), or magnesium salts, should immediately be followed with prevention using increased fibre (fruits, vegetables, and grains) and a nightly decreasing dose of osmotic laxative. With continuing narcotic use, for instance, nightly doses of osmotic agents can be given indefinitely (without harm) to cause a daily bowel movement.

Recent controlled studies have questioned the role of physical exercise in the prevention and management of chronic constipation, while exercise is often recommended by published materials on the subject.

In various conditions (such as the use of codeine or morphine), combinations of hydrating (e.g., lactulose or glycols), bulk-forming (e.g., psyllium) and stimulant agents may be necessary to prevent constipation.