What is the recommended evaluation, prophylaxis, and treatment for a patient with recent high‑risk Leptospira exposure?

Management of Recent High-Risk Leptospira Exposure

For patients with recent high-risk Leptospira exposure, immediately initiate doxycycline 100 mg orally twice daily for 7 days if clinical suspicion is high, or give a single 200 mg dose of doxycycline for post-exposure prophylaxis in high-risk settings such as post-flood exposure. 1

Evaluation of Exposure Risk

Identify High-Risk Exposures (Within Past 2-20 Days)

• Contact with flood water or contaminated fresh water is the most critical exposure to identify 1
• Recreational water sports in fresh water, including white water rafting, triathlons, and endurance races 2, 3
• Occupational exposure to animals or contaminated water (farmers, sewage workers, sanitary workers, animal caretakers) 2, 4
• Contact with rats, dogs, cattle, or other domestic/wild animals 2
• Recent flooding with water contact 2

Clinical Assessment for Early Disease

If the patient is symptomatic, assess for the characteristic biphasic pattern:

• Initial bacteremic phase (days 1-7): sudden high fever (≥39°C), severe myalgias (especially calves, thighs, lumbar region), frontal headache, and chills 1, 2
• Conjunctival suffusion (non-purulent redness without discharge) is highly characteristic and should immediately raise suspicion 1, 5, 2
• Assess for signs of severe disease: jaundice, hemorrhage, hepatomegaly, respiratory distress, or hypoxemia 1

Prophylaxis Strategy

Post-Exposure Prophylaxis

• Doxycycline 200 mg as a single oral dose provides 76.8% protection for post-flood exposure prophylaxis and should be reserved for high-risk settings 1
• This is most appropriate for asymptomatic individuals with documented high-risk exposure within the past 2-20 days 1

Special Population Considerations for Prophylaxis

• Avoid doxycycline in children <8 years due to risk of permanent tooth discoloration; use penicillin or ceftriaxone instead 1
• Avoid doxycycline in pregnant women; use penicillin or ceftriaxone instead 2

Treatment if Symptomatic

Mild to Moderate Disease

• Start doxycycline 100 mg orally twice daily for 7 days immediately upon clinical suspicion, as delay increases mortality 1
• Alternative oral antibiotics include amoxicillin or tetracycline if doxycycline is unavailable 1
• Do not wait for serological confirmation before starting antibiotics, as serology is often negative in the first week 1

Severe Disease (Weil's Disease)

If the patient presents with jaundice, renal failure, hemorrhage, or respiratory distress:

• Ceftriaxone 2g IV daily for 7 days is the preferred regimen 1
• Penicillin G 1.5 million units IV every 6 hours for 7 days is an alternative 1
• Start antibiotics within 1 hour of recognition, as each hour of delay increases mortality 2
• Aggressive IV fluid resuscitation with isotonic crystalloid up to 60 ml/kg as three boluses of 20 ml/kg, reassessing after each bolus 1
• Consult ICU early if repeated fluid boluses are required or signs of circulatory failure develop 1
• Monitor for fluid overload (development of crepitations) during resuscitation 2

Diagnostic Workup (If Symptomatic)

Initial Laboratory Tests

• Obtain blood cultures (ideally within first 5 days before antibiotics, but do not delay treatment) 1, 2
• Complete blood count (expect leukocytosis, possible thrombocytopenia, anemia if hemorrhage) 1, 2
• Comprehensive metabolic panel (elevated bilirubin with mild transaminase elevation, renal dysfunction) 1, 2
• Urinalysis (proteinuria and hematuria are characteristic) 1, 2

Serological Confirmation

• IgM ELISA with titer >1:320 is diagnostic 1
• Titers of 1:80 to 1:160 are consistent with early infection 2
• Convalescent serology with microscopic agglutination test (MAT) should be repeated >10 days after symptom onset to confirm diagnosis with fourfold or greater increase in titer 1, 2
• A single titer ≥200 supports a probable case 5

Common Pitfalls to Avoid

• Do not discontinue antibiotics early despite clinical improvement—complete the full 7-day course 1, 2
• Do not mistake leptospirosis for viral hepatitis in patients with fever and jaundice; leptospirosis shows marked hyperbilirubinemia with only modest transaminase elevations 1, 2
• Do not use urine for culture, as it is not suitable for leptospira isolation 1
• Expect clinical improvement within 3 days of antibiotic initiation; if no improvement, reassess for complications or alternative diagnoses 1, 2

Follow-Up

• Seriously ill patients should be followed up 2 days after the first visit to assess treatment response 1
• Patients should return if symptoms persist longer than 3 weeks 1