What is the recommended treatment for leptospirosis?

Leptospirosis Treatment Guidelines

Immediate Antibiotic Therapy

For severe leptospirosis, start antibiotics within 1 hour of recognition without waiting for laboratory confirmation, as each hour of delay increases mortality. 1

Severe Leptospirosis (Weil's Disease)

Recommended first-line regimens:

• Penicillin G (intravenous) - traditional standard of care 1, 2
• Ceftriaxone or cefotaxime - may be preferred agents at this time due to favorable safety profile and efficacy 2
• Doxycycline (intravenous or oral 100 mg twice daily) - acceptable alternative 1, 2

Duration: 7 days standard course, may extend to 10 days in patients with slow clinical response 1

Critical timing consideration: Treatment initiated after 4 days of symptoms may be less effective, emphasizing the need for prompt initiation 1

Mild to Moderate Leptospirosis

Recommended regimens:

• Doxycycline 100 mg orally twice daily for 7 days - first-line option 1, 3
• Penicillin (oral formulation) - alternative option 1

Clinical benefit: Doxycycline reduces illness duration by 2 days and favorably affects fever, malaise, headache, and myalgias 3

Hospitalization criteria: Consider admission for moderate leptospirosis with systemic signs of infection, even without criteria for severe disease 1

Clinical Classification and Recognition

Severe Form (Weil's Disease - 5-10% of cases)

• Hemorrhage 1
• Jaundice 1
• Hepato-renal failure 1
• Pulmonary involvement (20-70% of patients) 4
• Cardiac involvement (myocarditis/pericarditis) - independently predictive of severe disease 1

Mild to Moderate Form (Most Common)

Septicemic phase (4-7 days): 1

• High fever (≥39°C) 1
• Diffuse myalgias, especially calves 1
• Headache 1
• Conjunctival suffusion - highly suggestive sign 1

Diagnostic Approach

Laboratory Confirmation

Serology (most common method): 1

• IgM titers >1:320 = suggestive of leptospirosis 1
• IgM titers 1:80-1:160 = consistent with early infection 1
• Convalescent serology (>10 days after symptom onset) confirms diagnosis 1

Blood cultures: 1

• Obtain within first 5 days before antibiotics if no significant delay (<45 minutes) 1
• Three or more cultures taken at least 1 hour apart 1

Molecular testing:

• NAAT turnaround time: 1-2 hours 1

Supportive Laboratory Findings

• Proteinuria and hematuria 1
• Leukocytosis with polymorphonuclear cells 1
• Elevated bilirubin with mild transaminase elevation 1
• Alterations in renal function 1

Supportive Care for Severe Cases

Fluid resuscitation targets: 1

• Systolic blood pressure >90 mmHg in adults 1
• Normal heart rate and blood pressure in children 1

Monitoring: 1

• Continuous observation with frequent clinical examinations 1
• Watch for crepitations indicating fluid overload or impaired cardiac function 1

ICU admission criteria: Persistent or worsening tissue hypoperfusion despite initial fluid resuscitation 1

Prophylaxis Guidelines

Post-Flood Exposure

Single-dose regimen:

• Doxycycline 200 mg orally as single dose provides 76.8% protective efficacy against infection and 86.3% against clinical disease 5
• Increased efficacy for those with laceration wounds 5

Contraindication: Doxycycline contraindicated in children <8 years due to permanent tooth discoloration and enamel hypoplasia 5

Endemic Area Prophylaxis

Reserved for specific high-risk settings: 5

• Attack rates exceeding 10 cases per 100 person-years 5
• Military training exercises in highly endemic areas 5
• Short-term occupational exposures with unavoidable prolonged water contact 5

Prevention Strategies

Primary prevention measures: 1, 5

• Avoid contact with contaminated water, especially during floods 1, 5
• Use protective equipment (boots, gloves) during high-risk agricultural/occupational activities 5
• Implement rodent control measures in endemic areas 5

Common Pitfalls

Diagnostic pitfall: Leptospirosis may be misdiagnosed as viral hepatitis in patients presenting with fever and jaundice - always consider leptospirosis in the differential 1

Treatment pitfall: Do not discontinue antibiotics early; complete the full 7-day course even with clinical improvement 1

Prophylaxis pitfall: Do not prescribe doxycycline to children under 8 years for any flood exposure indication 5

Evidence Limitations

Recent meta-analysis (2021) shows no statistically significant mortality benefit of penicillin versus placebo (OR 1.65; 95% CI 0.76-3.57; p=0.21), and no differences between penicillin, cephalosporins, or doxycycline 6. However, given the severity of untreated disease and biological plausibility, antibiotic treatment remains standard of care based on guideline recommendations and clinical practice 1, 2.