Constipation

What constipation is

Constipation is one of the most common digestive complaints and often misunderstood: there is no “normal” number of movements that applies to everyone. The diagnosis rests on the person’s experience. It includes:

• hard or lumpy stools;
• straining during bowel movements;
• fewer than three movements a week;
• a feeling of blockage or incomplete emptying;
• the need for manual help or long time on the toilet.

It may be temporary (for example during travel, a change in diet or after an illness) or chronic, lasting for months. Chronic constipation may be primary (with no other disease) or secondary (from medicines or other diseases).

Causes

• little fiber in the diet, little fluid and little physical activity;
• changes in routine or repeatedly delaying the urge to go;
• medicines: opioids, some antidepressants and anticholinergics, iron preparations, calcium, some blood pressure drugs (for example verapamil), aluminum-containing antacids;
• diseases: hypothyroidism, diabetes, hypercalcemia, neurologic disease (Parkinson disease, multiple sclerosis, spinal cord injuries), depression;
• pregnancy and the postpartum period;
• mechanical obstruction (tumor, narrowing), which is rare but important.

In some people food moves slowly through the colon (slow-transit constipation); in others the pelvic floor muscles do not coordinate well during defecation (dyssynergic defecation). These two mechanisms need different treatment, so taking laxatives alone is not enough.

When to see a doctor

Consult a doctor if constipation lasts several weeks despite home measures, or if you have:

• blood in the stool (bright red or dark);
• anemia or unexplained weight loss;
• a new and persistent change in bowel habit, especially after age 45–50;
• a family history of colon cancer;
• pencil-thin stools or persistent pain.

How the diagnosis is made

The doctor asks about onset, stool form (a stool form chart is often used), diet and medicines, and performs a physical examination, including a rectal examination when needed, to look for hemorrhoids, fissures, impacted stool or pelvic floor problems. Tests are done as suspected: TSH, calcium, glucose, blood count.

Colonoscopy is recommended when there are alarm features or when you are due for colorectal cancer screening, not for every case of constipation. In cases that do not respond to treatment, specialized tests such as anorectal manometry or a transit study may be needed, to tell slow transit from dyssynergic defecation.

How it is treated

First measures:

• Add fiber gradually (vegetables, fruit, legumes, whole grains, or psyllium) to avoid bloating; the effect appears after a few days to weeks.
• Drink enough fluids, unless your doctor has limited fluids because of the kidneys or heart.
• Move regularly and set a quiet time for the toilet, for example after breakfast, when the bowel reflex is strongest.
• Resting your feet on a small stool while defecating eases passage, because it changes the rectal angle.

Medicines: the doctor may recommend osmotic laxatives (such as polyethylene glycol or magnesium oxide) or stimulant laxatives (such as senna). Laxatives that are chosen correctly and used as directed are safe; the worry that “the bowel gets used to them” does not apply to most of them. For resistant constipation there are also other medicines that act on bowel secretion or motility.

In dyssynergic defecation the main treatment is biofeedback with a pelvic floor physiotherapist, not laxatives.

When help is urgent and what to avoid

Complete bowel obstruction is rare but serious: severe pain, a swollen abdomen, vomiting and inability to pass stool or gas need emergency care. Do not use stimulant laxatives for a long time without medical advice and do not use them when there is unexplained severe abdominal pain. Do not stop medicines that may be causing it on your own; talk to the doctor who prescribed them.