Pathophysiology of Acute Gastroenteritis

Pathophysiology of Acute Gastroenteritis
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Gastroenteritis is a term used to describe a variety of gastrointestinal tract disorders. These disorders often cause patients to experience diarrhea, vomiting, nausea, and abdominal pain. The severity of these disorders ranges from mild to severe, and some can be life-threatening. The pathophysiology of acute gastroenteritis is always evolving and will require extensive assessment to find the best management plan or treatment plan.

Infectious Agents

When studying the pathophysiology of acute gastroenteritis, it is often determined that infectious agents are often the cause. These agents cause mucosal invasion, cytotoxin production, enterotoxin production, and/or diarrhea by adherence. These mechanisms lead to decreased absorption and/or increased fluid secretion. This leads to the production of increased luminal fluid content that is not able to be reabsorbed adequately. This then results in the loss of electrolytes, dehydration, and the loss of nutrients.

Classification of Diarrheal Illnesses

Diarrheal illnesses are classified as:

Secretory: Occurs when secretory activity increases.

Osmotic: Occurs when the osmotic load given to the intestinal lumen is increased through diminished absorption or excessive intake.

Motile: Caused by and associated with intestinal motility disorders.

Inflammatory (also referred to as mucosal): Occurs when the intestine’s mucosal lining is inflamed.

What is a Diarrheal Illness?

A diarrheal illness occurs when normal host defenses are overwhelmed by microbial virulence. There are other causes of diarrhea as well. Microorganisms can cause this if they produce infection-causing toxins. Bacteria can generate enterotoxins which can lead to copious, typical diarrhea by acting on the secretory mechanisms directly. When bacteria produce cytotoxin, it causes bloody stools containing inflammatory cells due to mucosal cell destruction. This results in a reduction in absorptive ability. Other causes include enterocyte invasion, achlorhydric states, hypomotility states, the ingestion of toxins and pathogenic organisms, norovirus, and normal bowel flora alteration (typically occurs after antibiotic administration).


Determining exactly how many people in the United States experience acute gastroenteritis is not possible because many people do not report it, especially when it is mild. Those who only have mild symptoms often deal with them at home and never see a doctor about them. So, the Centers for Disease Control and other disease reporting agencies can only make a rough estimation. They estimate that approximately 90 million people suffer from this condition each year. Several million people will need to see a doctor for treatment and thousands of people will need to be hospitalized for this condition.

Age and Mortality

This condition can affect people of all ages. However, those who are very old or very young are at a higher risk for more serious complications and death. It is estimated that approximately 10,000 young children die each year due to this condition and the complications that it causes.


eMedicine. (2010). Gastroenteritis. Retrieved on February 12, 2010 from eMedicine:

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Immune Response: DO11.10 – Wikimedia Commons