Pain Before Bowel Movement (Passing Stool) Causes

Having a bowel movement is not something that most of us give much thought to on the average day. However, for some people it can be marked with pain and discomfort which makes an otherwise mundane body process an unpleasant event to fear. Pain before, during or after a bowel movement is not normal. When it does occur, it should be investigated further to find the underlying cause and treat it appropriately. Sometimes the cause is just a temporary disturbance or illness but at other times pain with a bowel movement may be the symptom of a very serious and even life-threatening ailment.

Normal Bowel Movement Sensation

It is not uncommon for us to feel a slight discomfort before a bowel movement. This is the body’s way of signaling that it needs to pass out feces. It is an urging or discomfort at most, but should not be painful. If the sensation is ignored then the discomfort can increase substantially. This is intended to motivate a person to find a toilet and take the appropriate position to allow the body to release the feces.

The discomfort is mainly due to the strong colonic contractions that occur to move feces into the rectum. It also arises from the stretching of the rectum by feces in preparation for a bowel movement. Once the rectum is filled, the anal sphincters are ready to relax and let out the feces. There is a feeling of relief as the rectum empties.

Causes of Pain Before Passing Stool

Any pain prior to passing stool is not the same as the normal urging to defecate. Even the most intense urging should not be overt pain. When pain is present, it indicates a problem with the bowels and/or anus. Pain that starts just before stool usually is a result of disease or damage to the bowels. The strong contractions that occur prior to defecation triggers pain in the already injured or inflamed bowels.

Naturally there are other symptoms like diarrhea or constipation, mucus and/or blood in the stool, abdominal cramping or pain and excess gas (flatulence). The causes of pain before a bowel movement can be discussed according to the nature of the disease. These are some of the possible causes of pain before a bowel movement but there may also be other reasons.

Sometimes abdominal pain may occur for no clearly identifiable reason and is short-lived. The fact that it precedes a bowel movement may have no correlation.

Infections

Second to the seasonal flu, bowel infections like viral gastroenteritis are the most common causes of acute bowel symptoms. It usually does not last for more than a few days to a week at most. These infections are not serious in most cases and can resolve on its own with adequate bed rest and fluids. Some bowel infections may require medical intervention.

• Gastroenteritis caused by viruses, bacteria or protozoan.
• Food poisoning caused by eating food contaminated with microbes or its toxins.
• Clostridium difficile infection or pseudomembranous colitis which is caused by using antibiotics (also referred to as antibiotic-associated diarrhea).
• Intestinal worms like flukes infest the bowels of humans where there may initially cause symptoms like excessive hunger, abdominal pain/cramping, diarrhea and constipation.
• Diverticulitis is an infection of the abnormal outpouchings in the colon known as the diverticula. This condition is mainly seen in older people.
• Proctitis which may be due to the same infections as colitis (proctocolitis) or even occur with sexually transmitted diseases (STDs).

Injury

Injury to the bowel can be mechanical, chemical or electromagnetic in nature. This may cause inflammation in the bowel wall which leads to a host of symptoms including pain before a bowel movement. Usually the trauma is obvious and can be easily isolated but sometimes it may be difficult to pinpoint.

• Sharp or blunt force trauma to the abdomen and bowels.
• Radiation exposure, usually as part of radiation treatment for cancers.
• Poisons and certain drugs.

Immune

In some conditions, it is the malfunctioning immune system that is the cause of the disease. These are known as autoimmune conditions. Here the immune system attacks the bowels and causes inflammation. This disturbance in immune function may be triggered by some environmental factor, like a viral infection or toxin. However, the underlying problem is usually genetic.

• Inflammatory bowel disease (IBD) is a chronic condition where sores (ulcers) form in the digestive tract. There are two types – ulcerative colitis and Crohn’s disease. The colon is the most commonly affected part of the gut.
• Celiac disease where the presence of gluten (wheat protein) triggers the immune system to attack the bowel wall. As a result there are a number of bowel symptoms that arise.

Circulatory

Injury may arise with restricted blood flow to the bowel walls. This type of tissue injury is known as ischemia. If severe, the bowel tissue can eventually die. Ischemic bowel disease can affect any part of the small and large intestine. When the colon to the rectum is affected, then symptoms like pain related to bowel movements become more pronounced. This is also known as ischemic colitis.

Drugs & Toxins

Both drugs and toxins can cause chemical injury to the bowels, stimulate excessive and strong bowel contractions and/or cause bleeding from the bowel wall. There are a number of substances that can be involved. Usually the upper parts of the digestive tract is also affected. However, in the case of suppositories or enemas the irritation will be isolated to the anus, rectum and lowest parts of the colon.

• Laxative abuse
• Drug-induced enterocolitis
• Drugs that mimic the parasympathetic nervous system (parasympathomimetics)
• Poisoning with insecticide or pesticides, nerve gas and certain herbs like pilocarpus

Other

• Irritable bowel syndrome (IBS) is a functional disorder affecting bowel motility. It can be associated with diarrhea or constipation.
• Cancers, including colorectal cancer and anal cancer.
• Food intolerance where the bowel cannot digest or absorb certain types of food. The most common is lactose intolerance.
• Short bowel syndrome where a portion of the small intestine is surgically removed or missing since birth (congenital). Sometimes the bowel length may be normal but large sections cannot absorb nutrients.

Reference:

1. Painful bowel movements. WebMD

Last updated on August 9, 2018.