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  1. Accurately identify the most likely etiology when patients present with abnormal bowel function, through history, diagnostic tests, and patient findings on examination to enable recommendation of effective treatment or referral to an appropriate provider.

  2. Use the knowledge of the pathophysiology, etiology, and common presentations of diarrhea and constipation as a primary symptom to review prescription orders for appropriateness and to accurately educate patients about their disease and its treatment.

  3. Use the knowledge of the pathophysiology, etiology, and common presentation of diseases with diarrhea and constipation as a primary symptom to accurately interpret the diagnostic process to advise regarding the most appropriate prescription therapy.


Diarrhea and constipation are very common presentations in ambulatory and urgent care centers. In the United States, up to 27% of patients have experienced constipation. Similarly, 211 to 375 million cases of diarrhea are reported annually. While there are a variety of definitions for both conditions, normal frequency of bowel movements in most adults range from three times a day to every 3 days. Even though most causes are self-limiting, both can be a symptom of a serious or life-threatening disorder. Because both disorders are so common and generally self-limiting, patients frequently try treatment with nonprescription products prior to seeking medical care. Therefore, screening patients for those more serious forms of these disorders is critical before recommending from the multitude of products available for self-care.



Diarrhea, defined as three or more bowel movements within a 24-hour period, can be classified as acute, persistent, and chronic. Acute diarrhea lasts for less than 14 days; persistent diarrhea lasts for more than 14 days; and patients experiencing diarrhea for more than 30 days have chronic diarrhea. Dysentery is usually defined as acute diarrhea in which subjects have frequent watery stools, often with blood and mucous. The most common cause of acute diarrhea is infection with viral pathogens, such as norovirus and rotavirus. Common bacterial causes include Shigella and Salmonella species along with Campylobacter jejuni, Clostridium difficile, and Escherichia coli species. Giardia lamblia, Entamoeba histolytica, and Cryptosporidium species are the most common protozoal causes of diarrhea. Noninfectious causes of acute diarrhea include foods and medication. Inflammatory bowel diseases such as celiac disease, microcolitis, ulcerative colitis, and Crohn’s disease all cause chronic diarrhea. Irritable bowel syndrome is a noninflammatory condition that in two versions (diarrhea predominant and mixed) cause chronic diarrhea. Lastly, diabetic gastroparesis, acquired immunodeficiency syndrome (AIDS), and post-gastrointestinal (GI) tract surgery are uncommon causes for chronic diarrhea. While most viral diarrheas are self-limiting (typically lasting 24 to 48 hours) complications such as dehydration are uncommon, except in infants and the elderly. Some bacterial diarrheas produce toxins that result in more serious complications such as toxic megacolon, intestinal perforation, sepsis, and even death. Some parasitic infections can cause persistent diarrhea and some may migrate to other ...

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