What is the recommended management for a patient suspected of having leptospirosis?

Management of Leptospirosis

Immediate Antibiotic Therapy

Start antibiotics immediately upon clinical suspicion of leptospirosis without waiting for serological confirmation, as each hour of delay increases mortality. 1, 2

Mild to Moderate Disease

• Doxycycline 100 mg orally twice daily for 7 days is the treatment of choice for patients who can tolerate oral medications and do not have severe manifestations 2, 3
• This regimen reduces illness duration by approximately 2 days and favorably affects fever, malaise, headache, and myalgias 3
• Alternative oral antibiotics include amoxicillin or tetracycline if doxycycline is unavailable 4

Severe Disease (Weil's Disease)

• Ceftriaxone 2g IV daily for 7 days is the preferred regimen for severe leptospirosis with jaundice, renal failure, hemorrhage, or neurological involvement 2, 5
• Penicillin G 1.5 million units IV every 6 hours for 7 days is an acceptable alternative 2
• Ceftriaxone demonstrates superior convenience and adverse effect profile compared to penicillin regimens, with 95% recovery rate in severe cases 5
• For severe disease with neurological manifestations (status epilepticus, aseptic meningitis), intravenous penicillin or ceftriaxone should be initiated immediately 1
• Treatment duration may need extension to 10 days in patients with slow clinical response 6

Critical Timing Considerations

Antibiotic efficacy is time-dependent—treatment initiated after 4 days of symptoms may be less effective or show no benefit. 6, 7 This underscores the importance of:

• Starting treatment based on clinical suspicion and exposure history 2
• Not waiting for serological confirmation, as IgM antibodies typically appear 6-10 days after symptom onset 1
• Recognizing that serology is often negative in the first week 2

Supportive Care for Severe Disease

Fluid Resuscitation

• Administer aggressive IV fluid therapy with isotonic crystalloid or colloid solution up to 60 mL/kg as three boluses of 20 mL/kg if signs of shock are present 2
• Reassess after each bolus and target systolic blood pressure >90 mmHg in adults 6
• Monitor closely for crepitations indicating fluid overload or impaired cardiac function during resuscitation 6

ICU Admission Criteria

• Persistent or worsening tissue hypoperfusion despite initial fluid resuscitation 6
• Respiratory distress, hypoxemia, or pulmonary hemorrhage 2
• Repeated fluid boluses required or signs of circulatory failure 2
• Severe neurological manifestations including status epilepticus 1

Organ Support

• Monitor renal function closely, as acute kidney injury is common in severe disease 1, 2
• Assess hepatic function and coagulation parameters for bleeding risk 1
• Continue antiepileptic therapy as clinically indicated for seizures 1
• Consider methylprednisolone 0.5-1.0 mg/kg IV daily for 1-2 weeks for respiratory complications 2

Diagnostic Workup

Initial Laboratory Testing

• Obtain blood cultures before antibiotics if this causes no significant delay (<45 minutes), ideally within the first 5 days of illness 6
• Complete blood count (expect leukocytosis with polymorphonuclear cells, possible anemia if hemorrhage) 6
• Comprehensive metabolic panel (elevated bilirubin with mild transaminase elevation, renal dysfunction) 2, 6
• Urinalysis (proteinuria and hematuria are characteristic findings) 2, 6

Serological Confirmation

• IgM ELISA with titer >1:320 is diagnostic 2
• Titers of 1:80 to 1:160 are consistent with early infection 6
• Convalescent serology with microscopic agglutination test (MAT) should be repeated >10 days after symptom onset to confirm diagnosis 1, 2
• A fourfold or greater increase in titer between acute and convalescent specimens confirms diagnosis 6

Additional Diagnostic Samples

• Send CSF and aerobic blood cultures to reference laboratory at room temperature for confirmatory testing in severe cases 1
• Do not use urine for culture, as it is not suitable for leptospira isolation 2

Special Populations

Pediatric Patients

• Avoid doxycycline in children <8 years due to risk of permanent tooth discoloration 2
• Use penicillin or ceftriaxone instead for this age group 2

Post-Flood Exposure Prophylaxis

• Doxycycline 200 mg single dose orally provides 76.8% protection and should be reserved for high-risk settings 2

Clinical Recognition

Key Exposure History (within 2-20 days)

• Contact with flood water or contaminated fresh water 2
• Recreational water sports in fresh water 6
• Occupational exposure to animals or contaminated water 2, 6
• Contact with rats, dogs, cattle, or other domestic/wild animals 6

Characteristic Clinical Features

• Biphasic illness pattern: initial bacteremic phase (4-7 days) with high fever (≥39°C), severe myalgias (especially calves), and headache 6, 8
• Conjunctival suffusion is a highly suggestive physical finding 2, 6
• Jaundice indicates severe disease (Weil's disease) occurring in 5-10% of cases 6, 8
• Pulmonary involvement occurs in 20-70% of patients, with cough and respiratory symptoms 6, 8
• Neurological involvement (aseptic meningitis) occurs in approximately 19% of cases 6
• Cardiac involvement (myocarditis or pericarditis) is independently predictive of severe disease 6

Common Pitfalls to Avoid

• Do not wait for serological confirmation before starting antibiotics—serology is often negative in the first week and delay increases mortality 2, 6
• Do not mistake leptospirosis for viral hepatitis in patients presenting with fever and jaundice 2, 6
• Do not discontinue antibiotics early despite clinical improvement—complete the full 7-day course (or 10 days if slow response) 2, 6
• Do not leave septic patients alone—continuous observation and frequent clinical examinations are necessary 6
• Reassess antimicrobial regimen daily for potential de-escalation 6

Monitoring and Follow-up

• Patients should be monitored for development of complications including renal failure, hepatic dysfunction, hemorrhage, and respiratory distress 1
• Clinical effect should be expected within 3 days of antibiotic initiation 4
• Seriously ill patients should be followed up 2 days after the first visit 4
• Patients should return if symptoms persist longer than 3 weeks 4