What is the management approach for a patient with acute gastroenteritis in the Emergency Room (ER)?

Management of Acute Gastroenteritis in the Emergency Room

The primary management of acute gastroenteritis in the ER centers on assessing dehydration severity and initiating appropriate rehydration, with oral rehydration solution as first-line therapy for mild-to-moderate dehydration and IV fluids reserved for severe cases or those unable to tolerate oral intake. 1, 2

Initial Assessment and Risk Stratification

Evaluate Dehydration Severity

• Assess for clinical signs of ≥5% dehydration using the three most reliable predictors: abnormal capillary refill time, abnormal skin turgor, and abnormal respiratory pattern. 3
• Weight loss as percentage of normal body weight provides the best estimate of dehydration degree, though clinical signs are not present until at least 4% body weight loss. 4
• Check vital signs immediately for hemodynamic instability (tachycardia, hypotension, signs of shock). 5
• Obtain hemoglobin/hematocrit and electrolytes in severe cases; low serum bicarbonate combined with clinical parameters predicts dehydration. 5, 3

Determine Need for Diagnostic Testing

• Microbial studies are NOT needed for mild symptoms resolving within one week. 1
• Order multiplex antimicrobial testing (preferred over stool cultures) for: bloody diarrhea, symptoms lasting >7 days, severe dehydration, recent antibiotic exposure (test for Clostridioides difficile), or recent travel to developing countries. 1, 6

Rehydration Strategy

Mild-to-Moderate Dehydration (<10% body weight loss)

• Administer oral rehydration solution (ORS) as first-line therapy; oral or nasogastric rehydration is equally efficacious as IV rehydration in most cases. 2, 3
• ORS should contain appropriate sodium and glucose concentrations for optimal absorption. 4
• If vomiting limits oral intake, consider ondansetron (oral or IV) to decrease vomiting rate, improve oral hydration success, and reduce need for IV fluids and hospitalization. 2, 3

Severe Dehydration (≥10% body weight loss) or Hemodynamic Instability

• Initiate immediate IV fluid resuscitation to normalize blood pressure and heart rate, maintaining mean arterial pressure >65 mmHg while avoiding fluid overload. 5
• Maintain hemoglobin >7 g/dL during resuscitation (consider >9 g/dL for massive bleeding or cardiovascular comorbidities). 5
• Correct electrolyte abnormalities and anemia as identified. 7

Patients Unable to Tolerate Oral Intake

• Use nasogastric rehydration if oral route fails but patient is hemodynamically stable. 2
• Switch to IV hydration if nasogastric route is not tolerated or contraindicated. 2

Adjunctive Symptomatic Management

• Antiemetics (ondansetron) can be used to control vomiting and facilitate oral rehydration, with minimal serious side effects reported and reduced ED length of stay. 3
• Antimotility agents and antisecretory drugs may be used for symptom control in appropriate cases. 1
• Antiemetics and antidiarrhoeals are NOT routinely indicated in children with acute gastroenteritis. 4

Antimicrobial Therapy Indications

Antimicrobial therapy is indicated ONLY for:

• C. difficile infections (confirmed by testing). 1
• Travel-related diarrhea with moderate-to-severe symptoms. 1
• Bacterial infections with severe symptoms (high fever, bloody diarrhea, systemic toxicity). 1
• Confirmed parasitic infections. 1

Do NOT routinely administer antibiotics; reserve for suspected superinfection or presence of intra-abdominal abscesses. 7

Red Flags Requiring Urgent Intervention

Immediate Surgical Consultation Required For:

• Hemodynamic instability despite aggressive resuscitation. 7, 5
• Radiological signs of pneumoperitoneum with free fluid and acute abdomen. 7
• Toxic megacolon with perforation, massive bleeding, clinical deterioration, or shock. 7
• Life-threatening hemorrhage with persistent hemodynamic instability. 8, 5

Consider Alternative Diagnoses

• Vomiting and diarrhea can be nonspecific symptoms; carefully exclude other causes including surgical emergencies, metabolic disorders, and systemic infections before diagnosing viral gastroenteritis. 4
• Perform CT angiography in hemodynamically unstable patients with GI bleeding rather than endoscopy, as it can detect bleeding at rates of 0.3 mL/min. 5

Special Populations

Inflammatory Bowel Disease Patients

• Evaluate hemodynamically stable IBD patients with multidisciplinary gastroenterology input for initial medical treatment options. 5
• Perform sigmoidoscopy and esophagogastroduodenoscopy first in stable IBD patients with GI bleeding. 5
• Emergency surgery (subtotal colectomy with ileostomy) is indicated for acute severe ulcerative colitis with massive hemorrhage unresponsive to medical treatment. 8, 5

Pediatric Patients

• Preventing dehydration or providing appropriate rehydration is the primary treatment goal. 6
• Hypoglycemia may develop in cases of prolonged vomiting and diarrhea; monitor glucose levels in severe cases. 2

Critical Pitfalls to Avoid

• Do not delay IV rehydration in severely dehydrated or hemodynamically unstable patients while attempting oral rehydration. 5
• Do not assume lower GI source without excluding upper GI bleeding, as rapid transit can present with bright red rectal bleeding. 5
• Do not delay surgical consultation in critically ill patients with signs of perforation, toxic megacolon, or uncontrolled bleeding. 7
• Do not routinely order stool cultures; multiplex antimicrobial testing is preferred when testing is indicated. 1

Disposition and Follow-Up

• Most patients with mild-to-moderate gastroenteritis can be discharged after successful rehydration with ORS. 2
• Admit patients requiring IV rehydration, those with severe dehydration, hemodynamic instability, or inability to maintain oral intake. 3
• Counsel patients that approximately 9% develop postinfectious irritable bowel syndrome, accounting for >50% of all IBS cases. 1
• Advise that postinfectious lactose intolerance may occur temporarily. 1