Treatment of Nausea, Bilious Vomiting, and Diarrhea
Start oral rehydration solution (ORS) immediately at 50-100 mL/kg over 2-4 hours if the patient shows mild-to-moderate dehydration, and avoid empiric antibiotics unless specific high-risk features are present. 1
Immediate Assessment and Red Flags
First, assess hydration status by checking for:
- Abnormal capillary refill, skin turgor, or respiratory pattern 2
- Postural light-headedness or reduced urination 1
- Altered mental status 1
Critical warning: Bilious vomiting can signal intestinal obstruction or ileus—if the patient has severe abdominal distension, absent bowel sounds, or peritoneal signs, this requires immediate surgical evaluation and IV fluids, not oral rehydration. 1
Rehydration Protocol
For Mild-to-Moderate Dehydration (3-9% fluid deficit):
- Administer reduced-osmolarity ORS (e.g., Pedialyte, Ceralyte) at 50-100 mL/kg over 2-4 hours 1, 3
- Replace each watery stool with an additional 10 mL/kg of ORS 1, 3
- Replace each vomiting episode with 2 mL/kg of ORS 3
- If the patient cannot tolerate oral intake due to persistent vomiting, consider nasogastric administration of ORS rather than jumping to IV fluids 1, 3, 4
For Severe Dehydration or Treatment Failure:
- Start isotonic IV fluids (lactated Ringer's or normal saline) immediately if any of the following are present: 1, 3
- Severe dehydration (≥10% fluid deficit)
- Shock or altered mental status
- Inability to tolerate oral/NG intake
- Ileus (suggested by bilious vomiting with distension)
- Continue IV fluids until pulse, perfusion, and mental status normalize, then transition to ORS for remaining deficit 1, 3
Antiemetic Therapy
Ondansetron can be given to facilitate ORS tolerance if the patient is >4 years old 1, 3, 5
- This reduces vomiting, improves oral intake success, and decreases need for IV hydration 2
- In younger children or infants, use is more controversial but may be considered in select cases 6, 2
Antibiotic Decision Algorithm
Do NOT give empiric antibiotics for this presentation unless specific criteria are met: 1, 3, 5
Antibiotics ARE indicated if:
- Immunocompromised with severe illness 1, 3
- Infant <3 months appearing toxic 3, 5
- Bloody diarrhea with fever, abdominal pain, and tenesmus (suggests Shigella) 1, 3
- Recent international travel with fever ≥38.5°C or sepsis signs 3, 5
- Clinical sepsis with suspected enteric fever 1, 3
Antibiotics are CONTRAINDICATED if:
- Shiga toxin-producing E. coli (STEC) is suspected—antibiotics increase risk of hemolytic uremic syndrome 1, 3, 5
- Look for bloody diarrhea without fever in this context 1
For typical acute watery diarrhea with vomiting:
- Empiric antibiotics provide minimal benefit (shorten illness by ~1 day) and promote resistance 1, 3, 5
- Avoid antibiotics in persistent diarrhea lasting ≥14 days 1, 5
Dietary Management
Resume normal age-appropriate diet immediately during or after rehydration—do not withhold food 1, 3, 5
- Early refeeding prevents malnutrition and may reduce stool output 1, 3
- Continue breastfeeding throughout illness in infants 1, 3, 5
Antimotility Agents
Never give loperamide to children <18 years 1, 3, 5
For adults:
- Loperamide may be used only after adequate hydration and only if no fever or bloody diarrhea 1, 5
- Avoid in any patient with suspected inflammatory diarrhea due to toxic megacolon risk 1, 3, 5
Common Pitfalls to Avoid
- Don't assume all bilious vomiting is simple gastroenteritis—rule out obstruction/ileus first 1
- Don't order routine labs (electrolytes, BUN/Cr) in uncomplicated cases—they rarely change management and add cost 2, 4
- Don't give IV fluids reflexively—ORS or NG-ORS works equally well for moderate dehydration and has fewer complications 1, 3, 4
- Don't prescribe antibiotics "just in case"—they cause harm without benefit in viral or STEC infections 1, 3, 5
- Don't restrict diet during rehydration—this worsens outcomes 3, 5