What are the symptoms of leptospirosis?

Symptoms of Leptospirosis

Leptospirosis typically presents as a biphasic illness characterized by fever, headache, chills, myalgia, conjunctival suffusion, and less frequently by meningitis, rash, jaundice, or renal insufficiency. 1

Common Clinical Manifestations

Initial (Septicemic) Phase (4-7 days)

• High fever (up to 40°C)
• Severe headache
• Myalgia (especially in the calves)
• Conjunctival suffusion (redness without exudate)
• Chills
• Malaise
• Less commonly:
  • Gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain)
  • Rash

Immune Phase (after 7-10 days)

• Recurrence of fever
• Development of immunomediated manifestations:
  • Aseptic meningitis
  • Uveitis
  • Exanthema (skin rash)

Severe Manifestations (Weil's Syndrome)

Severe leptospirosis can lead to multi-organ involvement with:

• Jaundice (hepatic dysfunction)
• Acute renal failure
• Hemorrhagic manifestations
  • Pulmonary hemorrhage syndrome (mortality >50%)
  • Gastrointestinal bleeding
• Adult respiratory distress syndrome (ARDS)
• Disseminated intravascular coagulation (DIC)
• Myocarditis
• Shock

Laboratory Findings

Common laboratory abnormalities include:

• Thrombocytopenia
• Leukocytosis with neutrophilia
• Elevated hepatic transaminases
• Elevated bilirubin
• Proteinuria and hematuria
• Anemia (in severe cases)

Clinical Course and Progression

The disease typically develops 1-2 weeks after exposure to infected animal urine 2. Most infections in endemic areas are mild or asymptomatic 3. However, approximately 5-15% of cases progress to severe disease with multi-organ failure 4.

Factors associated with severe disease progression include:

• Advanced age (particularly >60 years)
• High levels of bacteremia
• Genetic factors (HLA DQ6 allele)
• Delayed diagnosis and treatment

Diagnostic Challenges

Leptospirosis can be confused with other febrile illnesses such as:

• Influenza
• Dengue fever
• Other viral hemorrhagic fevers
• Malaria
• Typhoid fever

Key Clinical Pearls

1. The biphasic nature of the illness is characteristic, with initial improvement followed by worsening symptoms
2. Conjunctival suffusion is a distinctive clinical sign that helps differentiate leptospirosis from other febrile illnesses
3. Severe calf muscle pain is often a prominent feature
4. Early recognition is critical as antibiotic therapy is most effective when started within the first 4-5 days of illness 4
5. Pulmonary involvement can range from mild symptoms to deadly pulmonary hemorrhage 5

Early diagnosis and treatment are essential to prevent progression to severe disease with multi-organ failure, which carries a significant mortality risk.