Constipation – Diagnosis, Symptoms, and Treatment

What is Constipation?

Constipation is a common condition characterized by trouble passing stool, pain with passing stool, and an abnormal appearance of the stool.  The stool tends to be hard and pellet-like.  Patients often attempt to pass stool by bearing down forcefully (straining) – this may eventually lead to the development of complications such as hemorrhoids and diverticulosis.  Both of which may lead to rectal discomfort and rectal bleeding. Constipation is typically related to inadequate physical activity, fluid intake, and dietary fiber consumption.  Other common causes are medication use, other underlying conditions that lead to impared intestinal motility.

Constipation is a frequent problem in the elderly population.  Severe cases of constipation and fecal impaction can lead to confusion and delirium in patients with advanced age.

What Causes Constipation?

Constipation results from the combination of multiple factors. The ability of the intestines to adequately contract and the quality of the stool are the two most important factors that can lead to the development of constipation. These factors can be altered for the worse by several factors, the most common being:

• Inadequate physical activity – exercise promotes the movement of stool through the intestines.
• Inadequate fluid intake – most people require 1.5-2 L fluids daily, consuming less fluid will increase the amount absorbed from the intestine, leading to dry and hard stool.
• Low dietary fiber consumption – the average person typically requires about 30g of fiber in their diet daily. Fiber lowers the density of stool and makes it easier to expel.
• Use of opiate analgesics for pain - Opiates decrease intestinal motility
• Other medical conditions 
  • Hypothyroidism
  • Hyperparathyroidism
  • Hypercalcemia
  • Colon cancer (mostly in people age >50)
• Impaired intestinal motility – due to diabetes mellitus, severe vascular disease, and advanced age

These factors either lead to slow transit of stool through the colon or obstruction of the colon.  Colon cancer is an important consideration in patients with a prior history of colon cancer, first degree relatives with colon cancer, history of ulcerative colitis, or age >50.  Colon cancer may cause unintentional weight loss, blood in the stool, changes in stool caliber (e.g., pencil thin stool), and trouble passing stool.

How Common is Constipation?

Constipation is extremely common in the United States, it is estimated that 12% to 19% of the population experiences constipation in any given year. The majority of people that experience severe constipation requiring medical care are either very young or very old. Children under the age of one year and adults over the age of 60 are at the highest risk. 

In adults over 60 years of age approximately 26% of men and 34% of women report issues with constipation in a given year. 

Signs and Symptoms

Constipation is one of the easiest conditions to identify and it is based on stool quality and patterns. Multiple days without a bowel movement, difficulty defecation despite an urgent need to, and abnormal quality of the stool are the most common symptoms. 

The three most common symptoms of constipation are:

• Straining on defecation
• Difficulty passing stool
• Hard pellet-like stool

Severe constipation can result from a condition called fecal impaction – this means that the stool literally impacts or blocks the rectal passage, not allowing any stool to pass.  This is more common in the elderly and may lead to confusion or delirium as the distention of the rectum leads to pain and pressure on surrounding structures..

Constipation may also result in the development of hemorrhoids and diverticulosis.  

Hemorrhoids are characterized by dilated veins in the rectum – these veins often bleed slightly during bowel movements.  Patients may complain of rectal itching or pain.  Hemorrhoids will occasionally thrombose (form a blood clot), which can be very painful and require outpatient surgery.

Diverticulosis is characterized by outpouchings in the colon – this usually affects the sigmoid colon, which is the most distant part of the large intestine.  The outpouchings in diverticulosis may bleed, resulting in significant rectal bleeding, potentially requiring hospitalization.  Diverticula can also become infected and inflamed, resulting in a condition termed diverticulitis.  This requires treatment with antibiotics.  Some patients who have recurrent diverticular bleeds or diverticulitis require surgery to remove the portion of the bowel that is affected.

How is Constipation diagnosed?

The diagnosis of constipation is based almost entirely on the history or your symptoms. Your physician will ask about your stool patterns and quality. In the majority of individuals no other specialised tests are required. In patients that are very old, very young, appear dehydrated, or have other severe medical conditions lab tests will often be run to rule out complications. 

Commonly ordered blood tests include a CMP (comprehensive metabolic panel), calcium level, thyroid function (TSH, free T4), CBC (complete blood cell count).  They will also usually screen for diabetes.  X-rays or a CT-scan may be ordered if bowel obstruction is suspected from a cancer or stool impactation. A CT scan will also be used if your physician suspects diverticulitis.

Constipation Medication and Treatment

Constipation is initially treated with dietary and lifestyle changes.  Patients are encouraged to increase the amount of dietary fiber in their meals – this can usually be achieved by increasing the consumption of fruits, vegetables, beans, nuts, and whole-grains. Most individuals should also be drinking about 1.5-2L clear fluids on average day, any less can result in excessively dry stool that increases the risk of conspiration.  Physical activity is also encouraged in patients with constipation who can tolerate exercise.  Most people are recommended to exercise for 30 minutes, 3 times a week. Exercise increases intestinal motility and helps the body break up large collections of stool into more manageable bits.

If there is a known underlying cause of constipation – hypothyroidism, opiate use, colon cancer – these conditions can often be reversed or treated, decreasing or eliminating the symptoms of constipation.

In some cases constipation requires treatment with laxatives. The most common laxatives are:

• Bulk-forming agents – Metamucil (psyllium), Citrucel (methylcellulose)
• Stool softeners – Colace (docusate)
• Stimulant laxatives – Senokot (senna),Dulcolax (bisacodyl)
• Osmotic laxatives – Constulose (lactulose),MiraLax (polyethylene glycol 3350)

Most of these agents are taken orally – occasionally you may require a rectal suppository (Dulcolax) or fleet enema.  Fecal impaction often requires manual disimpaction where physical tools mut be inserted into the rectum to break up the hard collections of stool.  In severe cases, it may require surgery.

References:

1. Bharucha AE, Pemberton JH, Locke GR 3rd. American Gastroenterological Association technical review on constipation. Gastroenterology 2013; 144:218. - https://www.ncbi.nlm.nih.gov/pubmed/23261065
2. Lee-Robichaud H, Thomas K, Morgan J, Nelson RL. Lactulose versus Polyethylene Glycol for Chronic Constipation. Cochrane Database Syst Rev 2010; :CD007570. - https://www.cochrane.org/CD007570/COLOCA_polyethylene-glycol-should-be-used-in-preference-to-lactulose-in-the-treatment-of-chronic-constipation.