What are the signs and symptoms of leptospirosis?

Signs and Symptoms of Leptospirosis

Leptospirosis presents with a wide spectrum of clinical manifestations ranging from mild flu-like symptoms to severe illness characterized by hemorrhage, jaundice, and hepatorenal failure (Weil's disease), typically following a biphasic course.

Clinical Presentation

Initial Bacteremic Phase (4-7 days)

• Fever: Usually high (39°C/102°F or higher, often reaching 40°C/104°F) 1
• Headache: Common and often severe 1
• Myalgia: Particularly prominent in calf muscles 1
• Conjunctival suffusion: Redness of the eyes without exudate, typically involving the bulbar conjunctivae while sparing the limbus 1
• Chills: Often accompanying the fever 1
• Gastrointestinal symptoms: Nausea, vomiting, abdominal pain, diarrhea 2, 3
• Respiratory symptoms: Cough or mild respiratory complaints in some cases 2

Immune Phase (after 1-3 day interval)

• Hepatorenal syndrome: Characterized by jaundice and renal dysfunction 1
• Hemorrhagic manifestations: Due to capillary fragility rather than clotting disorders 1
• Meningitis: Aseptic meningitis can occur during this phase 4
• Rash: Less common than other symptoms 1

Laboratory Findings

• Urinalysis: Proteinuria and hematuria 1
• Blood tests:
  • Polymorphonuclear leukocytosis
  • Thrombocytopenia
  • Anemia (if significant hemorrhage occurs)
  • Elevated bilirubin with mild elevation of transaminases
  • Evidence of renal failure 1, 5

Severe Manifestations (Weil's Disease)

• Jaundice: Due to hepatocellular damage 3
• Acute renal failure: Can progress from non-oliguric to oliguric 3
• Pulmonary hemorrhage: Severe cases can develop hemorrhagic pneumonia with high mortality 6, 3
• Coagulopathies: Including disseminated intravascular coagulation 2
• ARDS: Acute respiratory distress syndrome in severe cases 1
• Shock: Circulatory collapse can occur in severe cases 4

Clinical Course and Prognosis

• Without appropriate therapy, fever typically persists for a mean of 11 days but may continue for 3-4 weeks 1
• With appropriate antibiotic therapy, fever usually resolves within 2 days 1
• Mortality is higher in older patients (≥60 years) and immunocompromised individuals 3
• High levels of bacteremia correlate with poor clinical outcomes 3

Diagnostic Considerations

• The classic triad of fever, conjunctival suffusion, and myalgia should raise suspicion for leptospirosis 1
• Early diagnosis is challenging as symptoms overlap with many other febrile illnesses including influenza, dengue, and other tropical diseases 3
• Laboratory confirmation typically relies on serology, with earliest positives appearing 6-10 days after symptom onset 1
• PCR testing can be valuable in early disease before seroconversion 5

Common Pitfalls in Diagnosis

1. Delayed recognition: The non-specific nature of early symptoms often leads to delayed diagnosis
2. Overlooking exposure history: Failing to inquire about contact with potentially contaminated water or animals
3. Misdiagnosis: Confusing leptospirosis with viral illnesses, particularly in endemic areas where it may co-exist with dengue or other tropical diseases
4. Relying solely on serology early in disease: Antibodies may not be detectable in the first week of illness

Early recognition and treatment are crucial for preventing progression to severe disease, as mortality increases significantly with delayed therapy, particularly in cases that develop Weil's disease.