Constipation
(Hard Stools · Difficulty Passing Stool)
In this condition factsheet:
The Facts on Constipation
Constipation occurs when stool or waste material moves too slowly through the large intestine. Feces that stay in the bowel too long before elimination become hard and dry. This results in difficult, painful, and infrequent bowel movements. In many cases, constipation is harmless, but it can significantly lower your quality of life. It's not a disease, but it might be a symptom of a disease.
Many people believe they are constipated when they're not, thinking that less than one bowel movement a day is abnormal. In fact, as little as twice a week is fine so long as you go easily when you feel the need. A normal bowel movement, no matter how often, should be soft yet hold its shape and be easy to pass without needing to strain.
Causes of Constipation
When food leaves the stomach, it's still a partly digested mush. Your body recuperates valuable fluid from it while it's moved down the colon (large intestine). This transforms it into normal feces. The longer it stays in the colon, the drier it gets. This makes it harder.
Obviously, the quantity also increases if you wait to go to the toilet. A large, hard stool can be painful and difficult to pass. This can make people, especially children, reluctant to go, creating a vicious cycle. It's a common pattern of chronic constipation in children, which often begins when they start school. Many young children avoid school toilets and end up waiting too long.
Chronic constipation can last for months or years. It's usually caused by poor diet, some other disease, or regularly ignoring the urge to go to the toilet. Low-fibre diets and insufficient water intake are common causes of constipation.
While most otherwise healthy people will occasionally experience constipation, certain diseases or conditions can also cause it, such as:
- bowel obstructions due to a tumour or benign growth
- chronic kidney failure
- diabetes
- hypothyroidism
- irritable bowel syndrome
- neurologic disorders such as Parkinson's disease, multiple sclerosis, or spinal cord injury
- rectal or colon cancer
Acute constipation starts suddenly and lasts for a few days. It can be caused by a blockage, prolonged inactivity, medication, dehydration, or missing a bowel movement. Pregnant people can develop constipation when the womb presses on the intestine. Sometimes, general anesthesia affects the bowel muscles for a few days after surgery. Lead poisoning and swallowing indigestible objects are other rare causes.
Examples of medications that can provoke acute constipation include:
- anticonvulsants used for epilepsy
- antidepressants
- certain diuretics
- heart medications such as calcium-channel blockers
- iron supplements
- medications for Parkinson’s disease
- pain medications such as codeine* and morphine
- some cough and cold medications containing dextromethorphan
- some antacids
Overuse of laxatives eventually makes the bowels less sensitive to the need to eliminate feces and can cause chronic constipation. The bowels become dependent on laxatives to work, and this can lead to bowel distension and sometimes a condition called melanosis coli.
People who are bedridden can develop severe acute blockages called fecal impaction. The stools may have to be removed by their doctor.
Symptoms and Complications of Constipation
Symptoms of constipation can include:
- a sensation that the bowels haven't completely emptied
- bloating of the abdomen, and possibly a "rumbling" noise
- gas
- indigestion
- infrequent bowel movements
- loss of appetite
- lumpy and hard stools that are difficult to pass
- needing to strain to get stool out
- pain or pressure in the belly
- some bleeding as a result of straining
Constipation can cause complications. Very large, hard stools can stretch the anus, tearing the skin. These anal fissures can be very painful. Occasionally, a really tough bowel movement causes rectal prolapse, in which a small section of intestinal lining pokes out of the anus and has to be pushed back in. Hemorrhoids can also be caused by the chronic pushing of constipation.
If you have experienced constipation lasting longer than 7 days or your constipation has been accompanied by vomiting, blood in the stool, weight loss, a swollen and painful abdomen, fever, or small, pencil-sized stool, seek medical attention.
