What is the management for a 23-year-old female presenting with nausea, vomiting, and diarrhea that started today, possibly related to a viral illness contracted from her toddler daughter or food poisoning from eating tator tot casserole 2 days ago?

Management of Acute Gastroenteritis in a Young Adult

For this 23-year-old woman with acute nausea, vomiting, and diarrhea that started today, the primary management is oral rehydration therapy with assessment of hydration status, continuation of normal diet as tolerated, and symptomatic treatment without antibiotics or antimotility agents. 1

Initial Assessment

Assess hydration status by evaluating for signs of volume depletion including thirst, tachycardia, orthostatic vital signs, decreased skin turgor, dry mucous membranes, and decreased urination 2, 1. The clinical presentation—with symptom onset 2 days after her daughter's illness and acute onset today—is most consistent with viral gastroenteritis (likely norovirus) rather than bacterial food poisoning, given the timing and household transmission pattern 3, 4.

Rehydration Strategy

For Mild to Moderate Dehydration (Most Likely Scenario)

• Administer oral rehydration solution (ORS) containing 50-90 mEq/L sodium as first-line therapy 1
• If mildly dehydrated (3-5% fluid deficit): provide 50 mL/kg over 2-4 hours 2
• If moderately dehydrated (6-9% fluid deficit): increase to 100 mL/kg over 2-4 hours 2
• Start with small volumes (teaspoon amounts) and gradually increase as tolerated 2
• Replace ongoing losses: 10 mL/kg for each watery stool and 2 mL/kg for each vomiting episode 2

For Severe Dehydration (If Present)

• Administer isotonic IV fluids (Ringer's lactate or normal saline) immediately if there is severe dehydration (≥10% fluid deficit), shock, altered mental status, or inability to tolerate oral intake 2, 1
• Give 20 mL/kg boluses until pulse, perfusion, and mental status normalize 2
• Transition to ORS once the patient can tolerate oral intake 1

For No Dehydration

• Skip rehydration phase and proceed directly to maintenance therapy 2

Antiemetic Therapy

Administer ondansetron or other antiemetic agents to control vomiting and facilitate oral rehydration 1. This is particularly important given her prominent vomiting symptoms and will help her tolerate ORS more effectively.

Nutritional Management

Resume age-appropriate normal diet immediately or as soon as vomiting is controlled—do not withhold food during the illness 1. Provide easily digestible foods like starches, cereals, and cooked vegetables 1. Continuing normal diet during illness actually reduces stool output and improves outcomes 2.

Antimicrobial Therapy: NOT Indicated

Do not prescribe antibiotics for this patient 1. Empiric antimicrobial therapy is not recommended for acute watery diarrhea without recent international travel 1. This patient lacks the specific indications for antibiotics, which include: immunocompromised status, fever with bloody diarrhea suggesting shigellosis, recent international travel with fever ≥38.5°C, or signs of sepsis 1.

The clinical picture (household transmission from toddler, acute onset, predominantly vomiting with diarrhea) strongly suggests viral gastroenteritis, most likely norovirus, which is the most common cause of gastroenteritis in developed countries and frequently transmitted person-to-person in households 3, 4, 5.

Medications to AVOID

• Do not give antimotility agents (loperamide) in the setting of vomiting and acute gastroenteritis of unclear etiology, as these can worsen outcomes if bacterial pathogens are present and may cause toxic megacolon in inflammatory diarrhea 1
• Antimotility drugs should be avoided when there is any concern for inflammatory or febrile diarrhea 1

Adjunctive Therapies

Consider probiotic preparations to reduce symptom severity and duration in this immunocompetent patient 1.

Expected Clinical Course

The illness should resolve within 24-48 hours with supportive care 4. Most viral gastroenteritis cases are self-limited and require only hydration and symptomatic management 3.

Common Pitfalls to Avoid

• Prescribing antibiotics for routine acute watery diarrhea—this provides no benefit and contributes to antimicrobial resistance 1
• Withholding food during the diarrheal episode—early refeeding improves outcomes 1
• Neglecting adequate rehydration while focusing on other treatments 1
• Using antimotility agents in acute gastroenteritis of unclear etiology 1

When to Reassess

Reassess hydration status after 2-4 hours of ORS therapy 2. If symptoms persist beyond 48-72 hours, worsen, or if fever and bloody stools develop, further evaluation including stool studies may be warranted 2, 3.