Clinical Approach: Vomiting (5x) + Loose Stools (6x) + Fever + Generalized Weakness

Likely Diagnosis

Step 1: Immediate Assessment

Assess Dehydration Severity (MOST URGENT)

• Bloody diarrhea
• High fever (>39°C)
• Signs of sepsis (hypotension, altered consciousness)
• Inability to keep any fluids down
• Severe dehydration / shock

Step 2: History Taking

• Duration of symptoms (onset?)
• Character of stool - watery / mucoid / bloody?
• Associated abdominal pain / cramps?
• Recent food intake (shared meal? outside food? raw seafood?)
• Travel history
• Similar illness in contacts/family
• Last urine output (helps gauge dehydration)
• Comorbidities (diabetes, immunosuppression, renal disease)
• Current medications (especially antibiotics, PPIs, opioids)
• Age (elderly and very young are high-risk)

Step 3: Investigations

Routine (most cases don't need extensive workup)

• Blood glucose - hypoglycemia can cause weakness
• Serum electrolytes (Na, K, Cl, HCO3) - only if moderate-severe dehydration or IV fluids needed
• BUN/Creatinine - if suspecting prerenal AKI
• CBC - if bacterial cause suspected (leukocytosis)

Selective

• Stool routine + microscopy - if bloody stool, prolonged illness, or suspected parasites
• Stool culture - if high fever, bloody diarrhea, immunocompromised, travel history
• Blood cultures - if systemic sepsis suspected
• Stool for ova & parasites - if symptoms >2 weeks, travel, immunocompromised

Per Tintinalli's Emergency Medicine: "Investigations do not need to be performed routinely in children with signs and symptoms of acute gastroenteritis. Serum electrolytes are useful in children with severe dehydration requiring IV hydration." - Swanson's Family Medicine Review

Step 4: Management

A. Rehydration (Priority #1)

• WHO-recommended ORS composition: 75 mmol Na+, 20 mmol K+, 65 mmol Cl-, 10 mmol citrate, 75 mmol glucose
• Give small frequent sips (5-10 mL every 5 minutes initially if vomiting)
• Avoid: fruit juices, carbonated drinks, sports drinks - high osmolarity worsens fluid loss

• Severe dehydration / hemodynamic instability
• Persistent vomiting preventing oral intake
• Altered consciousness

• Bolus 20 mL/kg over 15-30 min if in shock, then reassess

B. Antiemetics

• Ondansetron 4-8 mg IV/oral - reduces vomiting, shortens ED stay, improves ability to tolerate ORS
• Metoclopramide as alternative
• Antiemetics allow oral rehydration to work - use them early

C. Antipyretics

• Paracetamol (Acetaminophen) 500-1000 mg (adult) for fever and weakness/malaise
• Avoid NSAIDs if severe dehydration (risk of renal impairment)

D. Antimotility agents

• Loperamide (2 mg after each loose stool, max 16 mg/day in adults) - only for non-bloody diarrhea WITHOUT fever
• Do NOT use if: bloody diarrhea, high fever, children - risk of prolonging illness or toxic megacolon

E. Antibiotics - NOT routinely indicated

• Immunocompromised patients with severe illness
• Documented fever + bloody diarrhea + suspected Shigella (bacillary dysentery)
• Recent international travelers with fever ≥38.5°C or signs of sepsis
• Infants <3 months

• Ciprofloxacin 500 mg PO twice daily x 3-5 days, OR
• Levofloxacin 500 mg PO once daily x 3-5 days, OR
• Azithromycin 500 mg PO once daily x 3 days (preferred in children, pregnant women, or fluoroquinolone-resistant areas)

Important: Avoid antibiotics if STEC (E. coli O157:H7) is suspected - increases risk of hemolytic-uremic syndrome (HUS).

F. Probiotics (adjunct)

• Lactobacillus strains may reduce duration of diarrhea by 1-2 days (supportive evidence)

G. Diet

• Resume normal feeding as soon as tolerated - do not starve the patient
• The old BRAT diet (bananas, rice, applesauce, toast) has no proven superiority over regular diet
• Avoid fatty, spicy foods initially

Step 5: Disposition

• Severe dehydration or hemodynamic instability
• Bloody diarrhea with high fever (possible dysentery/sepsis)
• Cannot tolerate any oral fluids despite antiemetics
• Elderly, infant, immunocompromised, pregnant
• Electrolyte abnormalities (hyponatremia, severe hypokalemia)

• Mild-moderate dehydration, tolerating ORS
• No red flags
• Clear follow-up plan
• Educate on: hand hygiene, proper food handling, when to return (worsening, blood in stool, no urine for 8+ hours, high fever)

Summary Algorithm

Vomiting + Diarrhea + Fever + Weakness
        ↓
Assess dehydration severity
        ↓
Mild-Moderate          Severe/Shock
ORS + Antiemetic    →   IV fluids stat (NS/RL)
        ↓
Check for bloody stool / high fever?
        ↓
No → Supportive care, no antibiotics
Yes → Consider stool culture, CBC, blood culture
      Empiric antibiotics if criteria met (IDSA 2017)
        ↓
Reassess in 4-6 hours

• Tintinalli's Emergency Medicine (9th Ed.) - Foodborne Illnesses chapter
• Swanson's Family Medicine Review - Acute Gastroenteritis
• IDSA 2017 Guidelines on Acute Diarrhea (cited in Tintinalli's)

Treatment Plan

1. REHYDRATION (Most Important)

If Mild-Moderate Dehydration → Oral Rehydration Therapy (ORT)

• ORS (WHO formula) - sip slowly, 200-400 mL after each loose stool
• Small sips every 5 minutes if still vomiting
• Target: 50-100 mL/kg over 4 hours for rehydration
• Avoid: fruit juice, cola, sports drinks

If Severe Dehydration / Cannot Tolerate Oral → IV Fluids

• Normal Saline (0.9% NaCl) or Ringer's Lactate
• If in shock: 20 mL/kg bolus over 15-30 min, then reassess
• If moderate dehydration on IV: 1-2 L over 2-4 hours
• Monitor urine output (target >0.5 mL/kg/hr)

2. ANTIEMETICS (Give Early)

3. ANTIPYRETICS (for Fever + Weakness)

4. ANTIDIARRHEAL

• Loperamide 2 mg after each loose stool (max 16 mg/day)
• ONLY for adults with watery (non-bloody) diarrhea
• Do NOT give if: bloody stool, high fever, children under 2 - risk of toxic megacolon and prolonged illness

5. ANTIBIOTICS

• Bloody diarrhea + high fever (suspected Shigella/Salmonella)
• Immunocompromised patient
• Traveler's diarrhea with fever ≥38.5°C
• Suspected cholera

Avoid antibiotics if E. coli O157:H7 suspected - increases risk of HUS (Hemolytic Uremic Syndrome)

6. ELECTROLYTE CORRECTION

• Hypokalemia - add KCl to IV fluids or give oral potassium (Syrup Potassium Chloride)
• Metabolic acidosis - ensure adequate rehydration; IV sodium bicarbonate if severe (pH <7.1)

7. DIET & SUPPORTIVE CARE

• NPO not recommended - resume feeding early once vomiting settles
• Start with light, easily digestible food: rice, boiled vegetables, banana, curd
• Avoid: spicy, fatty, oily foods for 2-3 days
• Zinc supplementation (10-20 mg/day x 10-14 days) - especially in children; reduces duration and severity
• Probiotics (Lactobacillus - Sporlac, Enterogermina) - adjunct to reduce diarrhea duration

8. MONITORING

• Vitals every 4-6 hours (BP, pulse, temperature)
• Urine output (keep input-output chart)
• Reassess dehydration after initial rehydration
• Repeat electrolytes if on IV fluids

When to Escalate / Admit

• Persistent vomiting despite antiemetics
• Bloody diarrhea with high fever
• No urine output for >6-8 hours
• Altered consciousness or shock
• Electrolyte imbalance on labs

Quick Prescription Summary (Adult Patient)

1. IV NS / RL 1L over 4 hrs (if moderate dehydration)
   OR ORS 200 mL after each loose stool (if mild)

2. Inj. Ondansetron 4 mg IV every 8 hrs

3. Tab. Paracetamol 500 mg PO every 6 hrs (if fever)

4. Tab. Loperamide 2 mg after each loose stool
   (only if no blood/no high fever)

5. ORS sachets - 1 sachet in 200 mL water after each stool

6. Tab. Norfloxacin 400 mg + Metronidazole 400 mg
   BD x 5 days (only if bacterial cause suspected)

7. Probiotics - BD x 5 days