What is the management algorithm for a patient with high fever (≥38.5 °C) and dysentery?

Management Algorithm for High Fever and Dysentery

For a patient presenting with high fever (≥38.5°C) and dysentery, empiric antibiotic therapy should be initiated immediately with either azithromycin 1000 mg single dose or a fluoroquinolone (ciprofloxacin 500 mg twice daily for 3 days), depending on travel history and local resistance patterns, while simultaneously obtaining stool cultures and blood cultures. 1

Initial Assessment and Stabilization

Immediate Vital Signs and Clinical Evaluation

• Measure temperature using oral or rectal methods (central monitoring if critically ill) 1, 2
• Assess for signs of sepsis: hypotension (systolic BP <90 mmHg), tachycardia (>100/min), tachypnea (>24/min), altered mental status 1
• Check oxygen saturation; maintain SaO2 ≥92% with supplemental oxygen if needed 1
• Document frequency of bloody stools, presence of tenesmus, and abdominal pain severity 1

Risk Stratification for Empiric Antibiotics

Empiric antibiotics are indicated if the patient has: 1

• Body temperature ≥38.5°C documented in medical setting
• Bloody diarrhea with fever and abdominal cramps
• Signs of bacillary dysentery (frequent scant bloody stools, fever, tenesmus)
• Recent international travel with fever ≥38.5°C
• Signs of sepsis or hemodynamic instability

Diagnostic Workup (Obtain Before Antibiotics When Possible)

Essential Laboratory Studies

• Blood cultures (two sets from separate sites) before antibiotic administration 1, 2
• Stool culture with specific request for Shigella, Salmonella, Campylobacter 1, 3
• Complete blood count (expect leukocytosis, possible anemia) 1
• Comprehensive metabolic panel including creatinine and electrolytes 1
• Do NOT test for Shiga toxin-producing E. coli (STEC) susceptibility if suspected, as antibiotics should be avoided 1

Additional Testing Based on Clinical Context

• Stool examination for ova and parasites if travel to endemic areas (consider Entamoeba histolytica) 1, 3
• Chest radiograph if respiratory symptoms present 2
• Blood lactate if signs of sepsis 1

Empiric Antibiotic Selection Algorithm

First-Line Therapy for Dysentery with High Fever

Option 1 (Preferred in most settings): 1, 4

• Azithromycin 1000 mg single dose (covers Shigella, Salmonella, Campylobacter including fluoroquinolone-resistant strains)

Option 2 (Alternative based on local resistance): 1, 4

• Ciprofloxacin 500 mg twice daily for 3 days OR
• Levofloxacin 500 mg once daily for 3 days
• Use fluoroquinolones ONLY if local Shigella resistance rates are low and patient has not traveled to South/Southeast Asia where resistance is high 1, 4

Special Populations Requiring Modified Approach

Immunocompromised patients: 1

• Initiate empiric broad-spectrum antibiotics immediately
• Consider third-generation cephalosporin (ceftriaxone) plus azithromycin
• Lower threshold for hospitalization

Infants <3 months: 1

• Ceftriaxone (third-generation cephalosporin) is preferred
• Hospitalize for parenteral therapy

Patients with neurologic symptoms: 1

• Use third-generation cephalosporin (suggests possible invasive Salmonella)

Critical Management Decisions

When to AVOID Antibiotics

Do NOT give antibiotics if STEC O157 or Shiga toxin 2-producing STEC is suspected or confirmed 1

• Antibiotics increase risk of hemolytic uremic syndrome (HUS)
• Suspect STEC if: bloody diarrhea without fever, recent ground beef consumption, outbreak setting
• If STEC confirmed, provide supportive care only with aggressive hydration

Supportive Care Measures

• Aggressive fluid resuscitation for hypotension or signs of dehydration 1
• Monitor urine output, aim for >0.5 mL/kg/hr 1
• Avoid loperamide in patients with bloody diarrhea or high fever (risk of toxic megacolon) 4
• Nutritional support in severe or prolonged illness 1

Fever Management Strategy

• Do NOT routinely use antipyretics solely for temperature reduction in hemodynamically stable patients 1, 5, 2
• Consider antipyretics for patient comfort if desired 2
• If temperature >39.5°C with hemodynamic compromise, consider active cooling measures 6, 7

Monitoring and Follow-Up

Inpatient Criteria (Admit if ANY present): 1

• Temperature >37.8°C with systolic BP <90 mmHg
• Heart rate >100/min with signs of dehydration
• Respiratory rate >24/min
• Oxygen saturation <90%
• Inability to maintain oral intake
• Altered mental status
• Immunocompromised state

Response Assessment

• Expect clinical improvement within 24-48 hours of appropriate antibiotic therapy 1
• Repeat blood cultures if persistent fever after 48-72 hours 2
• Consider alternative diagnoses if no improvement: amoebic liver abscess, typhoid fever, malaria (if travel history) 1

Common Pitfalls to Avoid

Critical Errors: 1, 4

• Giving antibiotics to patients with suspected STEC (increases HUS risk)
• Using fluoroquinolones without considering travel history (high resistance in Asia)
• Delaying antibiotics in septic patients while awaiting cultures
• Using metronidazole as first-line therapy (inadequate coverage for bacterial dysentery)
• Treating asymptomatic contacts empirically (not indicated)

Travel History Red Flags: 1

• Sub-Saharan Africa: consider malaria, typhoid fever
• South/Southeast Asia: high fluoroquinolone resistance, consider azithromycin first-line
• Middle East/Central Asia: consider amoebic dysentery if symptoms persist despite antibiotics