Abdominal Pain + Diarrhea + Vomiting: Diagnosis & Management

Step 1 - Differential Diagnosis

Key red flag: If peritoneal signs (rebound, guarding, rigidity) are present - do NOT label as gastroenteritis. Pursue surgical workup urgently. - Tintinalli's Emergency Medicine

Step 2 - History & Physical Exam Focus

• Onset, duration, frequency of stools, presence of blood/mucus
• Associated fever (suggests bacterial or invasive pathogen)
• Recent food intake (timing matters: 1-6 h = preformed toxin; 8-24 h = bacterial; >24 h = viral/parasitic)
• Travel history (traveler's diarrhea - ETEC most common cause)
• Antibiotic use (C. difficile risk)
• Contact with sick individuals, day care, institutionalized settings
• Immunocompromised state (HIV, transplant, steroids)

Step 3 - Investigations

Step 4 - Management

A. Rehydration (First Priority)

• Use hypotonic ORS (WHO-modified 245 mOsm solution)
• Mild dehydration: 50 mL/kg over 4 hours
• Moderate dehydration: 100 mL/kg over 4 hours
• IV fluids (isotonic, e.g., Lactated Ringer's): reserved for severe dehydration, intractable vomiting, or shock - give 20 mL/kg bolus
• Replace ongoing losses: 5-10 mL/kg per loose stool

B. Antiemetics

• Ondansetron (Zofran): 0.15 mg/kg (max 8 mg) PO or IV - safe, reduces IV fluid needs and hospitalization
• Mechanism: blocks 5-HT3 receptors on intestinal vagal afferents
• Reduces vomiting and improves tolerance of ORT

C. Diet

• Continue feeding - fasting worsens bowel absorptive capacity
• Restart age-appropriate diet as soon as tolerated (BRAT diet no longer recommended as it has low nutritional value)
• Continue breastfeeding in infants
• Avoid hyperosmolar sports drinks (worsen osmotic diarrhea)

D. Antimotility Agents

• Loperamide: can be used in adults with mild-moderate watery diarrhea (no fever/blood)
• Avoid in fever, bloody stools, suspected Shiga toxin-producing E. coli (increases HUS/TTP risk), or children
• If used with fever/bloody stools, must combine with antibiotics

E. Antibiotics - Pathogen-Specific

Step 5 - Admission vs. Discharge

• Moderate-severe dehydration not responding to ORT
• Intractable or bilious vomiting
• Suspected surgical condition (peritoneal signs)
• Significant laboratory abnormalities, neurologic changes (seizures, lethargy)
• Extremes of age (infants <3 months, elderly)
• Immunocompromised patients
• C. difficile with toxic megacolon features

• Mild/no dehydration, tolerating ORT
• No red flags on history or exam
• Adequate home support; give written instructions to return if unable to tolerate fluids, bilious vomiting, worsening dehydration

Step 6 - Common Pathogens Summary

Management of Acute Gastroenteritis (Short)

1. Rehydration

• Mild-Moderate: Oral Rehydration Solution (ORS) - WHO 245 mOsm
• Severe/intractable vomiting: IV Lactated Ringer's or Normal Saline 20 mL/kg bolus
• Replace ongoing losses: 5-10 mL/kg per loose stool

2. Antiemetics

• Ondansetron 0.15 mg/kg (max 8 mg) PO/IV

3. Diet

• Continue feeding early - do NOT fast
• Continue breastfeeding in infants
• Avoid sugary drinks/fruit juice

4. Antimotility (adults only)

• Loperamide - only for watery diarrhea, no fever, no blood
• Avoid in children and suspected STEC (E. coli O157:H7)

5. Antibiotics (selective, not routine)

6. Admit if:

• Severe dehydration, bilious vomiting, peritoneal signs
• Infants <3 months, elderly, immunocompromised
• Unable to tolerate ORT at home

7. Discharge if:

• Mild dehydration, tolerating ORS, no red flags
• Give written instructions to return if worsening

Inj. EELD-VIT-12 - What It Is & How to Use

What Is It?

What Is It Used For?

How to Use (Step by Step)

1. Mix the contents of Part 1 (yellow ampoule - Vitamin C) with Part 2 (red/brown ampoule - B12 + Folic acid + Nicotinamide) in one syringe
2. Check the solution - do NOT use if particles are visible or solution is cloudy
3. Administer by:
   • IM injection - usually given in the deltoid (upper arm) or gluteus muscle
   • IV drip - diluted and administered slowly
4. Dose: As directed by the physician (label states "as directed by physician")

Important Cautions

• Must be given by a qualified healthcare professional (doctor or nurse) - not for self-injection
• Do not use if the solution has visible particles or discoloration
• Store in a cool, dark place - away from sunlight (light degrades B12 and Vitamin C)
• Keep out of reach of children
• Prescription only - do not use without medical advice

Relevance to Your Gastroenteritis Patient

• Vomiting and diarrhea deplete water-soluble vitamins (B12, C, folate)
• Helps in recovery and nutritional rehabilitation
• Vitamin C supports immune function and tissue repair