What are the signs and symptoms of leptospirosis and how should it be managed?

Leptospirosis: Signs and Symptoms

Leptospirosis presents as a biphasic febrile illness characterized by fever, headache, chills, severe myalgia, and the highly suggestive finding of conjunctival suffusion, with severe cases progressing to jaundice, renal insufficiency, and hemorrhagic manifestations. 1

Classic Clinical Presentation

Early Bacteremic Phase (Days 1-7)

• Sudden onset high fever with severe general malaise 2, 3
• Severe myalgias, particularly affecting the calves, thighs, and lumbar region 1, 2
• Headache (often severe and frontal) 1, 4
• Chills 1
• Conjunctival suffusion (non-purulent redness without discharge) - this is a highly characteristic finding that should immediately raise suspicion for leptospirosis 1, 2, 5

Less Common Early Manifestations

• Rash (maculopapular or petechial) 1, 6
• Hepatomegaly 2
• Splenomegaly 7

Severe Disease (Weil's Disease)

Approximately 5-15% of patients progress to severe disease with multi-organ involvement, which carries a mortality rate of up to 40% if untreated. 7, 8

Critical Features to Assess

• Jaundice with hepatorenal syndrome (high bilirubin but only mild transaminase elevation) 1, 5, 7
• Renal failure (acute kidney injury occurs in approximately 30% of severe cases) 1, 6
• Hemorrhagic manifestations including petechiae, purpura, epistaxis, hemoptysis, or pulmonary hemorrhage 5, 7, 9
• Respiratory distress or signs of pulmonary hemorrhage syndrome 2, 6
• Meningitis (aseptic meningitis occurs in approximately 19% of cases) 2, 4
• Cardiac arrhythmias 7

Warning Signs of Severe Disease

• Dyspnea (strongly associated with severe disease, OR: 5.54) 6
• Tachycardia (strongly associated with severe disease, OR: 9.69) 6
• Rash (associated with severe disease, OR: 10.25) 6

Biphasic Pattern

The illness characteristically follows a biphasic course, though this may not be evident in all patients. 1, 5

• First phase (bacteremic): Lasts 4-7 days with high fever, myalgias, headache, and conjunctival suffusion 4
• Brief improvement: May occur for 1-3 days 5
• Second phase (immune): Recurrence of fever with potential development of meningitis, uveitis, or other immune-mediated complications 5, 4

Key Epidemiological Clues

Exposure history within the past 2-20 days is critical for diagnosis. 2

• Contact with flood water or contaminated fresh water 2, 7
• Occupational exposure to animals or their urine 5, 7
• Recreational water sports in endemic areas 5
• Contact with rats or other rodents 7

Laboratory Findings Supporting Diagnosis

• Proteinuria and hematuria on urinalysis 2, 5, 3
• Polymorphonuclear leukocytosis with neutrophilia 5, 3
• Elevated erythrocyte sedimentation rate 3
• High bilirubin with disproportionately mild transaminase elevation (unlike viral hepatitis) 5
• Serum amylase >250 IU/L is associated with poor prognosis 2

Critical Pitfalls to Avoid

Do not wait for laboratory confirmation before initiating treatment, as serology is often negative in the first week and delay increases mortality. 2, 5

• Do not mistake leptospirosis for viral hepatitis - the pattern of high bilirubin with modest transaminase elevation is characteristic of leptospirosis, not hepatitis 2, 5
• Do not underestimate disease severity based on initial mild presentation - patients can deteriorate rapidly 5
• Do not dismiss the diagnosis in urban settings, as leptospirosis is incorrectly perceived as only a rural disease 9
• Recognize that 90% of symptomatic cases present as undifferentiated febrile illness without classic Weil's disease features 9, 8

Differential Diagnosis Considerations

When evaluating suspected leptospirosis, consider these alternative diagnoses based on predominant features: 2

• Fever with jaundice: Viral hepatitis, malaria, yellow fever
• Acute febrile illness with myalgias: Dengue, influenza, rickettsial diseases
• Fever with renal failure: Hantavirus, hemolytic uremic syndrome
• Fever with pulmonary hemorrhage: Hantavirus pulmonary syndrome, Goodpasture syndrome