Overview
Definition:
Acute gastroenteritis is an acute inflammation of the gastrointestinal tract, primarily the stomach and intestines, characterized by vomiting and diarrhea
It is a leading cause of morbidity and mortality in children worldwide, often caused by viral, bacterial, or parasitic pathogens.
Epidemiology:
Affects millions of children annually, with viral pathogens like rotavirus being the most common cause in unvaccinated populations
Incidence peaks in younger children (6 months to 2 years)
Significant global health burden, especially in developing countries due to poor sanitation and limited access to clean water.
Clinical Significance:
Dehydration is the most serious complication, leading to electrolyte imbalances, shock, and potentially death if not managed promptly
Understanding appropriate fluid management strategies (ORT vs
IV fluids) and adjunctive therapies like antiemetics is crucial for effective pediatric patient care and successful DNB/NEET SS examination outcomes.
Clinical Presentation
Symptoms:
Sudden onset of watery diarrhea
Vomiting, often forceful and preceding diarrhea
Abdominal pain and cramping
Fever, anorexia, malaise
Blood or mucus in stool (suggestive of bacterial etiology)
Duration typically 1-7 days.
Signs:
Signs of dehydration: decreased urine output, dry mucous membranes, sunken eyes, poor skin turgor, lethargy, irritability, rapid heart rate, sunken fontanelle in infants
Severe dehydration may show altered mental status, absent urine output, and hypotension.
Diagnostic Criteria:
Diagnosis is primarily clinical, based on the history of acute onset vomiting and diarrhea, with assessment of hydration status being paramount
Laboratory investigations are usually not required for mild to moderate cases but may be indicated for severe or persistent symptoms, or suspicion of specific pathogens.
Diagnostic Approach
History Taking:
Detailed history of onset, frequency, and character of diarrhea and vomiting
Fluid intake and output
Presence of fever, abdominal pain
Recent travel, sick contacts, or consumption of contaminated food/water
Previous episodes of gastroenteritis or underlying medical conditions
Red flags include bloody stools, high fever, severe abdominal pain, signs of dehydration, and inability to tolerate oral fluids.
Physical Examination:
Thorough assessment of hydration status: mucous membranes, eyes, skin turgor, fontanelle in infants
Vital signs: heart rate, respiratory rate, blood pressure, temperature
Abdominal examination for distension, tenderness, or organomegaly
Neurological assessment for lethargy or irritability.
Investigations:
Stool examination: for ova, parasites, white blood cells, or occult blood (indicated in severe or persistent diarrhea)
Stool culture: for suspected bacterial pathogens (e.g., Salmonella, Shigella, Campylobacter, E
coli) if fever is high, stools are bloody, or outbreak is suspected
Electrolyte and renal function tests: essential in moderate to severe dehydration or if IV fluids are required
Complete blood count: may show hemoconcentration in dehydration.
Differential Diagnosis:
Surgical causes of abdominal pain and vomiting: intussusception, appendicitis, volvulus
Systemic infections: pneumonia, urinary tract infection, sepsis
Inborn errors of metabolism
Food allergies or intolerances
Inflammatory bowel disease (less common in acute settings).
Management
Initial Management:
The primary goal is to correct and prevent dehydration
Assessment of dehydration severity using WHO or modified clinical dehydration scales guides management
Prompt initiation of fluid therapy.
Medical Management:
Oral Rehydration Therapy (ORT): Preferred method for mild to moderate dehydration
Use of WHO oral rehydration solution (ORS) or commercially available pediatric ORS
Administer small, frequent sips (5-10 mL/kg) every few minutes, increasing frequency as tolerated
For vomiting, start with small amounts and increase gradually
Intravenous (IV) Fluids: Indicated for severe dehydration, shock, persistent vomiting, or inability to tolerate ORT
Initial bolus of isotonic crystalloids (e.g., Ringer's Lactate, 0.9% Normal Saline) at 20 mL/kg over 1-2 hours, followed by maintenance fluids and electrolyte correction based on ongoing losses and serum electrolyte levels
Ondansetron: A 5-HT3 receptor antagonist used as an antiemetic to reduce vomiting and improve ORT tolerance
Dose is typically 0.1 mg/kg per dose IV/PO, maximum 4 mg/dose, every 8 hours for up to 48 hours
Particularly useful in viral gastroenteritis
Antibiotics: Generally not indicated for viral gastroenteritis
Reserved for specific bacterial infections confirmed by stool culture (e.g., Shigella, Salmonella in specific hosts, severe Vibrio cholerae)
Antidiarrheals: Generally not recommended in children, especially those under 5 years old, due to potential for increased adverse effects and risk of toxic megacolon.
Surgical Management:
Rarely indicated for acute gastroenteritis itself, but essential if a surgical condition is the underlying cause (e.g., intussusception requiring reduction, appendicitis requiring appendectomy).
Supportive Care:
Frequent monitoring of hydration status, vital signs, and urine output
Encouragement of early feeding with breast milk or formula as tolerated after rehydration
Avoidance of sugary drinks or clear liquids which can worsen diarrhea
Education of caregivers on ORT administration and signs of worsening dehydration.
Complications
Early Complications:
Dehydration (mild, moderate, severe)
Electrolyte disturbances: hyponatremia, hypernatremia, hypokalemia, hyperkalemia
Hypoglycemia
Shock (hypovolemic)
Water intoxication (in cases of excessive hypotonic fluid intake).
Late Complications:
Malnutrition and growth faltering (especially with prolonged or recurrent episodes)
Reactive arthritis (post-Shigella)
Hemolytic Uremic Syndrome (HUS) (post-E
coli O157:H7 infection)
Post-infectious lactose intolerance.
Prevention Strategies:
Vaccination against rotavirus
Improved sanitation and hygiene practices
Safe food handling
Exclusive breastfeeding for infants
Prompt and appropriate rehydration with ORT.
Prognosis
Factors Affecting Prognosis:
Severity of dehydration at presentation
Promptness and adequacy of fluid management
Presence of co-morbidities
Age of the child (infants are at higher risk)
Etiological agent (some bacterial infections carry higher risks).
Outcomes:
With prompt and appropriate management, most cases of acute gastroenteritis in children have an excellent prognosis, with complete recovery
Severe dehydration and shock can be life-threatening if not managed effectively.
Follow Up:
Follow-up is generally not required for uncomplicated cases
Children with severe dehydration, complications, or specific bacterial infections may require follow-up to ensure complete recovery and monitor for any sequelae
Education on continued oral rehydration and nutrition is crucial.
Key Points
Exam Focus:
Prioritize hydration assessment and management
Differentiate ORT indications from IV fluid indications
Understand the role and dosing of ondansetron for vomiting
Recognize red flags for specific bacterial causes or surgical emergencies
Recall electrolyte derangements in dehydration.
Clinical Pearls:
Always assess hydration status first
Start ORT as early as possible
Small, frequent sips are key for ORT tolerance, especially with vomiting
Ondansetron can significantly improve ORT tolerance
Avoid anti-diarrheals in young children
Educate parents thoroughly on ORT administration at home.
Common Mistakes:
Underestimating dehydration severity
Delayed initiation of fluid therapy
Inadequate ORS volume or frequency
Over-reliance on IV fluids for mild dehydration
Using sugary drinks instead of ORS
Inappropriate use of antibiotics or anti-diarrheals.