Diarrhea: Causes, Diagnosis, and Modern Treatment Methods

What is diarrhea?

Diarrhea is characterized by frequent (usually more than three times a day) passing of loose or unformed stools. This condition may be accompanied by abdominal pain, bloating, nausea, vomiting, and general malaise. Diarrhea can be acute, lasting up to two weeks, or chronic if it persists for more than four weeks. Chronic diarrhea significantly reduces patients' quality of life, requiring a careful approach to diagnosis and treatment [1].

Main causes of diarrhea

The causes of diarrhea are diverse and can range from relatively harmless conditions to serious diseases requiring medical intervention:

• Irritable Bowel Syndrome with predominant diarrhea (IBS-D): This is a chronic functional bowel disorder that significantly reduces quality of life. IBS-D manifests as abdominal pain related to defecation and changes in stool frequency or consistency, including persistent or episodic diarrhea [1].
• Celiac disease: An autoimmune disorder in which the consumption of gluten (a protein found in wheat, rye, and barley) leads to damage to the small intestine mucosa. One of the key symptoms of celiac disease is chronic diarrhea. The American College of Gastroenterology (ACG) recommends serological testing to rule out celiac disease in patients with IBS and diarrhea symptoms [1].
• Inflammatory Bowel Disease (IBD): This includes Crohn's disease and ulcerative colitis. These chronic conditions cause inflammation in the digestive tract, leading to pain, bleeding, weight loss, and, of course, chronic diarrhea [5].
• Postoperative conditions: Certain surgical interventions can affect bowel function. For example, surgeries to bypass a portion of the small intestine, such as side-to-side jejunoileal anastomosis (SJA) used to treat type 2 diabetes mellitus, can lead to impaired absorption of nutrients and biliopancreatic secretions, manifesting as diarrhea [4].
• Infections: Viruses (e.g., rotavirus), bacteria (e.g., salmonella, E. coli), and parasites are frequent causes of acute diarrhea.
• Food poisoning and intolerances: Eating spoiled food or foods that cause individual intolerance (e.g., lactose) can trigger diarrhea.
• Medications: Certain drugs, including antibiotics, magnesium-containing antacids, and chemotherapy drugs, can cause diarrhea as a side effect.

Diagnosis: How to determine the cause?

Accurate diagnosis is the key to effective treatment of diarrhea. The diagnostic process typically includes:

• Medical history and physical examination: The physician clarifies the nature of the stool, frequency, presence of accompanying symptoms, diet, medications taken, and medical history.
• Positive diagnostic strategy for IBS: The ACG recommends using a "positive" diagnostic strategy for IBS rather than a strategy of exclusion. This means that a diagnosis of IBS can be established based on characteristic symptoms after ruling out other obvious causes, allowing appropriate therapy to be initiated faster [1].
• Serological testing for celiac disease: In patients with IBS symptoms and diarrhea, serological testing (blood test for antibodies) is mandatory to rule out celiac disease [1].
• Laboratory tests: General and biochemical blood tests, stool tests for infections, occult blood, and inflammatory markers.
• Instrumental methods: In some cases, colonoscopy, gastroscopy, abdominal ultrasound, or other studies may be required to visualize the condition of the digestive tract.

Effective approaches to treating diarrhea

Treatment for diarrhea depends on its cause and severity. It may include both general measures and specific approaches:

General principles of treatment

• Rehydration: Replenishing lost fluids and electrolytes is a primary objective, especially in acute diarrhea. This can be done using oral rehydration solutions. In severe fluid loss, especially in debilitated patients, hyponatremia (low sodium levels) can develop, requiring careful monitoring, particularly in settings where monitoring is difficult [2].
• Diet: It is recommended to avoid fatty, spicy, fried foods, dairy products (in case of lactose intolerance), caffeine, and alcohol. Easily digestible foods are preferred: bananas, rice, applesauce, toast.
• Fluid balance monitoring: Patients at risk of dehydration (e.g., after surgery or in severe conditions) are advised to weigh themselves daily for early detection of fluid loss. Specialists should monitor fluid replacement and the dosage of drugs that affect fluid balance [2].

Specific treatment methods

• Management of IBS-D: Treatment of IBS-D often includes a combination of dietary changes, probiotics, antispasmodics, and antidiarrheal medications. Stress management techniques, such as psychotherapy, can also be effective [1].
• Non-pharmacological methods in IBD: In addition to drug therapy, patients with inflammatory bowel disease are recommended the following non-pharmacological approaches [5]:
  • Diet: Individualized diets developed in collaboration with a physician or nutritionist can help reduce symptoms and improve well-being [5].
  • Physical activity and exercise: Regular moderate physical exertion contributes to overall health improvement and may reduce inflammation levels [5].
  • Psychotherapy: Methods such as cognitive behavioral therapy can be useful for managing stress associated with chronic illness and improving quality of life [5].
• Postoperative diarrhea: In cases where diarrhea is a consequence of surgical intervention (e.g., after intestinal bypass for type 2 diabetes treatment [4]), treatment aims to correct malabsorption and provide symptomatic relief. Dietary modifications, enzyme replacement, or bile acid sequestrants may be required.

When to see a doctor?

Although many cases of diarrhea resolve on their own, there are situations when it is necessary to seek medical attention immediately:

• Diarrhea lasts more than 2 days in adults or more than 24 hours in children.
• High fever (above 38.5°C).
• Severe abdominal or rectal pain.
• Signs of dehydration: severe thirst, dry mouth, decreased urination, weakness, dizziness.
• Presence of blood, mucus, or black stools.
• Diarrhea in infants, elderly individuals, or people with weakened immune systems, as well as in the presence of chronic diseases.

References

1. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. (The American journal of gastroenterology, 2021)
2. Endocrinology during COVID-19 – Updates 2021: Management of diabetes insipidus and hyponatremia. (European journal of endocrinology, 2021)
3. Simple food diversion surgery for the treatment of type 2 diabetes. Preliminary results in people with BMI 28-32 kg/m2. (Obesity surgery, 2017)
4. Non-pharmacological treatments in inflammatory bowel disease: Recommendations for self-care and guidance for physicians. (World journal of gastroenterology, 2018)

The information provided in this article is for reference purposes only and should not be used for self-diagnosis or self-treatment. Always consult a qualified medical specialist for diagnosis and treatment prescription.