What is the first line of treatment for a patient with Acute Gastroenteritis (AGE) and moderate dehydration?

Admission Orders for AGE with Moderate Dehydration

Initiate oral rehydration solution (ORS) at 100 mL/kg (approximately 5,300 mL for this 53 kg patient) administered over 2-4 hours as first-line therapy for moderate dehydration. 1, 2

Immediate Rehydration Protocol

Primary Treatment: Oral Rehydration Solution

• Administer reduced osmolarity ORS as the definitive first-line treatment for this patient with moderate dehydration (6-9% fluid deficit), as this represents strong evidence from the 2017 IDSA guidelines 1
• Start with small volumes using a syringe or medicine dropper (approximately 5-10 mL every few minutes), then gradually increase as tolerated given the 4-day history of vomiting 2
• The tachycardia (HR 118) and borderline blood pressure (100/50) indicate moderate dehydration requiring aggressive oral rehydration, not IV therapy at this stage 1

Alternative Route if Oral Intake Fails

• Consider nasogastric administration of ORS if the patient cannot tolerate oral intake or refuses to drink adequately, as this is preferred over immediate IV therapy for moderate dehydration 1, 2

Replace Ongoing Losses

• Administer 10 mL/kg (530 mL) of ORS for each watery stool passed 1, 2
• Administer 2 mL/kg (106 mL) of ORS for each vomiting episode 1, 2

Monitoring Parameters

Reassessment Timeline

• Reassess hydration status after 2-4 hours by evaluating vital signs (particularly heart rate and blood pressure), skin turgor, capillary refill, mental status, and mucous membrane moisture 1, 2
• If still dehydrated after initial ORS therapy, reestimate the fluid deficit and restart rehydration 1, 2
• Monitor vital signs every 2-4 hours to detect progression to severe dehydration 2

Criteria for IV Therapy

• Reserve intravenous rehydration only if: the patient develops altered mental status, shock, failure of ORS therapy, or ileus 1
• If IV therapy becomes necessary, use isotonic fluids (lactated Ringer's or normal saline) 1

Adjunctive Management

Antiemetic Therapy

• Ondansetron may be administered to facilitate tolerance of oral rehydration, though this patient at 33 years old is well above the guideline-specified age threshold (>4 years) 1
• This should only be used to enhance ORS compliance, not as a substitute for fluid therapy 1

Nutritional Management

• Resume age-appropriate diet immediately once rehydration begins or is completed 1, 2
• Do not restrict diet or implement fasting protocols 2
• Avoid foods high in simple sugars as they can worsen diarrhea through osmotic effects 2

Antimicrobial Therapy

• Do not initiate empiric antimicrobial therapy for this immunocompetent adult with acute watery diarrhea and no recent international travel 1
• Antimotility agents (loperamide) may be considered once adequately hydrated, but only if there is no fever or bloody diarrhea 1, 2

Critical Pitfalls to Avoid

• Do not delay rehydration while awaiting diagnostic testing; begin ORS immediately 2
• Do not use sports drinks or juices as primary rehydration solutions for moderate dehydration; only reduced osmolarity ORS is appropriate 2
• Do not jump to IV therapy prematurely; the evidence strongly supports ORS as first-line even for moderate dehydration in adults 1
• Do not administer antimotility drugs if fever develops or if bloody diarrhea occurs 1, 2

Disposition Planning

Discharge Criteria

• Patient tolerating oral intake without significant vomiting 2
• Producing adequate urine output 2
• Clinically rehydrated with normalized vital signs (HR <100, BP stable) 2
• Able to continue ORS at home for ongoing losses 1