What are the clinical signs and symptoms of leptospirosis?

Clinical Signs and Symptoms of Leptospirosis

Leptospirosis typically presents with an abrupt onset of high fever (≥39°C), severe myalgias (especially in the calves), headache, and conjunctival suffusion during the initial septicemic phase lasting 4-7 days. 1

Early Non-Specific Phase

The disease begins with non-specific symptoms that can easily be mistaken for viral illness:

• High fever with chills - usually 39°C or higher 1, 2
• Diffuse myalgias - particularly prominent in the calf muscles 1, 2
• Severe headache 1, 2
• Conjunctival suffusion - a highly suggestive sign when present (appears as redness without discharge) 1, 3

This early phase typically lasts 4-7 days and represents the bacteremic/septicemic period. 1

Mild to Moderate Form (Most Common Presentation)

The majority of cases present with flu-like symptoms:

• Fever with shivering 1, 2
• Myalgias and headache 1, 4
• Nausea and vomiting 4
• Conjunctival suffusion (when present, highly suggestive) 1, 3

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

Clinical jaundice is independently predictive of progression to severe leptospirosis and should trigger immediate intensive management. 2

Key Features of Severe Disease:

• Jaundice - strongly associated with severe outcomes 1, 2
• Acute renal failure - may require dialysis 1, 5, 2
• Hemorrhagic manifestations 1
• Hepato-renal failure 1

Organ-Specific Manifestations:

Renal involvement:

• Proteinuria and hematuria on urinalysis 1
• Elevated creatinine (sometimes >500 μmol/L in severe cases) 2
• May require dialysis (strongly associated with mortality) 5

Hepatic involvement:

• Jaundice 1, 2
• Elevated bilirubin with mild transaminase elevation (distinguishes from viral hepatitis) 1

Pulmonary involvement:

• Cough with hemoptysis 3
• Atypical radiographic findings 2
• Acute respiratory distress syndrome (ARDS) in severe cases 2
• Pulmonary hemorrhage (associated with significant mortality) 3

Cardiac involvement:

• Myocarditis or pericarditis 2
• ECG abnormalities 2
• Cardiac damage (clinical or ECG) is independently predictive of severe disease progression 2

Neurological involvement:

• Meningitis 2, 4
• Meningoencephalitis 2

Hematologic findings:

• Thrombocytopenia (platelets <140 G/L) in 65.5% of cases 2
• Leukocytosis with polymorphonuclear predominance 1
• Anemia if significant hemorrhage occurs 1

Uncommon Presentations

• Isolated meningitis without other systemic features 4
• Acute hepatitis mimicking viral hepatitis 4
• Secondary hemophagocytic syndrome 4
• Skin manifestations - rash or herpes eruption 2

Critical Clinical Pitfalls

The disease can be easily missed because early symptoms mimic common viral illnesses. 5 Key distinguishing features to actively seek include:

• Conjunctival suffusion - when present, highly suggestive 1, 3
• Severe calf myalgias - more prominent than typical viral illness 1
• Epidemiological clues - contact with contaminated water, flood exposure, occupational risk (agricultural workers), or rodent exposure 1, 6, 3

Two factors independently predict progression to severe disease and should trigger immediate intensive management:

1. Clinical jaundice (p=0.005) 2
2. Cardiac involvement on clinical exam or ECG (p<0.02) 2

Risk Factors for Mortality

The following are significantly associated with death:

• Presence of jaundice 5, 2
• Acute renal failure requiring dialysis 5
• Chronic liver disease 5
• Requirement for intensive care 5
• Multiorgan failure 5

Early recognition within the first 4 days of symptoms is critical, as delayed antibiotic therapy beyond this window significantly reduces treatment effectiveness. 1