Contents
Zoonotic disease of worldwide distribution, caused by spirochetes Leptospira.
Epidemiology
- Principal source: Rats
- Humans acquire infection after getting exposure to water or soil contaminated with rat urine
- Other reservoirs:
- Dogs, cats, livestock and wild animals
Aetiology

Risk factors:
- Occupational:
- Agricultural workers
- Veterinarians
- Meat handlers
- Rodent control workers
- Laboratory personnel
- Seasonal:
- Monsoons
- During flooding
Pathophysiology
Abrasions and cuts
(skin or mucous membranes)
↓
Enter body
↓
Hematogenous spread
Small blood vessels
- Damage endothelial lining
- Leakage and extravasation of blood cells
- Haemorrhage
- Ischemic damage to various organs:
- Liver, kidneys, meninges and muscles
Clinical features
- Biphasic presentation:
- Initial/septicemic phase (2-7 days)
- Immune/leptospiruric phase
A. Initial/septicemic phase (2-7 days)
Abrupt onset
- Anicteric febrile illness (70% cases)
- High-grade fever with rigors and chills
- Lethargy
- Severe myalgia
- Headache
- Nausea & vomiting
- Conjunctival suffusion
- Photophobia and orbital pain
- Generalized lymphadenopathy
- Hepatosplenomegaly
- Transient maculopapular rash (<10% cases)
- Rare:
- Hypotension with bradycardia and circulatory collapse
- Acute respiratory distress syndrome with respiratory failure
Most are asymptomatic within one week
(Brief) Asymptomatic phase
B. Immune/leptospiruric phase
Leptospira localize to tissues to cause specific signs and symptoms
- Circulating autoantibodies to Leptospira are present
- Organisms can no more be isolated from blood or CSF
- But persist in tissues like kidneys and aqueous humour
- Aseptic meningitis (20% cases) or uveitis with recurrence of fever
- Rare:
- Encephalitis, cranial nerve palsies, paralysis and papilledema
Central nervous system abnormalities usually normalize within 1 week; mortality is rare.
Icteric Leptospirosis (Weil syndrome)
After the initial phase of fever patients develop severe hepatic and renal dysfunction
- Jaundice and hepatomegaly
- Splenomegaly (20% cases)
- Renal failure
- Second week of illness
- Urinalysis:
- Abnormal urinary findings:
- Hematuria
- Proteinuria
- Casts
- Azotemia, often associated with oliguria or anuria
- Rare:
- Hemorrhagic manifestations
- Epistaxis, hemoptysis and gastrointestinal and adrenal hemorrhage.
- Transient thrombocytopenia
- Hemorrhagic manifestations
- Abnormal urinary findings:
Mortality is 5-15%
Case study
Diagnosis
Non-specific diagnoses:
- Complete blood count (CBC):
- Anemia
- Leukocytosis with polymorph predominance
- Thrombocytopenia
- ↑ CRP
- ↑ Liver enzymes (SGOT > SGPT)
- ↑ CPK
- Weil disease:
- ↑ Serum creatinine
- Deranged coagulation parameters
- Direct hyperbilirubinemia with raised transaminases
Specific diagnoses:
- Serologic diagnosis:
- Reference centres:
- Microscopic agglutination test (MAT) (GOLD STANDARD)
- Commercial kits:
- Rapid tests
- IgM ELISA
- Reference centres:
- Demonstration of organism in tissues or urine:
- Darkfield microscopy
- Immunofluorescence
- Cultures
Differential diagnosis:
Other febrile illnesses commonly seen in the monsoon season
- Malaria
- Dengue
- Enteric fever
- Acute viral hepatitis
- Hantavirus infections
Management
Severe cases:
- Parenteral treatment:
- Penicillin G (6-8 million U /m2 /24 hr q 4 hr IV) for 7 days (DRUG OF CHOICE)
- Alternatives:
- Ceftriaxone
- IV tetracycline
Mild cases:
- Oral treatment:
- Amoxicillin and doxycycline (children > 8 yr)