Gastroenteritis: Causes, Symptoms, Treatment, and Prevention


Gastroenteritis, often referred to as the stomach flu or stomach bug, is a common condition characterized by inflammation of the stomach and intestines. It is a prevalent gastrointestinal disorder that affects people of all ages worldwide. In this article, we will explore the causes, symptoms, treatment options, and preventive measures for gastroenteritis.

I. Causes of Gastroenteritis

Gastroenteritis is primarily caused by viral, bacterial, or parasitic infections. The most common causes include:

  1. Viral Infections: Viruses such as norovirus, rotavirus, and adenovirus are major culprits of gastroenteritis. These viruses are highly contagious and can spread through contaminated food, water, or close contact with an infected individual.
  2. Bacterial Infections: Bacteria like Salmonella, Escherichia coli (E. coli), Campylobacter, and Shigella can cause bacterial gastroenteritis. These bacteria are typically transmitted through contaminated food, poor hygiene practices, or contact with infected animals or individuals.
  3. Parasitic Infections: Parasites such as Giardia lamblia and Cryptosporidium are known to cause gastroenteritis. These parasites are commonly found in contaminated water sources or food, and their transmission occurs through ingestion.

II. Symptoms of Gastroenteritis

Gastroenteritis presents a range of symptoms that may vary in severity from mild to severe. Common symptoms include:

  1. Diarrhea: Loose, watery stools are a hallmark symptom of gastroenteritis. Diarrhea can be accompanied by urgency, frequent bowel movements, and sometimes, the presence of blood or mucus.
  2. Nausea and Vomiting: Gastroenteritis often leads to feelings of nausea and may cause vomiting. These symptoms can contribute to dehydration if fluids are not adequately replenished.
  3. Abdominal Pain and Cramps: The inflammation in the gastrointestinal tract can cause abdominal discomfort and cramps, which may range from mild to severe.
  4. Fever: In some cases, gastroenteritis can be accompanied by a low-grade fever. However, high fevers are typically indicative of a more severe infection.
  5. Other Symptoms: Fatigue, loss of appetite, muscle aches, and headache are additional symptoms that may be experienced during gastroenteritis.

III. Lab Tests for Gastroenteritis

Lab tests can play a crucial role in diagnosing and identifying the cause of gastroenteritis. While most cases of gastroenteritis can be diagnosed based on clinical symptoms and history, certain situations may require laboratory tests to confirm the diagnosis and determine the specific infectious agent responsible. Here are some common lab tests used in the evaluation of gastroenteritis:

  1. Stool Culture: A stool culture involves collecting a sample of stool and sending it to a laboratory for analysis. This test is performed to identify bacterial pathogens such as Salmonella, Shigella, Campylobacter, Clostridioides difficile (C. difficile), and Escherichia coli (E. coli) that may be causing the gastroenteritis. It helps determine the specific bacteria involved and guides appropriate treatment.
  2. Stool Ova and Parasite (O&P) Examination: This test examines the stool sample for the presence of parasites such as Giardia lamblia and Cryptosporidium. It involves microscopic examination of the sample to identify and characterize any parasites or their eggs.
  3. Stool Antigen Tests: Antigen tests detect specific proteins or antigens associated with certain viral pathogens. For example, enzyme immunoassays (EIAs) can detect antigens of viruses like rotavirus and norovirus in stool samples, aiding in the diagnosis of viral gastroenteritis.
  4. Polymerase Chain Reaction (PCR): PCR tests are molecular diagnostic techniques that can detect the genetic material (DNA or RNA) of various pathogens with high accuracy. PCR can identify specific viruses, bacteria, or parasites causing gastroenteritis, including less common pathogens.
  5. Blood Tests: In certain cases, blood tests may be performed to assess the overall health status, measure electrolyte levels, and evaluate the severity of the infection. Blood tests can help detect signs of dehydration, electrolyte imbalances, and assess the body’s immune response.

Not all cases of gastroenteritis require laboratory testing. Mild cases of viral gastroenteritis, for instance, may not require specific testing unless complications arise or the symptoms persist. The need for laboratory tests depends on the severity of symptoms, the duration of illness, risk factors, and the healthcare provider’s clinical judgment.

IV. Treatment of Gastroenteritis

The treatment for gastroenteritis aims to relieve symptoms, prevent complications, and promote recovery. Key treatment options include:

  1. Rehydration: Replacing lost fluids and electrolytes is crucial in managing gastroenteritis. Drinking plenty of fluids, including oral rehydration solutions, can help prevent dehydration. In severe cases, intravenous fluids may be necessary.
  2. Medications: Anti-diarrheal medications and antiemetics may be prescribed to manage symptoms, although they are not recommended for certain types of gastroenteritis, such as those caused by certain bacterial infections.
  3. Rest and Nutritional Support: Adequate rest and a bland, easily digestible diet can aid in recovery. Avoiding certain foods, such as spicy or fatty items, and opting for foods like rice, bananas, toast, and broth can be beneficial.

V. Preventive Measures for Gastroenteritis

Preventing gastroenteritis involves adopting good hygiene practices and taking precautions to reduce the risk of infection. Here are some preventive measures:

  1. Hand Hygiene: Regularly washing hands with soap and water for at least 20 seconds, especially after using the restroom and before handling food, can help minimize the spread of pathogens.
  2. Food Safety: Practicing proper food handling, storage, and preparation techniques can significantly reduce the risk of foodborne gastroenteritis. This includes washing fruits and vegetables, cooking food thoroughly, and avoiding cross-contamination.
  3. Clean Environment: Keeping surfaces clean and disinfected, particularly in public spaces, can help prevent the transmission of viruses and bacteria.
  4. Safe Water and Travel Precautions: Consuming safe drinking water and being cautious while traveling to regions with poor sanitation can reduce the risk of contracting parasitic gastroenteritis.

VI. When Should I Seek Help From A Gastroenterologist?

Knowing when to seek medical help for gastroenteritis is crucial for proper diagnosis, management, and prevention of complications. While many cases of gastroenteritis resolve on their own within a few days, there are certain situations where seeking medical assistance is advisable. Here are some instances when it is recommended to seek help:

  1. Severe Dehydration: If you or someone affected by gastroenteritis is experiencing severe dehydration symptoms, such as excessive thirst, dry mouth, infrequent urination, dark urine, dizziness, or lightheadedness, it is important to seek medical attention promptly. Severe dehydration can be particularly dangerous, especially for infants, young children, older adults, and individuals with weakened immune systems.
  2. Persistent or Bloody Diarrhea: If diarrhea persists for more than a few days, or if you notice blood or mucus in the stool, it is advisable to consult a gastroenterologist. These symptoms may indicate a more severe infection or an underlying condition that requires medical intervention.
  3. High Fever: While mild fever is common with gastroenteritis, a persistent or high-grade fever (above 101°F or 38.3°C) may suggest a more serious infection. Medical attention is recommended, especially if the fever is accompanied by other concerning symptoms.
  4. Prolonged or Worsening Symptoms: If the symptoms of gastroenteritis do not improve or become increasingly severe despite home care measures, it is best to consult a gastroenterologist. This is particularly important for individuals with weakened immune systems, chronic illnesses, or other pre-existing health conditions.
  5. Signs of Serious Illness: If you or someone affected by gastroenteritis experiences severe abdominal pain, severe vomiting that prevents the intake of fluids, signs of dehydration in young children (such as sunken eyes, no tears when crying, or dry diapers), or any other alarming symptoms, immediate medical attention should be sought.
  6. Travel History or Outbreak: If you have recently traveled to a region with poor sanitation or have been in close contact with someone with confirmed or suspected gastroenteritis, it is advisable to seek medical help, as the risk of certain infections or complications may be higher.

Remember, gastroenterologists are best equipped to evaluate your specific condition and provide appropriate advice and treatment. If you are unsure about the severity of your symptoms or have concerns about your health, it is always better to err on the side of caution and seek medical assistance.

Bottom Line

Gastroenteritis is a common gastrointestinal condition that can cause significant discomfort and distress. Understanding its causes, recognizing the symptoms, and adopting preventive measures are vital for managing the condition effectively. Timely medical attention, rehydration, and following a balanced diet can aid in a faster recovery. By practicing good hygiene and food safety habits, we can reduce the likelihood of gastroenteritis and its transmission within communities.

How can I contact gastroenterologist Dr. Zavos for an appointment?

Dr. Chris Zavos is a board-certified gastroenterologist and hepatologist, located in Thessaloniki Greece, and specifically in Kalamaria suburb, about 7 kilometres (4 miles) southeast of downtown Thessaloniki. His private office is at: Fanariou 8 street (near Aigaiou and Adrianoupoleos avenues), Kalamaria (Thessaloniki), Greece.

Thessaloniki International Airport is only 10 km away from his private office in Kalamaria and can be reached by taxi within 13 minutes from the airport.

Dr. Chris Zavos performs endoscopies at Bioclinic private hospital in downtown Thessaloniki (Mitropoleos 86 street).

You can contact Dr. Zavos at phone numbers: (+30)-6976596988 and (+30)-2311283833, or you can email him at Dr. Zavos responds to Greek and English languages.

Last update: 3 October 2023, 12:31


Gastroenterologist - Hepatologist, Thessaloniki

PhD at Medical School, Aristotle University of Thessaloniki, Greece

PGDip at Universitair Medisch Centrum Utrecht, The Netherlands

Ex President, Hellenic H. pylori & Microbiota Study Group