Acute Diarrhea
Diarrhea is a condition that can be difficult to define. If you ask 10 people what diarrhea is, you'll likely get 10 different answers. Generally, diarrhea is defined as having an increased frequency of abnormally liquid or unformed stools. Another tool used to define diarrhea is weight. Normal stool volume per day is 150-200g per day. Therefore, diarrhea can be characterized by a stool volume greater than 200-300g per day. However, measuring stool volume by weight is rarely done outside of research studies. Diarrhea can also be classified by its duration. Acute diarrhea lasts less than 2 weeks, persistent diarrhea lasts 2 to 4 weeks, and chronic diarrhea lasts more than 4 weeks. Acute diarrhea is often caused by a bacterial or viral infection. A bacterial infection, a parasitic infection, or inflammation of the intestines may cause persistent diarrhea. Chronic diarrhea may be caused by a chronic disease, such as Crohn's disease or ulcerative colitis.
Today we will focus on acute diarrhea, which usually lasts less than two weeks. Viral or bacterial infections cause most cases of acute diarrhea. However, other causes of loose stools include pseudodiarrhea, fecal incontinence, overflow diarrhea, and medication side effects which we will also discuss briefly in this article.
The good news is most episodes of acute diarrhea are mild and self-limited and do not need diagnostic or pharmacologic interventions. For these cases, symptomatic care with fluid replacement and diet adjustment are often all that is needed. If patients have poor appetite or have nausea and vomiting, a short period of consuming only liquids will not be harmful. Boiled starches and cereals, such as potatoes, noodles, rice, wheat, and oat with salt are indicated in patients with watery diarrhea; crackers, bananas, soup, and boiled vegetables may also be consumed Foods with high fat content should be avoided until the gut function returns to normal after a severe bout of diarrhea.
When to Seek Care for Acute Diarrhea
Reasons for further evaluation and possibly treatment include profuse diarrhea with resulting dehydration, bloody stools, fever, recent antibiotic use, associated with severe abdominal pain for patients over 50 years, and elderly (over 70 years) or immunocompromised patients. These patients may undergo lab testing, including stool tests to identify potential bacterial pathogens for which treatment options could be decided.
Good news! Most cases of short-term diarrhea are mild and don't require medical treatment. For these cases, managing symptoms with fluids and adjusting diet is usually sufficient. If a person has a poor appetite, nausea, or vomiting, it's okay to stick to liquids for a short period. It is recommended to eat boiled starches and cereals like potatoes, noodles, rice, wheat, and oat with salt when experiencing watery diarrhea; crackers, bananas, soup, and boiled vegetables are also good options. It's best to avoid high-fat foods until the digestive system returns to normal after a severe bout of diarrhea.
Further evaluation and possibly treatment are needed for cases of severe diarrhea leading to dehydration, presence of bloody stools, fever, recent antibiotic use, severe abdominal pain in individuals over 50 years old, and in elderly (over 70 years old) or immunocompromised persons. These people may require lab tests, including stool tests, to identify potential bacterial pathogens and determine appropriate treatment options.
Infectious Diarrhea
More than 90% of acute diarrhea cases are caused by infectious agents and are often accompanied by vomiting, fever, and abdominal pain. The infectious diarrhea can be spread by a fecal-oral route or by consuming contaminated food or water with human or animal feces.
The Role of Good Microorganisms in Your Gut
Did you know that your gut is home to a complex community of microorganisms, known as the gut microbiome? This includes over 500 different species of microscopic flora such as bacteria, viruses, fungi, archaea, and eukaryotic organisms. While these microorganisms usually do not cause acute diarrhea, they play a crucial role in preventing the growth of harmful pathogens. However, the use of antibiotics can disrupt the balance of the gut microbiome, leading to diarrhea due to reduced digestive function or the overgrowth of pathogens like Clostridium difficile (C. diff).
In cases of acute infection or injury, pathogens can overwhelm or bypass the body's natural defenses, including the immune syste m and non-immune defenses such as gastric acid, digestive enzymes, mucus secretions, and peristalsis.
Who is at risk for Infectious Diarrhea?
Travelers, especially those visiting endemic regions of Latin America, Africa, and Asia, may experience "traveler's diarrhea" due to microorganisms found in contaminated food and water. Common causes of traveler's diarrhea include E. coli, Campylobacter, Shigella, Aeromonas, norovirus, Coronavirus, and Salmonella. Travelers to Russia, particularly St. Petersburg, are at higher risk for Giardia-associated diarrhea. When visiting Nepal, Cyclospora is a common cause of diarrhea among tourists. Furthermore, people who engage in camping, backpacking, and swimming in natural waters may contract Giardia. Norovirus outbreaks are often linked to cruise ships. It's important to be aware of the specific types of diarrhea associated with the areas you plan to visit in order to take preventive measures. Keep an eye out for future articles where we will discuss prevention and care for traveler's diarrhea. If you do experience diarrhea, be sure to inform your primary care provider or gastroenterologist about your recent travel.
People who eat — isn’t that all of us!? It's important to be mindful of the foods we consume as some can increase the risk of diarrhea. For example, getting diarrhea right after eating at a picnic, self-serve food line, or restaurant could indicate a food-related infection. Packaged foods from grocery stores have also been linked to infectious diarrhea.
Specific infectious agents can be found in different types of food. For instance, chicken can transmit Salmonella, Campylobacter, or Shigella. Undercooked hamburger meat may contain Enterohemorrhagic E. coli. Fried or reheated rice and other reheated foods can cause Bacillus cereus-associated diarrhea. Mayonnaise or creams may transmit Staphylococcus aureus or Salmonella, while eggs can carry Salmonella. Listeria from fresh or frozen uncooked foods or soft cheese can also cause infectious diarrhea. Seafood, especially raw, can be home to Vibrio species, Salmonella, or acute Hepatitis A.
Immunocompromised individuals: Individuals with weaker immune systems can be more susceptible to common diarrheal illnesses. These illnesses can be more severe and last longer in immunocompromised people. These individuals can also get sick from opportunistic microorganisms that don't normally cause illness in people with healthy immune systems. Primary immunodeficiencies, like IgA deficiency, common variable hypogammaglobulinemia, or chronic granulomatous disease, can put a person at risk. Secondary or acquired immunodeficiencies, like HIV/AIDS and other infections, chronic diseases, severe burns, leukemia, malnutrition, and radiation or chemotherapy treatment, can also increase the risk.
Children or adults attending daycare facilities and their families: The most common pathogens in daycares are Shigella, Giardia, Cryptosporidium, and rotavirus.
Institutionalized individuals: These individuals are more prone to infectious diarrhea than the general population. Infectious diarrhea is one of the most frequent types of infection found in many hospitals and long-term care facilities. C. diff is the most common pathogen and is often associated with antibiotic use. However, C. diff can also be found in the community at large and may not be associated with prior antibiotic use. It’s important to test hospitalized and nursing home patients for C. diff because the treatment regimens for C. diff differ from the regimens for other causes of infectious diarrhea.
Other Types of Acute Diarrhea
Pseudodiarrhea
Pseudodiarrhea is characterized by the frequent passage of small volumes of stool and is often accompanied by a feeling of rectal urgency and tenesmus (the sensation of incomplete evacuation). It can be linked to conditions such as irritable bowel syndrome (IBS), hyperthyroidism, and anorectal disorders like proctitis.
Fecal Incontinence
Fecal incontinence occurs when there is an involuntary discharge of feces. This condition is often linked to neuromuscular disorders or structural anorectal problems. It's worth noting that severe diarrhea and urgency can exacerbate or even lead to fecal incontinence.
Overflow diarrhea
Overflow diarrhea occurs when an obstruction from fecal impaction due to constipation causes liquid stool to back up behind the obstruction. This liquid stool then leaks around the impaction or is eliminated once the impaction finally moves out of the rectum. This occurs frequently in patients with a history of chronic constipation or in patients with decreased physical activity, constipating medications, or poor dietary habits. In this case, it is important to treat the constipation in order to treat the overflow diarrhea.
Medication Side Effects
Innumerable medications list diarrhea as a possible adverse effect. Medications such as antibiotics, cardia antidysrhythmics, antihypertensives, NSAIDs, certain antidepressants, chemotherapeutic agents, bronchodilators, antiglycemic agents, antacids, and laxatives. Please see your physician if you suspect medication is causing your diarrheal symptoms.
