What is the treatment plan for an adult with nausea and diarrhea?

Treatment Plan for Nausea and Diarrhea in Adults

The cornerstone of treatment is immediate oral rehydration with reduced osmolarity oral rehydration solution (ORS), followed by early resumption of normal diet, with antiemetics and antimotility agents reserved as ancillary therapy only after adequate hydration is achieved. 1

Immediate Assessment

Assess hydration status first by evaluating for:

• Orthostatic hypotension
• Skin turgor and dry mucous membranes
• Mental status changes
• Urine output and weakness 2

Identify warning signs that require medical supervision:

• High fever (>38.5°C) with bloody stools (dysentery)
• Severe vomiting preventing oral intake
• Signs of severe dehydration or shock
• Altered mental status 1

Rehydration Strategy (First-Line Treatment)

Mild to Moderate Dehydration

Reduced osmolarity ORS is the first-line therapy (strong recommendation, moderate evidence) 1

• Start ORS immediately and continue until clinical dehydration is corrected 1
• Administer small, frequent volumes (5 mL every minute initially) if vomiting is present 2
• Use a spoon or syringe for gradual progression 2
• Replace ongoing losses from stools and vomiting with ORS until symptoms resolve 1
• Maintain adequate fluid intake guided by thirst; glucose-containing drinks (lemonades, fruit juices) or electrolyte-rich soups are acceptable alternatives 1

Severe Dehydration

Isotonic intravenous fluids (lactated Ringer's or normal saline) are required when there is:

• Severe dehydration with shock
• Altered mental status
• Failure of ORS therapy
• Ileus (strong recommendation, high evidence) 1

Continue IV rehydration until pulse, perfusion, and mental status normalize, then transition to ORS for remaining deficit replacement 1

Dietary Management

Resume age-appropriate normal diet immediately upon rehydration (strong recommendation, low evidence) 1

• Continue usual diet during diarrhea 2
• Recommended foods: starches, cereals, yogurt, fruits, vegetables 2
• Avoid foods high in simple sugars and fats 2
• There is no evidence that withholding solid food for 24 hours is beneficial 1

Symptomatic Treatment (Ancillary Only)

For Nausea/Vomiting

Antiemetics may be used to facilitate oral rehydration once adequate hydration begins, but are not a substitute for fluid therapy (weak recommendation, low evidence) 1

• Ondansetron can be given to facilitate tolerance of ORS 1
• Important caveat: Ondansetron may increase stool volume as a side effect 1, 3
• Simultaneous correction of dehydration often reduces vomiting frequency 2

For Diarrhea

Loperamide may be given to immunocompetent adults with acute watery diarrhea (weak recommendation, moderate evidence) 1

• Initial dose: 4 mg, followed by 2 mg every 4 hours or after each unformed stool 2
• Maximum: 16 mg/day 2
• Critical contraindications: Avoid loperamide if there is fever, bloody stools, or suspected inflammatory diarrhea due to risk of toxic megacolon 1
• Loperamide is the drug of choice for self-medication; other antimotility agents are not recommended 1

Antimicrobial Therapy

Empiric antimicrobials are NOT recommended for most adults with acute watery diarrhea without recent international travel (strong recommendation, low evidence) 1

Consider empiric antibiotics only if:

• Fever is present with suspected bacterial infection 2
• Fluoroquinolones are first-line agents when indicated 2

Avoid antimicrobials if:

• STEC (Shiga toxin-producing E. coli) is suspected or confirmed, as they increase risk of hemolytic uremic syndrome 2

Modify or discontinue antimicrobials when a specific pathogen is identified 1, 2

Adjunctive Therapies

Probiotics may be offered to reduce symptom severity and duration in immunocompetent adults (weak recommendation, moderate evidence) 1

When to Seek Medical Attention

Patients should seek medical care if:

• No improvement within 48 hours 1
• Symptoms worsen or overall condition deteriorates 1
• Warning signs develop: severe vomiting, dehydration, persistent fever, abdominal distension, or bloody stools 1
• Diarrhea persists beyond 48 hours despite treatment 2

Common Pitfalls to Avoid

• Do not delay ORS administration – it is the most effective intervention and should begin immediately 1
• Do not use antimotility agents as first-line therapy – hydration takes priority 1
• Do not give loperamide with fever or bloody stools – this can precipitate toxic megacolon 1
• Do not withhold food – early refeeding improves outcomes 1, 2
• Do not use empiric antibiotics routinely – they are rarely indicated and can cause harm 1, 2