Gastroenteritis, commonly known as stomach flu, is an inflammation of the gastrointestinal tract characterized by diarrhea, vomiting, and abdominal pain, primarily caused by infectious agents such as viruses, bacteria, and parasites. Transmission occurs through the fecal-oral route and contaminated food or water, and diagnosis involves clinical evaluation and stool tests. Treatment focuses on rehydration and dietary adjustments, with prevention strategies including hand hygiene, food safety, and vaccination against rotavirus.

1. GASTROENTERITIS
Ms. Sonam Sharma
Asst. Professor

2. Definition
• Gastroenteritis, commonly known as stomach flu, is an
inflammation of the gastrointestinal tract, including the
stomach and intestines. It is characterized by symptoms such as
diarrhea, vomiting, abdominal pain, and cramps

3. Causes
Gastroenteritis can be caused by various infectious agents, including:
• Viruses:
• Norovirus: Most common cause in adults and responsible for outbreaks in
closed environments like cruise ships.
• Rotavirus: Leading cause in infants and young children.
• Adenovirus, Astrovirus: Less common but can affect children and
adults.

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• Bacteria:
• Escherichia coli (E. coli): Some strains produce toxins causing severe
diarrhea.
• Salmonella: Often from contaminated food or water.
• Campylobacter: Usually from undercooked poultry.
• Shigella: Transmitted through contaminated water and food.
• Vibrio cholerae: Causes cholera, leading to severe watery diarrhea.

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• Parasites:
• Giardia lamblia: Spread through contaminated water.
• Cryptosporidium: Resistant to chlorine and can be found in swimming
pools.
• Entamoeba histolytica: Causes amebiasis, often in tropical regions.

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• Non-infectious Causes:
• Food allergies
• Medications
• Toxins

7. Transmission
• Fecal-oral route: This is the most common route, where pathogens from
fecal matter reach the mouth via contaminated food, water, or surfaces.
• Person-to-person contact: Particularly in environments such as daycare
centers, nursing homes, and hospitals.
• Contaminated food and water: Poor hygiene and improper food handling
can facilitate the spread.

8. Pathophysiology
Inflammation & Immune Response
Replication & Toxin Production
Adherence to Mucosal Lining
Pathogen Ingestion

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Dehydration
Symptoms: Diarrhea, Vomiting, Abdominal Pain, Fever
Increased Intestinal Secretion & Reduced Absorption

10. Symptoms
• Diarrhea: Often watery and can be frequent, leading to dehydration.
• Vomiting: Common, especially in viral gastroenteritis.
• Abdominal Pain and Cramps: Due to inflammation and increased intestinal
motility.
• Fever: A sign of the body’s immune response to infection.
• Dehydration: Symptoms include dry mouth, decreased urine output, dizziness,
and weakness.

11. Diagnosis
• Clinical Evaluation: Based on symptoms and patient history.
• Stool Tests: To identify the causative pathogen (bacteria, viruses, or
parasites).
• Blood Tests: To check for dehydration and electrolyte imbalances.

12. Treatment
• Rehydration: The primary treatment, particularly oral rehydration solutions
(ORS) to replace lost fluids and electrolytes.
• Dietary Adjustments: Bland, easy-to-digest foods such as the BRAT diet
(bananas, rice, applesauce, toast) can be helpful.

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• Medications:
• Antiemetics: To control vomiting (e.g., ondansetron).
• Antidiarrheals: Antidiarrheals: Loperamide may be used to reduce
diarrhea in non-bacterial cases.
• Antibiotics: Only for bacterial infections confirmed by stool tests.

14. Complications
• Severe Dehydration: Leading to electrolyte imbalances and shock, especially
dangerous in infants, young children, and the elderly.
• Chronic Diarrhea: May occur in cases with parasitic infections or in
immunocompromised individuals.
• Malnutrition: Particularly in prolonged cases, leading to weight loss and
nutritional deficiencies.

15. Prevention
• Hand Hygiene: Regular hand washing with soap and water.
• Food Safety: Proper cooking, handling, and storage of food.
• Clean Water: Ensuring access to clean drinking water and proper
sanitation facilities.

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• Vaccination: Rotavirus vaccine for infants to prevent severe viral
gastroenteritis.
• RotaTeq (RV5):
• Dosing Schedule: Three doses given at 2, 4, and 6 months of age.
• Rotarix (RV1):
• Dosing Schedule: Two doses given at 2 and 4 months of age.